View Filing Data

Amortization of interest rate contracts

$ 541,213

$ 856,966

$ 341,890

Other comprehensive income:

^[1]

2,508

2,513

2,594

Other comprehensive income

2,508

2,513

2,594

Comprehensive income

543,721

859,479

344,484

Comprehensive income attributable to noncontrolling interests

(31,584)

(7,393)

(7,289)

Comprehensive income attributable to Boston Properties Limited Partnership

$ 512,137

$ 852,086

$ 337,195

[1]	Amounts reclassified from comprehensive income primarily to interest expense within the Company's Consolidated Statements of Operations.

Consolidated Statements Of Partners' Capital $ in Thousands	USD ($)
Partners' Capital, Beginning Balance at Dec. 31, 2011	$ 3,124,688
Increase (Decrease) in Partners' Capital [Roll Forward]
Contributions	248,863
Net income allocable to general and limited partner units	299,401
Distributions	(346,555)
Accumulated other comprehensive loss	2,321
Unearned compensation	4,364
Conversion of redeemable partnership units	34,621
Adjustment to reflect redeemable partnership units at redemption value	(37,098)
Partners' Capital, Ending Balance at Dec. 31, 2012	3,330,605
Increase (Decrease) in Partners' Capital [Roll Forward]
Contributions	626,568
Net income allocable to general and limited partner units	765,337
Distributions	(748,378)
Accumulated other comprehensive loss	2,261
Unearned compensation	5,002
Conversion of redeemable partnership units	30,291
Adjustment to reflect redeemable partnership units at redemption value	175,485
Partners' Capital, Ending Balance at Dec. 31, 2013	4,187,171
Increase (Decrease) in Partners' Capital [Roll Forward]
Contributions	652,692
Net income allocable to general and limited partner units	458,767
Distributions	(1,097,523)
Accumulated other comprehensive loss	2,252
Unearned compensation	3,298
Conversion of redeemable partnership units	2,700
Adjustment to reflect redeemable partnership units at redemption value	(569,441)
Partners' Capital, Ending Balance at Dec. 31, 2014	$ 3,639,916

Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash flows from operating activities:
Net income	$ 541,213	$ 856,966	$ 341,890
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	620,064	557,349	445,861
Non-cash compensation expense	28,099	45,155	29,679
Impairment loss	0	4,401	0
Income from unconsolidated joint ventures	(12,769)	(75,074)	(49,078)
Gains on consolidation of joint ventures	0	(385,991)	0
Distributions of net cash flow from operations of unconsolidated joint ventures	7,372	32,600	47,002
Gains from investments in securities	(1,038)	(2,911)	(1,389)
Non-cash portion of interest expense	(39,343)	2,649	43,131
Settlement of accreted debt discount on repurchases/repayments of unsecured senior notes and unsecured exchangeable senior notes	(94,963)	(56,532)	(69,499)
Losses (gains) from early extinguishments of debt	0	(264)	(1,000)
Gain (Loss) on Sale of Properties	(174,686)	0	0
Gains on sales of real estate from discontinued operations	0	(115,459)	(38,445)
Gain on forgiveness of debt from discontinued operations	0	(20,736)	0
Impairment loss from discontinued operations	0	2,852	0
Change in assets and liabilities:
Cash held in escrows	3,433	315	10,272
Tenant and other receivables, net	12,869	(443)	23,155
Accrued rental income, net	(57,899)	(59,972)	(77,363)
Prepaid expenses and other assets	20,238	12,966	6,990
Accounts payable and accrued expenses	3,903	13,108	3,854
Accrued interest payable	(3,991)	21,302	3,356
Other liabilities	(57,873)	2,073	1,354
Tenant leasing costs	(99,076)	(56,428)	(76,821)
Total adjustments	154,340	(79,040)	301,059
Net cash provided by operating activities	695,553	777,926	642,949
Payments to Acquire Real Estate	4,670	522,900	788,052
Cash flows from investing activities:
Acquisitions of real estate	(405,942)	(396,835)	(356,397)
Building and other capital improvements	(82,479)	(73,821)	(49,943)
Tenant improvements	(106,003)	(105,425)	(139,662)
Proceeds from sales of real estate	419,864	250,078	61,963
Proceeds from sales of real estate and sales of interests in property partnerships placed in escrow	(1,912,347)	0	0
Proceeds from sales of real estate and sales of interests in property partnerships released from escrow	1,478,794	0	0
Cash recorded upon consolidation	0	79,468	0
Issuance of notes receivable, net	0	12,491	(2,049)
Capital contributions to unconsolidated joint ventures	(52,052)	0	(6,214)
Capital distributions from unconsolidated joint ventures	1,491	225,862	3,557
Investments in securities, net	(1,780)	(1,558)	(1,235)
Net cash used in investing activities	(665,124)	(532,640)	(1,278,032)
Cash flows from financing activities:
Repayments of mortgage notes payable	(87,758)	(80,311)	(253,877)
Proceeds from unsecured senior notes	0	1,194,753	997,790
Redemption/repurchase of unsecured senior notes	(548,016)	0	(224,261)
Redemption/repurchase/exchange of unsecured exchangeable senior notes	(654,521)	(393,468)	(507,434)
Proceeds from real estate transaction	14,523	0	0
Payments on real estate transaction	(234)	0	0
Deferred financing costs	(31)	(15,195)	(8,468)
Net proceeds from preferred stock issuance	0	193,623	0
Net proceeds from ATM stock issuances	0	0	247,027
Net proceeds from equity transaction	1,923	(334)	226
Redemption of preferred units	(17,373)	(43,070)	(18,329)
Distributions	(840,264)	(451,118)	(372,899)
Proceeds from sale of ownership interest and contributions from noncontrolling interest in property partnerships	1,536,382	682,617	0
Distributions to noncontrolling interest in property partnerships	(37,118)	(9,624)	(5,922)
Net cash provided by (used in) financing activities	(632,487)	1,077,873	(146,147)
Net increase (decrease) in cash and cash equivalents	(602,058)	1,323,159	(781,230)
Cash and cash equivalents, beginning of year	2,365,137	1,041,978	1,823,208
Cash and cash equivalents, end of year	1,763,079	2,365,137	1,041,978
Supplemental disclosures:
Cash paid for interest	646,516	547,973	480,866
Interest capitalized	52,476	68,152	44,278
Non-cash investing and financing activities:
Change in real estate included in accounts payable and accrued expenses	(1,431)	(19,824)	14,059
Real estate and related intangibles recorded upon consolidation	0	3,356,000	0
Debt recorded upon consolidation	0	2,056,000	0
Working capital recorded upon consolidation	0	177,315	0
Noncontrolling interests recorded upon consolidation	0	480,861	0
Investment in unconsolidated joint venture eliminated upon consolidation	0	361,808	0
Mortgage note payable extinguished through foreclosure	0	25,000	0
Real estate transferred upon foreclosure	0	7,508	0
Land improvements contributed by noncontrolling interest in property partnership	0	4,546	0
Mortgage note payable assumed in connection with the acquisition of real estate	0	0	211,250
Redeemable noncontrolling interest in property partnership	0	0	98,787
Preferred units issued in connection with the acquisition of real estate	0	0	79,405
Distributions declared but not paid	882,472	497,242	110,488
Issuance of common stock in connection with the exchange of exchangeable senior notes	0	43,834	0
Conversions of redeemable partnership units to partners’ capital	2,700	30,291	34,621
Conversion of redeemable preferred units to common units	33,306	16,494	5,852
Issuance of restricted securities to employees and directors	$ 27,445	$ 30,077	$ 26,198

Organization

12 Months Ended

Dec. 31, 2014

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Organization

Boston Properties Limited Partnership (the “Company”), a Delaware limited partnership, is the entity through which Boston Properties, Inc., a self-administered and self-managed real estate investment trust (“REIT”), conducts substantially all of its business and owns (either directly or through subsidiaries) substantially all of its assets. Boston Properties, Inc. is the sole general partner of the Company and at December 31, 2014 owned an approximate 89.5% (89.5% at December 31, 2013) general and limited partnership interest in the Company. Partnership interests in the Company are denominated as “common units of partnership interest” (also referred to as “OP Units”), “long term incentive units of partnership interest” (also referred to as “LTIP Units”) or “preferred units of partnership interest” (also referred to as “Preferred Units”). In addition, in February 2011 and February 2012, the Company issued LTIP Units in connection with the granting to employees of outperformance awards (also referred to as “2011 OPP Units” and “2012 OPP Units,” respectively, and collectively as “OPP Units”) (See Note 20). On January 31, 2014, the measurement period for the Company’s 2011 OPP Unit awards expired and the Company’s total return to shareholders (“TRS”) was not sufficient for employees to earn and therefore become eligible to vest in any of the 2011 OPP Unit awards. Accordingly, all 2011 OPP Unit awards were automatically forfeited (See Notes 11 and 17). In February 2013 and February 2014, the Company issued LTIP Units in connection with the granting to employees of multi-year, long-term incentive program ("MYLTIP") awards (also referred to as “2013 MYLTIP Units” and “2014 MYLTIP Units,” respectively, and collectively as "MYLTIP Units"). Because the rights, preferences and privileges of OPP Units and MYLTIP Units differ from other LTIP Units granted to employees as part of the annual compensation process, unless specifically noted otherwise, all references to LTIP Units exclude OPP Units and MYLTIP Units (See Notes 11 and 17).

Unless specifically noted otherwise, all references to OP Units exclude units held by Boston Properties, Inc. A holder of an OP Unit may present such OP Unit to the Company for redemption at any time (subject to restrictions agreed upon at the time of issuance of OP Units to particular holders that may restrict such redemption right for a period of time, generally one year from issuance). Upon presentation of an OP Unit for redemption, the Company is obligated to redeem such OP Unit for cash equal to the value of a share of common stock of Boston Properties, Inc. (“Common Stock”) at such time. In lieu of a cash redemption, Boston Properties, Inc. may elect to acquire such OP Unit for one share of Common Stock. Because the number of shares of Common Stock outstanding at all times equals the number of OP Units that Boston Properties, Inc. owns, one share of Common Stock is generally the economic equivalent of one OP Unit, and the quarterly distribution that may be paid to the holder of an OP Unit equals the quarterly dividend that may be paid to the holder of a share of Common Stock. An LTIP Unit is generally the economic equivalent of a share of restricted common stock of Boston Properties, Inc. LTIP Units, whether vested or not, will receive the same quarterly per unit distributions as OP Units, which equal per share dividends on Common Stock (See Note 12).

At December 31, 2014, there were two series of Preferred Units outstanding (i.e., Series Four Preferred Units and Series B Preferred Units).


•	The Series Four Preferred Units are not convertible into or exchangeable for any common equity of the Company or Boston Properties, Inc., have a per unit liquidation preference of $50.00 and are entitled to receive quarterly distributions of $0.25 per unit (or an annual rate of 2.00%) (See Note 11).

•

The Series B Preferred Units were issued to Boston Properties, Inc. in connection with Boston Properties, Inc.'s issuance of 80,000 shares of 5.25% Series B Cumulative Redeemable Preferred Stock (the "Series B Preferred Stock"). Boston Properties, Inc. contributed the net proceeds from the offering to the Company in exchange for 80,000 Series B Preferred Units having terms and preferences generally mirroring those of the Series B Preferred Stock (See Note 12).

All references herein to the Company refer to Boston Properties Limited Partnership and its consolidated subsidiaries, collectively, unless the context otherwise requires.

Properties

At December 31, 2014, the Company owned or had interests in a portfolio of 169 commercial real estate properties (the “Properties”) aggregating approximately 45.8 million net rentable square feet, including ten properties under construction totaling approximately 3.3 million net rentable square feet. In addition, the Company has structured parking for approximately 43,824 vehicles containing approximately 15.0 million square feet. At December 31, 2014, the Properties consist of:


•	160 office properties, including 129 Class A office properties (including nine properties under construction) and 31 Office/Technical properties;


•	one hotel;


•	five retail properties (including one property under construction); and


•	three residential properties.

The Company owns or controls undeveloped land parcels totaling approximately 490.8 acres.

The Company considers Class A office properties to be centrally located buildings that are professionally managed and maintained, attract high-quality tenants and command upper-tier rental rates, and that are modern structures or have been modernized to compete with newer buildings. The Company considers Office/Technical properties to be properties that support office, research and development, laboratory and other technical uses. The Company’s definitions of Class A Office and Office/Technical properties may be different than those used by other companies. Net rentable square feet amounts are unaudited.

Basis of Presentation

Boston Properties, Inc. does not have any other significant assets, liabilities or operations, other than its investment in the Company, nor does it have employees of its own. The Company, not Boston Properties, Inc., generally executes all significant business relationships other than transactions involving securities of Boston Properties, Inc. All majority-owned subsidiaries and joint ventures over which the Company has financial and operating control and variable interest entities ("VIE"s) in which the Company has determined it is the primary beneficiary are included in the consolidated financial statements. At December 31, 2014 and 2013, the Company did not have any VIEs. All significant intercompany balances and transactions have been eliminated in consolidation. The Company accounts for all other unconsolidated joint ventures using the equity method of accounting. Accordingly, the Company’s share of the earnings of these joint ventures and companies is included in consolidated net income.

Summary Of Significant Accounting Policies

12 Months Ended

Dec. 31, 2014

Accounting Policies [Abstract]

Basis Of Presentation And Summary Of Significant Accounting Policies

Real Estate

Upon acquisitions of real estate that constitutes a business, which includes the consolidation of previously unconsolidated joint ventures, the Company assesses the fair value of acquired tangible and intangible assets (including land, buildings, tenant improvements, “above-” and “below-market” leases, leasing and assumed financing origination costs, acquired in-place leases, other identified intangible assets and assumed liabilities) and allocates the purchase price to the acquired assets and assumed liabilities, including land and buildings as if vacant. The Company assesses and considers fair value based on estimated cash flow projections that utilize discount and/or capitalization rates that it deems appropriate, as well as available market information. Estimates of future cash flows are based on a number of factors including the historical operating results, known and anticipated trends, and market and economic conditions.

The fair value of the tangible assets of an acquired property considers the value of the property as if it were vacant. The Company also considers an allocation of purchase price of other acquired intangibles, including acquired in-place leases that may have a customer relationship intangible value, including (but not limited to) the nature and extent of the existing relationship with the tenants, the tenants' credit quality and expectations of lease renewals. Based on its acquisitions to date, the Company’s allocation to customer relationship intangible assets has been immaterial.

The Company records acquired “above-” and “below-market” leases at their fair values (using a discount rate which reflects the risks associated with the leases acquired) equal to the difference between (1) the contractual amounts to be paid pursuant to each in-place lease and (2) management’s estimate of fair market lease rates for each corresponding in-place lease, measured over a period equal to the remaining term of the lease for above-market leases and the initial term plus the term of any below-market fixed rate renewal options for below- market leases. Acquired “above-” and “below-market” lease values have been reflected within Prepaid Expenses and Other Assets and Other Liabilities, respectively, in the Company's Consolidated Balance Sheets. Other intangible assets acquired include amounts for in-place lease values that are based on the Company’s evaluation of the specific characteristics of each tenant's lease. Factors to be considered include estimates of carrying costs during hypothetical expected lease-up periods considering current market conditions, and costs to execute similar leases. In estimating carrying costs, the Company includes real estate taxes, insurance and other operating expenses and estimates of lost rentals at market rates during the expected lease-up periods, depending on local market conditions. In estimating costs to execute similar leases, the Company considers leasing commissions, legal and other related expenses.

Management reviews its long-lived assets for impairment following the end of each quarter and when there is an event or change in circumstances that indicates an impairment in value. An impairment loss is recognized if the carrying amount of its assets is not recoverable and exceeds its fair value. If such criteria are present, an impairment loss is recognized based on the excess of the carrying amount of the asset over its fair value. The evaluation of anticipated cash flows is highly subjective and is based in part on assumptions regarding future occupancy, rental rates and capital requirements that could differ materially from actual results in future periods. Since cash flows on properties considered to be “long-lived assets to be held and used” are considered on an undiscounted basis to determine whether an asset has been impaired, the Company’s established strategy of holding properties over the long term directly decreases the likelihood of recording an impairment loss. If the Company’s strategy changes or market conditions otherwise dictate an earlier sale date, an impairment loss may be recognized and such loss could be material. If the Company determines that an impairment has occurred, the affected assets must be reduced to their fair value, less cost to sell.

Guidance in Accounting Standards Codification (“ASC”) 360 “Property Plant and Equipment” (“ASC 360”) requires that qualifying assets and liabilities and the results of operations that have been sold, or otherwise qualify as “held for sale,” be presented as discontinued operations in all periods presented if the property operations are expected to be eliminated and the Company will not have significant continuing involvement following the sale. The components of the property’s net income that are reflected as discontinued operations include the net gain (or loss) upon the disposition of the property held for sale, operating results, depreciation and interest expense (if the property is subject to a secured loan). The Company generally considers assets to be “held for sale” when the transaction has been approved by Boston Properties, Inc.’s Board of Directors, or a committee thereof, and there are no known significant contingencies relating to the sale, such that a sale of the property within one year is considered probable. Following the classification of a property as “held for sale,” no further depreciation is recorded on the assets, and the asset is written down to the lower of carrying value or fair market value, less cost to sell. On April 10, 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-08, "Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity" (“ASU 2014-08”). ASU 2014-08 clarifies that discontinued operations presentation applies only to disposals representing a strategic shift that has (or will have) a major effect on an entity’s operations and financial results (e.g., a disposal of a major geographical area, a major line of business, a major equity method investment or other major parts of an entity). ASU 2014-08 is effective prospectively for reporting periods beginning after December 15, 2014. Early adoption is permitted, and the Company early adopted ASU 2014-08 during the first quarter of 2014. The Company’s adoption of ASU 2014-08 resulted in the operating results and gains on sales of real estate from operating properties sold during the year ended December 31, 2014 not being reflected within Discontinued Operations in the Company's Consolidated Statements of Operations (See Note 3).

Real estate is stated at depreciated cost. A variety of costs are incurred in the acquisition, development and leasing of properties. The cost of buildings and improvements includes the purchase price of property, legal fees and other acquisition costs. The Company expenses costs that it incurs to effect a business combination such as legal, due diligence and other closing related costs. Costs directly related to the development of properties are capitalized. Capitalized development costs include interest, internal wages, property taxes, insurance, and other project costs incurred during the period of development. After the determination is made to capitalize a cost, it is allocated to the specific component of a project that is benefited. Determination of when a development project commences and capitalization begins, and when a development project is substantially complete and held available for occupancy and capitalization must cease, involves a degree of judgment. The Company’s capitalization policy on development properties is guided by guidance in ASC 835-20 “Capitalization of Interest” and ASC 970 “Real Estate-General.” The costs of land and buildings under development include specifically identifiable costs.

The capitalized costs include pre-construction costs necessary to the development of the property, development costs, construction costs, interest costs, real estate taxes, salaries and related costs and other costs incurred during the period of development. The Company begins the capitalization of costs during the pre-construction period which it defines as activities that are necessary to the development of the property. The Company considers a construction project as substantially completed and held available for occupancy upon the completion of tenant improvements, but no later than one year from cessation of major construction activity. The Company ceases capitalization on the portion (1) substantially completed, (2) occupied or held available for occupancy, and capitalizes only those costs associated with the portion under construction or (3) if activities necessary for the development of the property have been suspended. Interest costs capitalized for the years ended December 31, 2014, 2013 and 2012 were $52.5 million, $68.2 million and $44.3 million, respectively. Salaries and related costs capitalized for the years ended December 31, 2014, 2013 and 2012 were $8.5 million, $7.7 million and $7.1 million, respectively.

Expenditures for repairs and maintenance are charged to operations as incurred. Significant betterments are capitalized. When assets are sold or retired, their costs and related accumulated depreciation are removed from the accounts with the resulting gains or losses reflected in net income or loss for the period.

The Company computes depreciation and amortization on properties using the straight-line method based on estimated useful asset lives. In accordance with ASC 805, the Company allocates the acquisition cost of real estate to its components and depreciates or amortizes these assets (or liabilities) over their useful lives. The amortization of acquired “above-” and “below-market” leases and acquired in-place leases is recorded as an adjustment to revenue and depreciation and amortization, respectively, in the Consolidated Statements of Operations.

Depreciation is computed on a straight-line basis over the estimated useful lives of the assets as follows:




Land improvements		25 to 40 years
Buildings and improvements		10 to 40 years
Tenant improvements		Shorter of useful life or terms of related lease
Furniture, fixtures, and equipment		3 to 7 years

Cash and Cash Equivalents

Cash and cash equivalents consist of cash on hand and investments with maturities of three months or less from the date of purchase. The majority of the Company’s cash and cash equivalents are held at major commercial banks which may at times exceed the Federal Deposit Insurance Corporation limit of $250,000. The Company has not experienced any losses to date on its invested cash.

Cash Held in Escrows

Escrows include amounts established pursuant to various agreements for security deposits, property taxes, insurance and other costs. Escrows also include cash held by qualified intermediaries for possible investments in a like-kind exchanges in accordance with Section 1031 of the Internal Revenue Code in connection with sales of the Company’s properties.

Investments in Securities

The Company accounts for investments in trading securities at fair value, with gains or losses resulting from changes in fair value recognized currently in earnings. The designation of trading securities is generally determined at acquisition. The Company maintains a deferred compensation plan that is designed to allow officers of the Company to defer a portion of their current income on a pre-tax basis and receive a tax-deferred return on these deferrals. The Company’s obligation under the plan is that of an unsecured promise to pay the deferred compensation to the plan participants in the future. At December 31, 2014 and 2013, the Company had maintained approximately $19.5 million and $16.6 million, respectively, in a separate account, which is not restricted as to its use. The Company recognized gains of approximately $1.0 million, $2.9 million and $1.4 million on its investments in the account associated with the Company’s deferred compensation plan during the years ended December 31, 2014, 2013 and 2012, respectively.

Tenant and Other Receivables

Tenant and other accounts receivable, other than accrued rents receivable, are expected to be collected within one year.

Deferred Charges

Deferred charges include leasing costs and financing fees. Leasing costs include an allocation for acquired intangible in-place lease values and direct and incremental fees and costs incurred in the successful negotiation of leases, including brokerage, legal, internal leasing employee salaries and other costs which have been deferred and are being amortized on a straight-line basis over the terms of the respective leases. Internal leasing salaries and related costs capitalized for the years ended December 31, 2014, 2013 and 2012 were $6.0 million, $5.1 million and $5.6 million, respectively. External fees and costs incurred to obtain long-term financing have been deferred and are being amortized over the terms of the respective loans and are included within interest expense. Unamortized financing and leasing costs are charged to expense upon the early repayment or significant modification of the financing or upon the early termination of the lease, respectively. Fully amortized deferred charges are removed from the books upon the expiration of the lease or maturity of the debt.

Investments in Unconsolidated Joint Ventures

The Company consolidates variable interest entities (“VIEs”) in which it is considered to be the primary beneficiary. VIEs are entities in which the equity investors do not have sufficient equity at risk to finance their endeavors without additional financial support or that the holders of the equity investment at risk do not have a controlling financial interest. The primary beneficiary is defined by the entity having both of the following characteristics: (1) the power to direct the activities that, when taken together, most significantly impact the variable interest entity's performance, and (2) the obligation to absorb losses and right to receive the returns from the variable interest entity that would be significant to the variable interest entity. For ventures that are not VIEs the Company consolidates entities for which it has significant decision making control over the ventures' operations. The Company's judgment with respect to its level of influence or control of an entity involves the consideration of various factors including the form of the Company's ownership interest, its representation in the entity's governance, the size of its investment (including loans), estimates of future cash flows, its ability to participate in policy making decisions and the rights of the other investors to participate in the decision making process and to replace the Company as manager and/or liquidate the venture, if applicable. The Company's assessment of its influence or control over an entity affects the presentation of these investments in the Company's consolidated financial statements. In addition to evaluating control rights, the Company consolidates entities in which the outside partner has no substantive kick-out rights to remove the Company as the managing member.

Accounts of the consolidated entity are included in the accounts of the Company and the non-controlling interest is reflected on the Consolidated Balance Sheets as a component of equity or in temporary equity between liabilities and equity. Investments in unconsolidated joint ventures are recorded initially at cost, and subsequently adjusted for equity in earnings and cash contributions and distributions. Any difference between the carrying amount of these investments on the balance sheet and the underlying equity in net assets is amortized as an adjustment to equity in earnings of unconsolidated joint ventures over the life of the related asset. Under the equity method of accounting, the net equity investment of the Company is reflected within the Consolidated Balance Sheets, and the Company's share of net income or loss from the joint ventures is included within the Consolidated Statements of Operations. The joint venture agreements may designate different percentage allocations among investors for profits and losses; however, the Company's recognition of joint venture income or loss generally follows the joint venture's distribution priorities, which may change upon the achievement of certain investment return thresholds. The Company may account for cash distributions in excess of its investment in an unconsolidated joint venture as income when the Company is not the general partner in a limited partnership and when the Company has neither the requirement nor the intent to provide financial support to the joint venture. The Company's investments in unconsolidated joint ventures are reviewed for impairment periodically and the Company records impairment charges when events or circumstances change indicating that a decline in the fair values below the carrying values has occurred and such decline is other-than-temporary. The ultimate realization of the investment in unconsolidated joint ventures is dependent on a number of factors, including the performance of each investment and market conditions. The Company will record an impairment charge if it determines that a decline in the value below the carrying value of an investment in an unconsolidated joint venture is other-than-temporary.

To the extent that the Company contributes assets to a joint venture, the Company’s investment in the joint venture is recorded at the Company’s cost basis in the assets that were contributed to the joint venture. To the extent that the Company’s cost basis is different than the basis reflected at the joint venture level, the basis difference is amortized over the life of the related asset and included in the Company’s share of equity in net income of the joint venture. In accordance with the provisions of ASC 970-323 “Investments—Equity Method and Joint Ventures” (“ASC 970-323”), the Company will recognize gains on the contribution of real estate to joint ventures, relating solely to the outside partner’s interest, to the extent the economic substance of the transaction is a sale.

The combined summarized financial information of the unconsolidated joint ventures is disclosed in Note 5 to the Consolidated Financial Statements.

Revenue Recognition

In general, the Company commences rental revenue recognition when the tenant takes possession of the leased space and the leased space is substantially ready for its intended use. Contractual rental revenue is reported on a straight-line basis over the terms of the respective leases. The impact of the straight-line rent adjustment increased revenue by approximately $63.1 million, $65.8 million and $77.6 million for the years ended December 31, 2014, 2013 and 2012, respectively, as the revenue recorded exceeded amounts billed. Accrued rental income, as reported on the Consolidated Balance Sheets, represents cumulative rental income earned in excess of rent payments received pursuant to the terms of the individual lease agreements. The Company maintains an allowance against accrued rental income for future potential tenant credit losses. The credit assessment is based on the estimated accrued rental income that is recoverable over the term of the lease. The Company also maintains an allowance for doubtful accounts for estimated losses resulting from the inability of tenants to make required rent payments. The computation of this allowance is based on the tenants’ payment history and current credit status, as well as certain industry or geographic specific credit considerations. If the Company’s estimates of collectability differ from the cash received, then the timing and amount of the Company’s reported revenue could be impacted. The credit risk is mitigated by the high quality of the Company’s existing tenant base, reviews of prospective tenants’ risk profiles prior to lease execution and consistent monitoring of the Company’s portfolio to identify potential problem tenants.

In accordance with ASC 805, the Company recognizes rental revenue of acquired in-place “above-” and “below-market” leases at their fair values over the original term of the respective leases. The impact of the acquired in-place “above-” and “below-market” leases increased revenue by approximately $48.3 million, $28.0 million and $14.6 million for the years ended December 31, 2014, 2013 and 2012, respectively. The following table summarizes the scheduled amortization of the Company's acquired “above-” and “below-market” lease intangibles for each of the five succeeding years (in thousands). Accrued rental income as reported on the Consolidated Balance Sheets represents rental income recognized in excess of rent payments actually received pursuant to the terms of the individual lease agreements.



	Acquired Above-Market Lease Intangibles		Acquired Below-Market Lease Intangibles
2015	$	22,671	$	57,019
2016	20,491		51,460
2017	12,277		35,896
2018	8,637		33,215
2019	7,106		27,615

Recoveries from tenants, consisting of amounts due from tenants for common area maintenance, real estate taxes and other recoverable costs, are recognized as revenue in the period during which the expenses are incurred. Tenant reimbursements are recognized and presented in accordance with guidance in ASC 605-45 “Principal Agent Considerations” (“ASC 605-45”). ASC 605-45 requires that these reimbursements be recorded on a gross basis, as the Company is generally the primary obligor with respect to purchasing goods and services from third-party suppliers, has discretion in selecting the supplier and has credit risk. The Company also receives reimbursement of payroll and payroll related costs from third parties which the Company reflects on a net basis.

The Company's parking revenues are derived from leases, monthly parking and transient parking. The Company recognizes parking revenue as earned.

The Company’s hotel revenues are derived from room rentals and other sources such as charges to guests for telephone service, movie and vending commissions, meeting and banquet room revenue and laundry services. Hotel revenues are recognized as earned.

The Company receives management and development fees from third parties. Property management fees are recorded and earned based on a percentage of collected rents at the properties under management, and not on a straight-line basis, because such fees are contingent upon the collection of rents. The Company records development fees as earned depending on the risk associated with each project. Profit on development fees earned from joint venture projects is recognized as revenue to the extent of the third party partners’ ownership interest.

Gains on sales of real estate are recognized pursuant to the provisions included in ASC 360-20 “Real Estate Sales” (“ASC 360-20”). The specific timing of the sale is measured against various criteria in ASC 360-20 related to the terms of the transaction and any continuing involvement in the form of management or financial assistance associated with the properties. If the sales criteria for the full accrual method are not met, the Company defers some or all of the gain recognition and accounts for the continued operations of the property by applying the finance, leasing, profit sharing, deposit, installment or cost recovery methods, as appropriate, until the sales criteria are met.

Depreciation and Amortization

The Company computes depreciation and amortization on its properties using the straight-line method based on estimated useful asset lives. The Company allocates the acquisition costs of real estate to its components and depreciate or amortize these assets over their useful lives. The amortization of acquired “above-” and “below-market” leases and acquired in-place leases is recorded as an adjustment to revenue and depreciation and amortization, respectively, in the Consolidated Statements of Operations.

Ground Leases

The Company has non-cancelable ground lease obligations with various initial term expiration dates through 2068 (See Note 20). The Company recognizes ground rent expense on a straight-line basis over the terms of the respective ground lease agreements. The future contractual minimum lease payments to be made by the Company as of December 31, 2014, under non-cancelable ground leases which expire on various dates through 2068, are as follows:




Years Ending December 31,	(in thousands)
2015	$	13,507
2016	13,732
2017	13,963
2018	14,198
2019	14,461
Thereafter	884,726

Earnings Per Common Unit

Basic earnings per common unit is computed by dividing net income available to common unitholders, as adjusted for undistributed earnings (if any) of certain securities issued by the Company, by the weighted average number of common units outstanding during the year. Diluted earnings per common unit reflects the potential dilution that could occur from units issuable in connection with awards under Boston Properties, Inc.’s stock-based compensation plans, including upon the exercise of stock options, and conversion of preferred units of the Company.

Fair Value of Financial Instruments

The carrying values of cash and cash equivalents, marketable securities, escrows, receivables, accounts payable, accrued expenses and other assets and liabilities are reasonable estimates of their fair values because of the short maturities of these instruments.

The Company follows the authoritative guidance for fair value measurements when valuing its financial instruments for disclosure purposes. The Company determines the fair value of its unsecured senior notes and unsecured exchangeable senior notes using market prices. The inputs used in determining the fair value of the Company’s unsecured senior notes and unsecured exchangeable senior notes is categorized at a level 1 basis (as defined in the accounting standards for Fair Value Measurements and Disclosures) due to the fact that the Company uses quoted market rates to value these instruments. However, the inputs used in determining the fair value could be categorized at a level 2 basis if trading volumes are low. The Company determines the fair value of its mortgage notes payable using discounted cash flow analyses by discounting the spread between the future contractual interest payments and hypothetical future interest payments on mortgage debt based on current market rates for similar securities. In determining the current market rates, the Company adds its estimates of market spreads to the quoted yields on federal government treasury securities with similar maturity dates to its debt. The inputs used in determining the fair value of the Company’s mortgage notes payable and mezzanine notes payable are categorized at a level 3 basis (as defined in the accounting standards for Fair Value Measurements and Disclosures) due to the fact that the Company considers the rates used in the valuation techniques to be unobservable inputs.

Because the Company’s valuations of its financial instruments are based on these types of estimates, the actual fair values of its financial instruments may differ materially if the Company’s estimates do not prove to be accurate. The following table presents the aggregate carrying value of the Company’s indebtedness and the Company’s corresponding estimate of fair value as of December 31, 2014 and December 31, 2013 (in thousands):



	December 31, 2014				December 31, 2013
	Carrying Amount		Estimated Fair Value		Carrying Amount			Estimated Fair Value
Mortgage notes payable	$	4,309,484	$	4,449,541	$	4,449,734		$	4,545,283
Mezzanine notes payable	309,796		306,156		311,040			311,064
Unsecured senior notes	5,287,704		5,645,819		5,835,854			6,050,517
Unsecured exchangeable senior notes	—		—		744,880		(1)	750,266
Total	$	9,906,984	$	10,401,516	$	11,341,508		$	11,657,130

_____________


(1)	Includes the net adjustment for the equity component allocation totaling approximately $2.4 million at December 31, 2013.

Derivative Instruments and Hedging Activities

Derivative instruments and hedging activities require management to make judgments on the nature of its derivatives and their effectiveness as hedges. These judgments determine if the changes in fair value of the derivative instruments are reported in the Consolidated Statements of Operations as a component of net income or as a component of comprehensive income and as a component of equity on the Consolidated Balance Sheets. While management believes its judgments are reasonable, a change in a derivative’s effectiveness as a hedge could materially affect expenses, net income and equity. The Company accounts for the effective portion of changes in the fair value of a derivative in other comprehensive income (loss) and subsequently reclassifies the effective portion to earnings over the term that the hedged transaction affects earnings. The Company accounts for the ineffective portion of changes in the fair value of a derivative directly in earnings.

Income Taxes

The partners are required to report their respective share of the Company’s taxable income or loss on their respective tax returns and are liable for any related taxes thereon. Accordingly, the only provision for federal income taxes in the accompanying consolidated financial statements relates to the Company’s consolidated taxable REIT subsidiaries. The Company’s taxable REIT subsidiaries did not have significant tax provisions or deferred income tax items. The Company has no uncertain tax positions recognized as of December 31, 2014 and 2013.

The Company owns a hotel property which is managed through a taxable REIT subsidiary. The hotel taxable REIT subsidiary, a wholly owned subsidiary of the Company, is the lessee pursuant to the lease for the hotel property. As lessor, the Company is entitled to a percentage of gross receipts from the hotel property. Marriott International, Inc. continues to manage the hotel property under the Marriott name and under terms of the existing management agreement. The hotel taxable REIT subsidiary is subject to tax at the federal and state level and, accordingly, the Company has recorded a tax provision in the Company’s Consolidated Statements of Operations for the years ended December 31, 2014, 2013 and 2012.

The net difference between the tax basis and the reported amounts of the Company’s assets and liabilities is approximately $1.4 billion and $0.9 billion as of December 31, 2014 and 2013, respectively, which is primarily related to the difference in basis of contributed property and accrued rental income.

Certain entities included in the Company’s consolidated financial statements are subject to certain state and local taxes. These taxes are recorded as operating expenses in the accompanying consolidated financial statements.

The following table reconciles GAAP net income attributable to Boston Properties Limited Partnership to taxable income:



	For the year ended December 31,
	2014			2013			2012
	(in thousands)
Net income attributable to Boston Properties Limited Partnership	$	509,629		$	849,573		$	334,601
Straight-line rent adjustments	(102,319		)	(82,904		)	(89,982		)
Book/Tax differences from depreciation and amortization	253,590			174,384			106,862
Book/Tax differences from interest expense	(48,128		)	(8,811		)	31,003
Book/Tax differences on gains/losses from capital transactions	1,065,518			(138,300		)	(24,958		)
Book/Tax differences from stock-based compensation	36,232			46,935			22,035
Tangible Property Regulations (1)	(493,731		)	—			—
Other book/tax differences, net	(11,403		)	8,589			11,001
Taxable income	$	1,209,388		$	849,466		$	390,562

__________

(1) In September 2013, the Internal Revenue Service released final Regulations governing when taxpayers like the Company must capitalize and depreciate costs for acquiring, maintaining, repairing and replacing tangible property and when taxpayers can deduct such costs. These final Regulations are effective for tax years beginning on or after January 1, 2014. These Regulations permitted the Company to deduct certain types of expenditures that were previously required to be capitalized. The Regulations also allowed the Company to make a one-time election to immediately deduct certain amounts that were capitalized in previous years that are not required to be capitalized under the new Regulations. The one-time deduction included above totaled approximately $430.1 million.

Stock-Based Employee Compensation Plans

At December 31, 2014, Boston Properties, Inc. has a stock-based employee compensation plan. Effective January 1, 2005, the Company adopted early ASC 718 “Compensation – Stock Compensation” (“ASC 718”), which revised the fair value based method of accounting for share-based payment liabilities, forfeitures and modifications of stock-based awards and clarified previous guidance in several areas, including measuring fair value, classifying an award as equity or as a liability and attributing compensation cost to reporting periods.

Use of Estimates in the Preparation of Financial Statements

The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting period. These estimates include such items as depreciation and allowances for doubtful accounts. Actual results could differ from those estimates.

Out-of-Period Adjustment

During the year ended December 31, 2014, the Company recorded an allocation of net income to the noncontrolling interest holder in its Fountain Square consolidated joint venture totaling approximately $1.9 million related to the cumulative non-cash adjustment to the accretion of the changes in the redemption value of the noncontrolling interest. This resulted in the overstatement of Noncontrolling Interests in Property Partnerships by approximately $1.9 million during the year ended December 31, 2014 and an understatement of Noncontrolling Interests in Property Partnerships in the aggregate amount of approximately $1.9 million in periods prior to 2014. Because this adjustment was not material to the prior periods’ consolidated financial statements and the impact of recording the adjustment in 2014 was not material to the Company’s consolidated financial statements, the Company recorded the related adjustment during the year ended December 31, 2014. The out of period adjustment was identified and recorded during the second quarter of 2014.

Revisions

The Company revised the presentation of certain investments in unconsolidated joint ventures with deficit balances to reflect the deficit balances within Other Liabilities on the Company's Consolidated Balance Sheets instead of within Investments in Unconsolidated Joint Ventures. The revision resulted in an aggregate of approximately $14.0 million at December 31, 2013 being presented within Other Liabilities on the Company's Consolidated Balance Sheets, which revision was not material to the period.

The Company revised the presentation of income allocated to the Series B Preferred Units to properly reflect the income allocation within Preferred Distributions on the Company's Consolidated Statements of Operations instead of within Noncontrolling Interest - Redeemable Preferred Units. The revision resulted in approximately $8.1 million for the year ended December 31, 2013 being presented within Preferred Distributions on the Company's Consolidated Statements of Operations, which revision was not material to the period. There were no Series B Preferred Units outstanding during the year ended December 31, 2012.

Recent Accounting Pronouncements

On April 10, 2014, the FASB issued ASU 2014-08, "Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity" (“ASU 2014-08”). ASU 2014-08 clarifies that discontinued operations presentation applies only to disposals representing a strategic shift that has (or will have) a major effect on an entity’s operations and financial results (e.g., a disposal of a major geographical area, a major line of business, a major equity method investment or other major parts of an entity). ASU 2014-08 is effective prospectively for reporting periods beginning after December 15, 2014. Early adoption is permitted, and the Company early adopted ASU 2014-08 during the first quarter of 2014. The Company’s adoption of ASU 2014-08 resulted in the operating results and gains on sales of real estate from operating properties sold during the year ended December 31, 2014 not being reflected within Discontinued Operations in the Company's Consolidated Statements of Operations (See Note 3).

In May 2014, the FASB issued ASU 2014-09, "Revenue from Contracts with Customers (Topic 606)" ("ASU 2014-09"). The objective of ASU 2014-09 is to establish a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers and will supersede most of the existing revenue recognition guidance, including industry-specific guidance. The core principle is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. In applying ASU 2014-09, companies will perform a five-step analysis of transactions to determine when and how revenue is recognized. ASU 2014-09 applies to all contracts with customers except those that are within the scope of other topics in the FASB's Accounting Standards Codification ("ASC"). ASU 2014-09 is effective for annual reporting periods (including interim periods within that reporting period) beginning after December 15, 2016 and shall be applied using either a full retrospective or modified retrospective approach. Early adoption is not permitted. The Company is currently assessing the potential impact that the adoption of ASU 2014-09 will have on its consolidated financial statements.

In June 2014, the FASB issued ASU 2014-12, “Accounting for Share-Based Payments When the Terms of an Award Provide That a Performance Target Could Be Achieved after the Requisite Service Period” (“ASU 2014-12”). The amendments in ASU 2014-12 require that a performance target that affects vesting and that could be achieved after the requisite service period be treated as a performance condition. A reporting entity should apply existing guidance in ASC Topic No. 718, “Compensation - Stock Compensation” (“ASC 718”), as it relates to awards with performance conditions that affect vesting to account for such awards. The amendments in ASU 2014-12 are effective for annual periods and interim periods within those annual periods beginning after December 15, 2015. Early adoption is permitted. Entities may apply the amendments in ASU 2014-12 either: (a) prospectively to all awards granted or modified after the effective date; or (b) retrospectively to all awards with performance targets that are outstanding as of the beginning of the earliest annual period presented in the financial statements and to all new or modified awards thereafter. The Company does not expect the adoption of ASU 2014-12 to have a material impact on its consolidated financial statements.

In August 2014, the FASB issued ASU 2014-15, "Presentation of Financial Statements - Going Concern: Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern" (“ASU 2014-15”). ASU 2014-15 requires an entity to evaluate whether there are conditions or events that raise substantial doubt about the entity’s ability to continue as a going concern within one year after the date that the financial statements are issued (or within one year after the financial statements are available to be issued when applicable) and to provide related footnote disclosures in certain circumstances. ASU 2014-15 is effective for the annual period ending after December 15, 2016, and for annual and interim periods thereafter with early adoption permitted. The Company does not expect the adoption of ASU 2014-15 to have a material impact on its consolidated financial statements.

In November 2014, the FASB issued ASU 2014-16, "Determining Whether the Host Contract in a Hybrid Financial Instrument Issued in the Form of a Share Is More Akin to Debt or to Equity" (“ASU 2014-16”). ASU 2014-16 clarifies how current GAAP should be interpreted in evaluating the economic characteristics and risks of a host contract in a hybrid financial instrument that is issued in the form of a share. Specifically, the amendments clarify that an entity should consider all relevant terms and features—including the embedded derivative feature being evaluated for bifurcation—in evaluating the nature of the host contract. Furthermore, the amendments clarify that no single term or feature would necessarily determine the economic characteristics and risks of the host contract. Rather, the nature of the host contract depends upon the economic characteristics and risks of the entire hybrid financial instrument. ASU 2014-16 is effective for fiscal years and interim periods beginning after December 15, 2015. Early adoption is permitted. The Company does not expect the adoption of ASU 2014-16 to have a material impact on its consolidated financial statements.

In February 2015, the FASB issued ASU 2015-02, “Consolidation (Topic 810): Amendments to the Consolidation Analysis” (“ASU 2015-02”). ASU 2015-02 affects reporting entities that are required to evaluate whether they should consolidate certain legal entities. ASU 2015-02 modifies the evaluation of whether limited partnerships and similar legal entities are VIEs or voting interest entities, eliminates the presumption that a general partner should consolidate a limited partnership and affects the consolidation analysis of reporting entities that are involved with VIEs, particularly those that have fee arrangements and related party relationships. ASU 2015-02 is effective for fiscal years, and for interim periods within those fiscal years, beginning after December 15, 2015. Early adoption is permitted. A reporting entity may apply the amendments in ASU 2015-02 using: (a) a modified retrospective approach by recording a cumulative-effect adjustment to equity as of the beginning of the fiscal year of adoption; or (b) by applying the amendments retrospectively. The Company is currently assessing the potential impact that the adoption of ASU 2015-02 will have on its consolidated financial statements.

Real Estate

12 Months Ended

Dec. 31, 2014

Real Estate [Abstract]

Real Estate

Real estate consisted of the following at December 31 (in thousands):



	2014			2013
Land	$	4,680,181		$	4,342,951
Land held for future development	268,114			297,376
Buildings and improvements	11,349,851			10,742,370
Tenant improvements	1,752,115			1,617,401
Furniture, fixtures and equipment	27,986			25,164
Construction in progress	736,311			1,523,179
Total	18,814,558			18,548,441
Less: Accumulated depreciation	(3,476,321		)	(3,096,910		)
	$	15,338,237		$	15,451,531

Developments

On February 10, 2014, the Company completed and fully placed in-service The Avant at Reston Town Center development project comprised of 359 apartment units and retail space aggregating approximately 355,000 square feet located in Reston, Virginia.

On April 1, 2014, the Company commenced construction of its 99 Third Avenue development project totaling approximately 17,000 net rentable square feet of retail space located in Waltham, Massachusetts.

On April 3, 2014, the Company commenced construction of its 690 Folsom Street development project totaling approximately 25,000 net rentable square feet of office and retail space located in San Francisco, California. This project was partially placed in-service on December 2, 2014.

On April 10, 2014, a consolidated joint venture in which the Company has a 95% interest signed a lease with salesforce.com for 714,000 square feet at the new Salesforce Tower, the 1.4 million square foot, 61-story Class A office development project currently under construction at 415 Mission Street in the South Financial District of San Francisco, California. In conjunction with the lease signing, the Company has commenced construction of the building.

On May 20, 2014, the Company commenced construction of its 888 Boylston Street development project totaling approximately 425,000 net rentable square feet of Class A office space located in Boston, Massachusetts.

On May 20, 2014, the Company commenced construction of its 10 CityPoint development project totaling approximately 245,000 net rentable square feet of Class A office space located in Waltham, Massachusetts.

On August 31, 2014, the Company completed and fully placed in-service 250 West 55th Street, a Class A office project with approximately 988,000 net rentable square feet located in New York City.

On September 17, 2014, the Company completed and fully placed in-service 680 Folsom Street, a Class A office project with approximately 525,000 net rentable square feet located in San Francisco, California.

On November 1, 2014, the Company partially placed in-service 535 Mission Street, a Class A office project with approximately 307,000 net rentable square feet located in San Francisco, California.

Dispositions

On July 29, 2014, the Company completed the sale of its Mountain View Technology Park properties and Mountain View Research Park Building Sixteen property located in Mountain View, California for an aggregate sale price of approximately $92.1 million. Net cash proceeds totaled approximately $90.6 million, resulting in a gain on sale of real estate totaling approximately $35.9 million. Mountain View Technology Park is a seven-building complex of Office/Technical properties aggregating approximately 135,000 net rentable square feet. Mountain View Research Park Building Sixteen is an Office/Technical property with approximately 63,000 net rentable square feet.

On August 20, 2014, a portion of the land parcel at the Company’s One Reston Overlook property located in Reston, Virginia was taken by eminent domain. Net cash proceeds totaled approximately $2.6 million, resulting in a gain on sale of real estate totaling approximately $1.2 million.

On August 22, 2014, the Company completed the sale of a parcel of land within its Broad Run Business Park property located in Loudoun County, Virginia for a sale price of approximately $9.8 million. Net cash proceeds totaled approximately $9.7 million, resulting in a gain on sale of real estate totaling approximately $4.3 million. The parcel is an approximately 15.5 acre land parcel subject to a ground lease that was scheduled to expire on October 31, 2048 with a tenant that exercised its purchase option under the ground lease.

On October 2, 2014, the Company completed the sale of its Patriots Park properties located in Reston, Virginia for a gross sale price of $321.0 million. Patriots Park consists of three Class A office properties aggregating approximately 706,000 net rentable square feet. Net cash proceeds totaled approximately $319.1 million, resulting in a gain on sale of real estate totaling approximately $91.2 million. The Company has agreed to provide rent support payments to the buyer with a maximum obligation of up to approximately $12.3 million related to the leasing of 17,762 net rentable square feet at the properties, which has been recorded as a reduction to the gain on sale. Patriots Park contributed approximately $8.2 million, $10.8 million and $5.3 million of net income to the Company for the period from January 1, 2014 through October 1, 2014 and the years ended December 31, 2013 and 2012, respectively.

On October 22, 2014, the tenant exercised its right to purchase the Company’s 415 Main Street property (formerly Seven Cambridge Center) located in Cambridge, Massachusetts on February 1, 2016. As part of its lease signed on July 14, 2004, the tenant was granted an option to purchase the building at the beginning of the 11th lease year for approximately $106 million. 415 Main Street is an Office/Technical property with approximately 231,000 net rentable square feet.

On October 24, 2014, the Company completed the sale of a parcel of land at 130 Third Avenue in Waltham, Massachusetts that is permitted for 129,000 square feet for a sale price of approximately $14.3 million. Net cash proceeds totaled approximately $13.6 million, resulting in a gain on sale of real estate totaling approximately $8.3 million.

On October 30, 2014, the Company completed the sale of a 45% interest in each of 601 Lexington Avenue in New York City and Atlantic Wharf Office Building and 100 Federal Street in Boston for an aggregate gross sale price of approximately $1.827 billion in cash, less the partner’s pro rata share of the indebtedness collateralized by 601 Lexington Avenue. Net cash proceeds totaled approximately $1.497 billion, after the payment of transaction costs. In connection with the sale, the Company formed a limited liability company for each property with the buyer and will provide customary property management and leasing services to the joint ventures. 601 Lexington Avenue is a 1,669,000 square foot Class A office complex located in Midtown Manhattan. The property consists of a 59-story tower as well as a six-story low-rise office and retail building. The property is subject to existing mortgage indebtedness of approximately $712.9 million. The Atlantic Wharf Office Building is a 791,000 square foot Class A office tower located on Boston's Waterfront. 100 Federal Street is a 1,323,000 square foot Class A office tower located in Boston's Financial District. The transaction did not qualify as a sale of real estate for financial reporting purposes as the Company continues to effectively control these properties and thus will continue to account for the properties on a consolidated basis in its financial statements. The Company has accounted for the transaction as an equity transaction and has recognized noncontrolling interest in its consolidated balance sheets totaling approximately $849.0 million, which is equal to 45% of the aggregate carrying value of the total equity of the properties immediately prior to the transaction. The difference between the net cash proceeds received and the noncontrolling interest recognized, which was approximately $648.4 million, has not been reflected as a gain on sale of real estate in the Company's consolidated statements of operations and has instead been reflected as an increase in Partners' Capital in the Company's Consolidated Balance Sheets.

On December 30, 2014, the Company completed the conveyance to an unrelated third party of a condominium interest in its 75 Ames Street property located in Cambridge, Massachusetts. On May 23, 2011, the Company had entered into a ground lease for the vacant land parcel at 75 Ames Street and had also entered into a development agreement to serve as project manager for a 250,000 square foot research laboratory building to be developed on the site at the ground lessee’s expense and to also serve, upon completion of development, as property manager. Gross proceeds to the Company were approximately $56.8 million, including $11.4 million in development fees for the Company’s services, and were received beginning in May 2011. The cash received under the ground lease was initially recognized as unearned revenue and recognized over the 99-year term of the ground lease as ground lease revenue totaling approximately $459,000 per year prior to the conveyance of the condominium interest. The terms of the ground lease required the Company to form a condominium for the site upon completion of the development, at which time each party would subject their respective interests in the buildings and land to the condominium and would in turn be conveyed a condominium unit comprised of their respective building as well as an undivided ownership interest in the land. As a result of the conveyance and the transfer of title, the Company recognized a gain on sale of real estate totaling approximately $33.8 million.

The Company did not have any dispositions during the year ended December 31, 2014 that qualified for discontinued operations presentation subsequent to its adoption of ASU 2014-08. The following table summarizes the income from discontinued operations related to One Preserve Parkway, 10 & 20 Burlington Mall Road, 1301 New York Avenue, 303 Almaden Boulevard, Montvale Center and Bedford Business Park and the related gains on sales of real estate, gain on forgiveness of debt and impairment loss for the years ended December 31, 2013 and 2012:



	For the year ended December 31,
	2013			2012
	(in thousands)
Total revenue	$	20,138		$	32,607
Expenses
Operating	6,996			12,038
Depreciation and amortization	4,760			8,169
Total expenses	11,756			20,207
Operating income	8,382			12,400
Other expense
Interest expense	360			2,594
Income from discontinued operations attributable to Boston Properties Limited Partnership	$	8,022		$	9,806

Gains on sales of real estate from discontinued operations attributable to Boston Properties Limited Partnership	$	115,459		$	38,445
Gain on forgiveness of debt from discontinued operations attributable to Boston Properties Limited Partnership	$	20,736		$	—
Impairment loss from discontinued operations attributable to Boston Properties Limited Partnership	$	(2,852	)	$	—

Acquisitions

On November 6, 2014, the Company entered into an option agreement pursuant to which the Company has been granted an option to purchase real property located at 425 Fourth Street in San Francisco, California. In connection with the execution of the agreement, the Company paid a non-refundable option payment to the current owner of $1.0 million.

On November 12, 2014, the Company completed the acquisition of a parcel of land at 804 Carnegie Center in Princeton, New Jersey for a purchase price of approximately $3.7 million. 804 Carnegie Center is a build-to-suit project with approximately 130,000 net rentable square feet of Class A office space, which is currently under construction.

Prior Year Acquisitions Included in Pro Forma Information

The accompanying unaudited pro forma information for the years ended December 31, 2013 and 2012 is presented as if the operating property acquisitions of (1) Mountain View Research Park and Mountain View Technology Park on April 10, 2013 and the approximately $26.5 million gain on consolidation and (2) 767 Fifth Avenue (the General Motors Building) on May 31, 2013 and the approximately $359.5 million gain on consolidation, had occurred on January 1, 2012. This unaudited pro forma information is based upon the historical consolidated financial statements of the Company and should be read in conjunction with the consolidated financial statements and notes thereto. This pro forma information does not purport to represent what the actual results of operations of the Company would have been had the above occurred, nor do they purport to predict the results of operations of future periods. Additional information for these transactions are provided below.



Pro Forma (Unaudited)	Year ended December 31,
(in thousands, except per unit data)	2013		2012
Total revenue	$	2,257,098	$	2,149,391
Income from continuing operations	$	314,307	$	642,640
Net income attributable to Boston Properties Limited Partnership	$	452,813	$	710,690
Basic earnings per unit:
Net income per unit attributable to Boston Properties Limited Partnership	$	2.68	$	4.21
Diluted earnings per unit:
Net income per unit attributable to Boston Properties Limited Partnership	$	2.67	$	4.20

On April 10, 2013, the Company acquired the Mountain View Research Park and Mountain View Technology Park properties from Boston Properties Office Value-Added Fund, L.P. (the "Value-Added Fund") for an aggregate net purchase price of approximately $233.1 million. Mountain View Research Park is a 16-building complex of Office/Technical properties aggregating approximately 604,000 net rentable square feet. Mountain View Technology Park is a seven-building complex of Office/Technical properties aggregating approximately 135,000 net rentable square feet. The following table summarizes the allocation of the aggregate purchase price of Mountain View Research Park and Mountain View Technology Park at the date of acquisition (in thousands) in accordance with the guidance in ASC 805 "Business Combinations."



Land	$	126,521
Building and improvements	82,451
Tenant improvements	7,326
In-place lease intangibles	23,279
Above-market rents	843
Below-market rents	(7,336		)
Net assets acquired	$	233,084

On May 31, 2013, the Company's two joint venture partners in 767 Venture, LLC (the entity that owns 767 Fifth Avenue (the General Motors Building) located in New York City) transferred all of their interests in the joint venture to third parties. 767 Fifth Avenue (the General Motors Building) is a Class A office property totaling approximately 1.8 million net rentable square feet. In connection with the transfer, the Company and its new joint venture partners modified the Company's relative decision making authority and consent rights with respect to the joint venture's assets and operations. These changes resulted in the Company having sufficient financial and operating control over 767 Venture, LLC such that, effective as of May 31, 2013, the Company accounts for the assets, liabilities and operations of 767 Venture, LLC on a consolidated basis in its financial statements instead of under the equity method of accounting (See Note 11). The following table summarizes the allocation of the aggregate purchase price of 767 Fifth Avenue (the General Motors Building) at the date of consolidation on May 31, 2013 (in thousands) in accordance with the guidance in ASC 805 "Business Combinations."



Real estate and related intangibles recorded upon consolidation
Land	$	1,796,252
Building and improvements	1,447,446
Tenant improvements	85,208
In-place lease intangibles	357,781
Above market rents	101,897
Below market rents	(239,641		)
Above market assumed debt adjustments	(192,943		)
	$	3,356,000
Debt recorded upon consolidation
Mortgage notes payable	$	(1,300,000	)
Mezzanine notes payable	(306,000		)
Members' notes payable	(450,000		)	(1)
	$	(2,056,000	)

Working capital recorded upon consolidation
Cash and cash equivalents	$	79,468
Cash held in escrows	2,403
Tenant and other receivables	7,104
Prepaid expenses and other assets	4,269
Accounts payable and accrued expenses	(2,418		)
Accrued interest payable	(182,369		)	(2)
Other liabilities	(6,304		)
	$	(97,847	)
Noncontrolling interest recorded upon consolidation
Noncontrolling interests	$	(520,000	)
Noncontrolling interests - working capital	39,139
	$	(480,861	)

Net assets recorded upon consolidation	$	721,292

_______________


(1)	The Company's member loan totaling $270.0 million eliminates in consolidation.


(2)	The Company's share of the accrued interest payable on the members' loans totaling approximately $105.5 million eliminates in consolidation.

Mountain View Research Park and Mountain View Technology Park contributed approximately $16.7 million of revenue and approximately $0.4 million of earnings to the Company for the period from April 10, 2013 through December 31, 2013. 767 Fifth Avenue (the General Motors Building) contributed approximately $168.4 million of revenue and approximately $8.4 million of earnings to the Company for the period from May 31, 2013 through December 31, 2013.

Deferred Charges

12 Months Ended

Dec. 31, 2014

Deferred Charges [Abstract]

Deferred Charges

4. Deferred Charges

Deferred charges consisted of the following at December 31, (in thousands):



	2014			2013
Leasing costs, including lease related intangibles	$	1,234,192		$	1,183,204
Financing costs	69,127			76,798
	1,303,319			1,260,002
Less: Accumulated amortization	(471,575		)	(375,552		)
	$	831,744		$	884,450

The following table summarizes the scheduled amortization of the Company's acquired in-place lease intangibles for each of the five succeeding years (in thousands).



	Acquired In-Place Lease Intangibles
2015	$	66,390
2016	55,327
2017	38,812
2018	33,964
2019	27,439

Investments in Unconsolidated Joint Ventures

12 Months Ended

Dec. 31, 2014

Investments In Unconsolidated Joint Ventures [Abstract]

Investments In Unconsolidated Joint Ventures

Investments in Unconsolidated Joint Ventures

The investments in unconsolidated joint ventures consist of the following at December 31, 2014:



Entity	Properties	Nominal % Ownership			Carrying Value of Investment (1)
					(in thousands)
Square 407 Limited Partnership	Market Square North	50.0	%		$	(8,022	)
The Metropolitan Square Associates LLC	Metropolitan Square	51.0	%		8,539
BP/CRF 901 New York Avenue LLC	901 New York Avenue	25.0	%	(2)	(1,080		)
WP Project Developer LLC	Wisconsin Place Land and Infrastructure	33.3	%	(3)	45,514
Annapolis Junction NFM, LLC	Annapolis Junction	50.0	%	(4)	25,246
540 Madison Venture LLC	540 Madison Avenue	60.0	%		68,128
500 North Capitol LLC	500 North Capitol Street, NW	30.0	%		(2,250		)
501 K Street LLC	1001 6th Street (formerly 501 K Street)	50.0	%	(5)	41,736
Podium Developer LLC	North Station (Phase I - Air Rights)	50.0	%		4,231
					$	182,042

_______________


(1)	Investments with deficit balances aggregating approximately $11.4 million have been reflected within Other Liabilities on the Company's Consolidated Balance Sheets.


(2)	The Company’s economic ownership has increased based on the achievement of certain return thresholds.


(3)	The Company’s wholly-owned entity that owns the office component of the project also owns a 33.3% interest in the entity owning the land, parking garage and infrastructure of the project.


(4)	The joint venture owns two in-service buildings, two buildings under construction and two undeveloped land parcels.


(5)	Under the joint venture agreement, the partner will be entitled to up to two additional payments from the venture based on increases in total square footage of the project above 520,000 square feet and achieving certain project returns at stabilization.

Certain of the Company’s unconsolidated joint venture agreements include provisions whereby, at certain specified times, each partner has the right to initiate a purchase or sale of its interest in the joint ventures at an agreed upon fair value. Under these provisions, the Company is not compelled to purchase the interest of its outside joint venture partners.

The combined summarized balance sheets of the Company's unconsolidated joint ventures are as follows:



	December 31, 2014			December 31, 2013
	(in thousands)
ASSETS
Real estate and development in process, net	$	1,034,552		$	924,297
Other assets	264,097			163,149
Total assets	$	1,298,649		$	1,087,446
LIABILITIES AND MEMBERS’/PARTNERS’ EQUITY
Mortgage and notes payable	$	830,075		$	749,732
Other liabilities	34,211			28,830
Members’/Partners’ equity	434,363			308,884
Total liabilities and members’/partners’ equity	$	1,298,649		$	1,087,446
Company’s share of equity	$	209,828		$	154,726
Basis differentials (1)	(27,786		)	(28,642		)
Carrying value of the Company’s investments in unconsolidated joint ventures (2)	$	182,042		$	126,084

_______________

(1)

This amount represents the aggregate difference between the Company’s historical cost basis and the basis reflected at the joint venture level, which is typically amortized over the life of the related assets and liabilities. Basis differentials occur from impairment of investments and upon the transfer of assets that were previously owned by the Company into a joint venture. In addition, certain acquisition, transaction and other costs may not be reflected in the net assets at the joint venture level.


(2)	Investments with deficit balances aggregating approximately $11.4 million and $14.0 million at December 31, 2014 and 2013, respectively, have been reflected within Other Liabilities on the Company's Consolidated Balance Sheets.

The combined summarized statements of operations of the Company's joint ventures are as follows:



	For the year ended December 31,
	2014			2013			2012
	(in thousands)
Total revenue (1)	$	158,161		$	311,548		$	564,205
Expenses
Operating	62,974			105,319			162,665
Depreciation and amortization	37,041			86,088			163,134
Total expenses	100,015			191,407			325,799
Operating income	58,146			120,141			238,406
Other income (expense)
Interest expense	(31,896		)	(112,535		)	(224,645		)
Losses from early extinguishments of debt	—			(1,677		)	—
Income from continuing operations	26,250			5,929			13,761
Gains on sales of real estate	—			14,207			990
Net income	$	26,250		$	20,136		$	14,751

Company’s share of net income	$	11,913		$	4,612		$	6,863
Gains on sales of real estate	—			54,501			—
Basis differential	856			(1,017		)	1,732
Elimination of inter-entity interest on partner loan	—			16,978			40,483
Income from unconsolidated joint ventures	$	12,769		$	75,074		$	49,078
Gains on consolidation of joint ventures	$	—		$	385,991		$	—

_______________

(1)

Includes straight-line rent adjustments of $3.0 million, $7.8 million and $12.0 million for the years ended December 31, 2014, 2013 and 2012, respectively. Includes net above-/below-market rent adjustments of $(0.1) million, $33.7 million and $91.1 million for the years ended December 31, 2014, 2013 and 2012, respectively. Total revenue for the year ended December 31, 2012 includes termination income totaling approximately $19.6 million (of which the Company's share is approximately $11.8 million) related to a lease termination with a tenant at 767 Fifth Avenue (The General Motors Building).

On April 10, 2014, the Company entered into a joint venture with an unrelated third party to acquire a parcel of land located at 1001 6th Street (formerly 501 K Street) in Washington, DC. The Company anticipates the land parcel will accommodate an approximate 520,000 square foot Class A office property to be developed in the future. The joint venture partner contributed the land for a 50% interest in the joint venture and the Company initially contributed cash of approximately $39.0 million for its 50% interest. Under the joint venture agreement, the partner may be entitled to up to two additional payments from the venture based on increases in total square footage of the project above 520,000 square feet and achieving certain project returns at stabilization.

On April 30, 2014, the Company's partner in its Annapolis Junction joint venture contributed a parcel of land and improvements and the Company contributed cash of approximately $5.4 million to the joint venture. The Company has a 50% interest in this joint venture. The joint venture has commenced construction of Annapolis Junction Building Eight, which when completed will consist of a Class A office property with approximately 125,000 net rentable square feet located in Annapolis, Maryland. In addition, on June 23, 2014, the joint venture obtained construction financing collateralized by the development project totaling $26.0 million. The construction financing bears interest at a variable rate equal to LIBOR plus 1.50% per annum and matures on June 23, 2017, with two, one-year extension options, subject to certain conditions.

On October 24, 2014, a joint venture in which the Company has a 50% interest extended the loan collateralized by its Annapolis Junction Building Six property. At the time of the extension, the outstanding balance of the construction loan totaled approximately $13.9 million and bore interest at a variable rate equal to LIBOR plus 1.65% per annum and was scheduled to mature on November 17, 2014. The extended loan has a total commitment amount of $16.4 million, bears interest at a variable rate equal to LIBOR plus 2.25% per annum and matures on November 17, 2015. Annapolis Junction Building Six is a Class A office property with approximately 119,000 net rentable square feet located in Annapolis, Maryland.

On December 17, 2014, a joint venture in which the Company has a 25% nominal ownership interest refinanced with a new lender its mortgage loan collateralized by 901 New York Avenue located in Washington, DC. The mortgage loan totaling approximately $150.4 million bore interest at a fixed rate of 5.19% per annum and was scheduled to mature on January 1, 2015. The new mortgage loan totaling $225.0 million bears interest at a fixed rate of 3.61% per annum and matures on January 5, 2025.

On December 19, 2014, the Company entered into a joint venture with an unrelated third party to acquire the air rights for the future development of the first phase at North Station, consisting of an atrium hall and podium building containing up to 377,000 net rentable square feet of retail and office space located in Boston, Massachusetts. The joint venture partner contributed air rights parcels and improvements, with a fair value of approximately $13.0 million, for its initial 50% interest in the joint venture. The Company contributed improvements totaling approximately $4.2 million and will contribute cash totaling approximately $8.8 million for its initial 50% interest. In addition, the Company entered into an option and development rights agreement with its partner pursuant to which the Company has the right to develop residential, hotel and office space in future phases, subject to certain terms and conditions including the partner's right to participate as a venture partner in each phase of the project.

Mortgage Notes Payable

12 Months Ended

Dec. 31, 2014

Loans Payable [Abstract]

Mortgage Notes Payable

The Company had outstanding mortgage notes payable totaling approximately $4.3 billion and $4.4 billion as of December 31, 2014 and 2013, respectively, each collateralized by one or more buildings and related land included in real estate assets. The mortgage notes payable are generally due in monthly installments and mature at various dates through April 10, 2022.

Fixed rate mortgage notes payable totaled approximately $4.3 billion and $4.4 billion at December 31, 2014 and 2013, respectively, with contractual interest rates ranging from 4.75% to 7.69% per annum at December 31, 2014 and 2013 (with a weighted-average of 5.70% (excluding the mezzanine notes payable) at December 31, 2014 and 2013).

There were no variable rate mortgage loans at December 31, 2014 and 2013. As of December 31, 2014 and 2013, the LIBOR rate was 0.17%.

On July 1, 2014, the Company used available cash to repay the mortgage loan collateralized by its New Dominion Technology Park Building Two property located in Herndon, Virginia totaling $63.0 million. The mortgage loan bore interest at a fixed rate of 5.55% per annum and was scheduled to mature on October 1, 2014. There was no prepayment penalty.

Four mortgage loans totaling approximately $2.2 billion at December 31, 2014 and 2013 have been accounted for at their fair values on the dates the mortgage loans were assumed. The impact of recording the mortgage loans at fair value resulted in a decrease to interest expense of approximately $52.5 million, $34.4 million and $7.0 million for the years ended December 31, 2014, 2013 and 2012, respectively. The cumulative liability related to the fair value adjustments was $138.7 million and $191.2 million at December 31, 2014 and 2013, respectively, and is included in mortgage notes payable in the Consolidated Balance Sheets.

Contractual aggregate principal payments of mortgage notes payable at December 31, 2014 are as follows:



	Principal Payments
	(in thousands)
2015	$	26,184
2016	608,879
2017	2,821,750
2018	18,633
2019	19,670
Thereafter	675,657
Total aggregate principal payments	4,170,773
Unamortized balance of historical fair value adjustments	138,711
Total carrying value of mortgage notes payable	$	4,309,484

Unsecured Senior Notes

12 Months Ended

Dec. 31, 2014

Debt Disclosure [Abstract]

Unsecured Senior Notes

The following summarizes the unsecured senior notes outstanding as of December 31, 2014 (dollars in thousands):



	Coupon/ Stated Rate		Effective Rate(1)		Principal Amount			Maturity Date(2)
10 Year Unsecured Senior Notes	5.875	%	5.967	%	$	700,000		October 15, 2019
10 Year Unsecured Senior Notes	5.625	%	5.708	%	700,000			November 15, 2020
10 Year Unsecured Senior Notes	4.125	%	4.289	%	850,000			May 15, 2021
7 Year Unsecured Senior Notes	3.700	%	3.853	%	850,000			November 15, 2018
11 Year Unsecured Senior Notes	3.850	%	3.954	%	1,000,000			February 1, 2023
10.5 Year Unsecured Senior Notes	3.125	%	3.279	%	500,000			September 1, 2023
10.5 Year Unsecured Senior Notes	3.800	%	3.916	%	700,000			February 1, 2024

Total principal					5,300,000
Net unamortized discount					(12,296		)
Total					$	5,287,704

_______________


(1)	Yield on issuance date including the effects of discounts on the notes and the amortization of financing costs.


(2)	No principal amounts are due prior to maturity.

On December 15, 2014, the Company used available cash to redeem $300.0 million in aggregate principal amount of its 5.625% senior notes due 2015 (the “5.625% Notes”) and $250.0 million in aggregate principal amount of its 5.000% senior notes due 2015 (the “5.000% Notes”). The redemption price for the 5.625% Notes was determined in accordance with the applicable indenture and totaled approximately $308.0 million. The redemption price included approximately $2.8 million of accrued and unpaid interest to, but not including, the redemption date. Excluding such accrued and unpaid interest, the redemption price was approximately 101.73% of the principal amount being redeemed. The redemption price for the 5.000% Notes was determined in accordance with the applicable indenture and totaled approximately $255.8 million. The redemption price included approximately $0.5 million of accrued and unpaid interest to, but not including, the redemption date. Excluding such accrued and unpaid interest, the redemption price was approximately 102.13% of the principal amount being redeemed. The Company recognized a loss on early extinguishment of debt totaling approximately $10.6 million, which amount included the payment of the redemption premium totaling approximately $10.5 million.

The indenture relating to the unsecured senior notes contains certain financial restrictions and requirements, including (1) a leverage ratio not to exceed 60%, (2) a secured debt leverage ratio not to exceed 50%, (3) an interest coverage ratio of greater than 1.50, and (4) an unencumbered asset value of not less than 150% of unsecured debt. At December 31, 2014, the Company was in compliance with each of these financial restrictions and requirements.

Unsecured Exchangeable Senior Notes	12 Months Ended
Unsecured Exchangeable Senior Notes	Dec. 31, 2014
Debt Disclosure [Abstract]
Unsecured Exchangeable Senior Notes	Unsecured Exchangeable Senior Notes ASC 470-20 "Debt with Conversion and Other Options" ("ASC 470-20") requires the liability and equity components of convertible debt instruments that may be settled in cash upon conversion (including partial cash settlement) to be separately accounted for in a manner that reflects the issuer’s nonconvertible debt borrowing rate. ASC 470-20 requires that the initial proceeds from the sale of the Company’s $862.5 million of 2.875% exchangeable senior notes due 2037 (all of which had been redeemed/repurchased as of December 31, 2012), $450.0 million of 3.75% exchangeable senior notes due 2036 (all of which have been redeemed/repurchased as of December 31, 2013) and $747.5 million of 3.625% exchangeable senior notes due 2014 (all of which have been repaid as of December 31, 2014) be allocated between a liability component and an equity component in a manner that reflects interest expense at the interest rate of similar nonconvertible debt that could have been issued by the Company at such time. The Company measured the fair value of the debt components of the 2.875%, 3.75% and 3.625% exchangeable senior notes for the periods presented based on effective interest rates of 5.630%, 5.958% and 6.555%, respectively. The aggregate carrying amount of the debt component was approximately $0.0 million and $744.9 million (net of the equity component allocation adjustment of approximately $0.0 million and $2.4 million) at December 31, 2014 and December 31, 2013, respectively. As a result, the Company attributed an aggregate of approximately $230.3 million of the proceeds to the equity component of the notes, which represents the excess proceeds received over the fair value of the notes at the date of issuance. The equity component of the notes has been reflected within Partners’ Capital in the Consolidated Balance Sheets. The Company reclassified approximately $1.0 million of deferred financing costs to Partners’ Capital, which represented the costs attributable to the equity components of the notes. The carrying amount of the equity component was approximately $0.0 million and $91.9 million at December 31, 2014 and December 31, 2013, respectively. The resulting debt discount has been amortized over the period during which the debt was expected to be outstanding (i.e., through the first optional redemption dates or, in the case of the 2014 notes, the maturity date) as additional non-cash interest expense. The aggregate contractual interest expense was approximately $3.3 million, $34.8 million and $48.4 million for the years ended December 31, 2014, 2013 and 2012, respectively. As a result, the Company reported additional non-cash interest expense of approximately $2.4 million, $23.1 million and $29.1 million for the years ended December 31, 2014, 2013 and 2012, respectively. On February 18, 2014, the Company repaid at maturity the $747.5 million aggregate principal amount of its 3.625% exchangeable senior notes due 2014 plus accrued and unpaid interest thereon.

Unsecured Line of Credit	12 Months Ended
Unsecured Line of Credit	Dec. 31, 2014
Unsecured Line of Credit [Abstract]
Unsecured Line of Credit [Text Block]	9. Unsecured Line of Credit The Company has a $1.0 billion revolving credit facility (the "Unsecured Line of Credit") with a maturity date of July 26, 2018. The Company may increase the total commitment to $1.5 billion, subject to syndication of the increase and other conditions. At the Company's option, loans outstanding under the Unsecured Line of Credit will bear interest at a rate per annum equal to (1), in the case of loans denominated in Dollars, Euro or Sterling, LIBOR or, in the case of loans denominated in Canadian Dollars, CDOR, in each case, plus a margin ranging from 0.925% to 1.70% based on the Company’s credit rating or (2) an alternate base rate equal to the greatest of (a) the Administrative Agent’s prime rate, (b) the Federal Funds rate plus 0.5% or (c) LIBOR for a one month period plus 1.00%, in each case, plus a margin ranging from 0.0% to 0.70% based on the Company’s credit rating. The Unsecured Line of Credit also contains a competitive bid option that allows banks that are part of the lender consortium to bid to make loan advances to the Company at a reduced interest rate. In addition, the Company is also obligated to pay (1) in quarterly installments a facility fee on the total commitment at a rate per annum ranging from 0.125% to 0.35% based on the Company’s credit rating and (2) an annual fee on the undrawn amount of each letter of credit equal to the LIBOR margin. Based on the Company’s current credit rating, the LIBOR and CDOR margin is 1.00%, the alternate base rate margin is 0.0% and the facility fee is 0.15%. At December 31, 2014 and 2013, there were no amounts outstanding on the Unsecured Line of Credit. The terms of the Unsecured Line of Credit require that the Company maintain a number of customary financial and other covenants on an ongoing basis, including: (1) a leverage ratio not to exceed 60%, however, the leverage ratio may increase to no greater than 65% provided that it is reduced back to 60% within one year, (2) a secured debt leverage ratio not to exceed 55%, (3) a fixed charge coverage ratio of at least 1.40, (4) an unsecured debt leverage ratio not to exceed 60%, however, the unsecured debt leverage ratio may increase to no greater than 65% provided that it is reduced back to 60% within one year, (5) an unsecured debt interest coverage ratio of at least 1.75 and (6) limitations on permitted investments. At December 31, 2014, the Company was in compliance with each of these financial and other covenant requirements.

Commitments And Contingencies	12 Months Ended
Commitments And Contingencies	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Commitments And Contingencies	Commitments and Contingencies General In the normal course of business, the Company guarantees its performance of services or indemnifies third parties against its negligence. In addition, in the normal course of business, the Company guarantees to certain tenants the obligations of its subsidiaries for the payment of tenant improvement allowances and brokerage commissions in connection with their leases and limited costs arising from delays in delivery of their premises. The Company has letter of credit and performance obligations of approximately $19.8 million related to lender and development requirements. Certain of the Company’s joint venture agreements include provisions whereby, at certain specified times, each partner has the right to initiate a purchase or sale of its interest in the joint ventures. With limited exception, under these provisions, the Company is not compelled to purchase the interest of its outside joint venture partners (See also Note 11). Under certain of the Company's joint venture agreements, if certain return thresholds are achieved the partners will be entitled to an additional promoted interest or payments. In connection with the assumption of 767 Fifth Avenue's (the General Motors Building) secured loan by the Company’s consolidated joint venture, 767 Venture, LLC, the Company guaranteed the consolidated joint venture’s obligation to fund various escrows, including tenant improvements, taxes and insurance in lieu of cash deposits. As of December 31, 2014, the maximum funding obligation under the guarantee was approximately $32.0 million. The Company earns a fee from the joint venture for providing the guarantee and has an agreement with the outside partners to reimburse the joint venture for their share of any payments made under the guarantee. In connection with the mortgage financing collateralized by the Company's John Hancock Tower property located in Boston, Massachusetts, the Company has agreed to guarantee approximately $25.7 million related to its obligation to provide funds for certain tenant re-leasing costs. The mortgage financing matures on January 6, 2017. In connection with the mortgage financing collateralized by the Company's consolidated joint venture's Fountain Square property located in Reston, Virginia, the Company has agreed to guarantee approximately $0.7 million related to its obligation to provide funds for certain tenant re-leasing costs. The mortgage financing matures on October 11, 2016. From time to time, the Company (or the applicable joint venture) has also agreed to guarantee portions of the principal, interest or other amounts in connection with other unconsolidated joint venture borrowings. In addition to the financial guarantees referenced above, the Company has agreed to customary construction completion guarantees for construction loans, environmental indemnifications and nonrecourse carve-outs (e.g., guarantees against fraud, misrepresentation and bankruptcy) on certain of its unconsolidated joint venture loans. In 2009, the Company filed a general unsecured creditor’s claim against Lehman Brothers, Inc. for approximately $45.3 million related to its rejection of a lease at 399 Park Avenue in New York City. On January 10, 2014, the trustee for the liquidation of the business of Lehman Brothers allowed the Company’s claim in the amount of approximately $45.2 million. On September 18, 2014, the Company received an initial distribution totaling approximately $7.7 million, which is included in Base Rent in the accompanying Consolidated Statements of Operations for the year ended December 31, 2014, leaving a remaining claim of approximately $37.5 million. Recently, claims of similar priority to that of the Company's remaining claim were quoted privately within a range of $0.24 to $0.25 per $1.00. The Company was notified on February 19, 2015 that the bankruptcy court approved the trustee’s motion to make a second interim distribution to holders of claims as of February 6, 2015. The Company will continue to evaluate whether to attempt to sell the remaining claim or wait until the trustee distributes proceeds from the Lehman estate. Given the inherent uncertainties in bankruptcy proceedings, there can be no assurance as to the timing or amount of proceeds, if any, that the Company may ultimately realize on the remaining claim, whether by sale to a third party or by one or more distributions from the trustee. Accordingly, the Company has not recorded any estimated recoveries associated with this gain contingency within its consolidated financial statements at December 31, 2014. Concentrations of Credit Risk Management of the Company performs ongoing credit evaluations of tenants and may require tenants to provide some form of credit support such as corporate guarantees and/or other financial guarantees. Although the Company’s properties are geographically diverse and the tenants operate in a variety of industries, to the extent the Company has a significant concentration of rental revenue from any single tenant, the inability of that tenant to make its lease payments could have an adverse effect on the Company. Some potential losses are not covered by insurance The Company carries insurance coverage on its properties of types and in amounts and with deductibles that it believes are in line with coverage customarily obtained by owners of similar properties. In response to the uncertainty in the insurance market following the terrorist attacks of September 11, 2001, the Federal Terrorism Risk Insurance Act (as amended, “TRIA”) was enacted in November 2002 to require regulated insurers to make available coverage for “certified” acts of terrorism (as defined by the statute). The expiration date of TRIA was extended to December 31, 2014 by the Terrorism Risk Insurance Program Reauthorization Act of 2007 and further extended to December 31, 2020 by the Terrorism Risk Insurance Program Reauthorization Act of 2015 (“TRIPRA”), and the Company can provide no assurance that it will be extended further. Currently, the Company’s property insurance program per occurrence limits are $1.0 billion for its portfolio insurance program, including coverage for acts of terrorism other than nuclear, biological, chemical or radiological terrorism (“Terrorism Coverage”). The Company also carries $250 million of Terrorism Coverage for 601 Lexington Avenue, New York, New York (“601 Lexington Avenue”) in excess of the $1.0 billion of coverage in the Company’s property insurance program. Certain properties, including the General Motors Building located at 767 Fifth Avenue in New York, New York (“767 Fifth Avenue”), are currently insured in separate insurance programs. The property insurance program per occurrence limits for 767 Fifth Avenue are $1.625 billion, including Terrorism Coverage. Through June 9, 2014, $1.375 billion of the Terrorism Coverage for 767 Fifth Avenue in excess of $250 million was provided by NYXP, LLC (“NYXP”), as a direct insurer. After June 9, 2014, all of the Terrorism Coverage for 767 Fifth Avenue has been provided by third party insurers. The Company also currently carries nuclear, biological, chemical and radiological terrorism insurance coverage for acts of terrorism certified under TRIA (“NBCR Coverage”), which is provided by IXP as a direct insurer, for the properties in our portfolio, including 767 Fifth Avenue, but excluding certain other properties owned in joint ventures with third parties or which the Company manages. The per occurrence limit for NBCR Coverage is $1.0 billion. Under TRIA, after the payment of the required deductible and coinsurance, the NBCR Coverage provided by IXP and the Terrorism Coverage provided by NYXP are backstopped by the Federal Government if the aggregate industry insured losses resulting from a certified act of terrorism exceed a “program trigger.” In 2015, the program trigger is $100 million and the coinsurance is 15%, however, both will increase in subsequent years pursuant to TRIPRA. If the Federal Government pays out for a loss under TRIA, it is mandatory that the Federal Government recoup the full amount of the loss from insurers offering TRIA coverage after the payment of the loss pursuant to a formula in TRIPRA. The Company may elect to terminate the NBCR Coverage if the Federal Government seeks recoupment for losses paid under TRIA, if there is a change in its portfolio or for any other reason. The Company intends to continue to monitor the scope, nature and cost of available terrorism insurance and maintain terrorism insurance in amounts and on terms that are commercially reasonable. The Company also currently carries earthquake insurance on its properties located in areas known to be subject to earthquakes in an amount and subject to self-insurance that the Company believes is commercially reasonable. In addition, this insurance is subject to a deductible in the amount of 5% of the value of the affected property. Specifically, the Company currently carries earthquake insurance which covers its San Francisco region (excluding 535 Mission Street and Salesforce Tower) with a $120 million per occurrence limit and a $120 million annual aggregate limit, $20 million of which is provided by IXP, as a direct insurer. The builders risk policy maintained for the development of 535 Mission Street in San Francisco included a $15 million per occurrence and annual aggregate limit of earthquake coverage through October 22, 2014, after which time 535 Mission Street was included in our portfolio earthquake insurance program. In addition, the builders risk policy maintained for the development of Salesforce Tower in San Francisco includes a $60 million per occurrence and annual aggregate limit of earthquake coverage (increased from $15 million on July 29, 2014). The amount of the Company’s earthquake insurance coverage may not be sufficient to cover losses from earthquakes. In addition, the amount of earthquake coverage could impact the Company’s ability to finance properties subject to earthquake risk. The Company may discontinue earthquake insurance or change the structure of its earthquake insurance program on some or all of its properties in the future if the premiums exceed the Company’s estimation of the value of the coverage. IXP, a captive insurance company which is a wholly-owned subsidiary of the Company, acts as a direct insurer with respect to a portion of the Company’s earthquake insurance coverage for its Greater San Francisco properties and the Company’s NBCR Coverage. NYXP, a captive insurance company which is a wholly-owned subsidiary of the Company, acted as a direct insurer with respect to a portion of the Company’s Terrorism Coverage for 767 Fifth Avenue through June 9, 2014. NYXP only insured losses which exceeded the program trigger under TRIA and NYXP reinsured with a third-party insurance company any coinsurance payable under TRIA. Insofar as the Company owns IXP and NYXP, it is responsible for their liquidity and capital resources, and the accounts of IXP and NYXP are part of the Company’s consolidated financial statements. In particular, if a loss occurs which is covered by the Company’s NBCR Coverage but is less than the applicable program trigger under TRIA, IXP would be responsible for the full amount of the loss without any backstop by the Federal Government. IXP and NYXP would also be responsible for any recoupment charges by the Federal Government in the event losses are paid out and their insurance policies are maintained after the payout by the Federal Government. If the Company experiences a loss and IXP or NYXP are required to pay under their insurance policies, the Company would ultimately record the loss to the extent of the required payment. Therefore, insurance coverage provided by IXP and NYXP should not be considered as the equivalent of third-party insurance, but rather as a modified form of self-insurance. In addition, the Company has issued a guarantee to cover liabilities of IXP in the amount of $20.0 million. The mortgages on the Company's properties typically contain requirements concerning the financial ratings of the insurers who provide policies covering the property. The Company provides the lenders on a regular basis with the identity of the insurance companies in the Company's insurance programs. The ratings of some of the Company's insurers are below the rating requirements in some of the Company's loan agreements and the lenders for these loans could attempt to claim that an event of default has occurred under the loan. The Company believes it could obtain insurance with insurers which satisfy the rating requirements. Additionally, in the future, the Company's ability to obtain debt financing secured by individual properties, or the terms of such financing, may be adversely affected if lenders generally insist on ratings for insurers or amounts of insurance which are difficult to obtain or which result in a commercially unreasonable premium. There can be no assurance that a deficiency in the financial ratings of one or more of the Company's insurers will not have a material adverse effect on the Company. The Company continues to monitor the state of the insurance market in general, and the scope and costs of coverage for acts of terrorism and California earthquake risk in particular, but the Company cannot anticipate what coverage will be available on commercially reasonable terms in future policy years. There are other types of losses, such as from wars, for which the Company cannot obtain insurance at all or at a reasonable cost. With respect to such losses and losses from acts of terrorism, earthquakes or other catastrophic events, if the Company experiences a loss that is uninsured or that exceeds policy limits, the Company could lose the capital invested in the damaged properties, as well as the anticipated future revenues from those properties. Depending on the specific circumstances of each affected property, it is possible that the Company could be liable for mortgage indebtedness or other obligations related to the property. Any such loss could materially and adversely affect the Company's business and financial condition and results of operations. Legal Matters The Company is subject to various legal proceedings and claims that arise in the ordinary course of business. These matters are generally covered by insurance. Management believes that the final outcome of such matters will not have a material adverse effect on the financial position, results of operations or liquidity of the Company. State and Local Tax Matters Because the Company is a limited partnership, it is generally not subject to federal income taxes, but is subject to certain state and local taxes. In the normal course of business, certain entities through which the Company owns real estate either have undergone, or are currently undergoing, tax audits. Although the Company believes that it has substantial arguments in favor of its positions in the ongoing audits, in some instances there is no controlling precedent or interpretive guidance on the specific point at issue. Collectively, tax deficiency notices received to date from the jurisdictions conducting the ongoing audits have not been material. However, there can be no assurance that future audits will not occur with increased frequency or that the ultimate result of such audits will not have a material adverse effect on the Company’s results of operations. Environmental Matters It is the Company’s policy to retain independent environmental consultants to conduct or update Phase I environmental assessments (which generally do not involve invasive techniques such as soil or ground water sampling) and asbestos surveys in connection with the Company’s acquisition of properties. These pre-purchase environmental assessments have not revealed environmental conditions that the Company believes will have a material adverse effect on its business, assets, financial condition, results of operations or liquidity, and the Company is not otherwise aware of environmental conditions with respect to its properties that the Company believes would have such a material adverse effect. However, from time to time environmental conditions at the Company’s properties have required and may in the future require environmental testing and/or regulatory filings, as well as remedial action. In February 1999, the Company (through a joint venture) acquired from Exxon Corporation a property in Massachusetts that was formerly used as a petroleum bulk storage and distribution facility and was known by the state regulatory authority to contain soil and groundwater contamination. The Company developed an office park on the property. The Company engaged a specially licensed environmental consultant to oversee the management of contaminated soil and groundwater that was disturbed in the course of construction. Under the property acquisition agreement, Exxon agreed to (1) bear the liability arising from releases or discharges of oil and hazardous substances which occurred at the site prior to the Company’s ownership, (2) continue monitoring and/or remediating such releases and discharges as necessary and appropriate to comply with applicable requirements, and (3) indemnify the Company for certain losses arising from preexisting site conditions. Any indemnity claim may be subject to various defenses, and there can be no assurance that the amounts paid under the indemnity, if any, would be sufficient to cover the liabilities arising from any such releases and discharges. Environmental investigations at some of the Company’s properties and certain properties owned by affiliates of the Company have identified groundwater contamination migrating from off-site source properties. In each case the Company engaged a licensed environmental consultant to perform the necessary investigations and assessments and to prepare any required submittals to the regulatory authorities. In each case the environmental consultant concluded that the properties qualify under the regulatory program or the regulatory practice for a status which eliminates certain deadlines for conducting response actions at a site. The Company also believes that these properties qualify for liability relief under certain statutory provisions or regulatory practices regarding upgradient releases. Although the Company believes that the current or former owners of the upgradient source properties may bear responsibility for some or all of the costs of addressing the identified groundwater contamination, the Company will take such further response actions (if any) that it deems necessary or advisable. Other than periodic testing at some of these properties, no such additional response actions are anticipated at this time. Some of the Company’s properties and certain properties owned by the Company’s affiliates are located in urban, industrial and other previously developed areas where fill or current or historical uses of the areas have caused site contamination. Accordingly, it is sometimes necessary to institute special soil and/or groundwater handling procedures and/or include particular building design features in connection with development, construction and other property operations in order to achieve regulatory closure and/or ensure that contaminated materials are addressed in an appropriate manner. In these situations it is the Company’s practice to investigate the nature and extent of detected contamination and estimate the costs of required response actions and special handling procedures. The Company then uses this information as part of its decision-making process with respect to the acquisition and/or development of the property. For example, the Company owns a parcel in Massachusetts which was formerly used as a quarry/asphalt batching facility. Pre-purchase testing indicated that the site contained relatively low levels of certain contaminants. The Company has developed an office park on this property. Prior to and during redevelopment activities, the Company engaged a specially licensed environmental consultant to monitor environmental conditions at the site and prepare necessary regulatory submittals based on the results of an environmental risk characterization. A submittal has been made to the regulatory authorities in order to achieve regulatory closure at this site. The submittal included an environmental deed restriction that mandates compliance with certain protective measures in a portion of the site where low levels of residual soil contamination have been left in place in accordance with applicable laws. The Company expects that resolution of the environmental matters relating to the above will not have a material impact on its business, assets, financial condition, results of operations or liquidity. However, the Company cannot assure you that it has identified all environmental liabilities at its properties, that all necessary remediation actions have been or will be undertaken at the Company’s properties or that the Company will be indemnified, in full or at all, in the event that such environmental liabilities arise. Tax Protection Obligations In connection with the acquisition or contribution of three properties, the Company entered into agreements for the benefit of the selling or contributing parties which specifically state that until such time as the contributors do not hold at least a specified percentage of the OP Units owned by such person following the contribution of the properties, or until June 9, 2017 for 767 Fifth Avenue (the General Motors Building), the Company will not sell or otherwise transfer the properties in a taxable transaction. If the Company does sell or transfer the properties in a taxable transaction, it would be liable to the contributors for contractual damages.

Noncontrolling Interests

12 Months Ended

Dec. 31, 2014

Noncontrolling Interest [Abstract]

Noncontrolling Interests

Noncontrolling interests relate to the interests in the Company not owned by Boston Properties, Inc. and interests in consolidated property partnerships not wholly-owned by the Company. As of December 31, 2014, the noncontrolling interests consisted of 16,453,670 OP Units, 1,496,799 LTIP Units, 394,590 2012 OPP Units, 313,936 2013 MYLTIP Units, 482,032 2014 MYLTIP Units and 12,667 Series Four Preferred Units (none of which are convertible into OP Units) held by parties other than Boston Properties, Inc.

Noncontrolling Interest—Redeemable Interest in Property Partnership

On October 4, 2012, the Company completed the formation of a joint venture, which owns and operates Fountain Square located in Reston, Virginia. The joint venture partner contributed the property valued at approximately $385.0 million and related mortgage indebtedness totaling approximately $211.3 million for a 50% interest in the joint venture. The Company contributed cash totaling approximately $87.0 million for its 50% interest, which cash was distributed to the joint venture partner. Pursuant to the joint venture agreement (i) the Company has rights to acquire the partner's nominal 50% interest and (ii) the partner has the right to cause the Company to acquire the partner's interest on January 4, 2016, in each case at a fixed price totaling approximately $102.0 million in cash. The fixed price option rights expire on January 31, 2016. The Company is consolidating this joint venture due to the Company's right to acquire the partner's nominal 50% interest. The Company initially recorded the noncontrolling interest at its acquisition-date fair value as temporary equity, due to the redemption option existing outside the control of the Company. The Company will accrete the changes in the redemption value quarterly over the period from the acquisition date to the earliest redemption date using the effective interest method. The Company will record the accretion after the allocation of net income and distributions of cash flow to the noncontrolling interest account balance.

The following table reflects the activity of the noncontrolling interest—redeemable interest in property partnership in the Company's Fountain Square consolidated joint venture for the years ended December 31, 2014, 2013 and 2012 (in thousands):



Balance at December 31, 2011	$	—
Acquisition-date fair value of redeemable interest	98,787
Net loss	(719		)
Distributions	(3,032		)
Adjustment to reflect redeemable interest at redemption value	2,522
Balance at December 31, 2012	97,558
Net loss	(1,839		)
Distributions	(4,585		)
Adjustment to reflect redeemable interest at redemption value	8,475
Balance at December 31, 2013	99,609
Net loss	(603		)
Distributions	(6,000		)
Adjustment to reflect redeemable interest at redemption value	11,686			(1)
Balance at December 31, 2014	$	104,692

_______________

(1) Includes an out-of-period adjustment totaling approximately $1.9 million (See Note 2).

Noncontrolling Interest—Redeemable Preferred Units

On March 11, 2014, the Company’s general partner notified the holders of the outstanding Series Two Preferred Units that it had elected to redeem all of such Series Two Preferred Units on May 12, 2014. As a result of the Company's election to redeem the units, as of May 12, 2014, the holders of all remaining 666,116 Series Two Preferred Units of partnership interest in the Company converted such units into an aggregate of 874,168 OP Units. The Series Two Preferred Units bore a preferred distribution equal to the greater of (1) the distribution which would have been paid in respect of the Series Two Preferred Unit had such Series Two Preferred Unit been converted into an OP Unit (including both regular and special distributions) or (2) 6.00% per annum on a liquidation preference of $50.00 per unit, and were convertible into OP Units at a rate of $38.10 per Preferred Unit (1.312336 OP Units for each Preferred Unit). In connection with the conversion of the remaining Series Two Preferred Units in May 2014, the Company paid accrued and unpaid distributions which included the special cash distribution on an as-converted basis. On February 18, 2014, the Company paid a distribution on its outstanding Series Two Preferred Units of $0.85302 per unit. Due to the holders' redemption option existing outside the control of the Company’s general partner, the Series Two Preferred Units were presented outside of permanent equity in the Company's Consolidated Balance Sheets.

During the year ended December 31, 2013, 329,881 Series Two Preferred Units of the Company were converted by the holders into 432,914 OP Units. In addition, the Company paid the accrued preferred distributions due to the holders of Preferred Units that were converted.

The Preferred Units at December 31, 2014 also included 12,667 Series Four Preferred Units, which bear a preferred distribution equal to 2.00% per annum on a liquidation preference of $50.00 per unit and are not convertible into OP Units. The holders of Series Four Preferred Units have the right, at certain times and subject to certain conditions set forth in the Certificate of Designations establishing the rights, limitations and preferences of the Series Four Preferred Units, to require the Company to redeem all their units for cash at the redemption price of $50.00 per unit. The Company also has the right, at certain times and subject to certain conditions, to redeem all of the Series Four Preferred Units for cash at the redemption price of $50.00 per unit. In order to secure the performance of certain post-issuance obligations by the holders, all of such outstanding Series Four Preferred Units were subject to forfeiture pursuant to the terms of a pledge agreement and not eligible for redemption until and unless such security interest is released. The Company's first right to redeem the Series Four Preferred Units was a 30-day period beginning on August 29, 2013. On August 29, 2013, the Company redeemed approximately 861,400 Series Four Preferred Units for cash at the redemption price of $50.00 per unit plus accrued and unpaid distributions through the redemption date. On May 19, 2014, the Company released to the holders 319,687 Series Four Preferred Units that were previously subject to the security interest. On July 3, 2014, the Company redeemed such units for cash totaling approximately $16.0 million, plus accrued and unpaid distributions. On October 16, 2014, the Company released to the holders 27,773 Series Four Preferred Units that were previously subject to the security interest under the pledge agreement. On November 5, 2014, the Company redeemed such units for cash totaling approximately $1.4 million. An aggregate of 12,667 Series Four Preferred Units remain outstanding and subject to the security interest under the pledge agreement. Due to the holders' redemption option existing outside the control of the Company, the Series Four Preferred Units are not included in Partners' Capital in the Company's Consolidated Balance Sheets.

On February 18, 2014, the Company paid a distribution on its outstanding Series Four Preferred Units of $0.25 per unit. On May 15, 2014, the Company paid a distribution on its outstanding Series Four Preferred Units of $0.25 per unit. On August 15, 2014, the Company paid a distribution on its outstanding Series Four Preferred Units of $0.25 per unit. On November 17, 2014, the Company paid a distribution on its outstanding Series Four Preferred Units of $0.25 per unit.

The following table reflects the activity of the noncontrolling interests—redeemable preferred units for the years ended December 31, 2014, 2013 and 2012 (in thousands):



Balance at December 31, 2011	$	145,484
Issuance of redeemable preferred units (Series Four Preferred Units)	79,405
Net income	3,497
Distributions	(3,497		)
Redemption of redeemable preferred units (Series Four Preferred Units)	(18,329		)
Reallocation of partnership interest (1)	(7,182		)
Balance at December 31, 2012	199,378
Net income	6,046
Distributions	(6,046		)
Redemption of redeemable preferred units (Series Four Preferred Units)	(43,070		)
Reallocation of partnership interest (1)	(50,562		)
Balance at December 31, 2013	105,746
Net income	1,023
Distributions	(1,023		)
Redemption of redeemable preferred units (Series Four Preferred Units)	(17,373		)
Reallocation of partnership interest (1)	(87,740		)
Balance at December 31, 2014	$	633

_____________


(1)	Includes the conversion of 666,116, 329,881 and 117,047 Series Two Preferred Units into 874,168, 432,914 and 153,605 OP Units during the years ended December 31, 2014, 2013 and 2012, respectively.

Noncontrolling Interest—Common Units

During the years ended December 31, 2014 and 2013, 80,246 and 929,441 OP Units, respectively, were presented by the holders for redemption (including 3,734 and 432,914 OP Units, respectively, issued upon conversion of Series Two Preferred Units and 67,857 and 24,028 OP Units, respectively, issued upon conversion of LTIP Units) and were redeemed by Boston Properties, Inc. in exchange for an equal number of shares of Common Stock.

At December 31, 2014, the Company had outstanding 394,590 2012 OPP Units, 313,936 2013 MYLTIP Units and 482,032 2014 MYLTIP Unit (See Note 17). Prior to the measurement date (February 6, 2015 for 2012 OPP Units (See Note 20), February 4, 2016 for 2013 MYLTIP Units and February 3, 2017 for 2014 MYLTIP Units), holders of OPP Units and MYLTIP Units will be entitled to receive per unit distributions equal to one-tenth (10%) of the regular quarterly distributions payable on an OP Unit, but will not be entitled to receive any special distributions. After the measurement date, the number of OPP Units and MYLTIP Units, both vested and unvested, that OPP and MYLTIP award recipients have earned, if any, based on the establishment of a performance pool, will be entitled to receive distributions in an amount per unit equal to distributions, both regular and special, payable on an OP Unit.

On January 31, 2014, the measurement period for the Company’s 2011 OPP Unit awards expired and Boston Properties, Inc.'s TRS was not sufficient for employees to earn and therefore become eligible to vest in any of the 2011 OPP Unit awards. As a result, the Company accelerated the then remaining unrecognized compensation expense totaling approximately $1.2 million during the year ended December 31, 2014. Accordingly, all 2011 OPP Unit awards were automatically forfeited.

On January 29, 2014, the Company paid a distribution on the OP Units and LTIP Units in the amount of $2.25 per unit, a regular quarterly cash distribution on the OP Units and LTIP Units in the amount of $0.65 per unit, and a regular quarterly distribution on the 2011 OPP Units, 2012 OPP Units and 2013 MYLTIP Units in the amount of $0.065 per unit, to holders of record as of the close of business on. On April 30, 2014, the Company paid a distribution on the OP Units and LTIP Units in the amount of $0.65 per unit, and a distribution on the 2012 OPP Units, 2013 MYLTIP Units and 2014 MYLTIP Units in the amount of $0.065 per unit, to holders of record as of the close of business on March 31, 2014. On July 31, 2014, the Company paid a distribution on the OP Units and LTIP Units in the amount of $0.65 per unit, and a distribution on the 2012 OPP Units, 2013 MYLTIP Units and 2014 MYLTIP Units in the amount of $0.065 per unit, to holders of record as of the close of business on June 30, 2014. On October 31, 2014, the Company paid a distribution on the OP Units and LTIP Units in the amount of $0.65 per unit and a distribution on the 2012 OPP Units, 2013 MYLTIP Units and 2014 MYLTIP Units in the amount of $0.065 per unit, to holders of record as of the close of business on September 30, 2014. On December 8, 2014, Boston Properties, Inc., as general partner of the Company, declared a special cash distribution on the OP Units and LTIP Units in the amount of $4.50 per unit payable on January 28, 2015 to holders of record as of the close of business on December 31, 2014. The special cash distribution was in addition to the regular quarterly distribution on the OP Units and LTIP Units of $0.65 per unit and the distribution on the 2012 OPP Units, 2013 MYLTIP Units and 2014 MYLTIP Units in the amount of $0.065 per unit, in each case payable on January 28, 2015 to holders of record as of the close of business on December 31, 2014. Holders of the 2012 OPP Units, 2013 MYLTIP Units and 2014 MYLTIP Units are not entitled to receive any special distributions.

The following table reflects the activity of the noncontrolling interests—redeemable common units for the years ended December 31, 2014, 2013 and 2012 (in thousands):



Balance at December 31, 2011	$	1,809,119
Contributions	24,588
Net income	35,200
Distributions	(41,434		)
Conversion of redeemable partnership units	(34,621		)
Unearned compensation	(883		)
Accumulated other comprehensive loss	273
Adjustment to reflect redeemable partnership units at redemption value	44,280
Balance at December 31, 2012	1,836,522
Contributions	26,398
Net income	84,236
Distributions	(83,448		)
Conversion of redeemable partnership units	(30,291		)
Unearned compensation	1,472
Accumulated other comprehensive loss	252
Adjustment to reflect redeemable partnership units at redemption value	(124,923		)
Balance at December 31, 2013	1,710,218
Contributions	23,990
Net income	50,862
Distributions	(126,948		)
Conversion of redeemable partnership units	(2,700		)
Unearned compensation	(2,813		)
Accumulated other comprehensive loss	256
Adjustment to reflect redeemable partnership units at redemption value	657,181
Balance at December 31, 2014	$	2,310,046

Pursuant to the Company’s Partnership Agreement, certain limited partners in the Company have the right to redeem all or any portion of their interest for cash from the Company. However, Boston Properties, Inc. may elect to acquire the limited partner’s interest by issuing its Common Stock in exchange for the interest. The amount of cash to be paid to the limited partner if the redemption right is exercised and Boston Properties, Inc. does not elect to issue its Common Stock is based on the trading price of Boston Properties, Inc.’s common stock at that time. Due to the redemption option existing outside the control of the Company, such limited partners’ units are not included in Partners’ Capital. The value of the OP Units not owned by Boston Properties, Inc. (including LTIP Units assuming that all conditions had been met for the conversion thereof), assuming all of such units had been redeemed at December 31, 2014 was approximately $2.3 billion based on the closing price of Boston Properties, Inc.’s common stock of $128.69 per share on December 31, 2014.

Noncontrolling Interests—Property Partnerships

The noncontrolling interests in property partnerships consist of the outside equity interests in ventures that are consolidated with the financial results of the Company because the Company exercises control over the entities that own the properties. The equity interests in these ventures that are not owned by the Company, totaling approximately $1.6 billion at December 31, 2014 and approximately $726.1 million at December 31, 2013, are included in Noncontrolling Interests—Property Partnerships on the accompanying Consolidated Balance Sheets.

On February 7, 2013, the partner in the Company's Salesforce Tower joint venture issued a notice that it was electing under the joint venture agreement to reduce its nominal ownership interest in the venture from 50% to 5%. On February 26, 2013, the Company issued a notice to the partner electing to proceed with the venture on that basis. As a result, the Company has a 95% nominal interest in and is consolidating the joint venture. Under the joint venture agreement, if certain return thresholds are achieved the partner will be entitled to an additional promoted interest. In addition, if the Company elects to fund the construction of Salesforce Tower without a construction loan (or a construction loan of less than 50% of project costs), then the partner has the option to require the Company to fund up to 2.5% of the total project costs (i.e., of 50% of the partner's 5% interest in the venture) in the form of a loan to the partner. This loan would bear interest at the then prevailing market construction loan interest rates. Also, under the agreement, (1) the partner has the right to cause the Company to purchase the partner's interest after the defined stabilization date and (2) the Company has the right to acquire the partner's interest on the third anniversary of the stabilization date, in each case at an agreed upon purchase price or appraised value.

On May 31, 2013, the Company's two joint venture partners in 767 Venture, LLC (the entity that owns 767 Fifth Avenue(the General Motors Building) in New York City) transferred all of their interests in the joint venture to third parties. In connection with the transfer, the Company and its new joint venture partners modified the Company's relative decision making authority and consent rights with respect to the joint venture's assets and operations. These changes resulted in the Company having sufficient financial and operating control over 767 Venture, LLC such that the Company now accounts for the assets, liabilities and operations of 767 Venture, LLC on a consolidated basis in its financial statements instead of under the equity method of accounting. Upon consolidation, the Company recognized the new joint venture partners' aggregate 40% equity interest at its aggregate fair value of approximately $480.9 million within Noncontrolling Interests—Property Partnerships on the accompanying Consolidated Balance Sheets.

On October 9, 2013, the Company completed the sale of a 45% ownership interest in its Times Square Tower property for a gross sale price of $684.0 million in cash. Net cash proceeds totaled approximately $673.1 million, after the payment of transaction costs. In connection with the sale, the Company formed a limited liability company with the buyer and will provide customary property management and leasing services to the joint venture. Times Square Tower is an approximately 1,246,000 net rentable square foot Class A office tower located in New York City. The transaction did not qualify as a sale of real estate for financial reporting purposes because the Company effectively continues to control the property and thus will continue to account for the entity on a consolidated basis in its financial statements. The Company has accounted for the transaction as an equity transaction and has recognized noncontrolling interest in its consolidated balance sheets totaling approximately $243.5 million, which is equal to 45% of the carrying value of the total equity of the property immediately prior to the transaction. The difference between the net cash proceeds received and the noncontrolling interest recognized, which was approximately $429.6 million, has not been reflected as a gain on sale of real estate in the Company’s consolidated statements of operations and has instead been reflected as an increase to Partners' Capital in the Company’s Consolidated Balance Sheets.

The following table reflects the activity of the noncontrolling interests—property partnerships for the years ended December 31, 2014, 2013 and 2012 (in thousands):



Balance at December 31, 2011	$	(1,063	)
Net income	1,989
Distributions	(2,890		)
Balance at December 31, 2012	(1,964		)
Fair value of capital recorded upon consolidation	480,861
Capital contributions	257,564
Net loss	(5,290		)
Distributions	(5,039		)
Balance at December 31, 2013	726,132
Capital contributions	887,975
Net income	19,478
Distributions	(31,118		)
Balance at December 31, 2014	$	1,602,467

Partners' Capital

12 Months Ended

Dec. 31, 2014

Partners' Capital [Abstract]

Partners' Capital

Partners’ Capital

The following table presents the changes in the issued and outstanding partners’ capital units since January 1, 2012:



	General Partner Units	Limited Partner Units	Total Partners’ Capital Units
Outstanding at December 31, 2011	1,662,715	146,444,896	148,107,611
Units issued to Boston Properties, Inc. related to Common Stock issued under the Employee Stock Purchase Plan	57	7,349	7,406
Units issued to Boston Properties, Inc. related to Common Stock issued under the Stock Option and Incentive Plan, net	216	27,816	28,032
Units issued to Boston Properties, Inc. related to Common Stock issued in exchange for OP Units	8,541	1,102,119	1,110,660
Units issued to Boston Properties, Inc. related to Common Stock issued under the “at the market” (ATM) stock offering programs	18,051	2,329,449	2,347,500
Outstanding at December 31, 2012	1,689,580	149,911,629	151,601,209
Units issued to Boston Properties, Inc. related to Common Stock issued under the Employee Stock Purchase Plan	50	6,392	6,442
Units issued to Boston Properties, Inc. related to Common Stock issued under the Stock Option and Incentive Plan, net	207	26,686	26,893
Units issued to Boston Properties, Inc. related to Common Stock issued in exchange for OP Units	7,158	922,283	929,441
Units issued to Boston Properties, Inc. related to Common Stock issued in connection with the exchange of Exchangeable Senior Notes	3,227	415,889	419,116
Outstanding at December 31, 2013	1,700,222	151,282,879	152,983,101
Units issued to Boston Properties, Inc. related to Common Stock issued under the Employee Stock Purchase Plan	555	6,409	6,964
Units issued to Boston Properties, Inc. related to Common Stock issued under the Stock Option and Incentive Plan, net	3,476	40,158	43,634
Units issued to Boston Properties, Inc. related to Common Stock issued in exchange for OP Units	6,391	73,855	80,246
Outstanding at December 31, 2014	1,710,644	151,403,301	153,113,945

As of December 31, 2014, Boston Properties, Inc. owned 1,710,644 general partnership units and 151,403,301 limited partnership units.

On January 29, 2014, the Company paid a special cash distribution and regular quarterly distribution aggregating $2.90 per OP Unit to unitholders of record as of the close of business on December 31, 2013. On April 30, 2014, the Company paid a distribution of $0.65 per OP Unit to unitholders of record as of the close of business on March 31, 2014. On July 31, 2014, the Company paid a distribution of $0.65 per OP Unit to unitholders of record as of the close of business on June 30, 2014. On October 31, 2014, the Company paid a distribution of $0.65 per OP Unit to unitholders of record as of the close of business on September 30, 2014.

On December 8, 2014, Boston Properties, Inc.'s Board of Directors declared a special cash distribution of $4.50 per OP Unit payable on January 28, 2015 to unitholders of record as of the close of business on December 31, 2014. The special cash distribution was in addition to the regular quarterly distribution of $0.65 per OP Unit declared by Boston Properties, Inc.'s Board of Directors and payable on January 28, 2015 to unitholders of record as of the close of business on December 31, 2014

As of December 31, 2014, Boston Properties, Inc. had 80,000 shares (8,000,000 depositary shares each representing 1/100th of a share) outstanding of its 5.25% Series B Cumulative Redeemable Preferred Stock with a liquidation preference of $2,500.00 per share ($25.00 per depositary share). Boston Properties, Inc. contributed the net proceeds of the offering to the Company in exchange for 80,000 Series B Preferred Units having terms and preferences generally mirroring those of the Series B Preferred Stock. Boston Properties, Inc. pays cumulative cash dividends on the Series B Preferred Stock at a rate of 5.25% per annum of the $2,500.00 liquidation preference per share. Boston Properties, Inc. may not redeem the Series B Preferred Stock prior to March 27, 2018, except in certain circumstances relating to the preservation of Boston Properties, Inc.'s REIT status. On or after March 27, 2018, Boston Properties, Inc., at its option, may redeem the Series B Preferred Stock for a cash redemption price of $2,500.00 per share ($25.00 per depositary share), plus all accrued and unpaid dividends. The Series B Preferred Stock is not redeemable by the holders, has no maturity date and is not convertible into any other security of Boston Properties, Inc., the Company or its affiliates.

On February 18, 2014, the Company paid a distribution on its outstanding Series B Preferred Units of $32.8125 per unit. On May 15, 2014, the Company paid a distribution on its outstanding Series B Preferred Units of $32.8125 per unit. On August 15, 2014, the Company paid a distribution on its outstanding Series B Preferred Units of $32.8125 per unit. On November 17, 2014, the Company paid a distribution on its outstanding Series B Preferred Units of $32.8125 per unit. On December 8, 2014, Boston Properties, Inc.'s Board of Directors declared a distribution of $32.8125 per unit of Series B Preferred Units payable on February 17, 2015 to shareholders of record as of the close of business on February 5, 2015.

The following table reflects the activity of the Series B Preferred Units for the for the year ended December 31, 2014 and 2013 (in thousands), which activity is included within the Company's Consolidated Statements of Partners' Capital:



Balance at December 31, 2012	$	—
Issuance of Series B Preferred Units	193,623
Net income	8,057
Distributions	(8,057		)
Balance at December 31, 2013	193,623
Net income	10,500
Distributions	(10,500		)
Balance at December 31, 2014	$	193,623

On June 3, 2014, Boston Properties, Inc. established a new “at the market” (ATM) stock offering program through which it may sell from time to time up to an aggregate of $600.0 million of its common stock through sales agents over a three-year period. This program replaced Boston Properties, Inc.'s prior $600.0 million ATM stock offering program that expired on June 2, 2014 with approximately $305.3 million of unsold common stock. Boston Properties, Inc. intends to use the net proceeds from any offering for general business purposes, which may include investment opportunities and debt reduction. Boston Properties, Inc. contributes the net proceeds from any such sales to the Company in exchange for a number of OP Units equal to the number of shares issued. No shares of common stock have been issued under this new ATM stock offering program.

During the year ended December 31, 2014, the Company issued 21,459 any OP Units to Boston Properties, Inc. in connection with the exercise by certain employees of options to purchase Common Stock of Boston Properties, Inc. During the year ended December 31, 2013, the Company did not issue any OP Units to Boston Properties, Inc. in connection with the exercise by employees of options to purchase Common Stock of Boston Properties, Inc.

During the year ended December 31, 2014 and 2013, Boston Properties, Inc. acquired 80,246 and 929,441 OP Units, respectively, in connection with the redemption of an equal number of redeemable OP Units from third parties.

Future Minimum Rents [Text Block]

The entire disclosure for shareholders' equity comprised of portions attributable to the parent entity and noncontrolling interest, including other comprehensive income. Includes, but is not limited to, balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings, accumulated balance for each classification of other comprehensive income and amount of comprehensive income.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(d),(e))
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Reference 3: http://www.xbrl.org/2003/role/presentationRef
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Reference 15: http://www.xbrl.org/2003/role/presentationRef
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Reference 16: http://www.xbrl.org/2003/role/presentationRef
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Reference 17: http://www.xbrl.org/2003/role/presentationRef
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Reference 19: http://www.xbrl.org/2003/role/presentationRef
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+ Details

Future Minimum Rents

12 Months Ended

Dec. 31, 2014

Future Minimum Rents [Abstract]

13. Future Minimum Rents

The properties are leased to tenants under net operating leases with initial term expiration dates ranging from 2015 to 2046. The future contractual minimum lease payments to be received (excluding operating expense reimbursements) by the Company as of December 31, 2014, under non-cancelable operating leases which expire on various dates through 2046, are as follows:



Years Ending December 31,	(in thousands)
2015	$	1,796,517
2016	1,788,978
2017	1,677,005
2018	1,568,200
2019	1,483,188
Thereafter	9,097,899

No single tenant represented more than 10.0% of the Company’s total rental revenue for the years ended December 31, 2014, 2013 and 2012.

Segment Information

12 Months Ended

Dec. 31, 2014

Segment Reporting [Abstract]

Segment Information

The Company’s segments are based on the Company’s method of internal reporting which classifies its operations by both geographic area and property type. The Company’s segments by geographic area are Boston, New York, San Francisco and Washington, DC. Segments by property type include: Class A Office, Office/Technical, Residential and Hotel.

Asset information by segment is not reported because the Company does not use this measure to assess performance. Therefore, depreciation and amortization expense is not allocated among segments. Interest and other income, development and management services income, general and administrative expenses, transaction costs, impairment loss, interest expense, depreciation and amortization expense, gains from investments in securities, gains (losses) from early extinguishments of debt, income from unconsolidated joint ventures, gains on consolidation of joint ventures, discontinued operations, gains on sales of real estate and noncontrolling interests are not included in Net Operating Income as internal reporting addresses these items on a corporate level.

Net Operating Income is not a measure of operating results or cash flows from operating activities as measured by accounting principles generally accepted in the United States of America, and it is not indicative of cash available to fund cash needs and should not be considered an alternative to cash flows as a measure of liquidity. All companies may not calculate Net Operating Income in the same manner. The Company considers Net Operating Income to be an appropriate supplemental measure to net income because it helps both investors and management to understand the core operations of the Company’s properties. The Company’s management also uses Net Operating Income to evaluate regional property level performance and to make decisions about resource allocations. Further, the Company believes Net Operating Income is useful to investors as a

performance measure because, when compared across periods, Net Operating Income reflects the impact on operations from trends in occupancy rates, rental rates, operating costs and acquisition and development activity on an unleveraged basis, providing perspectives not immediately apparent from net income attributable to Boston Properties Limited Partnership.

On May 31, 2013, the Company's two joint venture partners in 767 Venture, LLC (the entity that owns 767 Fifth Avenue (the General Motors Building) located in New York City) transferred all of their interests in the joint venture to third parties (See Note 3). Effective as of May 31, 2013, the Company accounts for the assets, liabilities and operations of 767 Venture, LLC on a consolidated basis in its financial statements instead of under the equity method of accounting. Upon consolidation, the operations for this building are included in the New York region.

Information by geographic area and property type (dollars in thousands):

For the year ended December 31, 2014:



	Boston			New York			San Francisco			Washington, DC			Total
Rental Revenue:
Class A Office	$	692,116		$	928,692		$	237,381		$	381,930		$	2,240,119
Office/Technical	23,801			—			23,840			14,344			61,985
Residential	4,528			—			—			21,665			26,193
Hotel	43,385			—			—			—			43,385
Total	763,830			928,692			261,221			417,939			2,371,682
% of Grand Totals	32.21		%	39.16		%	11.01		%	17.62		%	100.00		%
Rental Expenses:
Class A Office	270,947			315,330			85,178			131,447			802,902
Office/Technical	7,173			—			4,955			4,338			16,466
Residential	1,957			—			—			13,965			15,922
Hotel	29,236			—			—			—			29,236
Total	309,313			315,330			90,133			149,750			864,526
% of Grand Totals	35.78		%	36.47		%	10.43		%	17.32		%	100.00		%
Net operating income	$	454,517		$	613,362		$	171,088		$	268,189		$	1,507,156
% of Grand Totals	30.16		%	40.70		%	11.35		%	17.79		%	100.00		%

For the year ended December 31, 2013:



	Boston			New York			San Francisco			Washington, DC			Total
Rental Revenue:
Class A Office	$	665,991		$	725,566		$	214,755		$	381,359		$	1,987,671
Office/Technical	22,617			—			17,259			15,649			55,525
Residential	4,395			—			—			17,923			22,318
Hotel	40,330			—			—			—			40,330
Total	733,333			725,566			232,014			414,931			2,105,844
% of Grand Totals	34.82		%	34.46		%	11.02		%	19.70		%	100.00		%
Rental Expenses:
Class A Office	259,997			251,640			77,905			126,507			716,049
Office/Technical	6,879			—			3,708			4,190			14,777
Residential	1,823			—			—			10,307			12,130
Hotel	28,447			—			—			—			28,447
Total	297,146			251,640			81,613			141,004			771,403
% of Grand Totals	38.52		%	32.62		%	10.58		%	18.28		%	100.00		%
Net operating income	$	436,187		$	473,926		$	150,401		$	273,927		$	1,334,441
% of Grand Totals	32.69		%	35.51		%	11.27		%	20.53		%	100.00		%

For the year ended December 31, 2012:



	Boston			New York			San Francisco			Washington, DC			Total
Rental Revenue:
Class A Office	$	617,652		$	543,194		$	208,177		$	346,402		$	1,715,425
Office/Technical	22,460			—			494			16,264			39,218
Residential	3,936			—			—			16,632			20,568
Hotel	37,915			—			—			—			37,915
Total	681,963			543,194			208,671			379,298			1,813,126
% of Grand Totals	37.61		%	29.96		%	11.51		%	20.92		%	100.00		%
Rental Expenses:
Class A Office	242,904			187,987			75,542			111,049			617,482
Office/Technical	6,499			—			149			3,966			10,614
Residential	1,675			—			—			9,317			10,992
Hotel	28,120			—			—			—			28,120
Total	279,198			187,987			75,691			124,332			667,208
% of Grand Totals	41.85		%	28.18		%	11.34		%	18.63		%	100.00		%
Net operating income	$	402,765		$	355,207		$	132,980		$	254,966		$	1,145,918
% of Grand Totals	35.15		%	31.00		%	11.60		%	22.25		%	100.00		%

The following is a reconciliation of Net Operating Income to net income attributable to Boston Properties Limited Partnership (in thousands):



	Year ended December 31,
		2014			2013		2012
Net Operating Income		$	1,507,156		$	1,334,441	$	1,145,918
Add:
Development and management services income		25,316			29,695		34,060
Income from unconsolidated joint ventures		12,769			75,074		49,078
Gains on consolidation of joint ventures		—			385,991		—
Interest and other income		8,765			8,310		10,091
Gains from investments in securities		1,038			2,911		1,389
Gains (losses) from early extinguishments of debt		(10,633		)	122		(4,453		)
Income from discontinued operations		—			8,022		9,806
Gains on sales of real estate from discontinued operations		—			115,459		38,445
Gain on forgiveness of debt from discontinued operations		—			20,736		—
Gains on sales of real estate		174,686			—		—
Less:
General and administrative expense		98,937			115,329		90,129
Transaction costs		3,140			1,744		3,653
Depreciation and amortization expense		620,064			552,589		437,692
Interest expense		455,743			446,880		410,970
Impairment loss		—			4,401		—
Impairment loss from discontinued operations		—			2,852		—
Noncontrolling interest in property partnerships		30,561			1,347		3,792
Noncontrolling interest—redeemable preferred units		1,023			6,046		3,497
Preferred distributions		10,500			8,057		—
Net income attributable to Boston Properties Limited Partnership common unitholders		$	499,129		$	841,516	$	334,601

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

The entire disclosure for reporting segments including data and tables. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10 percent or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments.

+ References

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+ Details

Earnings Per Common Unit

12 Months Ended

Dec. 31, 2014

Earnings Per Share [Abstract]

Earnings Per Common Unit

The following table provides a reconciliation of both the net income attributable to Boston Properties Limited Partnership and the number of common units used in the computation of basic earnings per common unit, which is calculated by dividing net income attributable to Boston Properties Limited Partnership by the weighted-average number of common units outstanding during the period. The terms of the Series Two Preferred Units enable the holders to obtain OP Units of the Company and as a result these are considered participating securities. Unvested share-based payment awards that contain non-forfeitable rights to dividends or dividend equivalents (whether paid or unpaid) are also participating securities. As such, unvested restricted common stock of Boston Properties, Inc. and the Company’s LTIP Units, OPP Units and MYLTIP Units are considered participating securities. Participating securities are included in the computation of basic earnings per common unit using the two-class method. Participating securities are included in the computation of diluted earnings per common unit using the if-converted method if the impact is dilutive. Because the OPP Units and MYLTIP Units require Boston Properties, Inc. to outperform absolute and relative return thresholds, unless such thresholds have been met by the end of the applicable reporting period, the Company excludes such units from the diluted earnings per common unit calculation. Other potentially dilutive common units and the related impact on earnings are considered when calculating diluted earnings per common unit. Included in the number of units (the denominator) below are approximately 17,364,000, 16,925,000 and 17,649,000 redeemable common units for the years ended December 31, 2014, 2013 and 2012, respectively.



	For the Year Ended December 31, 2014
	Income (Numerator)		Units (Denominator)	Per Unit Amount
	(in thousands, except for per unit amounts)
Basic Earnings:
Net income attributable to Boston Properties Limited Partnership common unitholders	$	499,129	170,453	$	2.93
Effect of Dilutive Securities:
Stock Based Compensation	—		219	(0.01		)
Diluted Earnings:
Net income attributable to Boston Properties Limited Partnership common unitholders	$	499,129	170,672	$	2.92



	For the Year Ended December 31, 2013
	Income (Numerator)			Units (Denominator)	Per Unit Amount
	(in thousands, except for per unit amounts)
Basic Earnings:
Income from continuing operations attributable to Boston Properties Limited Partnership	$	700,151		169,126	$	4.14
Discontinued operations attributable to Boston Properties Limited Partnership	141,365			—	0.84
Allocation of undistributed earnings to participating securities	(178		)	—	(0.01		)
Net income attributable to Boston Properties Limited Partnership common unitholders	$	841,338		169,126	$	4.97
Effect of Dilutive Securities:
Stock Based Compensation and Exchangeable Senior Notes	—			320	—
Diluted Earnings:
Net income attributable to Boston Properties Limited Partnership common unitholders	$	841,338		169,446	$	4.97

	For the Year Ended December 31, 2012
	Income (Numerator)			Units (Denominator)	Per Unit Amount
	(in thousands, except for per unit amounts)
Basic Earnings:
Income from continuing operations attributable to Boston Properties Limited Partnership	$	286,350		167,769	$	1.70
Discontinued operations attributable to Boston Properties Limited Partnership	48,251			—	0.29
Net income attributable to Boston Properties Limited Partnership common unitholders	$	334,601		167,769	$	1.99
Effect of Dilutive Securities:
Stock Based Compensation and Exchangeable Senior Notes	—			591	—
Diluted Earnings:
Net income attributable to Boston Properties Limited Partnership common unitholders	$	334,601		168,360	$	1.99

Employee Benefit Plans	12 Months Ended
Employee Benefit Plans	Dec. 31, 2014
Employee Benefit Plans [Abstract]
Compensation and Employee Benefit Plans [Text Block]	16. Employee Benefit Plans Effective January 1, 1985, the predecessor of the Company adopted a 401(k) Savings Plan (the “Plan”) for its employees. Under the Plan, as amended, employees, as defined, are eligible to participate in the Plan after they have completed three months of service. Upon formation, the Company adopted the Plan and the terms of the Plan. Under the Plan, as amended, the Company’s matching contribution equals 200% of the first 3% of participant’s eligible earnings contributed (utilizing earnings that are not in excess of an amount established by the IRS ($260,000, $255,000 and $250,000 in 2014, 2013 and 2012, respectively), indexed for inflation) with no vesting requirement. The Company’s aggregate matching contribution for the years ended December 31, 2014, 2013 and 2012 was $3.5 million, $3.4 million and $3.2 million, respectively. The Plan also provides for supplemental retirement contributions to certain employees who had at least ten years of service on January 1, 2001, and who were 40 years of age or older as of January 1, 2001. The maximum supplemental retirement contribution will not exceed the annual limit on contributions established by the IRS. The Company will record an annual supplemental retirement credit for the benefit of each participant. The Company’s supplemental retirement contribution and credit for the years ended December 31, 2014, 2013 and 2012 was $52,000, $60,000 and $78,000, respectively. The Company also maintains a deferred compensation plan that is designed to allow officers of the Company to defer a portion of their current income on a pre-tax basis and receive a tax-deferred return on these deferrals. The Company’s obligation under the plan is that of an unsecured promise to pay the deferred compensation to the plan participants in the future. At December 31, 2014 and 2013, the Company had maintained approximately $19.5 million and $16.6 million, respectively, in a separate account, which is not restricted as to its use. The Company’s liability under the plan is equal to the total amount of compensation deferred by the plan participants and earnings on the deferred compensation pursuant to investments elected by the plan participants. The Company’s liability as of December 31, 2014 and 2013 was $19.5 million and $16.6 million, respectively, which are included in the accompanying Consolidated Balance Sheets.

Stock Option and Incentive Plan

12 Months Ended

Dec. 31, 2014

Stock Option and Incentive Plan

At Boston Properties, Inc.'s 2012 annual meeting of stockholders held on May 15, 2012, the stockholders of Boston Properties, Inc. approved the Boston Properties, Inc. 2012 Stock Option and Incentive Plan (the “2012 Plan”). The 2012 Plan replaced the 1997 Stock Option and Incentive Plan (the “1997 Plan”). The material terms of the 2012 Plan include, among other things: (1) the maximum number of shares of common stock reserved and available for issuance under the 2012 Plan is the sum of (i) 13,000,000 newly authorized shares, plus (ii) the number of shares available for grant under the 1997 Stock Plan immediately prior to the effective date of the 2012 Plan, plus (iii) any shares underlying grants under the 1997 Plan that are forfeited, canceled or terminated (other than by exercise) in the future; (2) “full-value” awards (i.e., awards other than stock options) are multiplied by a 2.32 conversion ratio to calculate the number of shares available under the 2012 Plan that are used for each full-value award, as opposed to a 1.0 conversion ratio for each stock option awarded under the 2012 Plan; (3) shares tendered or held back for taxes will not be added back to the reserved pool under the 2012 Plan; (4) stock options may not be re-priced without stockholder approval; and (5) the term of the 2012 Plan is for ten years from the date of stockholder approval.

On January 27, 2014, Boston Properties, Inc.'s Compensation Committee approved the 2014 MYLTIP awards under Boston Properties, Inc.'s 2012 Plan to certain officers and employees of Boston Properties, Inc. The 2014 MYLTIP awards utilize TRS over a three-year measurement period, on an annualized, compounded basis, as the performance metric. Earned awards, if any, will be based on Boston Properties, Inc.'s TRS relative to (i) the Cohen & Steers Realty Majors Portfolio Index (50% weight) and (ii) the NAREIT Office Index adjusted to exclude Boston Properties, Inc. (50% weight). Earned awards will range from $0 to a maximum of approximately $40.2 million depending on the Boston Properties, Inc.'s TRS relative to the two indices, with four tiers (threshold: approximately $6.7 million; target: approximately $13.4 million; high: approximately $26.8 million; and exceptional: approximately $40.2 million) and linear interpolation between tiers. Earned awards measured on the basis of relative TRS performance are subject to an absolute TRS component in the form of relatively simple modifiers that (A) reduce the level of earned awards in the event Boston Properties, Inc.'s annualized TRS is less than 0% and (B) cause some awards to be earned in the event Boston Properties, Inc.'s annualized TRS is more than 12% even though on a relative basis alone Boston Properties, Inc.'s TRS would not result in any earned awards.

Earned awards (if any) will vest 50% on February 3, 2017 and 50% on February 3, 2018, based on continued employment. Vesting will be accelerated in the event of a change in control, termination of employment by Boston Properties, Inc. without cause, termination of employment by the award recipient for good reason, death, disability or retirement. If there is a change of control prior to February 3, 2017, earned awards will be calculated as of the date of the change of control based upon performance through such date as measured against performance hurdles (without proration). The 2014 MYLTIP awards are in the form of LTIP Units issued on the grant date which (i) are subject to forfeiture to the extent awards are not earned and (ii) prior to the performance measurement date are only entitled to one-tenth (10%) of the regular quarterly distributions payable on common partnership units.

Under the FASB's ASC 718 “Compensation-Stock Compensation” the 2014 MYLTIP awards have an aggregate value of approximately $12.7 million, which amount will generally be amortized into earnings over the four-year plan period under the graded vesting method.

On March 11, 2013, Boston Properties, Inc. announced that Owen D. Thomas would succeed Mortimer B. Zuckerman as Boston Properties, Inc.'s Chief Executive Officer, effective April 2, 2013. On April 2, 2013, the Company issued 24,231 LTIP units, 38,926 2013 MYLTIP Units and 50,847 non-qualified stock options under the 2012 Plan to Mr. Thomas, pursuant to his employment agreement. Mr. Zuckerman continued to serve as Executive Chairman for a transition period which was completed effective as of the close of business on December 31, 2014 and thereafter is continuing to serve as the non-executive Chairman of the Board of Boston Properties, Inc. In connection with succession planning, Boston Properties, Inc. and Mr. Zuckerman entered into a Transition Benefits Agreement. If Mr. Zuckerman remained employed by Boston Properties, Inc. through July 1, 2014, he was entitled to receive on January 1, 2015 a lump sum cash payment of $6.7 million and an equity award with a targeted value of approximately $11.1 million. The cash payment and equity award vested one-third on each of March 10, 2013, October 1, 2013 and July 1, 2014. As a result, the Company recognized approximately $3.9 million and $13.8 million of compensation expense during the years ended December 31, 2014 and 2013, respectively. In addition, the agreement provided that if Mr. Zuckerman terminated his employment with Boston Properties, Inc. for any reason, voluntarily or involuntarily, he would become fully vested in any outstanding equity awards with time-based vesting. As a result, during the year ended December 31, 2013, the Company accelerated the remaining approximately $12.9 million of stock-based compensation expense associated with Mr. Zuckerman's unvested long-term equity awards.

Boston Properties, Inc. issued 23,968, 36,730 and 20,756 shares of restricted common stock and 127,094, 184,733 and 174,650 LTIP Units to employees and non-employee directors under the 1997 Plan and 2012 Plan during the years ended December 31, 2014, 2013 and 2012, respectively. Boston Properties, Inc. did not issue any non-qualified stock options under the 1997 Plan during the year ended December 31, 2014. Boston Properties, Inc. issued 252,220 and 186,007 non-qualified stock options under the 1997 Plan during the years ended December 31, 2013 and 2012, respectively. The amounts issued during 2013 include the amounts issued to Mr. Thomas pursuant to his employment agreement, as discussed above. Boston Properties, Inc. issued 400,000 2012 OPP Units to employees under the 1997 Plan during the year ended December 31, 2012. Boston Properties, Inc. issued 318,926 2013 MYLTIP Units to employees under the 2012 Plan during the year ended December 31, 2013, including the amounts issued to Mr. Thomas pursuant to his employment agreement, as discussed above. Boston Properties, Inc. issued 485,459 2014 MYLTIP Units to employees under the 2012 Plan during the year ended December 31, 2014. Employees and directors paid $0.01 per share of restricted common stock and $0.25 per LTIP Unit, OPP Unit and MYLTIP Unit. An LTIP Unit is generally the economic equivalent of a share of restricted stock in Boston Properties, Inc. The aggregate value of the LTIP Units is included in noncontrolling interests in the Consolidated Balance Sheets. Grants of restricted stock and LTIP Units to employees vest in four equal annual installments. Restricted stock is measured at fair value on the date of grant based on the number of shares granted, as adjusted for forfeitures, and the closing price of Boston Properties, Inc.’s Common Stock on the date of grant as quoted on the New York Stock Exchange. Such value is recognized as an expense ratably over the corresponding employee service period. Non-qualified stock options, which are valued using the Black-Scholes option-pricing model, are recognized as an expense ratably over the corresponding employee service period. As the 2012 OPP Awards, 2013 MYLTIP Awards and 2014 MYLTIP Awards are subject to both a service condition and a market condition, the Company recognizes the compensation expense related to the 2012 OPP Awards, 2013 MYLTIP Awards and 2014 MYLTIP Awards under the graded vesting attribution method. Under the graded vesting attribution method, each portion of the award that vests at a different date is accounted for as a separate award and recognized over the period appropriate to that portion so that the compensation cost for each portion should be recognized in full by the time that portion vests. Dividends paid on both vested and unvested shares of restricted stock are charged directly to Partners’ Capital in the Consolidated Balance Sheets. Aggregate stock-based compensation expense associated with restricted stock, non-qualified stock options, LTIP Units, 2011 OPP Units, 2012 OPP Units, 2013 MYLTIP Units and 2014 MYLTIP Units was approximately $26.0 million, $43.9 million and $28.3 million for the years ended December 31, 2014, 2013 and 2012, respectively. For the years ended December 31, 2014 and 2013, stock-based compensation expense includes approximately $2.5 million and $21.5 million, respectively, consisting of the acceleration of the expense of Boston Properties, Inc.’s Executive Chairman’s stock-based compensation awards and the stock-based compensation awards associated with his transition benefits agreement related to Boston Properties, Inc.'s succession planning. For the year ended December 31, 2012, stock-based compensation expense includes approximately $2.7 million consisting of the acceleration of vesting of Boston Properties, Inc.'s Chief Operating Officer’s stock-based compensation awards associated with his resignation. At December 31, 2014, there was $17.0 million of unrecognized compensation expense related to unvested restricted stock and LTIP Units and $14.5 million of unrecognized compensation expense related to unvested 2012 OPP Units, 2013 MYLTIP Units and 2014 MYLTIP Units that is expected to be recognized over a weighted-average period of approximately 2.7 years.

The shares of restricted stock were valued at approximately $2.6 million ($109.27 per share weighted-average), $3.9 million ($105.30 per share weighted-average) and $2.2 million ($107.31 per share weighted-average) for the years ended December 31, 2014, 2013 and 2012, respectively.

LTIP Units were valued using a Monte Carlo simulation method model in accordance with the provisions of ASC 718 “Compensation—Stock Compensation” (“ASC 718”). LTIP Units issued during the years ended December 31, 2014, 2013 and 2012 were valued at approximately $12.8 million, $17.8 million and $17.3 million, respectively. The weighted-average per unit fair value of LTIP Unit grants in 2014, 2013 and 2012 was $100.61, $96.13 and $98.83, respectively. The per unit fair value of each LTIP Unit granted in 2014, 2013 and 2012 was estimated on the date of grant using the following assumptions; an expected life of 5.7 years, 5.7 years and 5.8 years, a risk-free interest rate of 1.84%, 1.03% and 0.94% and an expected price volatility of 27.0%, 26.0% and 29.1%, respectively.

There were no non-qualified stock options granted during the year ended December 31, 2014. The non-qualified stock options granted during the years ended December 31, 2013 and 2012 had a weighted-average fair value on the date of grant of $18.46 and $19.50 per option, respectively, which was computed using the Black-Scholes option-pricing model utilizing the following assumptions: an expected life of 6.0 years and 5.4 years, a risk-free interest rate of 1.11% and 0.92%, an expected price volatility of 26.0% and 28.4% and an expected dividend yield of 3.0% and 2.9%, respectively. The exercise price of the options granted during the years ended December 31, 2013 and 2012 were $105.10 and $107.23, respectively, which was the closing price of Boston Properties, Inc.’s common stock on the date of grant.

A summary of the status of Boston Properties, Inc.’s stock options as of December 31, 2014, 2013 and 2012 and changes during the years then ended are presented below:



	Shares		Weighted Average Exercise Price
Outstanding at December 31, 2011	155,623		$	89.35
Granted	186,007		$	107.23
Exercised	(22,823	)	$	72.42
Canceled	(24,280	)	$	100.15
Outstanding at December 31, 2012	294,527		$	101.06
Granted	252,220		$	104.50
Special dividend adjustment	12,076		$	100.44
Outstanding at December 31, 2013	558,823		$	100.43
Exercised	(21,459	)	$	97.04
Canceled	(2,444	)	$	103.57
Special dividend adjustment	18,392		$	97.22
Outstanding at December 31, 2014	553,312		$	97.21

The following table summarizes information about stock options outstanding at December 31, 2014:



Options Outstanding				Options Exercisable
Number Outstanding at 12/31/14	Weighted-Average Remaining Contractual Life	Exercise Price		Number Exercisable at 12/31/14	Exercise Price
124,513	3.6 years	$	87.70	111,832	$	87.70
53,759	8.3 years	$	96.62	13,439	$	96.62
207,064	4.9 years	$	99.41	150,024	$	99.41
167,976	4.4 years	$	101.75	135,848	$	101.75

The total intrinsic value of the outstanding and exercisable stock options as of December 31, 2014 was approximately $13.1 million. In addition, Boston Properties, Inc. had 199,868 and 91,496 options exercisable at a weighted-average exercise price of $98.83 and $98.92 at December 31, 2013 and 2012, respectively.

Boston Properties, Inc. adopted the 1999 Non-Qualified Employee Stock Purchase Plan (the “Stock Purchase Plan”) to encourage the ownership of Common Stock by eligible employees. The Stock Purchase Plan became effective on January 1, 1999 with an aggregate maximum of 250,000 shares of Common Stock available for issuance. The Stock Purchase Plan provides for eligible employees to purchase on the business day immediately following the end of the biannual purchase periods (i.e., January 1-June 30 and July 1-December 31) shares of Common Stock at a purchase price equal to 85% of the average closing prices of the Common Stock during the last ten business days of the purchase period. Boston Properties, Inc. issued 6,964, 6,442 and 7,406 shares with the weighted average purchase price equal to $93.37 per share, $89.65 per share and $86.52 per share under the Stock Purchase Plan during the years ended December 31, 2014, 2013 and 2012, respectively.

Related Party Transactions

12 Months Ended

Dec. 31, 2014

18. Related Party Transactions

Prior to joining Boston Properties, Inc. effective January 2, 2014, Mr. John F. Powers provided commercial real estate brokerage services to the Company, on behalf of his prior employer, CBRE, in connection with certain leasing transactions. Mr. Powers received approximately $1,214,000 and $592,000 during the years ended December 31, 2014 and 2013, respectively, in connection with these transactions. Mr. John F. Powers is a Senior Vice President of Boston Properties, Inc. and the Regional Manager of its New York office.

A firm controlled by Mr. Raymond A. Ritchey’s brother was paid aggregate leasing commissions of approximately $674,000, $868,000 and $1,306,000 for the years ended December 31, 2014, 2013 and 2012, respectively, related to certain exclusive leasing arrangements for certain Northern Virginia properties. Mr. Ritchey is an Executive Vice President of Boston Properties, Inc.

On June 30, 1998, the Company acquired from entities controlled by Mr. Alan B. Landis a portfolio of properties known as the Carnegie Center Portfolio and Tower Center One and related operations and development rights (collectively, the “Carnegie Center Portfolio”). Mr. A. Landis is the brother of Mr. Mitchell S. Landis, Boston Properties, Inc.'s former Senior Vice President and Regional Manager of Boston Properties, Inc.'s Princeton office. Mr. M. Landis' employment with Boston Properties, Inc. terminated on March 31, 2014. In connection with the acquisition of the Carnegie Center Portfolio, the Company entered into a development agreement (the “Development Agreement”) with affiliates of Mr. A. Landis providing for up to approximately 2,000,000 square feet of development in or adjacent to the Carnegie Center office complex. An affiliate of Mr. A. Landis was entitled to a purchase price for each parcel developed under the Development Agreement calculated on the basis of $20 per rentable square foot of property developed. Another affiliate of Mr. A. Landis was eligible to earn a contingent payment for each developed property that achieves a stabilized return in excess of a target annual return ranging between 10.5% and 11%. The Development Agreement also provided that upon negotiated terms and conditions, the Company and Mr. A. Landis would form a development company to provide development services for these development projects and would share the expenses and profits, if any, of this new company.

On October 21, 2004, the Company and Mr. A. Landis entered into an agreement (the “2004 Agreement”) to modify several provisions of the Development Agreement. Under the terms of the 2004 Agreement, the Company and affiliates of Mr. A. Landis amended the Development Agreement to limit the rights of Mr. A. Landis and his affiliates to participate in the development of properties under the Development Agreement. Among other things, Mr. A. Landis agreed that (1) Mr. A. Landis and his affiliates will have no right to participate in any entity formed to acquire land parcels or the development company formed by the Company to provide development services under the Development Agreement, (2) Mr. A. Landis will have no right or obligation to play a role in development activities engaged in by the development company formed by the Company under the Development Agreement or receive compensation from the development company and (3) the affiliate of Mr. A. Landis will have no right to receive a contingent payment for developed properties based on stabilized returns. In exchange, the Company (together with Boston Properties, Inc.) agreed to:

•

effective as of June 30, 1998, pay Mr. A. Landis $125,000 on January 1 of each year until the earlier of (A) January 1, 2018, (B) the termination of the Development Agreement or (C) the date on which all development properties under the Development Agreement have been conveyed pursuant to the Development Agreement, with $750,000, representing payments of this annual amount from 1998 to 2004, being paid upon execution of the 2004 Agreement; and

•

pay an affiliate of Mr. A. Landis, in connection with the development of land parcels acquired under the Development Agreement, an aggregate fixed amount of $10.50 per rentable square foot of property developed (with a portion of this amount (i.e., $5.50) being subject to adjustment, in specified circumstances, based on future increases in the Consumer Price Index) in lieu of a contingent payment based on stabilized returns, which payment could have been greater or less than $10.50 per rentable square foot of property developed.

The Company also continues to be obligated to pay an affiliate of Mr. A. Landis the purchase price of $20 per rentable square foot of property developed for each land parcel acquired as provided in the original Development Agreement. During the 20-year term of the Development Agreement, until such time, if any, as the Company elects to acquire a land parcel, an affiliate of Mr. A. Landis will remain responsible for all carrying costs associated with such land parcel. Pursuant to the Development Agreement, as amended by the 2004 Agreement, the Company paid Mr. A. Landis $125,000 on each of January 1, 2013 and January 1, 2014. On November 12, 2014, the Company acquired from Mr. A. Landis 804 Carnegie Center, a land parcel located in Princeton, New Jersey for a purchase price of approximately $3.7 million.

In accordance with Boston Properties, Inc.’s 2012 Plan, and as approved by the Board of Directors of Boston Properties, Inc., six non-employee directors made an election to receive deferred stock units in lieu of cash fees for 2014. The deferred stock units will be settled in shares of common stock upon the cessation of such director’s service on the Board of Directors of Boston Properties, Inc. As a result of these elections, the aggregate cash fees otherwise payable to a non-employee director during a fiscal quarter are converted into a number of deferred stock units equal to the aggregate cash fees divided by the last reported sales price of a share of Boston Properties, Inc.’s common stock on the last trading of the applicable fiscal quarter. The deferred stock units are also credited with dividend equivalents as dividends are paid by Boston Properties, Inc. On May 20, 2014, in connection with the cessation of a director's service on the Board of Directors, Boston Properties, Inc. issued 7,542 shares of common stock in settlement of the director's outstanding deferred stock units. At December 31, 2014 and 2013, Boston Properties, Inc. had outstanding 84,435 and 83,995 deferred stock units, respectively.

Quarterly Financial Information Disclosure [Abstract]

The entire disclosure for related party transactions. Examples of related party transactions include transactions between (a) a parent company and its subsidiary; (b) subsidiaries of a common parent; (c) and entity and its principal owners; and (d) affiliates.

+ References + Details

Selected Interim Financial Information (unaudited)

12 Months Ended

Dec. 31, 2014

Quarterly Financial Information [Text Block]

19. Selected Interim Financial Information (unaudited)

The tables below reflect the Company’s selected quarterly information for the years ended December 31, 2014 and 2013.



	2014 Quarter Ended
	March 31,		June 30,		September 30,		December 31,
	(in thousands, except for per unit amounts)
Total revenue	$	574,694	$	589,794	$	618,803	$	613,707
Income from continuing operations	$	69,781	$	97,927	$	111,066	$	87,753
Net income attributable to Boston Properties Limited Partnership common unitholders	$	62,219	$	87,436	$	144,715	$	204,759
Income attributable to Boston Properties Limited Partnership per unit—basic	$	0.37	$	0.51	$	0.85	$	1.20
Income attributable to Boston Properties Limited Partnership per unit—diluted	$	0.37	$	0.51	$	0.85	$	1.20



	2013 Quarter Ended
	March 31,		June 30,		September 30,		December 31,
	(in thousands, except for per unit amounts)
Total revenue	$	477,826	$	510,033	$	571,481	$	576,199
Income from continuing operations	$	44,445	$	505,396	$	84,348	$	81,412
Net income attributable to Boston Properties Limited Partnership common unitholders	$	60,923	$	505,189	$	174,140	$	101,264
Income attributable to Boston Properties Limited Partnership per unit—basic	$	0.36	$	2.97	$	1.03	$	0.60
Income attributable to Boston Properties Limited Partnership per unit—diluted	$	0.36	$	2.96	$	1.02	$	0.60

Subsequent Events	12 Months Ended
Subsequent Events	Dec. 31, 2014
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events On January 15, 2015, the Company entered into a contract for the sale of its Residences on The Avenue property located in Washington, DC for a gross sale price of $196.0 million. The Company has agreed to provide net operating income support of up to $6.0 million should the property’s net operating income fail to achieve certain thresholds. The Residences on The Avenue is comprised of 335 apartment units and approximately 50,000 net rentable square feet of retail space, subject to a ground lease that expires on February 1, 2068. The sale is subject to the satisfaction of customary closing conditions and there can be no assurance that the sale will be consummated on the terms currently contemplated or at all. On January 21, 2015, Boston Properties, Inc.'s Compensation Committee approved the 2015 Multi-Year, Long-Term Incentive Program (the "2015 MYLTIP") awards under Boston Properties, Inc.'s 2012 Plan to certain officers and employees of Boston Properties, Inc. The 2015 MYLTIP awards utilize TRS over a three-year measurement period, on an annualized, compounded basis, as the performance metric. Earned awards will be based on Boston Properties, Inc.'s TRS relative to (i) the Cohen & Steers Realty Majors Portfolio Index (50% weight) and (ii) the NAREIT Office Index adjusted to exclude Boston Properties, Inc. (50% weight). Earned awards will range from zero to a maximum of approximately $40.8 million depending on Boston Properties, Inc.'s TRS relative to the two indices, with three tiers (threshold: approximately $8.2 million; target: approximately $16.3 million; high: approximately $40.8 million) and linear interpolation between tiers. Earned awards measured on the basis of relative TRS performance are subject to an absolute TRS component in the form of relatively simple modifiers that (A) reduce the level of earned awards in the event Boston Properties, Inc.'s annualized TRS is less than 0% and (B) cause some awards to be earned in the event Boston Properties, Inc.'s annualized TRS is more than 12% even though on a relative basis alone Boston Properties, Inc.'s TRS would not result in any earned awards. Earned awards (if any) will vest 50% on February 4, 2018 and 50% on February 4, 2019, based on continued employment. Vesting will be accelerated in the event of a change in control, termination of employment by Boston Properties, Inc. without cause, or termination of employment by the award recipient for good reason, death, disability or retirement. If there is a change of control prior to February 4, 2018, earned awards will be calculated based on TRS performance up to the date of the change of control. The 2015 MYLTIP awards are in the form of LTIP Units issued on the grant date which (i) are subject to forfeiture to the extent awards are not earned and (ii) prior to the performance measurement date are only entitled to one-tenth (10%) of the regular quarterly distributions payable on common partnership units. Under the Financial Accounting Standards Board's Accounting Standards Codification (“ASC”) 718 “Compensation-Stock Compensation” the 2015 MYLTIP awards have an aggregate value of approximately $15.7 million, which amount will generally be amortized into earnings over the four-year plan period under the graded vesting method. On February 3, 2015, Boston Properties, Inc. issued 30,965 shares of restricted common stock and the Company issued 96,830 LTIP units under the 2012 Plan to certain employees of Boston Properties, Inc. On February 6, 2015, the measurement period for the Company’s 2012 OPP Awards ended and Boston Properties, Inc.’s TRS performance was sufficient for employees to earn and therefore become eligible to vest in the 2012 OPP Awards. The final outperformance pool was determined to be approximately $32.1 million, or approximately 80% of the total maximum outperformance pool of $40.0 million. On February 19, 2015, the Company completed the sale of a parcel of land within its Washingtonian North property located in Gaithersburg, Maryland for a sale price of approximately $8.7 million, which exceeded its carrying value. The parcel contains approximately 8.5 acres of the approximately 27 acre property. During February 2015, the Company entered into forward-starting interest rate swap contracts which fix the ten-year swap rate at a weighted-average rate of 2.514% per annum on notional amounts aggregating $125.0 million. The interest rate swap contracts were entered into in advance of a financing with a target commencement date in September 2016 and expiration in September 2026.

Real Estate and Accumulated Depreciation

12 Months Ended

Dec. 31, 2014

Real Estate and Accumulated Depreciation [Line Items]

SEC Schedule III, Real Estate and Accumulated Depreciation Disclosure [Text Block]

Boston Properties Limited Partnership

Schedule 3—Real Estate and Accumulated Depreciation

December 31, 2014

(dollars in thousands)



				Original				Costs Capitalized Subsequent to Acquisition		Land and Improvements		Building and Improvements		Land Held for Development		Development and Construction in Progress		Total		Accumulated Depreciation		Year(s) Built/ Renovated	Depreciable Lives (Years)
Property Name	Type	Location	Encumbrances	Land		Building		Costs Capitalized Subsequent to Acquisition		Land and Improvements		Building and Improvements		Land Held for Development		Development and Construction in Progress		Total		Accumulated Depreciation		Year(s) Built/ Renovated	Depreciable Lives (Years)
767 Fifth Avenue (The General Motors Building)	Office	New York, NY	1,421,083	$	1,796,252	$	1,532,654	$	19,627	$	1,796,252	$	1,552,281	$	—	$	—	$	3,348,533	$	80,075	1968	(1)
Embarcadero Center	Office	San Francisco, CA	354,680	179,697		847,410		254,939		180,420		1,101,626		—		—		1,282,046		495,091		1970/1989	(1)
Prudential Center	Office	Boston, MA	—	92,077		734,594		319,846		92,328		1,018,741		404		35,044		1,146,517		411,161		1965/1993/2002	(1)
399 Park Avenue	Office	New York, NY	—	339,200		700,358		50,022		339,200		750,380		—		—		1,089,580		232,464		1961	(1)
The John Hancock Tower and Garage	Office	Boston, MA	649,108	219,543		667,884		74,060		219,616		740,863		1,008		—		961,487		104,888		1976	(1)
601 Lexington Avenue	Office	New York, NY	710,932	241,600		494,782		188,718		279,281		645,819		—		—		925,100		221,412		1977/1997	(1)
250 West 55th Street	Office	New York, NY	—	285,263		603,167		—		285,263		603,167		—		—		888,430		9,240		2014	(1)
Times Square Tower	Office	New York, NY	—	165,413		380,438		46,509		159,694		432,666		—		—		592,360		144,194		2004	(1)
100 Federal Street	Office	Boston, MA	—	131,067		435,954		9,711		131,067		445,432		233		—		576,732		44,931		1971-1975	(1)
Carnegie Center	Office	Princeton, NJ	—	105,107		377,259		65,735		98,733		437,666		2,350		9,352		548,101		180,935		1983-1999	(1)
Atlantic Wharf	Office	Boston, MA	—	63,988		454,537		15,169		63,988		469,706		—		—		533,694		55,070		2011	(1)
Fountain Square	Office	Reston, VA	220,133	56,853		306,298		6,938		56,853		313,236		—		—		370,089		27,645		1986-1990	(1)
510 Madison Avenue	Office	New York, NY	—	103,000		253,665		12,912		103,000		266,577		—		—		369,577		24,871		2012	(1)
680 Folsom Street	Office	San Francisco, CA	—	106,510		185,801		—		106,510		185,801		—		—		292,311		4,161		2014	(1)
599 Lexington Avenue	Office	New York, NY	750,000	81,040		100,507		101,407		81,040		201,914		—		—		282,954		148,356		1986	(1)
South of Market and Democracy Tower	Office	Reston, VA	—	13,603		237,479		9,454		13,603		246,933		—		—		260,536		60,626		2008-2009	(1)
Bay Colony Corporate Center	Office	Waltham, MA	—	18,789		148,451		58,126		18,789		206,577		—		—		225,366		31,089		1985-1989	(1)
Gateway Center	Office	San Francisco, CA	—	28,255		139,245		46,379		29,029		184,850		—		—		213,879		86,679		1984/1986/2002	(1)
2200 Pennsylvania Avenue	Office	Washington, DC	—	—		183,541		5,141		—		188,682		—		—		188,682		26,612		2011	(1)
Mountain View Research Park	Office	Mountain View, CA	—	95,066		68,373		3,267		95,066		71,640		—		—		166,706		6,044		1977-1981/2007-2013	(1)
3100-3130 Zanker Road (formerly 3200 Zanker Road)	Office	San Jose, CA	—	36,705		82,863		27,751		36,705		106,861		3,753		—		147,319		25,721		1988	(1)



Reservoir Place	Office	Waltham, MA	—	18,605	92,619	30,657		19,099	122,774	8	—	141,881	56,766	1955/1987	(1)
505 9th Street	Office	Washington, DC	118,919	38,885	83,719	5,409		42,011	86,002	—	—	128,013	23,331	2007	(1)
Kingstowne Towne Center	Office	Alexandria, VA	31,364	18,021	109,038	849		18,021	109,887	—	—	127,908	29,800	2003-2006	(1)
1333 New Hampshire Avenue	Office	Washington, DC	—	34,032	85,660	4,553		34,032	90,213	—	—	124,245	32,028	1996	(1)
1330 Connecticut Avenue	Office	Washington, DC	—	25,982	82,311	11,766		25,982	94,077	—	—	120,059	31,959	1984	(1)
Weston Corporate Center	Office	Weston, MA	—	25,753	92,312	(123	)	25,854	92,088	—	—	117,942	13,972	2010	(1)
Capital Gallery	Office	Washington, DC	—	4,725	29,565	77,947		6,128	106,109	—	—	112,237	51,604	1981/2006	(1)
One Freedom Square	Office	Reston, VA	—	9,929	84,504	13,261		9,883	97,811	—	—	107,694	35,957	2000	(1)
Two Freedom Square	Office	Reston, VA	—	13,930	77,739	13,351		13,866	91,154	—	—	105,020	37,225	2001	(1)
One and Two Reston Overlook	Office	Reston, VA	—	16,456	66,192	20,902		15,074	88,476	—	—	103,550	34,527	1999	(1)
415 Main Street (formerly Seven Cambridge Center)	Office	Cambridge, MA	—	3,457	97,136	210		3,457	97,346	—	—	100,803	53,022	2006	(1)
355 Main Street (formerly Five Cambridge Center)	Office	Cambridge, MA	—	18,863	53,346	25,601		21,098	76,712	—	—	97,810	20,817	1981/1996/2013	(1)
Discovery Square	Office	Reston, VA	—	11,198	71,782	14,432		11,146	86,266	—	—	97,412	31,385	2001	(1)
140 Kendrick Street	Office	Needham, MA	—	18,095	66,905	10,880		18,095	77,785	—	—	95,880	19,519	2000	(1)
90 Broadway (formerly Four Cambridge Center)	Office	Cambridge, MA	—	19,104	52,078	13,501		20,741	63,942	—	—	84,683	12,401	1983/1998/2013	(1)
77 CityPoint	Office	Waltham, MA	—	13,847	60,383	3,058		13,847	63,441	—	—	77,288	14,625	2008	(1)
230 CityPoint	Office	Waltham, MA	—	13,189	49,823	14,127		13,189	63,950	—	—	77,139	18,760	1992	(1)
Waltham Weston Corporate Center	Office	Waltham, MA	—	10,385	60,694	5,118		10,350	65,847	—	—	76,197	21,645	2003	(1)
North First Business Park	Office	San Jose, CA	—	58,402	13,069	4,005		23,371	16,197	35,908	—	75,476	12,174	1981	(1)
300 Binney Street (Seventeen Cambridge Center)	Office	Cambridge, MA	—	18,080	51,262	165		18,080	51,427	—	—	69,507	2,938	2013	(1)
2440 West El Camino Real	Office	Mountain View, CA	—	16,741	51,285	716		16,741	52,001	—	—	68,742	6,400	1987/2003	(1)
Wisconsin Place	Office	Chevy Chase, MD	—	—	53,349	12,787		—	66,136	—	—	66,136	14,300	2009	(1)
Reston Corporate Center	Office	Reston, VA	—	9,135	50,857	2,750		9,496	53,246	—	—	62,742	22,099	1984	(1)
New Dominion Technology Park, Bldg. Two	Office	Herndon, VA	—	5,584	51,868	166		5,574	52,044	—	—	57,618	17,674	2004	(1)
Sumner Square	Office	Washington, DC	—	624	28,745	22,924		958	51,335	—	—	52,293	24,802	1985	(1)
200 West Street	Office	Waltham, MA	—	16,148	24,983	7,121		16,148	32,104	—	—	48,252	15,987	1999	(1)
New Dominion Technology Park, Bldg. One	Office	Herndon, VA	40,975	3,880	43,227	1,073		3,880	44,300	—	—	48,180	20,681	2001	(1)
191 Spring Street	Office	Lexington, MA	—	2,850	27,166	17,359		2,850	44,525	—	—	47,375	30,882	1971/1995	(1)
255 Main Street (formerly One Cambridge Center)	Office	Cambridge, MA	—	134	25,110	18,940		134	44,050	—	—	44,184	26,889	1987	(1)
University Place	Office	Cambridge, MA	12,290	—	37,091	5,344		27	42,408	—	—	42,435	21,913	1985	(1)
2600 Tower Oaks Boulevard	Office	Rockville, MD	—	4,243	31,125	5,761		4,244	36,885	—	—	41,129	16,625	2001	(1)
Quorum Office Park	Office	Chelmsford, MA	—	3,750	32,454	4,116		4,762	35,558	—	—	40,320	13,423	2001	(1)
150 Broadway (formerly Eight Cambridge Center)	Office	Cambridge, MA	—	850	25,042	6,502		822	31,572	—	—	32,394	12,264	1999	(1)
500 E Street	Office	Washington, DC	—	109	22,420	9,780		1,569	30,740	—	—	32,309	21,054	1987	(1)



325 Main Street (formerly Three Cambridge Center)	Office	Cambridge, MA	—	174	12,200	11,003		772	22,605	—	—	23,377	10,364	1987/2013	(1)
105 Broadway (formerly Ten Cambridge Center)	Office	Cambridge, MA	—	1,299	12,943	4,745		1,868	17,119	—	—	18,987	11,590	1990	(1)
40 Shattuck Road	Office	Andover, MA	—	709	14,740	1,961		709	16,701	—	—	17,410	6,046	2001	(1)
201 Spring Street	Office	Lexington, MA	—	2,849	15,303	(1,253	)	2,849	14,050	—	—	16,899	6,324	1997	(1)
Lexington Office Park	Office	Lexington, MA	—	998	1,426	13,177		1,073	14,528	—	—	15,601	11,219	1982	(1)
92-100 Hayden Avenue	Office	Lexington, MA	—	594	6,748	7,090		619	13,813	—	—	14,432	10,541	1985	(1)
91 Hartwell Avenue	Office	Lexington, MA	—	784	6,464	6,120		784	12,584	—	—	13,368	7,547	1985	(1)
181 Spring Street	Office	Lexington, MA	—	1,066	9,520	1,573		1,066	11,093	—	—	12,159	4,242	1999	(1)
33 Hayden Avenue	Office	Lexington, MA	—	266	3,234	8,150		266	11,384	—	—	11,650	5,450	1979	(1)
195 West Street	Office	Waltham, MA	—	1,611	6,652	3,278		1,611	9,930	—	—	11,541	6,456	1990	(1)
145 Broadway (formerly Eleven Cambridge Center)	Office	Cambridge, MA	—	121	5,535	4,465		121	10,000	—	—	10,121	7,430	1984	(1)
7501 Boston Boulevard, Building Seven	Office	Springfield, VA	—	665	9,273	15		665	9,288	—	—	9,953	4,027	1997	(1)
7435 Boston Boulevard, Building One	Office	Springfield, VA	—	392	3,822	3,105		486	6,833	—	—	7,319	5,677	1982	(1)
7450 Boston Boulevard, Building Three	Office	Springfield, VA	—	1,165	4,681	1,466		1,327	5,985	—	—	7,312	2,983	1987	(1)
453 Ravendale Drive	Office	Mountain View, CA	—	5,477	1,090	230		5,477	1,320	—	—	6,797	213	1977	(1)
8000 Grainger Court, Building Five	Office	Springfield, VA	—	366	4,282	2,090		453	6,285	—	—	6,738	5,042	1984	(1)
7500 Boston Boulevard, Building Six	Office	Springfield, VA	—	138	3,749	2,005		273	5,619	—	—	5,892	4,175	1985	(1)
7300 Boston Boulevard, Building Thirteen	Office	Springfield, VA	—	608	4,773	18		608	4,791	—	—	5,399	4,193	2002	(1)
7601 Boston Boulevard, Building Eight	Office	Springfield, VA	—	200	878	4,133		378	4,833	—	—	5,211	3,571	1986	(1)
250 Binney Street (formerly Fourteen Cambridge Center)	Office	Cambridge, MA	—	110	4,483	569		110	5,052	—	—	5,162	3,835	1983	(1)
8000 Corporate Court, Building Eleven	Office	Springfield, VA	—	136	3,071	1,260		687	3,780	—	—	4,467	2,432	1989	(1)
7375 Boston Boulevard, Building Ten	Office	Springfield, VA	—	23	2,685	822		47	3,483	—	—	3,530	2,333	1988	(1)
7374 Boston Boulevard, Building Four	Office	Springfield, VA	—	241	1,605	1,346		303	2,889	—	—	3,192	2,172	1984	(1)
7451 Boston Boulevard, Building Two	Office	Springfield, VA	—	249	1,542	1,348		535	2,604	—	—	3,139	2,081	1982	(1)
32 Hartwell Avenue	Office	Lexington, MA	—	168	1,943	223		168	2,166	—	—	2,334	1,584	1968-1979/1987	(1)
164 Lexington Road	Office	Billerica, MA	—	592	1,370	117		592	1,487	—	—	2,079	708	1982	(1)
17 Hartwell Avenue	Office	Lexington, MA	—	26	150	861		26	995	16	—	1,037	687	1968	(1)
Residences on The Avenue, 2221 I St., NW	Residential	Washington, DC	—	—	119,874	(28	)	—	119,846	—	—	119,846	11,039	2011	(1)
The Avant at Reston Town Center	Residential	Reston, VA	—	20,350	91,995	—		20,350	91,995	—	—	112,345	2,397	2014	(1)
The Lofts at Atlantic Wharf	Residential	Boston, MA	—	3,529	54,891	1,543		3,529	56,434	—	—	59,963	5,093	2011	(1)
Boston Marriott Cambridge (formerly Cambridge Center Marriott)	Hotel	Cambridge, MA	—	478	37,918	33,269		478	71,187	—	—	71,665	46,709	1986	(1)
Cambridge Center East Garage	Garage	Cambridge, MA	—	—	35,035	1,147		—	36,182	—	—	36,182	7,579	1984	(1)
Cambridge Center West Garage	Garage	Cambridge, MA	—	1,256	15,697	859		1,256	16,556	—	—	17,812	3,700	2006	(1)
Cambridge Center North Garage	Garage	Cambridge, MA	—	1,163	11,633	1,105		1,163	12,738	—	—	13,901	8,252	1990	(1)



Salesforce Tower	Development	San Francisco, CA	—				—		—		345,303		—		—		—		345,303		345,303		—		N/A	N/A
601 Massachusetts Avenue	Development	Washington, DC	—				—		—		189,161		—		—		—		189,161		189,161		—		N/A	N/A
535 Mission Street	Development	San Francisco, CA	—				—		—		171,096		10,789		39,307		—		121,000		171,096		225		N/A	N/A
10 CityPoint	Development	Waltham, MA	—				—		—		21,370		—		—		—		21,370		21,370		—		N/A	N/A
690 Folsom Street	Development	San Francisco, CA	—				—		—		13,237		1,777		6,546		—		4,914		13,237		11		N/A	N/A
Springfield Metro Center	Land	Springfield, VA	—				—		—		32,445		—		—		32,445		—		32,445		—		N/A	N/A
Reston Signature Site	Land	Reston, VA	—				—		—		30,256		—		—		30,256		—		30,256		—		N/A	N/A
Plaza at Almaden	Land	San Jose, CA	—				—		—		29,006		—		—		29,006		—		29,006		—		N/A	N/A
Tower Oaks Master Plan	Land	Rockville, MD	—				—		—		28,919		—		—		28,919		—		28,919		—		N/A	N/A
214 Third Avenue (formerly Prospect Hill)	Land	Waltham, MA	—				—		—		23,255		—		132		12,956		10,167		23,255		—		N/A	N/A
Washingtonian North	Land	Gaithersburg, MD	—				—		—		18,813		—		—		18,813		—		18,813		—		N/A	N/A
6601 & 6605 Springfield Center Drive	Land	Springfield, VA	—				—		—		13,866		—		—		13,866		—		13,866		—		N/A	N/A
103 Fourth Avenue	Land	Waltham, MA	—				—		—		11,920		—		—		11,920		—		11,920		—		N/A	N/A
Reston Gateway	Land	Reston, VA	—				—		—		9,933		—		—		9,933		—		9,933		—		N/A	N/A
Reston Eastgate	Land	Reston, VA	—				—		—		8,817		—		—		8,817		—		8,817		—		N/A	N/A
Crane Meadow	Land	Marlborough, MA	—				—		—		8,726		—		—		8,726		—		8,726		—		N/A	N/A
Broad Run Business Park	Land	Loudoun County, VA	—				—		—		6,311		—		—		6,311		—		6,311		—		N/A	N/A
20 CityPoint	Land	Waltham, MA	—				—		—		4,801		—		—		4,801		—		4,801		—		N/A	N/A
Cambridge Master Plan	Land	Cambridge, MA	—				—		—		3,527		—		—		3,527		—		3,527		—		N/A	N/A
North First Master Plan	Land	San Jose, CA	—				—		—		1,664		—		—		1,664		—		1,664		—		N/A	N/A
425 Fourth Street	Land	San Francisco, CA	—				—		—		1,261		—		—		1,261		—		1,261		—		N/A	N/A
30 Shattuck Road	Land	Andover, MA	—				—		—		1,213		—		—		1,213		—		1,213		—		N/A	N/A
			$	4,309,484	(2	)	$	4,661,817	$	11,331,324	$	2,793,431	$	4,680,181	$	13,101,966	$	268,114	$	736,311	$	18,786,572	$	3,458,640

Note: Total Real Estate does not include Furniture, Fixtures and Equipment totaling approximately $27,986. Accumulated Depreciation does not include approximately $17,681 of accumulated depreciation related to Furniture, Fixtures and Equipment.

The aggregate cost and accumulated depreciation for tax purposes was approximately $16.0 billion and $2.9 billion, respectively.


(1)	Depreciation of the buildings and improvements are calculated over lives ranging from the life of the lease to 40 years.


(2)	Includes the unamortized balance of the historical fair value adjustment totaling approximately $138.7 million.

Boston Properties Limited Partnership

Real Estate and Accumulated Depreciation

December 31, 2014

(dollars in thousands)

A summary of activity for real estate and accumulated depreciation is as follows:



	2014			2013			2012
Real Estate:
Balance at the beginning of the year	$	18,523,277		$	14,431,521		$	12,922,967
Additions to/improvements of real estate	594,296			4,410,622			1,602,583
Assets sold/written-off	(331,001		)	(318,866		)	(94,029		)
Balance at the end of the year	$	18,786,572		$	18,523,277		$	14,431,521
Accumulated Depreciation:
Balance at the beginning of the year	$	3,081,040		$	2,862,302		$	2,577,118
Depreciation expense	447,667			411,860			359,442
Assets sold/written-off	(70,067		)	(193,122		)	(74,258		)
Balance at the end of the year	$	3,458,640		$	3,081,040		$	2,862,302

Note: Real Estate and Accumulated Depreciation amounts do not include Furniture, Fixtures and Equipment.

Summary Of Significant Accounting Policies Summary Of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2014

Accounting Policies [Abstract]

Real Estate

Depreciation is computed on a straight-line basis over the estimated useful lives of the assets as follows:




Land improvements		25 to 40 years
Buildings and improvements		10 to 40 years
Tenant improvements		Shorter of useful life or terms of related lease
Furniture, fixtures, and equipment		3 to 7 years

Cash and Cash Equivalents

Cash Held in Escrows

Investments in Securities

Tenant and Other Receivables

Tenant and other accounts receivable, other than accrued rents receivable, are expected to be collected within one year.

Deferred Charges

Investments in Unconsolidated Joint Ventures

The combined summarized financial information of the unconsolidated joint ventures is disclosed in Note 5 to the Consolidated Financial Statements.

Revenue Recognition



	Acquired Above-Market Lease Intangibles		Acquired Below-Market Lease Intangibles
2015	$	22,671	$	57,019
2016	20,491		51,460
2017	12,277		35,896
2018	8,637		33,215
2019	7,106		27,615

The Company's parking revenues are derived from leases, monthly parking and transient parking. The Company recognizes parking revenue as earned.

Depreciation and Amortization

Ground Leases




Years Ending December 31,	(in thousands)
2015	$	13,507
2016	13,732
2017	13,963
2018	14,198
2019	14,461
Thereafter	884,726

Earnings Per Common Unit

Fair Value of Financial Instruments



	December 31, 2014				December 31, 2013
	Carrying Amount		Estimated Fair Value		Carrying Amount			Estimated Fair Value
Mortgage notes payable	$	4,309,484	$	4,449,541	$	4,449,734		$	4,545,283
Mezzanine notes payable	309,796		306,156		311,040			311,064
Unsecured senior notes	5,287,704		5,645,819		5,835,854			6,050,517
Unsecured exchangeable senior notes	—		—		744,880		(1)	750,266
Total	$	9,906,984	$	10,401,516	$	11,341,508		$	11,657,130

_____________


(1)	Includes the net adjustment for the equity component allocation totaling approximately $2.4 million at December 31, 2013.

Derivatives Instruments and Hedging Activities

Derivative Instruments and Hedging Activities

Income Taxes

The following table reconciles GAAP net income attributable to Boston Properties Limited Partnership to taxable income:



	For the year ended December 31,
	2014			2013			2012
	(in thousands)
Net income attributable to Boston Properties Limited Partnership	$	509,629		$	849,573		$	334,601
Straight-line rent adjustments	(102,319		)	(82,904		)	(89,982		)
Book/Tax differences from depreciation and amortization	253,590			174,384			106,862
Book/Tax differences from interest expense	(48,128		)	(8,811		)	31,003
Book/Tax differences on gains/losses from capital transactions	1,065,518			(138,300		)	(24,958		)
Book/Tax differences from stock-based compensation	36,232			46,935			22,035
Tangible Property Regulations (1)	(493,731		)	—			—
Other book/tax differences, net	(11,403		)	8,589			11,001
Taxable income	$	1,209,388		$	849,466		$	390,562

__________

Stock-Based Employee Compensation Plans

Use of Estimates in the Preperation of Financial Statements

Use of Estimates in the Preparation of Financial Statements

Recent Accounting Pronouncements

Summary Of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2014

Accounting Policies [Abstract]

Fair Value, by Balance Sheet Grouping [Table Text Block]



	December 31, 2014				December 31, 2013
	Carrying Amount		Estimated Fair Value		Carrying Amount			Estimated Fair Value
Mortgage notes payable	$	4,309,484	$	4,449,541	$	4,449,734		$	4,545,283
Mezzanine notes payable	309,796		306,156		311,040			311,064
Unsecured senior notes	5,287,704		5,645,819		5,835,854			6,050,517
Unsecured exchangeable senior notes	—		—		744,880		(1)	750,266
Total	$	9,906,984	$	10,401,516	$	11,341,508		$	11,657,130

_____________


(1)	Includes the net adjustment for the equity component allocation totaling approximately $2.4 million at December 31, 2013.

Gaap Reconciliation Of Net Income To Taxable Income, Table [Table Text Block]

The following table reconciles GAAP net income attributable to Boston Properties Limited Partnership to taxable income:



	For the year ended December 31,
	2014			2013			2012
	(in thousands)
Net income attributable to Boston Properties Limited Partnership	$	509,629		$	849,573		$	334,601
Straight-line rent adjustments	(102,319		)	(82,904		)	(89,982		)
Book/Tax differences from depreciation and amortization	253,590			174,384			106,862
Book/Tax differences from interest expense	(48,128		)	(8,811		)	31,003
Book/Tax differences on gains/losses from capital transactions	1,065,518			(138,300		)	(24,958		)
Book/Tax differences from stock-based compensation	36,232			46,935			22,035
Tangible Property Regulations (1)	(493,731		)	—			—
Other book/tax differences, net	(11,403		)	8,589			11,001
Taxable income	$	1,209,388		$	849,466		$	390,562

__________

Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]

The following table summarizes the scheduled amortization of the Company's acquired “above-” and “below-market” lease intangibles for each of the five succeeding years (in thousands). Accrued rental income as reported on the Consolidated Balance Sheets represents rental income recognized in excess of rent payments actually received pursuant to the terms of the individual lease agreements.



	Acquired Above-Market Lease Intangibles		Acquired Below-Market Lease Intangibles
2015	$	22,671	$	57,019
2016	20,491		51,460
2017	12,277		35,896
2018	8,637		33,215
2019	7,106		27,615

The following table summarizes the scheduled amortization of the Company's acquired in-place lease intangibles for each of the five succeeding years (in thousands).



	Acquired In-Place Lease Intangibles
2015	$	66,390
2016	55,327
2017	38,812
2018	33,964
2019	27,439

Schedule Of Future Contractual Minimum Lease Payments Under Non-Cancelable Ground Leases [Table Text Block]




Years Ending December 31,	(in thousands)
2015	$	13,507
2016	13,732
2017	13,963
2018	14,198
2019	14,461
Thereafter	884,726

Property, Plant and Equipment [Table Text Block]

Depreciation is computed on a straight-line basis over the estimated useful lives of the assets as follows:




Land improvements		25 to 40 years
Buildings and improvements		10 to 40 years
Tenant improvements		Shorter of useful life or terms of related lease
Furniture, fixtures, and equipment		3 to 7 years

Real Estate (Tables)

12 Months Ended

Dec. 31, 2014

Real Estate Properties [Line Items]

Schedule of Property Subject to or Available for Operating Lease [Table Text Block]

Real estate consisted of the following at December 31 (in thousands):



	2014			2013
Land	$	4,680,181		$	4,342,951
Land held for future development	268,114			297,376
Buildings and improvements	11,349,851			10,742,370
Tenant improvements	1,752,115			1,617,401
Furniture, fixtures and equipment	27,986			25,164
Construction in progress	736,311			1,523,179
Total	18,814,558			18,548,441
Less: Accumulated depreciation	(3,476,321		)	(3,096,910		)
	$	15,338,237		$	15,451,531

Pro Forma in Connection With Acquisition



Pro Forma (Unaudited)	Year ended December 31,
(in thousands, except per unit data)	2013		2012
Total revenue	$	2,257,098	$	2,149,391
Income from continuing operations	$	314,307	$	642,640
Net income attributable to Boston Properties Limited Partnership	$	452,813	$	710,690
Basic earnings per unit:
Net income per unit attributable to Boston Properties Limited Partnership	$	2.68	$	4.21
Diluted earnings per unit:
Net income per unit attributable to Boston Properties Limited Partnership	$	2.67	$	4.20

Summary of the Discontinued Operations

The following table summarizes the income from discontinued operations related to One Preserve Parkway, 10 & 20 Burlington Mall Road, 1301 New York Avenue, 303 Almaden Boulevard, Montvale Center and Bedford Business Park and the related gains on sales of real estate, gain on forgiveness of debt and impairment loss for the years ended December 31, 2013 and 2012:



	For the year ended December 31,
	2013			2012
	(in thousands)
Total revenue	$	20,138		$	32,607
Expenses
Operating	6,996			12,038
Depreciation and amortization	4,760			8,169
Total expenses	11,756			20,207
Operating income	8,382			12,400
Other expense
Interest expense	360			2,594
Income from discontinued operations attributable to Boston Properties Limited Partnership	$	8,022		$	9,806

Gains on sales of real estate from discontinued operations attributable to Boston Properties Limited Partnership	$	115,459		$	38,445
Gain on forgiveness of debt from discontinued operations attributable to Boston Properties Limited Partnership	$	20,736		$	—
Impairment loss from discontinued operations attributable to Boston Properties Limited Partnership	$	(2,852	)	$	—

Mountain View Research And Technology Parks [Member]

Real Estate Properties [Line Items]

Schedule of Allocation of the Aggregate Purchase Price of Acquisition



Land	$	126,521
Building and improvements	82,451
Tenant improvements	7,326
In-place lease intangibles	23,279
Above-market rents	843
Below-market rents	(7,336		)
Net assets acquired	$	233,084

767 5th Avenue (The General Motors Building) [Member]

Real Estate Properties [Line Items]

Schedule of Allocation of the Aggregate Purchase Price of Acquisition



Real estate and related intangibles recorded upon consolidation
Land	$	1,796,252
Building and improvements	1,447,446
Tenant improvements	85,208
In-place lease intangibles	357,781
Above market rents	101,897
Below market rents	(239,641		)
Above market assumed debt adjustments	(192,943		)
	$	3,356,000
Debt recorded upon consolidation
Mortgage notes payable	$	(1,300,000	)
Mezzanine notes payable	(306,000		)
Members' notes payable	(450,000		)	(1)
	$	(2,056,000	)

Working capital recorded upon consolidation
Cash and cash equivalents	$	79,468
Cash held in escrows	2,403
Tenant and other receivables	7,104
Prepaid expenses and other assets	4,269
Accounts payable and accrued expenses	(2,418		)
Accrued interest payable	(182,369		)	(2)
Other liabilities	(6,304		)
	$	(97,847	)
Noncontrolling interest recorded upon consolidation
Noncontrolling interests	$	(520,000	)
Noncontrolling interests - working capital	39,139
	$	(480,861	)

Net assets recorded upon consolidation	$	721,292

_______________


(1)	The Company's member loan totaling $270.0 million eliminates in consolidation.


(2)	The Company's share of the accrued interest payable on the members' loans totaling approximately $105.5 million eliminates in consolidation.

Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]

Tabular disclosure of disposal groups, which may include the gain (loss) recognized in the income statement and the income statement caption that includes that gain (loss), amounts of revenues and pretax profit or loss reported in discontinued operations, the classification and carrying value of the assets and liabilities comprising the disposal group, and the segment in which the disposal group was reported. Also may include the amount of adjustments to amounts previously reported in discontinued operations such as resolution of contingencies arising from the disposal transaction or the operations of the component prior to disposal.

+ References + Details

Deferred Charges (Tables)

12 Months Ended

Dec. 31, 2014

Deferred Charges [Abstract]

Deferred Charges

Deferred charges consisted of the following at December 31, (in thousands):



	2014			2013
Leasing costs, including lease related intangibles	$	1,234,192		$	1,183,204
Financing costs	69,127			76,798
	1,303,319			1,260,002
Less: Accumulated amortization	(471,575		)	(375,552		)
	$	831,744		$	884,450



	Acquired Above-Market Lease Intangibles		Acquired Below-Market Lease Intangibles
2015	$	22,671	$	57,019
2016	20,491		51,460
2017	12,277		35,896
2018	8,637		33,215
2019	7,106		27,615

The following table summarizes the scheduled amortization of the Company's acquired in-place lease intangibles for each of the five succeeding years (in thousands).



	Acquired In-Place Lease Intangibles
2015	$	66,390
2016	55,327
2017	38,812
2018	33,964
2019	27,439

Investments in Unconsolidated Joint Ventures (Tables)

12 Months Ended

Dec. 31, 2014

Investments In Unconsolidated Joint Ventures [Abstract]

Investments In Unconsolidated Joint Ventures

The investments in unconsolidated joint ventures consist of the following at December 31, 2014:



Entity	Properties	Nominal % Ownership			Carrying Value of Investment (1)
					(in thousands)
Square 407 Limited Partnership	Market Square North	50.0	%		$	(8,022	)
The Metropolitan Square Associates LLC	Metropolitan Square	51.0	%		8,539
BP/CRF 901 New York Avenue LLC	901 New York Avenue	25.0	%	(2)	(1,080		)
WP Project Developer LLC	Wisconsin Place Land and Infrastructure	33.3	%	(3)	45,514
Annapolis Junction NFM, LLC	Annapolis Junction	50.0	%	(4)	25,246
540 Madison Venture LLC	540 Madison Avenue	60.0	%		68,128
500 North Capitol LLC	500 North Capitol Street, NW	30.0	%		(2,250		)
501 K Street LLC	1001 6th Street (formerly 501 K Street)	50.0	%	(5)	41,736
Podium Developer LLC	North Station (Phase I - Air Rights)	50.0	%		4,231
					$	182,042

_______________


(1)	Investments with deficit balances aggregating approximately $11.4 million have been reflected within Other Liabilities on the Company's Consolidated Balance Sheets.


(2)	The Company’s economic ownership has increased based on the achievement of certain return thresholds.


(3)	The Company’s wholly-owned entity that owns the office component of the project also owns a 33.3% interest in the entity owning the land, parking garage and infrastructure of the project.


(4)	The joint venture owns two in-service buildings, two buildings under construction and two undeveloped land parcels.


(5)	Under the joint venture agreement, the partner will be entitled to up to two additional payments from the venture based on increases in total square footage of the project above 520,000 square feet and achieving certain project returns at stabilization.

Balance Sheets Of The Unconsolidated Joint Ventures

The combined summarized balance sheets of the Company's unconsolidated joint ventures are as follows:



	December 31, 2014			December 31, 2013
	(in thousands)
ASSETS
Real estate and development in process, net	$	1,034,552		$	924,297
Other assets	264,097			163,149
Total assets	$	1,298,649		$	1,087,446
LIABILITIES AND MEMBERS’/PARTNERS’ EQUITY
Mortgage and notes payable	$	830,075		$	749,732
Other liabilities	34,211			28,830
Members’/Partners’ equity	434,363			308,884
Total liabilities and members’/partners’ equity	$	1,298,649		$	1,087,446
Company’s share of equity	$	209,828		$	154,726
Basis differentials (1)	(27,786		)	(28,642		)
Carrying value of the Company’s investments in unconsolidated joint ventures (2)	$	182,042		$	126,084

_______________

(1)


(2)	Investments with deficit balances aggregating approximately $11.4 million and $14.0 million at December 31, 2014 and 2013, respectively, have been reflected within Other Liabilities on the Company's Consolidated Balance Sheets.

Statements Of Operations Of The Joint Ventures

The combined summarized statements of operations of the Company's joint ventures are as follows:



	For the year ended December 31,
	2014			2013			2012
	(in thousands)
Total revenue (1)	$	158,161		$	311,548		$	564,205
Expenses
Operating	62,974			105,319			162,665
Depreciation and amortization	37,041			86,088			163,134
Total expenses	100,015			191,407			325,799
Operating income	58,146			120,141			238,406
Other income (expense)
Interest expense	(31,896		)	(112,535		)	(224,645		)
Losses from early extinguishments of debt	—			(1,677		)	—
Income from continuing operations	26,250			5,929			13,761
Gains on sales of real estate	—			14,207			990
Net income	$	26,250		$	20,136		$	14,751

Company’s share of net income	$	11,913		$	4,612		$	6,863
Gains on sales of real estate	—			54,501			—
Basis differential	856			(1,017		)	1,732
Elimination of inter-entity interest on partner loan	—			16,978			40,483
Income from unconsolidated joint ventures	$	12,769		$	75,074		$	49,078
Gains on consolidation of joint ventures	$	—		$	385,991		$	—

_______________

(1)

Mortgage Notes Payable Schedule of Aggregate Principal Payments on Mortgage Notes (Tables)

12 Months Ended

Dec. 31, 2014

Mortgage Notes Payable [Abstract]

Schedule of Aggregate Principal Payments On Mortgage Notes [Table Text Block]

Contractual aggregate principal payments of mortgage notes payable at December 31, 2014 are as follows:



	Principal Payments
	(in thousands)
2015	$	26,184
2016	608,879
2017	2,821,750
2018	18,633
2019	19,670
Thereafter	675,657
Total aggregate principal payments	4,170,773
Unamortized balance of historical fair value adjustments	138,711
Total carrying value of mortgage notes payable	$	4,309,484

Unsecured Senior Notes (Tables)

12 Months Ended

Dec. 31, 2014

Debt Disclosure [Abstract]

Schedule of Senior Notes

The following summarizes the unsecured senior notes outstanding as of December 31, 2014 (dollars in thousands):



	Coupon/ Stated Rate		Effective Rate(1)		Principal Amount			Maturity Date(2)
10 Year Unsecured Senior Notes	5.875	%	5.967	%	$	700,000		October 15, 2019
10 Year Unsecured Senior Notes	5.625	%	5.708	%	700,000			November 15, 2020
10 Year Unsecured Senior Notes	4.125	%	4.289	%	850,000			May 15, 2021
7 Year Unsecured Senior Notes	3.700	%	3.853	%	850,000			November 15, 2018
11 Year Unsecured Senior Notes	3.850	%	3.954	%	1,000,000			February 1, 2023
10.5 Year Unsecured Senior Notes	3.125	%	3.279	%	500,000			September 1, 2023
10.5 Year Unsecured Senior Notes	3.800	%	3.916	%	700,000			February 1, 2024

Total principal					5,300,000
Net unamortized discount					(12,296		)
Total					$	5,287,704

_______________


(1)	Yield on issuance date including the effects of discounts on the notes and the amortization of financing costs.


(2)	No principal amounts are due prior to maturity.

Noncontrolling Interests (Tables)

12 Months Ended

Dec. 31, 2014

Noncontrolling Interest [Abstract]

Schedule of Redeemable Interest in Property Partnerships [Table Text Block]



Balance at December 31, 2011	$	—
Acquisition-date fair value of redeemable interest	98,787
Net loss	(719		)
Distributions	(3,032		)
Adjustment to reflect redeemable interest at redemption value	2,522
Balance at December 31, 2012	97,558
Net loss	(1,839		)
Distributions	(4,585		)
Adjustment to reflect redeemable interest at redemption value	8,475
Balance at December 31, 2013	99,609
Net loss	(603		)
Distributions	(6,000		)
Adjustment to reflect redeemable interest at redemption value	11,686			(1)
Balance at December 31, 2014	$	104,692

_______________

(1) Includes an out-of-period adjustment totaling approximately $1.9 million (See Note 2).

Schedule Of Preferred Units

he following table reflects the activity of the noncontrolling interests—redeemable preferred units for the years ended December 31, 2014, 2013 and 2012 (in thousands):



Balance at December 31, 2011	$	145,484
Issuance of redeemable preferred units (Series Four Preferred Units)	79,405
Net income	3,497
Distributions	(3,497		)
Redemption of redeemable preferred units (Series Four Preferred Units)	(18,329		)
Reallocation of partnership interest (1)	(7,182		)
Balance at December 31, 2012	199,378
Net income	6,046
Distributions	(6,046		)
Redemption of redeemable preferred units (Series Four Preferred Units)	(43,070		)
Reallocation of partnership interest (1)	(50,562		)
Balance at December 31, 2013	105,746
Net income	1,023
Distributions	(1,023		)
Redemption of redeemable preferred units (Series Four Preferred Units)	(17,373		)
Reallocation of partnership interest (1)	(87,740		)
Balance at December 31, 2014	$	633

_____________


(1)	Includes the conversion of 666,116, 329,881 and 117,047 Series Two Preferred Units into 874,168, 432,914 and 153,605 OP Units during the years ended December 31, 2014, 2013 and 2012, respectively.

Noncontrolling Interests-Redeemable Common Units

he following table reflects the activity of the noncontrolling interests—redeemable common units for the years ended December 31, 2014, 2013 and 2012 (in thousands):



Balance at December 31, 2011	$	1,809,119
Contributions	24,588
Net income	35,200
Distributions	(41,434		)
Conversion of redeemable partnership units	(34,621		)
Unearned compensation	(883		)
Accumulated other comprehensive loss	273
Adjustment to reflect redeemable partnership units at redemption value	44,280
Balance at December 31, 2012	1,836,522
Contributions	26,398
Net income	84,236
Distributions	(83,448		)
Conversion of redeemable partnership units	(30,291		)
Unearned compensation	1,472
Accumulated other comprehensive loss	252
Adjustment to reflect redeemable partnership units at redemption value	(124,923		)
Balance at December 31, 2013	1,710,218
Contributions	23,990
Net income	50,862
Distributions	(126,948		)
Conversion of redeemable partnership units	(2,700		)
Unearned compensation	(2,813		)
Accumulated other comprehensive loss	256
Adjustment to reflect redeemable partnership units at redemption value	657,181
Balance at December 31, 2014	$	2,310,046

Noncontrolling Interests-Property Partnerships

he following table reflects the activity of the noncontrolling interests—property partnerships for the years ended December 31, 2014, 2013 and 2012 (in thousands):



Balance at December 31, 2011	$	(1,063	)
Net income	1,989
Distributions	(2,890		)
Balance at December 31, 2012	(1,964		)
Fair value of capital recorded upon consolidation	480,861
Capital contributions	257,564
Net loss	(5,290		)
Distributions	(5,039		)
Balance at December 31, 2013	726,132
Capital contributions	887,975
Net income	19,478
Distributions	(31,118		)
Balance at December 31, 2014	$	1,602,467

Partners' Capital Schedule Of Changes In Partners Capital Unit (Tables)

12 Months Ended

Dec. 31, 2014

Partners' Capital [Abstract]

Schedule Of Changes In Partners Capital Unit [Table Text Block]



	General Partner Units	Limited Partner Units	Total Partners’ Capital Units
Outstanding at December 31, 2011	1,662,715	146,444,896	148,107,611
Units issued to Boston Properties, Inc. related to Common Stock issued under the Employee Stock Purchase Plan	57	7,349	7,406
Units issued to Boston Properties, Inc. related to Common Stock issued under the Stock Option and Incentive Plan, net	216	27,816	28,032
Units issued to Boston Properties, Inc. related to Common Stock issued in exchange for OP Units	8,541	1,102,119	1,110,660
Units issued to Boston Properties, Inc. related to Common Stock issued under the “at the market” (ATM) stock offering programs	18,051	2,329,449	2,347,500
Outstanding at December 31, 2012	1,689,580	149,911,629	151,601,209
Units issued to Boston Properties, Inc. related to Common Stock issued under the Employee Stock Purchase Plan	50	6,392	6,442
Units issued to Boston Properties, Inc. related to Common Stock issued under the Stock Option and Incentive Plan, net	207	26,686	26,893
Units issued to Boston Properties, Inc. related to Common Stock issued in exchange for OP Units	7,158	922,283	929,441
Units issued to Boston Properties, Inc. related to Common Stock issued in connection with the exchange of Exchangeable Senior Notes	3,227	415,889	419,116
Outstanding at December 31, 2013	1,700,222	151,282,879	152,983,101
Units issued to Boston Properties, Inc. related to Common Stock issued under the Employee Stock Purchase Plan	555	6,409	6,964
Units issued to Boston Properties, Inc. related to Common Stock issued under the Stock Option and Incentive Plan, net	3,476	40,158	43,634
Units issued to Boston Properties, Inc. related to Common Stock issued in exchange for OP Units	6,391	73,855	80,246
Outstanding at December 31, 2014	1,710,644	151,403,301	153,113,945

Partners' Capital Schedule of changes in Series B Preferred Units (Tables)

12 Months Ended

Dec. 31, 2014

Statement of Partners' Capital [Abstract]

Schedule of changes in Series B Preferred Units [Table Text Block]



Balance at December 31, 2012	$	—
Issuance of Series B Preferred Units	193,623
Net income	8,057
Distributions	(8,057		)
Balance at December 31, 2013	193,623
Net income	10,500
Distributions	(10,500		)
Balance at December 31, 2014	$	193,623

Future Minimum Rents (Tables)

12 Months Ended

Dec. 31, 2014

Future Minimum Rents [Abstract]

Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]



Years Ending December 31,	(in thousands)
2015	$	1,796,517
2016	1,788,978
2017	1,677,005
2018	1,568,200
2019	1,483,188
Thereafter	9,097,899

Segment Information (Tables)

12 Months Ended

Dec. 31, 2014

Segment Reporting [Abstract]

Schedule Of Segment Information By Geographic Area And Property Type

Information by geographic area and property type (dollars in thousands):

For the year ended December 31, 2014:



	Boston			New York			San Francisco			Washington, DC			Total
Rental Revenue:
Class A Office	$	692,116		$	928,692		$	237,381		$	381,930		$	2,240,119
Office/Technical	23,801			—			23,840			14,344			61,985
Residential	4,528			—			—			21,665			26,193
Hotel	43,385			—			—			—			43,385
Total	763,830			928,692			261,221			417,939			2,371,682
% of Grand Totals	32.21		%	39.16		%	11.01		%	17.62		%	100.00		%
Rental Expenses:
Class A Office	270,947			315,330			85,178			131,447			802,902
Office/Technical	7,173			—			4,955			4,338			16,466
Residential	1,957			—			—			13,965			15,922
Hotel	29,236			—			—			—			29,236
Total	309,313			315,330			90,133			149,750			864,526
% of Grand Totals	35.78		%	36.47		%	10.43		%	17.32		%	100.00		%
Net operating income	$	454,517		$	613,362		$	171,088		$	268,189		$	1,507,156
% of Grand Totals	30.16		%	40.70		%	11.35		%	17.79		%	100.00		%

For the year ended December 31, 2013:



	Boston			New York			San Francisco			Washington, DC			Total
Rental Revenue:
Class A Office	$	665,991		$	725,566		$	214,755		$	381,359		$	1,987,671
Office/Technical	22,617			—			17,259			15,649			55,525
Residential	4,395			—			—			17,923			22,318
Hotel	40,330			—			—			—			40,330
Total	733,333			725,566			232,014			414,931			2,105,844
% of Grand Totals	34.82		%	34.46		%	11.02		%	19.70		%	100.00		%
Rental Expenses:
Class A Office	259,997			251,640			77,905			126,507			716,049
Office/Technical	6,879			—			3,708			4,190			14,777
Residential	1,823			—			—			10,307			12,130
Hotel	28,447			—			—			—			28,447
Total	297,146			251,640			81,613			141,004			771,403
% of Grand Totals	38.52		%	32.62		%	10.58		%	18.28		%	100.00		%
Net operating income	$	436,187		$	473,926		$	150,401		$	273,927		$	1,334,441
% of Grand Totals	32.69		%	35.51		%	11.27		%	20.53		%	100.00		%

For the year ended December 31, 2012:



	Boston			New York			San Francisco			Washington, DC			Total
Rental Revenue:
Class A Office	$	617,652		$	543,194		$	208,177		$	346,402		$	1,715,425
Office/Technical	22,460			—			494			16,264			39,218
Residential	3,936			—			—			16,632			20,568
Hotel	37,915			—			—			—			37,915
Total	681,963			543,194			208,671			379,298			1,813,126
% of Grand Totals	37.61		%	29.96		%	11.51		%	20.92		%	100.00		%
Rental Expenses:
Class A Office	242,904			187,987			75,542			111,049			617,482
Office/Technical	6,499			—			149			3,966			10,614
Residential	1,675			—			—			9,317			10,992
Hotel	28,120			—			—			—			28,120
Total	279,198			187,987			75,691			124,332			667,208
% of Grand Totals	41.85		%	28.18		%	11.34		%	18.63		%	100.00		%
Net operating income	$	402,765		$	355,207		$	132,980		$	254,966		$	1,145,918
% of Grand Totals	35.15		%	31.00		%	11.60		%	22.25		%	100.00		%

Schedule Of Reconciliation Of Net Operating Income To Net Income

The following is a reconciliation of Net Operating Income to net income attributable to Boston Properties Limited Partnership (in thousands):



	Year ended December 31,
		2014			2013		2012
Net Operating Income		$	1,507,156		$	1,334,441	$	1,145,918
Add:
Development and management services income		25,316			29,695		34,060
Income from unconsolidated joint ventures		12,769			75,074		49,078
Gains on consolidation of joint ventures		—			385,991		—
Interest and other income		8,765			8,310		10,091
Gains from investments in securities		1,038			2,911		1,389
Gains (losses) from early extinguishments of debt		(10,633		)	122		(4,453		)
Income from discontinued operations		—			8,022		9,806
Gains on sales of real estate from discontinued operations		—			115,459		38,445
Gain on forgiveness of debt from discontinued operations		—			20,736		—
Gains on sales of real estate		174,686			—		—
Less:
General and administrative expense		98,937			115,329		90,129
Transaction costs		3,140			1,744		3,653
Depreciation and amortization expense		620,064			552,589		437,692
Interest expense		455,743			446,880		410,970
Impairment loss		—			4,401		—
Impairment loss from discontinued operations		—			2,852		—
Noncontrolling interest in property partnerships		30,561			1,347		3,792
Noncontrolling interest—redeemable preferred units		1,023			6,046		3,497
Preferred distributions		10,500			8,057		—
Net income attributable to Boston Properties Limited Partnership common unitholders		$	499,129		$	841,516	$	334,601

Earnings Per Common Unit (Tables)

12 Months Ended

Dec. 31, 2014

Earnings Per Share [Abstract]

Computation Of Basic And Diluted Earnings Per Unit

Included in the number of units (the denominator) below are approximately 17,364,000, 16,925,000 and 17,649,000 redeemable common units for the years ended December 31, 2014, 2013 and 2012, respectively.



	For the Year Ended December 31, 2014
	Income (Numerator)		Units (Denominator)	Per Unit Amount
	(in thousands, except for per unit amounts)
Basic Earnings:
Net income attributable to Boston Properties Limited Partnership common unitholders	$	499,129	170,453	$	2.93
Effect of Dilutive Securities:
Stock Based Compensation	—		219	(0.01		)
Diluted Earnings:
Net income attributable to Boston Properties Limited Partnership common unitholders	$	499,129	170,672	$	2.92



	For the Year Ended December 31, 2013
	Income (Numerator)			Units (Denominator)	Per Unit Amount
	(in thousands, except for per unit amounts)
Basic Earnings:
Income from continuing operations attributable to Boston Properties Limited Partnership	$	700,151		169,126	$	4.14
Discontinued operations attributable to Boston Properties Limited Partnership	141,365			—	0.84
Allocation of undistributed earnings to participating securities	(178		)	—	(0.01		)
Net income attributable to Boston Properties Limited Partnership common unitholders	$	841,338		169,126	$	4.97
Effect of Dilutive Securities:
Stock Based Compensation and Exchangeable Senior Notes	—			320	—
Diluted Earnings:
Net income attributable to Boston Properties Limited Partnership common unitholders	$	841,338		169,446	$	4.97

	For the Year Ended December 31, 2012
	Income (Numerator)			Units (Denominator)	Per Unit Amount
	(in thousands, except for per unit amounts)
Basic Earnings:
Income from continuing operations attributable to Boston Properties Limited Partnership	$	286,350		167,769	$	1.70
Discontinued operations attributable to Boston Properties Limited Partnership	48,251			—	0.29
Net income attributable to Boston Properties Limited Partnership common unitholders	$	334,601		167,769	$	1.99
Effect of Dilutive Securities:
Stock Based Compensation and Exchangeable Senior Notes	—			591	—
Diluted Earnings:
Net income attributable to Boston Properties Limited Partnership common unitholders	$	334,601		168,360	$	1.99

Stock Option and Incentive Plan Stock Option and Incentive Plan and Stock Purchase Plan (Tables)

12 Months Ended

Dec. 31, 2014

Stock Option and Incentive Plan and Stock Purchase Plan [Abstract]

Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block]



	Shares		Weighted Average Exercise Price
Outstanding at December 31, 2011	155,623		$	89.35
Granted	186,007		$	107.23
Exercised	(22,823	)	$	72.42
Canceled	(24,280	)	$	100.15
Outstanding at December 31, 2012	294,527		$	101.06
Granted	252,220		$	104.50
Special dividend adjustment	12,076		$	100.44
Outstanding at December 31, 2013	558,823		$	100.43
Exercised	(21,459	)	$	97.04
Canceled	(2,444	)	$	103.57
Special dividend adjustment	18,392		$	97.22
Outstanding at December 31, 2014	553,312		$	97.21

Schedule of Stock Options Outstanding [Table Text Block]

The following table summarizes information about stock options outstanding at December 31, 2014:



Options Outstanding				Options Exercisable
Number Outstanding at 12/31/14	Weighted-Average Remaining Contractual Life	Exercise Price		Number Exercisable at 12/31/14	Exercise Price
124,513	3.6 years	$	87.70	111,832	$	87.70
53,759	8.3 years	$	96.62	13,439	$	96.62
207,064	4.9 years	$	99.41	150,024	$	99.41
167,976	4.4 years	$	101.75	135,848	$	101.75

Selected Interim Financial Information (unaudited) (Tables)

12 Months Ended

Dec. 31, 2014

Quarterly Financial Information Disclosure [Abstract]

Schedule of Quarterly Financial Information [Table Text Block]



	2014 Quarter Ended
	March 31,		June 30,		September 30,		December 31,
	(in thousands, except for per unit amounts)
Total revenue	$	574,694	$	589,794	$	618,803	$	613,707
Income from continuing operations	$	69,781	$	97,927	$	111,066	$	87,753
Net income attributable to Boston Properties Limited Partnership common unitholders	$	62,219	$	87,436	$	144,715	$	204,759
Income attributable to Boston Properties Limited Partnership per unit—basic	$	0.37	$	0.51	$	0.85	$	1.20
Income attributable to Boston Properties Limited Partnership per unit—diluted	$	0.37	$	0.51	$	0.85	$	1.20



	2013 Quarter Ended
	March 31,		June 30,		September 30,		December 31,
	(in thousands, except for per unit amounts)
Total revenue	$	477,826	$	510,033	$	571,481	$	576,199
Income from continuing operations	$	44,445	$	505,396	$	84,348	$	81,412
Net income attributable to Boston Properties Limited Partnership common unitholders	$	60,923	$	505,189	$	174,140	$	101,264
Income attributable to Boston Properties Limited Partnership per unit—basic	$	0.36	$	2.97	$	1.03	$	0.60
Income attributable to Boston Properties Limited Partnership per unit—diluted	$	0.36	$	2.96	$	1.02	$	0.60

Real Estate and Accumulated Depreciation Real estate and accumulated depreciation (Tables)

12 Months Ended

Dec. 31, 2014

SEC Schedule III, Real Estate and Accumulated Depreciation Disclosure [Abstract]

Real Estate And Accumulated Depreciation Disclosure [Table Text Block]

Boston Properties Limited Partnership

Schedule 3—Real Estate and Accumulated Depreciation

December 31, 2014

(dollars in thousands)



				Original				Costs Capitalized Subsequent to Acquisition		Land and Improvements		Building and Improvements		Land Held for Development		Development and Construction in Progress		Total		Accumulated Depreciation		Year(s) Built/ Renovated	Depreciable Lives (Years)
Property Name	Type	Location	Encumbrances	Land		Building		Costs Capitalized Subsequent to Acquisition		Land and Improvements		Building and Improvements		Land Held for Development		Development and Construction in Progress		Total		Accumulated Depreciation		Year(s) Built/ Renovated	Depreciable Lives (Years)
767 Fifth Avenue (The General Motors Building)	Office	New York, NY	1,421,083	$	1,796,252	$	1,532,654	$	19,627	$	1,796,252	$	1,552,281	$	—	$	—	$	3,348,533	$	80,075	1968	(1)
Embarcadero Center	Office	San Francisco, CA	354,680	179,697		847,410		254,939		180,420		1,101,626		—		—		1,282,046		495,091		1970/1989	(1)
Prudential Center	Office	Boston, MA	—	92,077		734,594		319,846		92,328		1,018,741		404		35,044		1,146,517		411,161		1965/1993/2002	(1)
399 Park Avenue	Office	New York, NY	—	339,200		700,358		50,022		339,200		750,380		—		—		1,089,580		232,464		1961	(1)
The John Hancock Tower and Garage	Office	Boston, MA	649,108	219,543		667,884		74,060		219,616		740,863		1,008		—		961,487		104,888		1976	(1)
601 Lexington Avenue	Office	New York, NY	710,932	241,600		494,782		188,718		279,281		645,819		—		—		925,100		221,412		1977/1997	(1)
250 West 55th Street	Office	New York, NY	—	285,263		603,167		—		285,263		603,167		—		—		888,430		9,240		2014	(1)
Times Square Tower	Office	New York, NY	—	165,413		380,438		46,509		159,694		432,666		—		—		592,360		144,194		2004	(1)
100 Federal Street	Office	Boston, MA	—	131,067		435,954		9,711		131,067		445,432		233		—		576,732		44,931		1971-1975	(1)
Carnegie Center	Office	Princeton, NJ	—	105,107		377,259		65,735		98,733		437,666		2,350		9,352		548,101		180,935		1983-1999	(1)
Atlantic Wharf	Office	Boston, MA	—	63,988		454,537		15,169		63,988		469,706		—		—		533,694		55,070		2011	(1)
Fountain Square	Office	Reston, VA	220,133	56,853		306,298		6,938		56,853		313,236		—		—		370,089		27,645		1986-1990	(1)
510 Madison Avenue	Office	New York, NY	—	103,000		253,665		12,912		103,000		266,577		—		—		369,577		24,871		2012	(1)
680 Folsom Street	Office	San Francisco, CA	—	106,510		185,801		—		106,510		185,801		—		—		292,311		4,161		2014	(1)
599 Lexington Avenue	Office	New York, NY	750,000	81,040		100,507		101,407		81,040		201,914		—		—		282,954		148,356		1986	(1)
South of Market and Democracy Tower	Office	Reston, VA	—	13,603		237,479		9,454		13,603		246,933		—		—		260,536		60,626		2008-2009	(1)
Bay Colony Corporate Center	Office	Waltham, MA	—	18,789		148,451		58,126		18,789		206,577		—		—		225,366		31,089		1985-1989	(1)
Gateway Center	Office	San Francisco, CA	—	28,255		139,245		46,379		29,029		184,850		—		—		213,879		86,679		1984/1986/2002	(1)
2200 Pennsylvania Avenue	Office	Washington, DC	—	—		183,541		5,141		—		188,682		—		—		188,682		26,612		2011	(1)
Mountain View Research Park	Office	Mountain View, CA	—	95,066		68,373		3,267		95,066		71,640		—		—		166,706		6,044		1977-1981/2007-2013	(1)
3100-3130 Zanker Road (formerly 3200 Zanker Road)	Office	San Jose, CA	—	36,705		82,863		27,751		36,705		106,861		3,753		—		147,319		25,721		1988	(1)



Reservoir Place	Office	Waltham, MA	—	18,605	92,619	30,657		19,099	122,774	8	—	141,881	56,766	1955/1987	(1)
505 9th Street	Office	Washington, DC	118,919	38,885	83,719	5,409		42,011	86,002	—	—	128,013	23,331	2007	(1)
Kingstowne Towne Center	Office	Alexandria, VA	31,364	18,021	109,038	849		18,021	109,887	—	—	127,908	29,800	2003-2006	(1)
1333 New Hampshire Avenue	Office	Washington, DC	—	34,032	85,660	4,553		34,032	90,213	—	—	124,245	32,028	1996	(1)
1330 Connecticut Avenue	Office	Washington, DC	—	25,982	82,311	11,766		25,982	94,077	—	—	120,059	31,959	1984	(1)
Weston Corporate Center	Office	Weston, MA	—	25,753	92,312	(123	)	25,854	92,088	—	—	117,942	13,972	2010	(1)
Capital Gallery	Office	Washington, DC	—	4,725	29,565	77,947		6,128	106,109	—	—	112,237	51,604	1981/2006	(1)
One Freedom Square	Office	Reston, VA	—	9,929	84,504	13,261		9,883	97,811	—	—	107,694	35,957	2000	(1)
Two Freedom Square	Office	Reston, VA	—	13,930	77,739	13,351		13,866	91,154	—	—	105,020	37,225	2001	(1)
One and Two Reston Overlook	Office	Reston, VA	—	16,456	66,192	20,902		15,074	88,476	—	—	103,550	34,527	1999	(1)
415 Main Street (formerly Seven Cambridge Center)	Office	Cambridge, MA	—	3,457	97,136	210		3,457	97,346	—	—	100,803	53,022	2006	(1)
355 Main Street (formerly Five Cambridge Center)	Office	Cambridge, MA	—	18,863	53,346	25,601		21,098	76,712	—	—	97,810	20,817	1981/1996/2013	(1)
Discovery Square	Office	Reston, VA	—	11,198	71,782	14,432		11,146	86,266	—	—	97,412	31,385	2001	(1)
140 Kendrick Street	Office	Needham, MA	—	18,095	66,905	10,880		18,095	77,785	—	—	95,880	19,519	2000	(1)
90 Broadway (formerly Four Cambridge Center)	Office	Cambridge, MA	—	19,104	52,078	13,501		20,741	63,942	—	—	84,683	12,401	1983/1998/2013	(1)
77 CityPoint	Office	Waltham, MA	—	13,847	60,383	3,058		13,847	63,441	—	—	77,288	14,625	2008	(1)
230 CityPoint	Office	Waltham, MA	—	13,189	49,823	14,127		13,189	63,950	—	—	77,139	18,760	1992	(1)
Waltham Weston Corporate Center	Office	Waltham, MA	—	10,385	60,694	5,118		10,350	65,847	—	—	76,197	21,645	2003	(1)
North First Business Park	Office	San Jose, CA	—	58,402	13,069	4,005		23,371	16,197	35,908	—	75,476	12,174	1981	(1)
300 Binney Street (Seventeen Cambridge Center)	Office	Cambridge, MA	—	18,080	51,262	165		18,080	51,427	—	—	69,507	2,938	2013	(1)
2440 West El Camino Real	Office	Mountain View, CA	—	16,741	51,285	716		16,741	52,001	—	—	68,742	6,400	1987/2003	(1)
Wisconsin Place	Office	Chevy Chase, MD	—	—	53,349	12,787		—	66,136	—	—	66,136	14,300	2009	(1)
Reston Corporate Center	Office	Reston, VA	—	9,135	50,857	2,750		9,496	53,246	—	—	62,742	22,099	1984	(1)
New Dominion Technology Park, Bldg. Two	Office	Herndon, VA	—	5,584	51,868	166		5,574	52,044	—	—	57,618	17,674	2004	(1)
Sumner Square	Office	Washington, DC	—	624	28,745	22,924		958	51,335	—	—	52,293	24,802	1985	(1)
200 West Street	Office	Waltham, MA	—	16,148	24,983	7,121		16,148	32,104	—	—	48,252	15,987	1999	(1)
New Dominion Technology Park, Bldg. One	Office	Herndon, VA	40,975	3,880	43,227	1,073		3,880	44,300	—	—	48,180	20,681	2001	(1)
191 Spring Street	Office	Lexington, MA	—	2,850	27,166	17,359		2,850	44,525	—	—	47,375	30,882	1971/1995	(1)
255 Main Street (formerly One Cambridge Center)	Office	Cambridge, MA	—	134	25,110	18,940		134	44,050	—	—	44,184	26,889	1987	(1)
University Place	Office	Cambridge, MA	12,290	—	37,091	5,344		27	42,408	—	—	42,435	21,913	1985	(1)
2600 Tower Oaks Boulevard	Office	Rockville, MD	—	4,243	31,125	5,761		4,244	36,885	—	—	41,129	16,625	2001	(1)
Quorum Office Park	Office	Chelmsford, MA	—	3,750	32,454	4,116		4,762	35,558	—	—	40,320	13,423	2001	(1)
150 Broadway (formerly Eight Cambridge Center)	Office	Cambridge, MA	—	850	25,042	6,502		822	31,572	—	—	32,394	12,264	1999	(1)
500 E Street	Office	Washington, DC	—	109	22,420	9,780		1,569	30,740	—	—	32,309	21,054	1987	(1)



325 Main Street (formerly Three Cambridge Center)	Office	Cambridge, MA	—	174	12,200	11,003		772	22,605	—	—	23,377	10,364	1987/2013	(1)
105 Broadway (formerly Ten Cambridge Center)	Office	Cambridge, MA	—	1,299	12,943	4,745		1,868	17,119	—	—	18,987	11,590	1990	(1)
40 Shattuck Road	Office	Andover, MA	—	709	14,740	1,961		709	16,701	—	—	17,410	6,046	2001	(1)
201 Spring Street	Office	Lexington, MA	—	2,849	15,303	(1,253	)	2,849	14,050	—	—	16,899	6,324	1997	(1)
Lexington Office Park	Office	Lexington, MA	—	998	1,426	13,177		1,073	14,528	—	—	15,601	11,219	1982	(1)
92-100 Hayden Avenue	Office	Lexington, MA	—	594	6,748	7,090		619	13,813	—	—	14,432	10,541	1985	(1)
91 Hartwell Avenue	Office	Lexington, MA	—	784	6,464	6,120		784	12,584	—	—	13,368	7,547	1985	(1)
181 Spring Street	Office	Lexington, MA	—	1,066	9,520	1,573		1,066	11,093	—	—	12,159	4,242	1999	(1)
33 Hayden Avenue	Office	Lexington, MA	—	266	3,234	8,150		266	11,384	—	—	11,650	5,450	1979	(1)
195 West Street	Office	Waltham, MA	—	1,611	6,652	3,278		1,611	9,930	—	—	11,541	6,456	1990	(1)
145 Broadway (formerly Eleven Cambridge Center)	Office	Cambridge, MA	—	121	5,535	4,465		121	10,000	—	—	10,121	7,430	1984	(1)
7501 Boston Boulevard, Building Seven	Office	Springfield, VA	—	665	9,273	15		665	9,288	—	—	9,953	4,027	1997	(1)
7435 Boston Boulevard, Building One	Office	Springfield, VA	—	392	3,822	3,105		486	6,833	—	—	7,319	5,677	1982	(1)
7450 Boston Boulevard, Building Three	Office	Springfield, VA	—	1,165	4,681	1,466		1,327	5,985	—	—	7,312	2,983	1987	(1)
453 Ravendale Drive	Office	Mountain View, CA	—	5,477	1,090	230		5,477	1,320	—	—	6,797	213	1977	(1)
8000 Grainger Court, Building Five	Office	Springfield, VA	—	366	4,282	2,090		453	6,285	—	—	6,738	5,042	1984	(1)
7500 Boston Boulevard, Building Six	Office	Springfield, VA	—	138	3,749	2,005		273	5,619	—	—	5,892	4,175	1985	(1)
7300 Boston Boulevard, Building Thirteen	Office	Springfield, VA	—	608	4,773	18		608	4,791	—	—	5,399	4,193	2002	(1)
7601 Boston Boulevard, Building Eight	Office	Springfield, VA	—	200	878	4,133		378	4,833	—	—	5,211	3,571	1986	(1)
250 Binney Street (formerly Fourteen Cambridge Center)	Office	Cambridge, MA	—	110	4,483	569		110	5,052	—	—	5,162	3,835	1983	(1)
8000 Corporate Court, Building Eleven	Office	Springfield, VA	—	136	3,071	1,260		687	3,780	—	—	4,467	2,432	1989	(1)
7375 Boston Boulevard, Building Ten	Office	Springfield, VA	—	23	2,685	822		47	3,483	—	—	3,530	2,333	1988	(1)
7374 Boston Boulevard, Building Four	Office	Springfield, VA	—	241	1,605	1,346		303	2,889	—	—	3,192	2,172	1984	(1)
7451 Boston Boulevard, Building Two	Office	Springfield, VA	—	249	1,542	1,348		535	2,604	—	—	3,139	2,081	1982	(1)
32 Hartwell Avenue	Office	Lexington, MA	—	168	1,943	223		168	2,166	—	—	2,334	1,584	1968-1979/1987	(1)
164 Lexington Road	Office	Billerica, MA	—	592	1,370	117		592	1,487	—	—	2,079	708	1982	(1)
17 Hartwell Avenue	Office	Lexington, MA	—	26	150	861		26	995	16	—	1,037	687	1968	(1)
Residences on The Avenue, 2221 I St., NW	Residential	Washington, DC	—	—	119,874	(28	)	—	119,846	—	—	119,846	11,039	2011	(1)
The Avant at Reston Town Center	Residential	Reston, VA	—	20,350	91,995	—		20,350	91,995	—	—	112,345	2,397	2014	(1)
The Lofts at Atlantic Wharf	Residential	Boston, MA	—	3,529	54,891	1,543		3,529	56,434	—	—	59,963	5,093	2011	(1)
Boston Marriott Cambridge (formerly Cambridge Center Marriott)	Hotel	Cambridge, MA	—	478	37,918	33,269		478	71,187	—	—	71,665	46,709	1986	(1)
Cambridge Center East Garage	Garage	Cambridge, MA	—	—	35,035	1,147		—	36,182	—	—	36,182	7,579	1984	(1)
Cambridge Center West Garage	Garage	Cambridge, MA	—	1,256	15,697	859		1,256	16,556	—	—	17,812	3,700	2006	(1)
Cambridge Center North Garage	Garage	Cambridge, MA	—	1,163	11,633	1,105		1,163	12,738	—	—	13,901	8,252	1990	(1)



Salesforce Tower	Development	San Francisco, CA	—				—		—		345,303		—		—		—		345,303		345,303		—		N/A	N/A
601 Massachusetts Avenue	Development	Washington, DC	—				—		—		189,161		—		—		—		189,161		189,161		—		N/A	N/A
535 Mission Street	Development	San Francisco, CA	—				—		—		171,096		10,789		39,307		—		121,000		171,096		225		N/A	N/A
10 CityPoint	Development	Waltham, MA	—				—		—		21,370		—		—		—		21,370		21,370		—		N/A	N/A
690 Folsom Street	Development	San Francisco, CA	—				—		—		13,237		1,777		6,546		—		4,914		13,237		11		N/A	N/A
Springfield Metro Center	Land	Springfield, VA	—				—		—		32,445		—		—		32,445		—		32,445		—		N/A	N/A
Reston Signature Site	Land	Reston, VA	—				—		—		30,256		—		—		30,256		—		30,256		—		N/A	N/A
Plaza at Almaden	Land	San Jose, CA	—				—		—		29,006		—		—		29,006		—		29,006		—		N/A	N/A
Tower Oaks Master Plan	Land	Rockville, MD	—				—		—		28,919		—		—		28,919		—		28,919		—		N/A	N/A
214 Third Avenue (formerly Prospect Hill)	Land	Waltham, MA	—				—		—		23,255		—		132		12,956		10,167		23,255		—		N/A	N/A
Washingtonian North	Land	Gaithersburg, MD	—				—		—		18,813		—		—		18,813		—		18,813		—		N/A	N/A
6601 & 6605 Springfield Center Drive	Land	Springfield, VA	—				—		—		13,866		—		—		13,866		—		13,866		—		N/A	N/A
103 Fourth Avenue	Land	Waltham, MA	—				—		—		11,920		—		—		11,920		—		11,920		—		N/A	N/A
Reston Gateway	Land	Reston, VA	—				—		—		9,933		—		—		9,933		—		9,933		—		N/A	N/A
Reston Eastgate	Land	Reston, VA	—				—		—		8,817		—		—		8,817		—		8,817		—		N/A	N/A
Crane Meadow	Land	Marlborough, MA	—				—		—		8,726		—		—		8,726		—		8,726		—		N/A	N/A
Broad Run Business Park	Land	Loudoun County, VA	—				—		—		6,311		—		—		6,311		—		6,311		—		N/A	N/A
20 CityPoint	Land	Waltham, MA	—				—		—		4,801		—		—		4,801		—		4,801		—		N/A	N/A
Cambridge Master Plan	Land	Cambridge, MA	—				—		—		3,527		—		—		3,527		—		3,527		—		N/A	N/A
North First Master Plan	Land	San Jose, CA	—				—		—		1,664		—		—		1,664		—		1,664		—		N/A	N/A
425 Fourth Street	Land	San Francisco, CA	—				—		—		1,261		—		—		1,261		—		1,261		—		N/A	N/A
30 Shattuck Road	Land	Andover, MA	—				—		—		1,213		—		—		1,213		—		1,213		—		N/A	N/A
			$	4,309,484	(2	)	$	4,661,817	$	11,331,324	$	2,793,431	$	4,680,181	$	13,101,966	$	268,114	$	736,311	$	18,786,572	$	3,458,640

The aggregate cost and accumulated depreciation for tax purposes was approximately $16.0 billion and $2.9 billion, respectively.


(1)	Depreciation of the buildings and improvements are calculated over lives ranging from the life of the lease to 40 years.


(2)	Includes the unamortized balance of the historical fair value adjustment totaling approximately $138.7 million.

Reconciliation of Real Estate and Accumulated Depreciation (Tables)

12 Months Ended

Dec. 31, 2014

Real Estate and Accumulated Depreciation [Abstract]

US SEC Schedule III, Reconciliation of Real Estate Accumulated Depreciation [Table Text Block]

A summary of activity for real estate and accumulated depreciation is as follows:



	2014			2013			2012
Real Estate:
Balance at the beginning of the year	$	18,523,277		$	14,431,521		$	12,922,967
Additions to/improvements of real estate	594,296			4,410,622			1,602,583
Assets sold/written-off	(331,001		)	(318,866		)	(94,029		)
Balance at the end of the year	$	18,786,572		$	18,523,277		$	14,431,521
Accumulated Depreciation:
Balance at the beginning of the year	$	3,081,040		$	2,862,302		$	2,577,118
Depreciation expense	447,667			411,860			359,442
Assets sold/written-off	(70,067		)	(193,122		)	(74,258		)
Balance at the end of the year	$	3,458,640		$	3,081,040		$	2,862,302

Organization (Details) ft² in Millions	12 Months Ended
Organization (Details) ft² in Millions	Dec. 31, 2014 ft² a Vehicles Real_Estate_Properties $ / shares yr shares	Dec. 31, 2013 shares
Real Estate Properties [Line Items]
General and limited partnership interest in the operating partnership (percent)	89.50%	89.50%
Restriction on redemption of OP units from date of issuance (years) \| yr	1
One OP unit is equivalent to one share of Common Stock (in shares) \| shares	1
OP unit conversion rate (in shares) \| shares	1
Number of series of preferred units outstanding	2
Number of vehicles in structured parking \| Vehicles	43,824
Area of parking (in square feet) \| ft²	15.0
Area of undeveloped land parcels owned (in acres) \| a	490.8
Commercial Real Estate Properties [Member]
Real Estate Properties [Line Items]
Number of real estate properties	169
Net Rentable Area \| ft²	45.8
Total Properties Under Construction [Member]
Real Estate Properties [Line Items]
Number of real estate properties	10
Net Rentable Area \| ft²	3.3
Total Office Properties [Member]
Real Estate Properties [Line Items]
Number of real estate properties	160
Class A Office Properties [Member]
Real Estate Properties [Line Items]
Number of real estate properties	129
Office Properties Under Construction [Member]
Real Estate Properties [Line Items]
Number of real estate properties	9
Office/Technical Properties [Member]
Real Estate Properties [Line Items]
Number of real estate properties	31
Hotel Properties [Member]
Real Estate Properties [Line Items]
Number of real estate properties	1
Retail Properties [Member]
Real Estate Properties [Line Items]
Number of real estate properties	5
Retail property under construction [Member]
Real Estate Properties [Line Items]
Number of real estate properties	1
Residential Properties [Member]
Real Estate Properties [Line Items]
Number of real estate properties	3
Series Four Preferred Units [Member]
Real Estate Properties [Line Items]
Preferred Units Liquidation Preference \| $ / shares	$ 50.00
Quarterly distribution to Series Four Preferred Units \| $ / shares	$ 0.25
Series Four Preferred Units Annual Dividend Payable Rate	2.00%
Series B Cumulative Redeemable Preferred Stock [Member]
Real Estate Properties [Line Items]
Preferred Stock, Shares Outstanding \| shares	80,000	80,000
Preferred Stock, Dividend Rate, Percentage	5.25%
Series B Preferred Units [Member]
Real Estate Properties [Line Items]
Preferred Stock, Shares Outstanding \| shares	80,000

Summary Of Significant Accounting Policies (Narrative) (Details)	12 Months Ended
	Dec. 31, 2014 USD ($) yr	Dec. 31, 2013 USD ($)	Dec. 31, 2012 USD ($)
Significant Acquisitions and Disposals [Line Items]
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	$ (193,394,000)	$ (140,097,000)
Probable Sale Term of Property After Classified As Held For Sale (Years) \| yr	1
Maximum Period After Construction The Company Considers A Construction Project As Substantially Completed (In Years) \| yr	1
Interest Costs Capitalized	$ 52,476,000	68,152,000	$ 44,278,000
Salaries And Related Costs Capitalized	8,500,000	7,700,000	7,100,000
Cash FDIC Insured Limit	250,000
Separate Unrestricted Cash For Deferred Compensation Plan.	19,500,000	16,600,000
Gains from investments in securities	1,038,000	2,911,000	1,389,000
Internal Leasing Salaries And Related Costs Capitalized	6,000,000	5,100,000	5,600,000
Straight Line Rent Adjustments	(63,100,000)	(65,800,000)	(77,600,000)
Above And Below Market Rent Adjustments	$ 48,300,000	28,000,000	14,600,000
Ground Lease Expiration Date, Maximum	2068
Net Difference Between Tax Basis And Company's Assets And Liabilities.	$ 1,400,000,000	900,000,000
Misstatement of real estate operating expense	1,900,000
Interest and other income	8,765,000	8,310,000	10,091,000
Preferred Distributions	10,500,000	8,057,000	$ 0
Unconsolidated Joint Ventures [Member]
Significant Acquisitions and Disposals [Line Items]
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	$ 11,400,000	$ 14,000,000

Summary Of Significant Accounting Policies Schedule of Estimated Useful Lives (Details)	12 Months Ended
	Dec. 31, 2014
Land Improvements [Member] \| Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life (years)	25 years
Land Improvements [Member] \| Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life (years)	40 years
Building and improvements [Member] \| Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life (years)	10 years
Building and improvements [Member] \| Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life (years)	40 years
Tenant Improvements [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life, description	Shorter of useful life or terms of related lease
Furniture, fixtures and equipment [Member] \| Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life (years)	3 years
Furniture, fixtures and equipment [Member] \| Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life (years)	7 years

Summary Of Significant Accounting Policies (Carrying Value Of Indebtedness And Corresponding Estimate Of Fair Value) (Details) - USD ($)
$ in Thousands

Dec. 31, 2014

Dec. 31, 2013

Summary Of Significant Accounting Policies [Line Items]

$ 4,309,484

$ 4,449,734

Unsecured exchangeable senior notes

309,796

311,040

Unsecured senior notes

5,287,704

5,835,854

744,880

Impact of accounting pronouncement

4,170,773

2,400

Carrying Amount [Member]

Summary Of Significant Accounting Policies [Line Items]

4,309,484

4,449,734

Unsecured exchangeable senior notes

309,796

311,040

Unsecured senior notes

5,287,704

5,835,854

744,880

^[1]

Estimated Fair Value [Member]

9,906,984

11,341,508

Summary Of Significant Accounting Policies [Line Items]

4,449,541

4,545,283

Unsecured exchangeable senior notes

306,156

311,064

Unsecured senior notes

5,645,819

6,050,517

750,266

ASC 470-20 Adjustment [Member]

$ 10,401,516

11,657,130

Summary Of Significant Accounting Policies [Line Items]

Impact of accounting pronouncement

$ 2,400

[1]	(1)Includes the net adjustment for the equity component allocation totaling approximately $2.4 million at December 31, 2013.

Summary Of Significant Accounting Policies Schedule Of Future Contractual Minimum Lease Payments Under Non-Cancelable Ground Leases (Details) $ in Thousands	Dec. 31, 2014 USD ($)
Summary of Significant Accounting Policies [Abstract]
2015	$ 13,507
2016	13,732
2017	13,963
2018	14,198
2019	14,461
Thereafter	$ 884,726

Summary Of Significant Accounting Policies GAAP Reconciliation Of Net Income To Taxable Income (Details) - USD ($)
$ in Thousands

12 Months Ended

Dec. 31, 2014

Dec. 31, 2013

Dec. 31, 2012

Reconciliaton of GAAP to taxable income [Abstract]

One-time deduction for Tangible Repair Regulations

$ 430,100

Net income attributable to Boston Properties Limited Partnership

509,629

$ 849,573

$ 334,601

Straight-line rent adjustments

(102,319)

(82,904)

(89,982)

Book/Tax differences from depreciation and amortization

253,590

174,384

106,862

Income Tax Reconciliation, Book/Tax Differences On Interest Expense

(48,128)

(8,811)

31,003

Book/Tax differences on gains/losses from capital transactions

1,065,518

(138,300)

(24,958)

Book/Tax differences from stock-based compensation

36,232

46,935

22,035

Income Tax Reconciliation, Book/Tax Differences On Tngible Property Regulations

(493,731)

^[1]

Other book/tax differences, net

(11,403)

8,589

11,001

Taxable Income

$ 1,209,388

$ 849,466

$ 390,562

[1]

Summary Of Significant Accounting Policies Schedule of Finite Lived Intangible Assets Future Amortization Expense (Details) $ in Thousands	Dec. 31, 2014 USD ($)
Finite-Lived Intangible Assets [Line Items]
2015	$ 66,390
2016	55,327
2017	38,812
2018	33,964
2019	27,439
Acquired Above-Market Lease Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
2015	22,671
2016	20,491
2017	12,277
2018	8,637
2019	7,106
Acquired Below-Market Lease Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
2015	57,019
2016	51,460
2017	35,896
2018	33,215
2019	$ 27,615

Real Estate (Narrative) (Details)												3 Months Ended								7 Months Ended	9 Months Ended		12 Months Ended
Real Estate (Narrative) (Details)	Dec. 30, 2014 USD ($)	Oct. 30, 2014 USD ($) ft² floor	Oct. 24, 2014 USD ($) ft²	Oct. 02, 2014 USD ($) ft² Buildings	Aug. 22, 2014 USD ($) a	Aug. 20, 2014 USD ($)	Jul. 29, 2014 USD ($) ft² Buildings	Apr. 10, 2014 ft² floor	May 31, 2013 USD ($) ft² partners	Apr. 10, 2013 USD ($) ft²	May 23, 2011 USD ($) ft² yr	Dec. 31, 2014 USD ($)	Sep. 30, 2014 USD ($)	Jun. 30, 2014 USD ($)	Mar. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Sep. 30, 2013 USD ($)	Jun. 30, 2013 USD ($)	Mar. 31, 2013 USD ($)	Dec. 31, 2013 USD ($)	Oct. 03, 2014 USD ($)	Dec. 31, 2013 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Dec. 31, 2012 USD ($)	Nov. 12, 2014 USD ($) ft²	Nov. 06, 2014 USD ($)	Nov. 01, 2014 ft²	Oct. 22, 2014 USD ($) ft² leaseyear	Sep. 17, 2014 ft²	Aug. 31, 2014 ft²	May 20, 2014 ft²	Apr. 03, 2014 ft²	Apr. 01, 2014 ft²	Feb. 10, 2014 ft² apartments	Feb. 07, 2014	Oct. 09, 2013 ft²	Apr. 10, 2013 USD ($)	Apr. 10, 2013 Buildings	Feb. 26, 2013
Real Estate Properties [Line Items]
Gains on consolidation of joint ventures																							$ 0	$ 385,991,000	$ 0
Payments to Acquire and Develop Real Estate																							405,942,000	396,835,000	356,397,000
Impairment loss from discontinued operations																							0	2,852,000	0
Revenue contributed by acquisitions												$ 613,707,000	$ 618,803,000	$ 589,794,000	$ 574,694,000	$ 576,199,000	$ 571,481,000	$ 510,033,000	$ 477,826,000				2,396,998,000	2,135,539,000	1,847,186,000
Earnings																							810,331,000	690,073,000	648,504,000
Gain on forgiveness of debt from discontinued operations																							0	20,736,000	0
Proceeds from sales of real estate																							419,864,000	250,078,000	61,963,000
Gains on sales of real estate																							174,686,000	0	0
Gains on sales of real estate from discontinued operations																							0	115,459,000	38,445,000
Impairment loss																							0	4,401,000	0
Development and management services																							$ 25,316,000	29,695,000	34,060,000
425 Fourth Street [Member]
Real Estate Properties [Line Items]
Non-refundable option payment																											$ 1,000,000
Mountain View Research And Technology Parks [Member]
Real Estate Properties [Line Items]
Gains on consolidation of joint ventures										$ 26,500,000
Net Rentable Area \| ft²										604,000
Aggregate purchase price																																						$ 233,084,000
Revenue contributed by acquisitions																						$ 16,700,000
Earnings																						$ 400,000
Number of real estate properties \| Buildings																																							16
Mountain View Technology [Member]
Real Estate Properties [Line Items]
Number of real estate properties										135,000																													7
767 5th Avenue (The General Motors Building) [Member]
Real Estate Properties [Line Items]
Gains on consolidation of joint ventures									$ 359,500,000
Net Rentable Area \| ft²									1,800,000
Number of Joint Venture Partners \| partners									2
Revenue contributed by acquisitions																				$ 168,400,000
Earnings																				$ 8,400,000
767 5th Avenue (The General Motors Building) [Member] \| Consolidated Properties [Member]
Real Estate Properties [Line Items]
Partners Joint Venture Ownership Percentage									40.00%
804 carnegie center [Member]
Real Estate Properties [Line Items]
Aggregate purchase price																										$ 3,700,000
Area of Real Estate Property \| ft²																										130,000
Mountain View Technology Park and Mountain View Research Building Sixteen [Member]
Real Estate Properties [Line Items]
Proceeds from sales of real estate							$ 90,600,000
Gains on sales of real estate							35,900,000
Sale Price Of Sold Property							$ 92,100,000
Land at One Reston Overlook [Member]
Real Estate Properties [Line Items]
Proceeds from sales of real estate						$ 2,600,000
Gains on sales of real estate						$ 1,200,000
Land Parcel Within Broad Run Business Park [Member]
Real Estate Properties [Line Items]
Proceeds from sales of real estate					$ 9,700,000
Gains on sales of real estate					$ 4,300,000
Area of Land \| a					15.5
Sale Price Of Sold Property					$ 9,800,000
Patriots park [Member]
Real Estate Properties [Line Items]
Earnings																					$ 8,200,000			$ 10,800,000	$ 5,300,000
Proceeds from sales of real estate				$ 319,100,000
Rental revenue supoprt payments to buyer maximum				12,300,000
Gains on sales of real estate				$ 91,200,000
Number of real estate properties \| Buildings				3
Area of Real Estate Property \| ft²				706,000
Sale Price Of Sold Property				$ 321,000,000
415 Main Street (formerly Seven Cambridge Center) [Member]
Real Estate Properties [Line Items]
Area of Real Estate Property \| ft²																													231,000
130 Third Avenue [Member]
Real Estate Properties [Line Items]
Proceeds from sales of real estate			$ 13,600,000
Gains on sales of real estate			$ 8,300,000
Area of Real Estate Property \| ft²			129,000
Sale Price Of Sold Property			$ 14,300,000
75 Ames Street [Member]
Real Estate Properties [Line Items]
Gains on sales of real estate	$ 33,800,000
Area of Real Estate Property \| ft²											250,000
Proceeds from the sale of a condominium interest in real estate											$ 56,800,000
Development and management services											$ 11,400,000
Ground lease term (Years) \| yr											99
Ground lease revenue											$ 459,000
690 Folsom Street [Member]
Real Estate Properties [Line Items]
Area of Real Estate Property \| ft²																																	25,000
535 Mission Street [Member]
Real Estate Properties [Line Items]
Area of Real Estate Property \| ft²																												307,000
Mountain View Research Building Sixteen [Member] \| Mountain View Technology Park and Mountain View Research Building Sixteen [Member]
Real Estate Properties [Line Items]
Area of Real Estate Property \| ft²							63,000
Mountain View Technology [Member] \| Mountain View Technology Park and Mountain View Research Building Sixteen [Member]
Real Estate Properties [Line Items]
Number of real estate properties \| Buildings							7
Area of Real Estate Property \| ft²							135,000
Eight Eight Eight Boylston Street [Member]
Real Estate Properties [Line Items]
Area of Real Estate Property \| ft²																																425,000
Nine Nine Third Avenue [Member]
Real Estate Properties [Line Items]
Area of Real Estate Property \| ft²																																		17,000
The Avant at Reston Town Center Residential [Member]
Real Estate Properties [Line Items]
Number of apartment units \| apartments																																			359
Area of Real Estate Property \| ft²																																			355,000
Salesforce Tower [Member] \| Consolidated Properties [Member]
Real Estate Properties [Line Items]
Number of floors in building \| floor								61
Area of Real Estate Property \| ft²								1,400,000
Noncontrolling Interest, Ownership Percentage by Parent								95.00%
Square Footage Of Signed Lease \| ft²								714,000
10 CityPoint [Member]
Real Estate Properties [Line Items]
Area of Real Estate Property \| ft²																																245,000
250 West 55thStreet [Member]
Real Estate Properties [Line Items]
Area of Real Estate Property \| ft²																															988,000
680 Folsom Street [Member]
Real Estate Properties [Line Items]
Area of Real Estate Property \| ft²																														525,000
415 Main Street (formerly Seven Cambridge Center) [Member]
Real Estate Properties [Line Items]
Purchase option date (lease year) \| leaseyear																													11
Purchase Option Price for Real Estate Property																													$ 106,000,000
767 5th Avenue (The General Motors Building) [Member]
Real Estate Properties [Line Items]
Number of Joint Venture Partners \| partners									2
Noncontrolling Interests [Member] \| Consolidated Properties [Member]
Real Estate Properties [Line Items]
Net Rentable Area \| ft²																																					1,246,000
Number of Joint Venture Partners \| partners									2
Noncontrolling Interests [Member] \| 601 Lexington Avenue, Atlantic Wharf Office Building and One Hundred Federal Street [Member] \| Consolidated Properties [Member]
Real Estate Properties [Line Items]
Ownership Percentage		45.00%
Disposal Group, Including Discontinued Operation, Secured Debt		$ 712,900,000
Proceeds from sale of an interest in a real estate asset		1,497,000,000
Difference between net cash proceeds received and noncontrolling interest recognized		648,400,000
Noncontrolling Interest, Increase from Sale of Parent Equity Interest		849,000,000
Sale Price Of Sold Property		$ 1,827,000,000
Noncontrolling Interests [Member] \| One Hundred Federal Street [Member] \| 601 Lexington Avenue, Atlantic Wharf Office Building and One Hundred Federal Street [Member] \| Consolidated Properties [Member]
Real Estate Properties [Line Items]
Area of Real Estate Property \| ft²		1,323,000
Noncontrolling Interests [Member] \| Salesforce Tower [Member] \| Consolidated Properties [Member]
Real Estate Properties [Line Items]
Ownership Percentage																																				50.00%				5.00%
Noncontrolling Interest, Ownership Percentage by Parent																																								95.00%
Noncontrolling Interests [Member] \| 601 Lexington Avenue [Member] \| 601 Lexington Avenue, Atlantic Wharf Office Building and One Hundred Federal Street [Member] \| Consolidated Properties [Member]
Real Estate Properties [Line Items]
Area of Real Estate Property \| ft²		1,669,000
Noncontrolling Interests [Member] \| Atlantic Wharf Office [Member] \| 601 Lexington Avenue, Atlantic Wharf Office Building and One Hundred Federal Street [Member] \| Consolidated Properties [Member]
Real Estate Properties [Line Items]
Area of Real Estate Property \| ft²		791,000
Noncontrolling Interests [Member] \| Low Rise [Member] \| 601 Lexington Avenue [Member] \| 601 Lexington Avenue, Atlantic Wharf Office Building and One Hundred Federal Street [Member] \| Consolidated Properties [Member]
Real Estate Properties [Line Items]
Number of floors in building \| floor		6
Noncontrolling Interests [Member] \| Office Tower [Member] \| 601 Lexington Avenue [Member] \| 601 Lexington Avenue, Atlantic Wharf Office Building and One Hundred Federal Street [Member] \| Consolidated Properties [Member]
Real Estate Properties [Line Items]
Number of floors in building \| floor		59
related to rental support payment [Member] \| Patriots park [Member]
Real Estate Properties [Line Items]
Area of Real Estate Property \| ft²				17,762

Real Estate Schedule of Real Estate Properties (Details) - USD ($) $ in Thousands	Dec. 31, 2014	Dec. 31, 2013
Real Estate [Abstract]
Land	$ 4,680,181	$ 4,342,951
Land held for future development	268,114	297,376
Buildings and improvements	11,349,851	10,742,370
Tenant improvements	1,752,115	1,617,401
Furniture, fixtures and equipment	27,986	25,164
Construction in progress	736,311	1,523,179
Total	18,814,558	18,548,441
Less: accumulated depreciation	(3,476,321)	(3,096,910)
Total real estate	$ 15,338,237	$ 15,451,531

Real Estate (Schedule Of Allocation Of The Aggregate Purchase Price Of Acquisition) (Details) - USD ($)
$ in Thousands

12 Months Ended

May 31, 2013

Apr. 10, 2013

Dec. 31, 2014

Dec. 31, 2013

Dec. 31, 2012

Real estate and related intangibles recorded upon consolidation

$ 0

$ 3,356,000

$ 0

4,309,484

4,449,734

Outside members' notes payable

309,796

311,040

180,000

Debt recorded upon consolidation

2,056,000

Cash and cash equivalents

79,468

Accrued interest payable

163,532

167,523

Working capital recorded upon consolidation

177,315

Noncontrolling interests recorded upon consolidation

$ 0

$ 480,861

$ 0

767 5th Avenue (The General Motors Building) [Member]

Building and improvements

Land

$ 1,796,252

1,447,446

Tenant Improvements

85,208

In-place lease intangibles

357,781

Above market rents

101,897

Below market rents

239,641

Above Market Assumed Debt Adjustments

192,943

Real estate and related intangibles recorded upon consolidation

3,356,000

1,300,000

Outside members' notes payable

306,000

^[1]

450,000

Debt recorded upon consolidation

2,056,000

Cash and cash equivalents

79,468

Cash held in escrows

2,403

Tenant and other receivables

7,104

Prepaid expense and other assets

4,269

Accounts payable and accrued expenses

2,418

Accrued interest payable

^[2]

182,369

Other Liabilities

6,304

Working capital recorded upon consolidation

97,847

Noncontrolling Interest

520,000

Noncontrolling interest - working capital

39,139

Noncontrolling interests recorded upon consolidation

480,861

Net Assets Recorded Upon Consolidation

721,292

Mountain View Research And Technology Parks [Member]

Building and improvements

Land

$ 126,521

82,451

Tenant Improvements

7,326

In-place lease intangibles

23,279

Above market rents

843

Below market rents

7,336

Aggregate purchase price

$ 233,084

Consolidation, Eliminations [Member] | 767 5th Avenue (The General Motors Building) [Member]

Outside members' notes payable

270,000

Accrued interest payable

$ 105,500

[1]	(1)The Company's member loan totaling $270.0 million eliminates in consolidation.
[2]	(2)The Company's share of the accrued interest payable on the members' loans totaling approximately $105.5 million eliminates in consolidation.

Real Estate (Pro Forma In Connection With Acquisition) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Real Estate [Abstract]
Total revenue	$ 2,257,098	$ 2,149,391
Income from continuing operations	314,307	642,640
Net income attributable to Boston Properties Limited Partnership	$ 452,813	$ 710,690
Basic earnings per unit: Net income per unit attributable to Boston Properties Limited Partnership (in dollars per unit)	$ 2.68	$ 4.21
Diluted earnings per unit: Net income per unit attributable to Boston Properties Limited Partnership (in dollars per unit)	$ 2.67	$ 4.20

Real Estate (Summary Of The Discontinued Operations Related To Bedford Business Park) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total revenue	$ 613,707	$ 618,803	$ 589,794	$ 574,694	$ 576,199	$ 571,481	$ 510,033	$ 477,826	$ 2,396,998	$ 2,135,539	$ 1,847,186
Expenses
Depreciation and amortization									620,064	552,589	437,692
Total expenses									1,586,667	1,445,466	1,198,682
Operating income									810,331	690,073	648,504
Other Expenses
Interest expense									455,743	446,880	410,970
Income from discontinued operations attributable to Boston Properties Limited Partnership										141,365	48,251
Gain on sale of real estate from discontinued operations attributable to Boston Properties Limited Partnership									0	115,459	38,445
Gain on forgiveness of debt from discontinued operations									0	20,736	0
Impairment loss from discontinued operations									$ 0	(2,852)	0
10 & 20 Burlington Mall Road, One Preserve Parkway, 1301 New York Avenue, 303 Almaden Blvd, Montvale Center and Bedford Business Park [Member] [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total revenue											32,607
Expenses
Operating											12,038
Depreciation and amortization											8,169
Total expenses											20,207
Operating income											12,400
Other Expenses
Interest expense											2,594
Income from discontinued operations attributable to Boston Properties Limited Partnership											9,806
Gain on sale of real estate from discontinued operations attributable to Boston Properties Limited Partnership											38,445
Gain on forgiveness of debt from discontinued operations											0
Impairment loss from discontinued operations											$ 0
Montvale Center, 303 Almaden Blvd, 1301 New York Avenue, One Preserve Parkway and 10 & 20 Burlington Mall Road [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total revenue										20,138
Expenses
Operating										6,996
Depreciation and amortization										4,760
Total expenses										11,756
Operating income										8,382
Other Expenses
Interest expense										360
Income from discontinued operations attributable to Boston Properties Limited Partnership										8,022
Gain on sale of real estate from discontinued operations attributable to Boston Properties Limited Partnership										115,459
Gain on forgiveness of debt from discontinued operations										20,736
Impairment loss from discontinued operations										$ (2,852)

Deferred Charges (Details) - USD ($) $ in Thousands	Dec. 31, 2014	Dec. 31, 2013
Deferred Charges [Abstract]
Leasing costs, including lease related intangibles	$ 1,234,192	$ 1,183,204
Financing costs	69,127	76,798
Deferred charges gross	1,303,319	1,260,002
Less: Accumulated amortization	471,575	375,552
Deferred charges, total	$ 831,744	$ 884,450

Deferred Charges Schedule of Acquired In-Place Lease Intangibles (Details) $ in Thousands	Dec. 31, 2014 USD ($)
Deferred Charges [Abstract]
2015	$ 66,390
2016	55,327
2017	38,812
2018	33,964
2019	$ 27,439

Investments in Unconsolidated Joint Ventures (Investments in Unconsolidated Joint Ventures) (Details)
$ in Thousands

12 Months Ended

Apr. 10, 2014

USD ($)

ft²

Dec. 31, 2014

USD ($)

ft²

Land_Parcels

Buildings

payments

Dec. 31, 2013

USD ($)

Dec. 31, 2012

USD ($)

Schedule of Equity Method Investments [Line Items]

Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures

$ 52,052

$ 0

$ 6,214

193,394

140,097

Investments In Affiliates Subsidiaries Associates And Joint Ventures, net

^[1]

182,042

Schedule of Equity Method Investments [Line Items]

Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures

$ (11,400)

$ (14,000)

Square 407 Limited Partnership

Schedule of Equity Method Investments [Line Items]

Market Square North

Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures

50.00%

^[1]

$ (8,022)

The Metropolitan Square Associates LLC

Schedule of Equity Method Investments [Line Items]

Metropolitan Square

Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures

51.00%

$ 8,539

BP/CRF 901 New York Avenue LLC

Schedule of Equity Method Investments [Line Items]

901 New York Avenue

Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures

^[2]

25.00%

^[1]

$ (1,080)

WP Project Developer LLC

Schedule of Equity Method Investments [Line Items]

Wisconsin Place Land and Infrastructure

Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures

^[3]

33.30%

$ 45,514

Annapolis Junction NFM, LLC

Schedule of Equity Method Investments [Line Items]

Annapolis Junction

Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures

^[4]

50.00%

$ 25,246

Number of real estate properties | Buildings

Number of buildings under construction | Buildings

Parcels of undeveloped land | Land_Parcels

540 Madison Venture LLC

Schedule of Equity Method Investments [Line Items]

540 Madison Avenue

Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures

60.00%

$ 68,128

500 North Capitol LLC

Schedule of Equity Method Investments [Line Items]

500 North Capitol Street, NW

Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures

30.00%

^[1]

$ (2,250)

Entity Owning Land And Infrastructure Of Project [Member]

Schedule of Equity Method Investments [Line Items]

Schedule of Equity Method Investments [Line Items]

33.30%

501 K Street LLC

520,000

$ 39,000

1001 6th Street (formerly 501 K Street)

Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures

^[5]

50.00%

$ 41,736

Potential additonal payments to joint venture partner | payments

Minimum square footage to make a potential additional payment to joint venture partner (in sqft) | ft²

520,000

Podium Developer LLC

Schedule of Equity Method Investments [Line Items]

North Station (Phase I - Air Rights)

Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures

50.00%

$ 4,231

[1]	Investments with deficit balances aggregating approximately $11.4 million have been reflected within Other Liabilities on the Company's Consolidated Balance Sheets.
[2]	The Company’s economic ownership has increased based on the achievement of certain return thresholds.
[3]	The Company’s wholly-owned entity that owns the office component of the project also owns a 33.3% interest in the entity owning the land, parking garage and infrastructure of the project.
[4]	The joint venture owns two in-service buildings, two buildings under construction and two undeveloped land parcels
[5]	Under the joint venture agreement, the partner will be entitled to up to two additional payments from the venture based on increases in total square footage of the project above 520,000 square feet and achieving certain project returns at stabilization.

Investments in Unconsolidated Joint Ventures (Balance Sheets of the Unconsolidated Joint Ventures) (Details) - USD ($)
$ in Thousands

Dec. 31, 2014

Dec. 31, 2013

ASSETS

Real estate and development in process, net

$ 15,338,237

$ 15,451,531

LIABILITIES AND MEMBERS'/PARTNERS' EQUITY

Other liabilities

502,255

592,982

Total liabilities and capital

19,536,260

19,810,601

Carrying value of the Company's investments in unconsolidated joint ventures

193,394

140,097

Real estate and development in process, net

ASSETS

1,034,552

924,297

Other assets

264,097

163,149

Total assets

1,298,649

1,087,446

LIABILITIES AND MEMBERS'/PARTNERS' EQUITY

Other liabilities

34,211

28,830

Members'/Partners' equity

434,363

308,884

Total liabilities and capital

1,298,649

1,087,446

Company’s share of equity

209,828

154,726

Basis differentials

^[1]

(27,786)

(28,642)

Carrying value of the Company's investments in unconsolidated joint ventures

^[2]

182,042

126,084

LIABILITIES AND MEMBERS'/PARTNERS' EQUITY

Carrying value of the Company's investments in unconsolidated joint ventures

$ (11,400)

$ (14,000)

[1]

[2]

Investments with deficit balances aggregating approximately $11.4 million and $14.0 million at December 31, 2014 and 2013, respectively, have been reflected within Other Liabilities on the Company's Consolidated Balance Sheets.

Investments in Unconsolidated Joint Ventures (Statements of Operations of the Joint Ventures) (Details) - USD ($)
$ in Thousands

3 Months Ended

12 Months Ended

Dec. 31, 2014

Sep. 30, 2014

Jun. 30, 2014

Mar. 31, 2014

Dec. 31, 2013

Sep. 30, 2013

Jun. 30, 2013

Mar. 31, 2013

Dec. 31, 2014

Dec. 31, 2013

Dec. 31, 2012

Schedule of Equity Method Investments [Line Items]

Total revenue

$ 613,707

$ 618,803

$ 589,794

$ 574,694

$ 576,199

$ 571,481

$ 510,033

$ 477,826

$ 2,396,998

$ 2,135,539

$ 1,847,186

Expenses

Depreciation and amortization

620,064

552,589

437,692

Total expenses

1,586,667

1,445,466

1,198,682

Operating income

810,331

690,073

648,504

Other income (expense)

Interest expense

(455,743)

(446,880)

(410,970)

Losses from early extinguishments of debt

(10,633)

122

(4,453)

Income from continuing operations

366,527

715,601

293,639

Income from unconsolidated joint ventures

541,213

856,966

341,890

12,769

75,074

49,078

Straight-line rent adjustments

63,100

65,800

77,600

Below market rent adjustments, net

48,300

28,000

14,600

Gains on consolidation of joint ventures

385,991

Schedule of Equity Method Investments [Line Items]

Total revenue

^[1]

158,161

311,548

564,205

Expenses

Operating

62,974

105,319

162,665

Depreciation and amortization

37,041

86,088

163,134

Total expenses

100,015

191,407

325,799

Operating income

58,146

120,141

238,406

Other income (expense)

Interest expense

(31,896)

(112,535)

(224,645)

Losses from early extinguishments of debt

(1,677)

Income from continuing operations

26,250

5,929

13,761

Gains on sales of real estate

14,207

990

Company’s share of net income

26,250

20,136

14,751

11,913

4,612

6,863

Gains on sales of real estate

54,501

Basis differential

856

(1,017)

1,732

Elimination of inter-entity interest on partner loan

16,978

40,483

Income from unconsolidated joint ventures

12,769

75,074

49,078

Straight-line rent adjustments

3,000

7,800

12,000

Below market rent adjustments, net

(100)

33,700

91,100

Lease termination income

19,600

Company share of lease termination income

11,800

Gains on consolidation of joint ventures

$ 0

$ 385,991

$ 0

[1]

Investments in Unconsolidated Joint Ventures Investment in Unconsolidated Joint Ventures (Narrative) (Details)
$ in Thousands

12 Months Ended

Dec. 19, 2014

USD ($)

ft²

Dec. 17, 2014

USD ($)

Oct. 24, 2014

USD ($)

ft²

Oct. 23, 2014

Jun. 23, 2014

USD ($)

Apr. 30, 2014

USD ($)

ft²

Apr. 10, 2014

USD ($)

ft²

Dec. 31, 2014

USD ($)

payments

Dec. 31, 2013

USD ($)

Dec. 31, 2012

USD ($)

Schedule of Equity Method Investments [Line Items]

Repayments of Secured Debt

$ 87,758

$ 80,311

$ 253,877

(Losses) gains from early extinguishments of debt

52,052

6,214

(10,633)

122

(4,453)

Gains on consolidation of joint ventures

$ 0

$ 385,991

$ 0

501 K Street LLC

Schedule of Equity Method Investments [Line Items]

^[1]

50.00%

520,000

Potential additonal payments to joint venture partner | payments

$ 39,000

Annapolis Junction Building Six [Member]

Schedule of Equity Method Investments [Line Items]

125,000

Construction Loan Facility Borrowing Capacity

$ 5,400

$ 26,000

Debt Instrument, Basis Spread on Variable Rate

1.50%

Extension Option (in years) | yr

Jun. 23, 2017

Number of extensions

Annapolis Junction Building Six [Member]

Schedule of Equity Method Investments [Line Items]

Area of Real Estate Property | ft²

119,000

901 New York Avenue [Member]

Schedule of Equity Method Investments [Line Items]

First phase of North Station [Member]

25.00%

Schedule of Equity Method Investments [Line Items]

Company [Member] | 501 K Street LLC

377,000

Schedule of Equity Method Investments [Line Items]

Company [Member] | Annapolis Junction Building Six [Member]

50.00%

Schedule of Equity Method Investments [Line Items]

Company [Member] | First phase of North Station [Member]

50.00%

Schedule of Equity Method Investments [Line Items]

50.00%

joint venture partner [Member] | 501 K Street LLC

$ 4,200

Schedule of Equity Method Investments [Line Items]

joint venture partner [Member] | First phase of North Station [Member]

50.00%

Schedule of Equity Method Investments [Line Items]

50.00%

First Mortgage [Member] | 901 New York Avenue [Member]

$ 13,000

Schedule of Equity Method Investments [Line Items]

Proceeds from mortgage notes payable

3.61%

$ 225,000

Prior to refinance first mortgage loan [Member] | 901 New York Avenue [Member]

Schedule of Equity Method Investments [Line Items]

Repayments of Secured Debt

$ 150,400

Construction Loans [Member] | Annapolis Junction Building Six [Member]

5.19%

Schedule of Equity Method Investments [Line Items]

Debt Instrument, Description of Variable Rate Basis

LIBOR

Construction Loan Facility Borrowing Capacity

50.00%

$ 16,400

Debt Instrument, Basis Spread on Variable Rate

2.25%

1.65%

Construction Loan

$ 13,900

Maximum [Member] | Company [Member] | First phase of North Station [Member]

Schedule of Equity Method Investments [Line Items]

$ 8,800

[1]	Under the joint venture agreement, the partner will be entitled to up to two additional payments from the venture based on increases in total square footage of the project above 520,000 square feet and achieving certain project returns at stabilization.

Mortgage Notes Payable Schedule Of Aggregate Principal Payments On Mortgage Notes (Details) - USD ($) $ in Thousands	Dec. 31, 2014	Dec. 31, 2013
Mortgage Notes Payable [Abstract]
2015	$ 26,184
2016	608,879
2017	2,821,750
2018	18,633
2019	19,670
Thereafter	675,657
Total	4,170,773
Unamoritzed balance of histroical fair value adjustments	138,711
Total carrying value of mortgage notes payable	$ 4,309,484	$ 4,449,734

Mortgage Notes Payable (Narrative) (Details)	3 Months Ended	12 Months Ended
Mortgage Notes Payable (Narrative) (Details)	Sep. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Dec. 31, 2012 USD ($)	Jul. 01, 2014
Mortgage Notes Payable [Line Items]
Mortgage notes payable		$ 4,309,484,000	$ 4,449,734,000
Final maturity date of mortgage notes		Apr. 10, 2022
Outside members' notes payable		$ 180,000,000	180,000,000
Gain on forgiveness of debt from discontinued operations		0	20,736,000	$ 0
Repayments of mortgage notes payable		87,758,000	80,311,000	253,877,000
(Losses) gains from early extinguishments of debt		$ (10,633,000)	$ 122,000	(4,453,000)
Number Of Mortgage Loans Accounted For Fair Value		4	4
Outstanding balance of mortgage loans accounted for at fair value		$ 2,200,000,000	$ 2,184,800,000
Interest Expense Decrease Due To Recording Mortgage Loans At Fair Value		52,500,000	34,400,000	$ 7,000,000
Cumulative Liability Related to the Fair Value of Debt Adjustment		138,700,000	191,200,000
Accrued interest payable		163,532,000	167,523,000
Fixed Rate Mortgages [Member]
Mortgage Notes Payable [Line Items]
Mortgage notes payable		$ 4,300,000,000	$ 4,400,000,000
Contractual interest rate range, minimum		4.75%	4.75%
Contractual interest rate range, maximum		7.69%	9.93%
Contractual interest rate weighted average interest rate		5.70%	5.70%
Variable Rate Mortgages [Member]
Mortgage Notes Payable [Line Items]
Number of variable rate mortgage loans		0	0
London Interbank Offered Rate		0.17%	0.17%
Mortgages [Member] \| New Dominion Technology Park, Bldg. Two [Member]
Mortgage Notes Payable [Line Items]
Repayments of mortgage notes payable	$ 63,000,000
Interest at a fixed rate (percent)					5.55%
Penalty for early repayment of debt	$ 0.00
Minimum [Member]
Mortgage Notes Payable [Line Items]
Number Real Estate Assets Used For Mortgage Loan Collateral		1	1

Unsecured Senior Notes Schedule of Unsecured Senior Notes (Details) - USD ($)
$ in Thousands

12 Months Ended

Dec. 31, 2014

Dec. 31, 2013

Debt instrument principal due prior to maturity

$ 0

Net unamortized discount

(12,296)

$ (14,146)

5,287,704

$ 5,835,854

Senior Notes [Member]

5,300,000

Net unamortized discount

(12,296)

Senior Notes [Member] | Ten Year Unsecured Senior Notes Five Point Nine Six Seven Percent [Member]

$ 5,287,704

5.875%

^[1]

5.967%

$ 700,000

Senior Notes [Member] | Ten Year Unsecured Senior Notes Five Point Seven Zero Eight Percent [Member]

^[2]

Oct. 15, 2019

5.625%

^[1]

5.708%

$ 700,000

Senior Notes [Member] | Ten Year Unsecured Senior Notes Four Point Two Eight Nine Percent [Member]

^[2]

Nov. 15, 2020

4.125%

^[1]

4.289%

$ 850,000

Senior Notes [Member] | Seven Year Unsecured Senior Notes Three Point Eight Five Three Percent [Member]

^[2]

May 15, 2021

3.70%

^[1]

3.853%

$ 850,000

Senior Notes [Member] | Eleven Year Unsecured Senior Notes Three Point Nine Five Four Percent [Member]

^[2]

Nov. 15, 2018

3.85%

^[1]

3.954%

$ 1,000,000

Senior Notes [Member] | Ten and Half Year Unsecured Senior Notes Three Point Two Seven Nine Percent [Member]

^[2]

Feb. 01, 2023

3.125%

^[1]

3.279%

$ 500,000

Senior Notes [Member] | Ten and Half Year Unsecured Senior Notes Three Point Nine One Six Percent [Member]

^[2]

Sep. 01, 2023

3.80%

^[1]

3.916%

$ 700,000

Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]

^[2]

Feb. 01, 2024

[1]	Yield on issuance date including the effects of discounts on the notes and the amortization of financing costs.
[2]	principal amounts are due prior to maturity.

Unsecured Senior Notes Unsecured Senior Notes (Narrative) (Details) - USD ($) $ in Thousands		12 Months Ended
	Dec. 15, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Debt Instrument [Line Items]
Proceeds from unsecured senior notes		$ 0	$ 1,194,753	$ 997,790
Maximum Secured Debt Leverage Ratio		55.00%
Repayments of Unsecured Debt		$ 548,016	0	224,261
(Losses) gains from early extinguishments of debt		$ (10,633)	$ 122	$ (4,453)
Senior Notes [Member]
Debt Instrument [Line Items]
Maximum Leverage Ratio		60.00%
Maximum Secured Debt Leverage Ratio		50.00%
Minimum Interest Coverage Ratio		1.50
Minimum Unencumbered Asset Value Percentage Of Unsecured Debt		150.00%
(Losses) gains from early extinguishments of debt	$ (10,600)
Payment Of debt redemption premium	10,500
Senior Notes [Member] \| 5.625% Percent Unsecured Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 300,000
Coupon/Stated Rate (percent)	5.625%
Repayments of Unsecured Debt	$ 308,000
Debt Instrument, Increase, Accrued Interest	$ 2,800
Debt Instrument, Redemption Price, Percentage	101.73%
Senior Notes [Member] \| 5.000% Unsecured Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 250,000
Coupon/Stated Rate (percent)	5.00%
Repayments of Unsecured Debt	$ 255,800
Debt Instrument, Increase, Accrued Interest	$ 500
Debt Instrument, Redemption Price, Percentage	102.13%

Unsecured Exchangeable Senior Notes (Narrative) (Details) - USD ($) $ in Thousands		12 Months Ended
	Feb. 18, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Debt Instrument [Line Items]
Debt Instrument, Convertible, Carrying Amount of Equity Component		$ 0	$ 91,900
Debt Instrument Convertible Initial Carrying Amount Of The Equity Component		230,300
Deferred Financing Costs Equity Component		1,000
Amount paid for repurchase		548,016	0	$ 224,261
Convertible Notes Payable		0	744,880
Net Of Adjustment For Equity Component Allocation		0	2,400
Debt Instrument, Convertible, Interest Expense		3,300	34,800	48,400
Interest Expense Adjustment Related To Convertible Debt		2,400	23,100	29,100
2.875% Exchangeable Senior Notes
Debt Instrument [Line Items]
Debt Instrument, Face Amount				$ 862,500
Coupon/Stated Rate (percent)				2.875%
Convertible Debt Effective Interest Rate				5.63%
Three Point Seven Five Zero Percent Exchangeable Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount			$ 450,000
Coupon/Stated Rate (percent)			3.75%
Convertible Debt Effective Interest Rate			5.958%
3.625% Exchangeable Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount		$ 747,500
Coupon/Stated Rate (percent)		3.625%
Convertible Debt Effective Interest Rate		6.555%
3.625% Exchangeable Senior Notes [Member] \| Unsecured Debt [Member]
Debt Instrument [Line Items]
Coupon/Stated Rate (percent)	3.625%
Amount paid for repurchase	$ 747,500

Unsecured Line of Credit (Details) $ in Thousands	12 Months Ended
Unsecured Line of Credit (Details) $ in Thousands	Dec. 31, 2014 USD ($) yr mo	Dec. 31, 2013 USD ($)
Line of Credit Facility [Line Items]
Line of Credit Facility, Current Borrowing Capacity	$ 1,000,000
Line of Credit Facility, Expiration Date	Jul. 26, 2018
Line of Credit Facility, Frequency of Commitment Fee Payment	quarterly
Line of Credit Facility, Amount Outstanding	$ 0	$ 0
Leverage Ratio, Maximum	60.00%
Leverage Ratio Maximum Increasing Limit	65.00%
Leverage Ratio Reduction Limit	60.00%
Leverage Ratio Reduction Period, Years \| yr	1
Maximum Secured Debt Leverage Ratio	55.00%
Fixed Charge Coverage Ratio Minimum.	1.40
Maximum Unsecured Debt Leverage Ratio	60.00%
Unsecured Debt Leverage Ratio Reduction Limit	60.00%
Unsecured Debt Leverage Ratio Maximum Increasing Limit	65.00%
Unsecured Debt Leverage Ratio Reduction Period, Years \| yr	1
Unsecured Debt Interest Coverage Ratio Minimum.	1.75
Alternative Base Interest Rate Calculation [Member]
Line of Credit Facility [Line Items]
Amount added to Federal Funds Rate to Calculate Interest Rate	0.50%
LIBOR Period Used to Calculate Interest Rate (in months) \| mo	1
Amount added to LIBOR to Calculate Interest Rate	1.00%
Maximum [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Current Borrowing Capacity	$ 1,500,000
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage	0.35%
Maximum [Member] \| Interest Rate Based on LIBOR or CDOR [Member]
Line of Credit Facility [Line Items]
Margin added to Calculated Interest Rate	1.70%
Maximum [Member] \| Alternative Base Interest Rate Calculation [Member]
Line of Credit Facility [Line Items]
Margin added to Calculated Interest Rate	0.70%
Minimum [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage	0.125%
Minimum [Member] \| Interest Rate Based on LIBOR or CDOR [Member]
Line of Credit Facility [Line Items]
Margin added to Calculated Interest Rate	0.925%
Minimum [Member] \| Alternative Base Interest Rate Calculation [Member]
Line of Credit Facility [Line Items]
Margin added to Calculated Interest Rate	0.00%
Rate Based on Current Credit Rating [Member] \| Interest Rate Based on LIBOR or CDOR [Member]
Line of Credit Facility [Line Items]
Margin added to Calculated Interest Rate	1.00%
Rate Based on Current Credit Rating [Member] \| Alternative Base Interest Rate Calculation [Member]
Line of Credit Facility [Line Items]
Margin added to Calculated Interest Rate	0.00%
Rate Based on Current Credit Rating [Member] \| Current Rates Based on Credit Ratings [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage	0.15%

Commitments And Contingencies (Details) $ in Millions	5 Months Ended		7 Months Ended	10 Months Ended	12 Months Ended
Commitments And Contingencies (Details) $ in Millions	Dec. 31, 2014 USD ($) Buildings	Jun. 09, 2014 USD ($)	Jul. 28, 2014 USD ($)	Oct. 22, 2014 USD ($)	Dec. 31, 2014 USD ($) Buildings	Dec. 31, 2009 USD ($)	Sep. 18, 2014 USD ($)	Jan. 10, 2014 USD ($)
Commitments And Contingencies [Line Items]
Letter of credit and performance obligations	$ 19.8				$ 19.8
Property insurance program per occurrence limits	1,000.0				1,000.0
Per occurrence limit for NBCR Coverage					1,000.0
Value of program trigger	100.0				$ 100.0
Coinsurance of program trigger (percent)					15.00%
Deductible in insurance as a percentage of the value of the affected property, San Francisco (percent)					5.00%
Per occurrence limit of the earthquake insurance which covers San Francisco region					$ 120.0
Annual aggregate limit of the earthquake insurance which covers San Francisco region					120.0
Amount of earthquake insurance provided by IXP, LLC as direct insurer San Francisco					20.0
Earthquake Coverage Included In Builders Risk Policy For 535 Mission				$ 15.0
Earthquake Coverage Included In Builders Risk Policy for below grade improvements for Salesforce Tower	60.0		$ 15.0
Operating partnership guarantee to cover liabilities of IXP	$ 20.0				$ 20.0
Number of Insurer(s)	1				1
Contractual Tax Agreements Number Of Properties \| Buildings	3				3
Expiration of Tax Protection for 767 5th Avenue (the General Motors Building)					Jun. 09, 2017
Lehman [Member]
Commitments And Contingencies [Line Items]
Bankruptcy claim, amount filed by general creditor						$ 45.3
Bankruptcy claim amount allowed by court to creditor	$ 37.5				$ 37.5			$ 45.2
Bankruptcy Claims, Amount of Claims Settled							$ 7.7
Bankruptcy claim, denominator used to evaluate claim price amount					1.00
Minimum [Member] \| Lehman [Member]
Commitments And Contingencies [Line Items]
Bankruptcy claim, price on the private market					0.24
Maximum [Member] \| Lehman [Member]
Commitments And Contingencies [Line Items]
Bankruptcy claim, price on the private market					0.25
767 Venture, LLC [Member]
Commitments And Contingencies [Line Items]
Maximum funding obligation	32.0				$ 32.0
Property insurance program per occurrence limits	$ 1,625.0				1,625.0
Coverage for acts of Terrorism certified under TRIA in excess of amount provided by NYXP, LLC, as a direct insurer		$ 1,375.0
Coverage for acts of terrorism certified under TRIA covered by NYXP		$ 250.0
Fountain Square [Member]
Commitments And Contingencies [Line Items]
Guarantee Obligation Related To Tenant Re-Leasing Costs					$ 0.7
Maturity date					Oct. 11, 2016
John Hancock Tower [Member]
Commitments And Contingencies [Line Items]
Guarantee Obligation Related To Tenant Re-Leasing Costs					$ 25.7
Maturity date					Jan. 06, 2017
601 Lexington Avenue [Member]
Commitments And Contingencies [Line Items]
Coverage For Acts Of Terrorism Under TRIA Covered in Excess of Amount Covered by IXP					$ 250.0

Noncontrolling Interests (Narrative) (Details)	Dec. 31, 2014 shares
Noncontrolling Interests [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Operating Partnership (OP) Units (in shares)	16,453,670
Long-Term Incentive Plan (LTIP) Units (in shares)	1,496,799
Series Four Preferred Units (in shares)	12,667
OPP Units 2012 [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Outperformance awards in LTIP Units (in shares)	394,590
MYLTIP 2013 [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Outperformance awards in LTIP Units (in shares)	313,936
MYLTIP 2014 [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Outperformance awards in LTIP Units (in shares)	482,032

Noncontrolling Interests (Redeemable Preferred Units) (Narrative) (Details) $ / shares in Units, $ in Millions		12 Months Ended
	May 12, 2014 $ / shares shares	Dec. 31, 2014 $ / shares shares	Dec. 31, 2013 shares	Dec. 31, 2012 shares	Nov. 17, 2014 $ / shares	Nov. 05, 2014 USD ($)	Oct. 16, 2014 shares	Sep. 30, 2014 $ / shares	Aug. 15, 2014 $ / shares	Jul. 03, 2014 USD ($)	May 19, 2014 shares	May 15, 2014 $ / shares	Feb. 18, 2014 $ / shares	Aug. 29, 2013 d $ / shares shares
Noncontrolling Interests [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Series Four Preferred Units		12,667
Series Two Preferred Units [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Units converted (in shares)		666,116	329,881	117,047
Series Two Preferred Units [Member] \| Noncontrolling Interests [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Series Two Preferred Units (in shares)	666,116
Series Two Preferred Units On Converted Basis	874,168		432,914
Liquidation preference percentage	6.00%
Operating Units liquidation preference (in dollars per share) \| $ / shares	$ 38.10
OP Units for each Preferred Unit (in shares)	1.312336
Units converted (in shares)			329,881
Distributions to Series Two Preferred Units (in dollars per share) \| $ / shares													$ 0.85302
Preferred Units Liquidation Preference \| $ / shares	$ 50.00
Series Four Preferred Units [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Preferred Units Liquidation Preference \| $ / shares		$ 50.00
Series Four Preferred Units Annual Dividend Payable Rate		2.00%
Series Four Preferred Units [Member] \| Noncontrolling Interests [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Distributions to Series Two Preferred Units (in dollars per share) \| $ / shares					$ 0.25				$ 0.25			$ 0.25	$ 0.25
Preferred Units Liquidation Preference \| $ / shares		$ 50.00						$ 50.00						$ 50.00
First opportunity to redeem Series Four Preferred Units (in days) \| d														30
Series Four Preferred Units Annual Dividend Payable Rate		2.00%
Series Four Preferred Units Redeemed														861,400
Series Four Preferred Units Released from Escrow							27,773				319,687
Redemption of Series Four Preferred Units \| $						$ 1.4				$ 16.0
OP Units [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Units converted (in shares)		874,168	432,914	153,605
Closing price of common stock (in dollars per share) \| $ / shares		$ 128.69

Noncontrolling Interests (Common Units) (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions					12 Months Ended
	Oct. 31, 2014	Jul. 31, 2014	Apr. 30, 2014	Jan. 29, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 08, 2014
OP Units [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
OP Units for redemption (in shares)					80,246	929,441
Redemption of OP units issued on conversion of Series Two Preferred Units (in shares)					3,734	432,914
Redemption of OP units issued on conversion of LTIP Units (in shares)					67,857	24,028
OPP Units and MYLTIP Units distribution prior to measurement date					10.00%
Distributions made to OP and LTIP units per unit (in dollars per share)	$ 0.65	$ 0.65	$ 0.65	$ 0.65
Distribution paid to OPP and MYLTIP Units (in dollars per share)	$ 0.065	$ 0.065	$ 0.065	0.065
Common units of operating partnership if converted value					$ 2,300.0
Distributions Declared To OP And LTIP Units Per Unit							$ 0.65
Distributions Declared To Outperformance Awards Long Term Incentive Plan Units Per Unit							0.065
OPP Units 2012 [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Outperformance awards in LTIP Units (in shares)					394,590
MYLTIP 2013 [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Outperformance awards in LTIP Units (in shares)					313,936
MYLTIP 2014 [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Outperformance awards in LTIP Units (in shares)					482,032
OP Units [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Closing price of common stock (in dollars per share)					$ 128.69
Quarter 4 2013 [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Dividend payable date					Jan. 29, 2014
Quarter 4 2013 [Member] \| OP Units [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Dividend payable date					Jan. 29, 2014
Quarter 1 2014 [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Dividend payable date					Apr. 30, 2014
Quarter 1 2014 [Member] \| OP Units [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Distribution Made to Limited Partner, Date of Record					Mar. 31, 2014
Dividend payable date					Apr. 30, 2014
Quarter 2 2014 [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Dividend payable date					Jul. 31, 2014
Quarter 2 2014 [Member] \| OP Units [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Distribution Made to Limited Partner, Date of Record					Jun. 30, 2014
Dividend payable date					Jul. 31, 2014
Quarter 3 2014 [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Dividend payable date					Oct. 31, 2014
Quarter 3 2014 [Member] \| OP Units [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Distribution Made to Limited Partner, Date of Record					Sep. 30, 2014
Dividend payable date					Oct. 31, 2014
Quarter 4 2014 [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Dividend payable date					Jan. 28, 2015
Dividends Payable, Date Declared					Dec. 08, 2014
Quarter 4 2014 [Member] \| OP Units [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Distribution Made to Limited Partner, Date of Record					Dec. 31, 2014
Dividend payable date					Jan. 28, 2015
Dividends Payable, Date Declared					Dec. 08, 2014
special dividend [Member] \| OP Units [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Distributions made to OP and LTIP units per unit (in dollars per share)				$ 2.25
Distributions Declared To OP And LTIP Units Per Unit							$ 4.50
OPP Units 2011 [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Accelerated Compensation Expenses Related To 2011 OPP Units					$ 1.2

Noncontrolling Interests (Property Partnerships) (Narrative) (Details) $ in Thousands					12 Months Ended
	Oct. 30, 2014 USD ($) ft² floor	Apr. 10, 2014 ft² floor	May 31, 2013 USD ($) ft² partners	Feb. 26, 2013	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Dec. 31, 2012 USD ($)	Feb. 07, 2014	Oct. 09, 2013 USD ($) ft²
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Noncontrolling interests recorded upon consolidation					$ 0	$ 480,861	$ 0
Noncontrolling interests in property partnerships					$ 1,602,467	$ 726,132
Consolidated Properties [Member] \| Noncontrolling Interests [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Net Rentable Area \| ft²									1,246,000
Number of Joint Venture Partners \| partners			2
767 5th Avenue (The General Motors Building) [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Net Rentable Area \| ft²			1,800,000
Number of Joint Venture Partners \| partners			2
Noncontrolling interests recorded upon consolidation			$ 480,861
767 5th Avenue (The General Motors Building) [Member] \| Consolidated Properties [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Partners Joint Venture Ownership Percentage			40.00%
Noncontrolling interests recorded upon consolidation			$ 480,900
767 5th Avenue (The General Motors Building) [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Number of Joint Venture Partners \| partners			2
601 Lexington Avenue, Atlantic Wharf Office Building and One Hundred Federal Street [Member] \| Consolidated Properties [Member] \| Noncontrolling Interests [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Ownership Percentage	45.00%
Sale Price Of Sold Property	$ 1,827,000
Disposal Group, Including Discontinued Operation, Secured Debt	712,900
Proceeds from sale of an interest in a real estate asset	1,497,000
Difference between net cash proceeds received and noncontrolling interest recognized	$ 648,400
Time Square Tower [Member] \| Consolidated Properties [Member] \| Noncontrolling Interests [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
ownership interest sold (percent)									45.00%
Net Contractual Sales Price									$ 684,000
Proceeds from sale of an interest in a real estate asset									673,100
Portion allocation to noncontrolling interest based on carrying value of the total equity of the property prior to the sale									243,500
Difference between net cash proceeds received and noncontrolling interest recognized									$ 429,600
One Hundred Federal Street [Member] \| 601 Lexington Avenue, Atlantic Wharf Office Building and One Hundred Federal Street [Member] \| Consolidated Properties [Member] \| Noncontrolling Interests [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Area of Real Estate Property \| ft²	1,323,000
601 Lexington Avenue [Member] \| 601 Lexington Avenue, Atlantic Wharf Office Building and One Hundred Federal Street [Member] \| Consolidated Properties [Member] \| Noncontrolling Interests [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Area of Real Estate Property \| ft²	1,669,000
Atlantic Wharf Office [Member] \| 601 Lexington Avenue, Atlantic Wharf Office Building and One Hundred Federal Street [Member] \| Consolidated Properties [Member] \| Noncontrolling Interests [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Area of Real Estate Property \| ft²	791,000
Salesforce Tower [Member] \| Consolidated Properties [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Number of floors in building \| floor		61
Area of Real Estate Property \| ft²		1,400,000
Noncontrolling Interest, Ownership Percentage by Parent		95.00%
Salesforce Tower [Member] \| Consolidated Properties [Member] \| Noncontrolling Interests [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Ownership Percentage				5.00%				50.00%
Noncontrolling Interest, Ownership Percentage by Parent				95.00%
maximum percentage of construction costs to allow partner to have a loan				50.00%
Portion of total costs partner can require the company to fund				2.50%
portion of partners equity that can be funded by the company				50.00%
Office Tower [Member] \| 601 Lexington Avenue [Member] \| 601 Lexington Avenue, Atlantic Wharf Office Building and One Hundred Federal Street [Member] \| Consolidated Properties [Member] \| Noncontrolling Interests [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Number of floors in building \| floor	59
Low Rise [Member] \| 601 Lexington Avenue [Member] \| 601 Lexington Avenue, Atlantic Wharf Office Building and One Hundred Federal Street [Member] \| Consolidated Properties [Member] \| Noncontrolling Interests [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Number of floors in building \| floor	6

Noncontrolling Interests (Redeemable Preferred Units) (Details) - USD ($)
$ in Thousands

12 Months Ended

Dec. 31, 2014

Dec. 31, 2013

Dec. 31, 2012

Beginning Balance

$ 105,746

$ 199,378

Redemption of redeemable preferred units (Series Four Preferred Units)

1,023

6,046

$ 3,497

(17,373)

(43,070)

(18,329)

Ending Balance

633

105,746

199,378

Redeemable Preferred Units [Member]

Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]

Beginning Balance

145,484

Issuance of redeemable preferred units (Series Four Preferred Units)

79,405

Redemption of redeemable preferred units (Series Four Preferred Units)

1,023

6,046

3,497

Distributions

(1,023)

(6,046)

(3,497)

(17,373)

(43,070)

(18,329)

Reallocation of partnership interest (1)

^[1]

$ (87,740)

$ (50,562)

$ (7,182)

Series Two Preferred Units [Member]

Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]

Units converted (in shares)

666,116

329,881

117,047

Op Units [Member]

Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]

Units converted (in shares)

874,168

432,914

153,605

[1]	Includes the conversion of 666,116, 329,881 and 117,047 Series Two Preferred Units into 874,168, 432,914 and 153,605 OP Units during the years ended December 31, 2014, 2013 and 2012, respectively.

Noncontrolling Interests (Noncontrolling Interests-Redeemable Common Units) (Details) - Noncontrolling Interests [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Activity of noncontrolling interests
Beginning Balance	$ 1,710,218	$ 1,836,522	$ 1,809,119
Contributions	23,990	26,398	24,588
Net income	50,862	84,236	35,200
Distributions	(126,948)	(83,448)	(41,434)
Conversion of redeemable partnership units	(2,700)	(30,291)	(34,621)
Unearned compensation	(2,813)	1,472	(883)
Accumulated other comprehensive loss	256	252	273
Adjustments to reflect redeemable partnership units at redemption value	657,181	(124,923)	44,280
Ending Balance	$ 2,310,046	$ 1,710,218	$ 1,836,522

Noncontrolling Interests (Noncontrolling Interests-Property Partnerships) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Activity of noncontrolling interests
Beginning balance	$ 726,132
Net income (loss)	30,561	$ 1,347	$ 3,792
Fair value of capital recorded upon consolidation	0	480,861	0
Ending balance	1,602,467	726,132
Property Partnerships [Member]
Activity of noncontrolling interests
Beginning balance	726,132	(1,964)	(1,063)
Net income (loss)	19,478	(5,290)	1,989
Distributions	(31,118)	(5,039)	(2,890)
Fair value of capital recorded upon consolidation			480,861
Capital contributions	887,975		257,564
Ending balance	$ 1,602,467	$ 726,132	$ (1,964)

Noncontrolling Interests Redeemable Interest in Property Partnerships (Details) - USD ($)
$ in Thousands

12 Months Ended

Dec. 31, 2014

Dec. 31, 2013

Dec. 31, 2012

Redeemable Interest in Property Partnership [Abstract]

Misstatement of real estate operating expense

$ 1,900

Activity of noncontrolling interests

Beginning Balance

99,609

$ 97,558

$ 0

Acquisition-date fair value of redeemable interest

98,787

Net loss

603

1,839

719

Distributions

6,000

4,585

3,032

Adjustment to reflect redeemable interest at redemption value

11,686

^[1]

8,475

2,522

Ending Balance

$ 104,692

$ 99,609

$ 97,558

[1]	(1) Includes an out-of-period adjustment totaling approximately $1.9 million (See Note 2).

Noncontrolling Interests Redeemable Interest in Property Partnerships (Narrative) (Details) - Fountain Square [Member] - Noncontrolling Interests [Member] - Consolidated Properties [Member] $ in Millions	Oct. 04, 2012 USD ($)
Noncontrolling Interest [Line Items]
Aggregate purchase price	$ 385.0
Consideration paid	$ 87.0
Noncontrolling Interest, Ownership Percentage by Parent	50.00%
Future Fixed Price to Acquire Remaining Portion of Joint venture	$ 102.0
Fixed Price Option Expiration Date	Jan. 31, 2016
Debt recorded upon consolidation	$ 211.3
Ownership Percentage	50.00%

Partners' Capital (Details)										7 Months Ended	12 Months Ended
Partners' Capital (Details)	Nov. 17, 2014 $ / shares	Oct. 31, 2014 $ / shares	Aug. 15, 2014 $ / shares	Jul. 30, 2014 $ / shares	Jun. 03, 2014 USD ($) yr	May 15, 2014 $ / shares	Apr. 30, 2014 $ / shares	Feb. 18, 2014 $ / shares	Jan. 29, 2014 $ / shares	Dec. 31, 2014 USD ($) $ / shares shares	Dec. 31, 2014 USD ($) $ / shares shares	Dec. 31, 2013 USD ($) $ / shares shares	Dec. 31, 2012 USD ($) shares	Mar. 27, 2018 $ / shares	Dec. 08, 2014 $ / shares	Jun. 02, 2014 USD ($)
Class of Stock [Line Items]
General partnership units (in shares) \| shares										1,710,644	1,710,644	1,700,222
Limited partnership units (in shares) \| shares										151,403,301	151,403,301	151,282,879
Shares of Common Stock upon the exercise of options to purchase Common Stock by certain employees (in shares) \| shares											21,459	0	22,823
Shares of its Common Stock in connection with the redemption of an equal number of OP Units (in shares) \| shares											80,246	929,441	1,110,660
Dividends Payable, Amount Per Share															$ 0.65
Dividend paid on common stock (in dollars per share)		$ 0.65		$ 0.65			$ 0.65		$ 2.90
Proceeds from Issuance of Preferred Stock and Preference Stock \| $											$ 0	$ 193,623,000	$ 0
New ATM program [Member]
Class of Stock [Line Items]
At the market stock offering program, aggregate value of common stock \| $					$ 600,000,000
At Market Stock Offering Program Maximum Length Of Sale In Years \| yr					3
ATM program amount issued \| $										$ 0
ATM Program [Member]
Class of Stock [Line Items]
At the market stock offering program, aggregate value of common stock \| $																$ 600,000,000
At Market Stock Offering Program Remained Available For Issuance \| $																$ 305,300,000
Quarter 4 2013 [Member]
Class of Stock [Line Items]
Dividend payable date											Jan. 29, 2014
Dividend shareholder of record date											Dec. 31, 2013
Quarter 4 2014 [Member]
Class of Stock [Line Items]
Dividend payable date											Jan. 28, 2015
Dividend shareholder of record date											Dec. 31, 2014
Dividends Payable, Date Declared											Dec. 08, 2014
Quarter 1 2014 [Member]
Class of Stock [Line Items]
Dividend payable date											Apr. 30, 2014
Dividend shareholder of record date											Mar. 31, 2014
Quarter 2 2014 [Member]
Class of Stock [Line Items]
Dividend payable date											Jul. 31, 2014
Dividend shareholder of record date											Jun. 30, 2014
Quarter 3 2014 [Member]
Class of Stock [Line Items]
Dividend payable date											Oct. 31, 2014
Dividend shareholder of record date											Sep. 30, 2014
Quarter 1 2015 [Member]
Class of Stock [Line Items]
Dividend payable date											Feb. 17, 2015
Dividends Payable, Date Declared											Dec. 08, 2014
Series B Preferred Units [Member]
Class of Stock [Line Items]
Preferred Stock, Shares Outstanding \| shares										80,000	80,000
Depository shares of Series B Cumulative Redeemable Preferred [Member]
Class of Stock [Line Items]
Preferred Stock, Shares Outstanding \| shares										8,000,000	8,000,000
Preferred Stock, Liquidation Preference Per Share										$ 25.00	$ 25.00			$ 25.00
Series B Cumulative Redeemable Preferred Stock [Member]
Class of Stock [Line Items]
Dividends Payable, Amount Per Share															32.8125
Dividend paid on common stock (in dollars per share)	$ 32.8125		$ 32.8125			$ 32.8125		$ 32.8125
Preferred Stock, Shares Outstanding \| shares										80,000	80,000	80,000
Preferred Stock, Dividend Rate, Percentage											5.25%
Preferred Stock, Liquidation Preference Per Share										$ 2,500.00	$ 2,500.00	$ 2,500
Series B Cumulative Redeemable Preferred Stock [Member] \| Quarter 4 2014 [Member]
Class of Stock [Line Items]
Dividend payable date											Nov. 17, 2014
Series B Cumulative Redeemable Preferred Stock [Member] \| Quarter 1 2014 [Member]
Class of Stock [Line Items]
Dividend payable date											Feb. 18, 2014
Series B Cumulative Redeemable Preferred Stock [Member] \| Quarter 2 2014 [Member]
Class of Stock [Line Items]
Dividend payable date											May 15, 2014
Series B Cumulative Redeemable Preferred Stock [Member] \| Quarter 3 2014 [Member]
Class of Stock [Line Items]
Dividend payable date											Aug. 15, 2014
Series B Cumulative Redeemable Preferred Stock [Member] \| Quarter 1 2015 [Member]
Class of Stock [Line Items]
Dividend shareholder of record date											Feb. 05, 2015
special dividend [Member]
Class of Stock [Line Items]
Dividends Payable, Amount Per Share															$ 4.50
Subsequent Event [Member] \| Series B Cumulative Redeemable Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Stock, Liquidation Preference Per Share														$ 2,500.00

Partners' Capital Changes in Issued and Outstanding Partners' Capital Units (Details) - shares	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Limited Partners' Capital Account [Line Items]
General partnership units, beginning balance	1,700,222
Limited partnership units, beginning balance	151,282,879
Partners' Capital Account, Units	152,983,101	151,601,209	148,107,611
Units issued to Boston Properties, Inc. related to Common Stock issued under the Employee Stock Purchase Plan	6,964	6,442	7,406
Units issued to Boston Properties, Inc. related to Common Stock issued under Stock Option and Incentive Plans, net	43,634	26,893	28,032
Units issued to Boston Proeprties, inc. related to Common Stock issued in exchange of OP Units	80,246	929,441	1,110,660
Units issued to Boston Properties, Inc. related to Common Stock issued under the at the market (ATM) stock offering program		419,116	2,347,500
General partnership units, ending balance	1,710,644	1,700,222
Limited partnership units, ending balance	151,403,301	151,282,879
Partners' Capital Account, Units	153,113,945	152,983,101	151,601,209
General Partner Units [Member]
Limited Partners' Capital Account [Line Items]
General partnership units, beginning balance	1,700,222	1,689,580	1,662,715
Units issued to Boston Properties, Inc. related to Common Stock issued under the Employee Stock Purchase Plan	555	50	57
Units issued to Boston Properties, Inc. related to Common Stock issued under Stock Option and Incentive Plans, net	3,476	207	216
Units issued to Boston Proeprties, inc. related to Common Stock issued in exchange of OP Units	6,391	7,158	8,541
Units issued to Boston Properties, Inc. related to Common Stock issued under the at the market (ATM) stock offering program		3,227	18,051
General partnership units, ending balance	1,710,644	1,700,222	1,689,580
Limited Partner Units [Member]
Limited Partners' Capital Account [Line Items]
Limited partnership units, beginning balance	151,282,879	149,911,629	146,444,896
Units issued to Boston Properties, Inc. related to Common Stock issued under the Employee Stock Purchase Plan	6,409	6,392	7,349
Units issued to Boston Properties, Inc. related to Common Stock issued under Stock Option and Incentive Plans, net	40,158	26,686	27,816
Units issued to Boston Proeprties, inc. related to Common Stock issued in exchange of OP Units	73,855	922,283	1,102,119
Units issued to Boston Properties, Inc. related to Common Stock issued under the at the market (ATM) stock offering program		415,889	2,329,449
Limited partnership units, ending balance	151,403,301	151,282,879	149,911,629

Partners' Capital Change in Series B Preferred Units (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Statement of Partners' Capital [Abstract]
Beginning Balance	$ 193,623	$ 0
Issuance of Series B Preferred Units		193,623
Net income	10,500	8,057
Distributions	(10,500)	(8,057)
Ending Balance	$ 193,623	$ 193,623

Future Minimum Rents Schedule of Future Minimum Renal Payments for Operating Leases (Details) $ in Thousands	Dec. 31, 2014 USD ($)
Future Minimum Rents [Abstract]
2015	$ 1,796,517
2016	1,788,978
2017	1,677,005
2018	1,568,200
2019	1,483,188
Thereafter	$ 9,097,899

Future Minimum Rents Narrative (Details) - tenants	12 Months Ended
Future Minimum Rents Narrative (Details) - tenants	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Future Minimum Rent [Line Items]
Number Of Tenants Above Concentration Amount.	0	0	0
Concentration Risk, Percentage	10.00%	10.00%	10.00%
Minimum [Member]
Future Minimum Rent [Line Items]
Initial Term Lease Expiration Date	2015
Maximum [Member]
Future Minimum Rent [Line Items]
Initial Term Lease Expiration Date	2046

Segment Information (Schedule Of Segment Reporting By Geographic Area And Property Type) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Rental Revenue: Class A Office	$ 2,240,119	$ 1,987,671	$ 1,715,425
Rental Revenue: Office/Technical	61,985	55,525	39,218
Rental Revenue: Residential	26,193	22,318	20,568
Rental Revenue: Hotel	43,385	40,330	37,915
Rental Revenue Total	$ 2,371,682	$ 2,105,844	$ 1,813,126
Rental Revenue: % of Grand Totals	100.00%	100.00%	100.00%
Rental Expenses: Class A Office	$ 802,902	$ 716,049	$ 617,482
Rental Expenses: Office/Technical	16,466	14,777	10,614
Rental Expenses: Residential	15,922	12,130	10,992
Rental Expenses: Hotel	29,236	28,447	28,120
Rental Expenses: Total	$ 864,526	$ 771,403	$ 667,208
Rental Expenses: % Of Grand Totals	100.00%	100.00%	100.00%
Net Operating Income	$ 1,507,156	$ 1,334,441	$ 1,145,918
Net Operating Income: % of Grand Totals	100.00%	100.00%	100.00%
Boston [Member]
Segment Reporting Information [Line Items]
Rental Revenue: Class A Office	$ 692,116	$ 665,991	$ 617,652
Rental Revenue: Office/Technical	23,801	22,617	22,460
Rental Revenue: Residential	4,528	4,395	3,936
Rental Revenue: Hotel	43,385	40,330	37,915
Rental Revenue Total	$ 763,830	$ 733,333	$ 681,963
Rental Revenue: % of Grand Totals	32.21%	34.82%	37.61%
Rental Expenses: Class A Office	$ 270,947	$ 259,997	$ 242,904
Rental Expenses: Office/Technical	7,173	6,879	6,499
Rental Expenses: Residential	1,957	1,823	1,675
Rental Expenses: Hotel	29,236	28,447	28,120
Rental Expenses: Total	$ 309,313	$ 297,146	$ 279,198
Rental Expenses: % Of Grand Totals	35.78%	38.52%	41.85%
Net Operating Income	$ 454,517	$ 436,187	$ 402,765
Net Operating Income: % of Grand Totals	30.16%	32.69%	35.15%
New York [Member]
Segment Reporting Information [Line Items]
Rental Revenue: Class A Office	$ 928,692	$ 725,566	$ 543,194
Rental Revenue: Office/Technical	0	0	0
Rental Revenue: Residential	0	0	0
Rental Revenue: Hotel	0	0	0
Rental Revenue Total	$ 928,692	$ 725,566	$ 543,194
Rental Revenue: % of Grand Totals	39.16%	34.46%	29.96%
Rental Expenses: Class A Office	$ 315,330	$ 251,640	$ 187,987
Rental Expenses: Office/Technical	0	0	0
Rental Expenses: Residential	0	0	0
Rental Expenses: Hotel	0	0	0
Rental Expenses: Total	$ 315,330	$ 251,640	$ 187,987
Rental Expenses: % Of Grand Totals	36.47%	32.62%	28.18%
Net Operating Income	$ 613,362	$ 473,926	$ 355,207
Net Operating Income: % of Grand Totals	40.70%	35.51%	31.00%
San Francisco [Member]
Segment Reporting Information [Line Items]
Rental Revenue: Class A Office	$ 237,381	$ 214,755	$ 208,177
Rental Revenue: Office/Technical	23,840	17,259	494
Rental Revenue: Residential	0	0	0
Rental Revenue: Hotel	0	0	0
Rental Revenue Total	$ 261,221	$ 232,014	$ 208,671
Rental Revenue: % of Grand Totals	11.01%	11.02%	11.51%
Rental Expenses: Class A Office	$ 85,178	$ 77,905	$ 75,542
Rental Expenses: Office/Technical	4,955	3,708	149
Rental Expenses: Residential	0	0	0
Rental Expenses: Hotel	0	0	0
Rental Expenses: Total	$ 90,133	$ 81,613	$ 75,691
Rental Expenses: % Of Grand Totals	10.43%	10.58%	11.34%
Net Operating Income	$ 171,088	$ 150,401	$ 132,980
Net Operating Income: % of Grand Totals	11.35%	11.27%	11.60%
Washington, DC [Member]
Segment Reporting Information [Line Items]
Rental Revenue: Class A Office	$ 381,930	$ 381,359	$ 346,402
Rental Revenue: Office/Technical	14,344	15,649	16,264
Rental Revenue: Residential	21,665	17,923	16,632
Rental Revenue: Hotel	0	0	0
Rental Revenue Total	$ 417,939	$ 414,931	$ 379,298
Rental Revenue: % of Grand Totals	17.62%	19.70%	20.92%
Rental Expenses: Class A Office	$ 131,447	$ 126,507	$ 111,049
Rental Expenses: Office/Technical	4,338	4,190	3,966
Rental Expenses: Residential	13,965	10,307	9,317
Rental Expenses: Hotel	0	0	0
Rental Expenses: Total	$ 149,750	$ 141,004	$ 124,332
Rental Expenses: % Of Grand Totals	17.32%	18.28%	18.63%
Net Operating Income	$ 268,189	$ 273,927	$ 254,966
Net Operating Income: % of Grand Totals	17.79%	20.53%	22.25%

Segment Information (Schedule Of Reconciliation Of Net Operating Income To Net Income) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Reconciliation of Net Operating Income to net income attributable to Boston Properties Limited Partnership
Development and management services income									$ 25,316	$ 29,695	$ 34,060
Income from unconsolidated joint ventures									12,769	75,074	49,078
Gains on consolidation of joint ventures									0	385,991	0
Interest and other income									8,765	8,310	10,091
Gains from investments in securities									1,038	2,911	1,389
(Losses) gains from early extinguishments of debt									(10,633)	122	(4,453)
Income from discontinued operations									0	8,022	9,806
Gains on sales of real estate from discontinued operations									0	115,459	38,445
Gain on forgiveness of debt from discontinued operations									0	20,736	0
Gains on sales of real estate									174,686	0	0
General and administrative expense									98,937	115,329	90,129
Transaction costs									3,140	1,744	3,653
Depreciation and amortization expense									620,064	552,589	437,692
Interest expense									455,743	446,880	410,970
Impairment loss									0	4,401	0
Impairment loss from discontinued operations									0	2,852	0
Noncontrolling interest in property partnerships									30,561	1,347	3,792
Noncontrolling interest-redeemable preferred units									1,023	6,046	3,497
Preferred Distributions									10,500	8,057	0
Net income attributable to Boston Properties Limited Partnership common unitholders	$ 204,759	$ 144,715	$ 87,436	$ 62,219	$ 101,264	$ 174,140	$ 505,189	$ 60,923	499,129	841,516	334,601
Intersegment Eliminations [Member]
Reconciliation of Net Operating Income to net income attributable to Boston Properties Limited Partnership
Net Operating Income									1,507,156	1,334,441	1,145,918
Development and management services income									25,316	29,695	34,060
Income from unconsolidated joint ventures									12,769	75,074	49,078
Gains on consolidation of joint ventures									0	385,991	0
Interest and other income									8,765	8,310	10,091
Gains from investments in securities									1,038	2,911	1,389
(Losses) gains from early extinguishments of debt									(10,633)	122	(4,453)
Income from discontinued operations									0	8,022	9,806
Gains on sales of real estate from discontinued operations									0	115,459	38,445
Gain on forgiveness of debt from discontinued operations									0	20,736	0
Gains on sales of real estate									174,686	0	0
General and administrative expense									98,937	115,329	90,129
Transaction costs									3,140	1,744	3,653
Depreciation and amortization expense									620,064	552,589	437,692
Interest expense									455,743	446,880	410,970
Impairment loss									0	4,401	0
Impairment loss from discontinued operations									0	2,852	0
Noncontrolling interest in property partnerships									30,561	1,347	3,792
Noncontrolling interest-redeemable preferred units									1,023	6,046	3,497
Preferred Distributions									10,500	8,057	0
Net income attributable to Boston Properties Limited Partnership common unitholders									$ 499,129	$ 841,516	$ 334,601

Segment Information Segment reporting (narrative) (Details)	May 31, 2013 partners
767 5th Avenue (The General Motors Building) [Member]
Segment Reporting Information [Line Items]
Number of Joint Venture Partners	2

Earnings Per Common Unit (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Earnings Per Share [Abstract]
Income (loss) from continuing operations before discontinued operations and allocation of undistributed earnings (share)										169,126,000	167,769,000
Redeemable common units (in shares)									17,364,000	16,925,000	17,649,000
Basic Earnings:
Net income attributable to Boston Properties Limited Partnership, Units (Denominator) (in shares)									170,453,000	169,126,000	167,769,000
Discontinued operations attributable to Boston Properties Limited Partnership, Income (Numerator)										$ 141,365	$ 48,251
Discontinued Operations (in shares)										0	0
Other Preferred Stock Dividends And Adjustments (per share)										$ (0.01)
Discontinued operations attributable to Boston Properties Limited Partnership, Per Unit Amount (in dollars per share)										$ 0.84	$ 0.29
Other Preferred Stock Dividends and Adjustments										$ (178)
Net income attributable to Boston Properties Limited Partnership									$ 499,129	$ 841,338	$ 334,601
Net income (in dollars per share)	$ 1.20	$ 0.85	$ 0.51	$ 0.37	$ 0.60	$ 1.03	$ 2.97	$ 0.36	$ 2.93	$ 4.97	$ 1.99
Effect of Dilutive Securities:
Stock Based Compensation and Exchangeable Senior Notes, Income (Numerator)									$ 0	$ 0	$ 0
Stock Based Compensation and Exchangeable Senior Notes, Units (Denominator) (in shares)									219,000	320,000	591,000
Stock Based Compensation and Exchangeable Senior Notes, Per Unit Amount (in dollars per share)									$ (0.01)	$ 0.00	$ 0.00
Diluted Earnings:
Diluted Earnings: Net income, Income (Numerator)									$ 499,129	$ 841,338	$ 334,601
Diluted Earnings: Net income, Units (Denominator) (in shares)									170,672,000	169,446,000	168,360,000
Diluted Earnings: Net income, Per Unit Amount (in dollars per share)	$ 1.20	$ 0.85	$ 0.51	$ 0.37	$ 0.60	$ 1.02	$ 2.96	$ 0.36	$ 2.92	$ 4.97	$ 1.99
Income (Loss) from Continuing Operations Attributable to Parent	$ 87,753	$ 111,066	$ 97,927	$ 69,781	$ 81,412	$ 84,348	$ 505,396	$ 44,445		$ 700,151	$ 286,350

Employee Benefit Plans (Details)	12 Months Ended			168 Months Ended	180 Months Ended
Employee Benefit Plans (Details)	Dec. 31, 2014 USD ($) mo	Dec. 31, 2013 USD ($)	Dec. 31, 2012 USD ($)	Dec. 31, 2014 USD ($) yr age	Dec. 31, 2014 USD ($)
Employee Benefit Plans [Abstract]
Eligibility Period For 401K Savings Plan In Months \| mo	3
Employer Matching Contribution, Percent of Match					200.00%
Employer Matching Contribution, Percent of Employees' Gross Pay					3.00%
Maximum Eligible Earnings As Established By IRS For Matching Contributions	$ 260,000	$ 255,000	$ 250,000
Employer Contribution Amount	3,500,000	3,400,000	3,200,000
Years Of Service For Supplemental Retirement Contribution \| yr				10
Age Of Employee For Supplemental Retirement Contribution \| age				40
Annual Supplemental Retirement Contribution And Credit Total.	52,000	60,000	$ 78,000
Separate Unrestricted Cash For Deferred Compensation Plan.	19,500,000	16,600,000		$ 19,500,000	$ 19,500,000
Deferred Compensation Liability	$ 19,500,000	$ 16,600,000		$ 19,500,000	$ 19,500,000

Stock Option and Incentive Plan (Narrative) (Details)			12 Months Ended
Stock Option and Incentive Plan (Narrative) (Details)	Jan. 27, 2014 USD ($) tiers indices yr	May 15, 2012 yr shares	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Dec. 31, 2012 USD ($)	Apr. 02, 2013 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense			$ 26,000,000	$ 43,900,000	$ 28,300,000
Two Thousand Twelve Stock Option and Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Additional Shares Authorized \| shares		13,000,000
Other Than Stock Options Awards Conversion Ratio		2.32
Stock Option Awards Conversion Ratio		1.0
Stock Option and Incentive Plan Term Period \| yr		10
MYLTIP 2014 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
TRS measurement (in years) \| yr	3
Distributions percent before measurement date	10.00%
Indices Used to Compare TRS \| indices	2
Number of Tiers \| tiers	4
Percentage of annualized TRS for Reduction of Earned Awards	0.00%
Percentage to Cause Some Awards to be Earned Even if on a Relative Basis it Would Not Result in any Earned Awards	12.00%
Target [Member] \| MYLTIP 2014 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Amount of Each Tier	$ 13,400,000
Minimum [Member] \| MYLTIP 2014 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Potential Awards Earned	0
Maximum [Member] \| MYLTIP 2014 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Potential Awards Earned	40,200,000
Threshold [Member] \| MYLTIP 2014 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Amount of Each Tier	6,700,000
High [Member] \| MYLTIP 2014 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Amount of Each Tier	26,800,000
Exceptional [Member] \| MYLTIP 2014 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Amount of Each Tier	$ 40,200,000
Chief Executive Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
LTIP units issued (in shares) \| shares						24,231
Board of Directors Chairman [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense			2,500,000	21,500,000
Compensation Expense associated with Transition Agreement			3,900,000	$ 13,800,000
Executive Vice President [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense			$ 2,700,000
Cohen & Steers Realty Majors Portfolio Index [Member] \| MYLTIP 2014 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted Percentage of Index Used to Compare to TRS	50.00%
NAREIT Office Index adjusted [Member] \| MYLTIP 2014 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted Percentage of Index Used to Compare to TRS	50.00%
MYLTIP Vesting 2017 [Member] \| MYLTIP 2014 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting Percentage	50.00%
Vesting Date	Feb. 03, 2017
MYLTIP vesting 2018 [Member] \| MYLTIP 2014 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting Percentage	50.00%
Vesting Date	Feb. 03, 2018

Stock Option and Incentive Plan (Restricted Stock) (Narrative) (Details) $ / shares in Units, $ in Millions		12 Months Ended
	Jan. 27, 2014 USD ($) yr tiers indices	Dec. 31, 2014 USD ($) d VestingInstallments $ / shares shares	Dec. 31, 2013 USD ($) $ / shares shares	Dec. 31, 2012 USD ($) $ / shares shares	Apr. 02, 2013 shares	Mar. 11, 2013 USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation associated with restricted stock, non-qualified options, LTIP Units, 2008 OPP Units, 2011 OPP Units, and 2012 OPP Units		$ 26.0	$ 43.9	$ 28.3
Weighted-average grant date fair value (in dollars per share) \| $ / shares			$ 104.50	$ 107.23
Exercisable, Weighted Average Exercise Price \| $ / shares			$ 98.83	$ 98.92
Number Exercisable \| shares			199,868	91,496
Total intrinsic value of the outstanding and exercisable stock options		$ 13.1
MYLTIP 2013 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
MYLTIP units issued \| shares			318,926
MYLTIP 2014 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Indices Used to Compare TRS \| indices	2
Number of Tiers \| tiers	4
Percentage of annualized TRS for Reduction of Earned Awards	0.00%
Percentage to Cause Some Awards to be Earned Even if on a Relative Basis it Would Not Result in any Earned Awards	12.00%
Distributions percent before measurement date	10.00%
MYLTIP units issued \| shares		485,459
TRS measurement (in years) \| yr	3
Value of MYLTIP Awards	$ 12.7
MYLTIP Value Amortized Into Earnings, Years \| yr	4
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued \| shares		23,968	36,730	20,756
Employee and director payment per share (in dollars per share) \| $ / shares		$ 0.01
Value of shares of common stock		$ 2.6	$ 3.9	$ 2.2
Employee's weighted average cost per share (in dollars per share) \| $ / shares		$ 109.27	$ 105.30	$ 107.31
Ltip Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
LTIP units issued (in shares) \| shares		127,094	184,733	174,650
Value Of LTIP Units Issued		$ 12.8	$ 17.8	$ 17.3
Per unit fair value weighted-average (in dollars per share) \| $ / shares		$ 100.61	$ 96.13	$ 98.83
Expected life assumed to calculate per unit fair value per LTIP unit (years)		5 years 8 months 12 days	5 years 8 months 12 days	5 years 9 months 19 days
Risk-free rate		1.84%	1.03%	0.94%
Expected price volatility		27.00%	26.00%	29.10%
LTIPS And Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting Annual Installments \| VestingInstallments		4
Unrecognized compensation expenses		$ 17.0
LTIPS, OPP and MYLTIP Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee and director payment per share (in dollars per share) \| $ / shares		$ 0.25
OPP Units 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
2012 OPP units issued (in shares) \| shares				400,000
Non Qualified Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-qualified stock options issued (in shares) \| shares		0	252,220	186,007
Expected life assumed to calculate per unit fair value per LTIP unit (years)			6 years	5 years 4 months 24 days
Risk-free rate			1.11%	0.92%
Expected price volatility			26.00%	28.40%
Expected dividend rate			3.00%	2.90%
Weighted-average grant date fair value (in dollars per share) \| $ / shares			$ 18.46	$ 19.50
Weighted-average exercise price (in dollars per share) \| $ / shares			$ 105.10	$ 107.23
OPP Units 2011 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Accelerated Compensation Expenses Related To 2011 OPP Units		$ 1.2
Unvested 2011 and 2012 OPP Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expenses		$ 14.5
Weighted-average period (years)		2 years 8 months 12 days
Non-Qualified Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum Common Stock available for issuance \| shares		250,000
Employee Common Stock options, percent of average closing price		85.00%
Number Of Days Used In Calculation, Average Closing Prices Of Common Stock \| d		10
Shares issued \| shares		6,964	6,442	7,406
Shares issued, weighted-average purchase price per share \| $ / shares		$ 93.37	$ 89.65	$ 86.52
Chief Executive Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
LTIP units issued (in shares) \| shares					24,231
MYLTIP units issued \| shares					38,926
Non-qualified stock options issued (in shares) \| shares					50,847
Board of Directors Chairman [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation associated with restricted stock, non-qualified options, LTIP Units, 2008 OPP Units, 2011 OPP Units, and 2012 OPP Units		$ 2.5	$ 21.5
Compensation Expense associated with Transition Agreement		3.9	13.8
Cash Payment Related to Transition Agreement						$ 6.7
Target Equity Award Compensation Associated with Transition Agreement						$ 11.1
Acceleration of Stock Based Compensation in Association with Transition Agreement			$ 12.9
Executive Vice President [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation associated with restricted stock, non-qualified options, LTIP Units, 2008 OPP Units, 2011 OPP Units, and 2012 OPP Units		$ 2.7

Stock Option and Incentive Plan Schedule of Stock Options Status (Details) - $ / shares	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Beginning Outstanding, Shares	558,823	294,527	155,623
Beginning Oustanding, Weighted Average Exercise Price	$ 100.43	$ 101.06	$ 89.35
Granted, Shares		252,220	186,007
Granted, Weighted Average Exercise Price		$ 104.50	$ 107.23
Exercised, Shares	(21,459)	0	(22,823)
Exercised, Weighted Averge Exercise Price	$ 97.04		$ 72.42
Canceled, Shares	(2,444)		(24,280)
Canceled, Weighted Average Exercise Price	$ 103.57		$ 100.15
Special dividend adjustment shares	18,392	12,076
Special dividend adjustment, weighted average exercise price	$ 97.22	$ 100.44
Ending Outstanding, Shares	553,312	558,823	294,527
Ending Oustanding, Weighted Average Exercise Price	$ 97.21	$ 100.43	$ 101.06

Stock Option and Incentive Plan Schedule of Stock Options Outstanding (Details) - $ / shares	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number Outstanding at 12/31/14	553,312	558,823	294,527	155,623
Outstanding, Weighted Average Exercise Price	$ 97.21	$ 100.43	$ 101.06	$ 89.35
Number Exercisable at 12/31/14		199,868	91,496
Exercisable, Weighted Average Exercise Price		$ 98.83	$ 98.92
Exercise Price of $87.70 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Weighted Average Remaining Contractual Life (Years)	3 years 7 months 6 days
Number Outstanding at 12/31/14	124,513
Outstanding, Weighted Average Exercise Price	$ 87.70
Number Exercisable at 12/31/14	111,832
Exercisable, Weighted Average Exercise Price	$ 87.70
Exercise Price of $96.62 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Weighted Average Remaining Contractual Life (Years)	8 years 3 months 18 days
Number Outstanding at 12/31/14	53,759
Outstanding, Weighted Average Exercise Price	$ 96.62
Number Exercisable at 12/31/14	13,439
Exercisable, Weighted Average Exercise Price	$ 96.62
Exercise Price of $99.41 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Weighted Average Remaining Contractual Life (Years)	4 years 10 months 24 days
Number Outstanding at 12/31/14	207,064
Outstanding, Weighted Average Exercise Price	$ 99.41
Number Exercisable at 12/31/14	150,024
Exercisable, Weighted Average Exercise Price	$ 99.41
Exercise Price of $101.75 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Weighted Average Remaining Contractual Life (Years)	4 years 4 months 24 days
Number Outstanding at 12/31/14	167,976
Outstanding, Weighted Average Exercise Price	$ 101.75
Number Exercisable at 12/31/14	135,848
Exercisable, Weighted Average Exercise Price	$ 101.75

Related Party Transactions (Details)		12 Months Ended				76 Months Ended	122 Months Ended	198 Months Ended
Related Party Transactions (Details)	Jun. 30, 1998	Dec. 31, 2014 USD ($) nonemployeedirectors	Dec. 31, 2013 USD ($)	Dec. 31, 2012 USD ($)	Dec. 31, 2004 USD ($)	Oct. 20, 2004	Dec. 31, 2014 USD ($)	Dec. 31, 2014 USD ($) ft² yr	Nov. 12, 2014 USD ($)	May 20, 2014 shares
Related Party Transaction [Line Items]
Number Of Non employee Directors Electing To Receive Deferred Stock Units \| nonemployeedirectors		6
Deferred Stock Units issued \| shares										7,542
Deferred Stock Units Outstanding		84,435	83,995				84,435	84,435
New York regional manager [Member]
Related Party Transaction [Line Items]
Aggregate leasing commissions paid to related parties		$ 1,214,000	$ 592,000
Brother of Executive Vice President [Member]
Related Party Transaction [Line Items]
Aggregate leasing commissions paid to related parties		674,000	$ 868,000	$ 1,306,000
Former Director [Member]
Related Party Transaction [Line Items]
Related Party Acquisition Date	Jun. 30, 1998
Annual Development Agreement Payments.		$ 125,000
Development Agreement Payment Made For 1998 Through 2004					$ 750,000
Affiliate of Former Director [Member]
Related Party Transaction [Line Items]
Purchase price per rentable square feet of property developed.								$ 20
Target Annual Return Minimum						10.50%
Target Annual Return Maximum.						11.00%
Aggregate Fixed Rentable Per Square Foot Of Developed Property.							$ 10.50
Term of Development Agreement., Years \| yr								20
Square Feet of Development \| ft²								2,000,000
Adjustment To Aggregate Fixed Amount Per Square Foot Of Developed Property							$ 5.50
804 carnegie center [Member]
Related Party Transaction [Line Items]
Aggregate purchase price									$ 3,700,000

Selected Interim Financial Information (unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Quarterly Financial Information Disclosure [Abstract]
Total revenue	$ 613,707	$ 618,803	$ 589,794	$ 574,694	$ 576,199	$ 571,481	$ 510,033	$ 477,826	$ 2,396,998	$ 2,135,539	$ 1,847,186
Income from continuing operations	87,753	111,066	97,927	69,781	81,412	84,348	505,396	44,445		700,151	286,350
Net income attributable to Boston Properties Limited Partnership common unitholders	$ 204,759	$ 144,715	$ 87,436	$ 62,219	$ 101,264	$ 174,140	$ 505,189	$ 60,923	$ 499,129	$ 841,516	$ 334,601
Income attributable to Boston Properties Limited Partnership per share - basic	$ 1.20	$ 0.85	$ 0.51	$ 0.37	$ 0.60	$ 1.03	$ 2.97	$ 0.36	$ 2.93	$ 4.97	$ 1.99
Income attributable to Boston Properties Limited Partnership per share - diluted	$ 1.20	$ 0.85	$ 0.51	$ 0.37	$ 0.60	$ 1.02	$ 2.96	$ 0.36	$ 2.92	$ 4.97	$ 1.99

Real Estate and Accumulated Depreciation [Line Items]

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

+ References + Details

Subsequent Events Subsequent Events (Details) - Subsequent Event [Member]	Feb. 06, 2015 USD ($)	Jan. 21, 2015 USD ($) yr tiers indices	Jan. 15, 2015 USD ($) ft² apartments	Feb. 19, 2015 USD ($) a	Feb. 03, 2015 shares
Subsequent Event [Line Items]
LTIP units issued (in shares) \| shares					96,830
Derivative, Average Fixed Interest Rate				2.514%
Derivative, Notional Amount				$ 125,000,000
MYLTIP two thousand 2015 [Member]
Subsequent Event [Line Items]
Indices Used to Compare TRS \| indices		2
Number of Tiers \| tiers		3
Percentage to Cause Some Awards to be Earned Even if on a Relative Basis it Would Not Result in any Earned Awards		12.00%
Percentage of annualized TRS for Reduction of Earned Awards		0.00%
Distributions percent before measurement date		10.00%
Value of MYLTIP Awards		$ 15,700,000
TRS measurement (in years) \| yr		3
MYLTIP Value Amortized Into Earnings, Years \| yr		4
OPP Units 2012 [Member]
Subsequent Event [Line Items]
potential maximum amount of Outperformance Awards earned (percent)	0.80
Outperformance awards earned	$ 32,100,000
Cohen & Steers Realty Majors Portfolio Index [Member] \| MYLTIP two thousand 2015 [Member]
Subsequent Event [Line Items]
Weighted Percentage of Index Used to Compare to TRS		50.00%
NAREIT Office Index adjusted [Member] \| MYLTIP two thousand 2015 [Member]
Subsequent Event [Line Items]
Weighted Percentage of Index Used to Compare to TRS		50.00%
Minimum [Member] \| MYLTIP two thousand 2015 [Member]
Subsequent Event [Line Items]
Potential Awards Earned		$ 0
Maximum [Member] \| MYLTIP two thousand 2015 [Member]
Subsequent Event [Line Items]
Potential Awards Earned		40,800,000
Maximum [Member] \| OPP Units 2012 [Member]
Subsequent Event [Line Items]
Potential Awards Earned	$ 40,000,000
Threshold [Member] \| MYLTIP two thousand 2015 [Member]
Subsequent Event [Line Items]
Amount of Each Tier		8,200,000
Target [Member] \| MYLTIP two thousand 2015 [Member]
Subsequent Event [Line Items]
Amount of Each Tier		16,300,000
High [Member] \| MYLTIP two thousand 2015 [Member]
Subsequent Event [Line Items]
Amount of Each Tier		$ 40,800,000
MYLTIP Vesting 2018 [Member] \| MYLTIP two thousand 2015 [Member]
Subsequent Event [Line Items]
Vesting Percentage		50.00%
Vesting Date		Feb. 04, 2018
MYLTIP vesting two thousand nineteen [Member] \| MYLTIP two thousand 2015 [Member]
Subsequent Event [Line Items]
Vesting Percentage		50.00%
Vesting Date		Feb. 04, 2019
Restricted Stock [Member]
Subsequent Event [Line Items]
Shares issued \| shares					30,965
Residences on The Avenue, 2221 I St., NW [Member]
Subsequent Event [Line Items]
Sale Price Of Sold Property			$ 196,000,000
Rental revenue supoprt payments to buyer maximum			$ 6,000,000
Number of apartment units \| apartments			335
Area of Real Estate Property \| ft²			50,000
Washingtonian North [Member]
Subsequent Event [Line Items]
Sale Price Of Sold Property				$ 8,700,000
Are of land sold \| a				8.5
Area of Land \| a				27

Real Estate and Accumulated Depreciation Schedule of Real Estate and Accumulated Depreciation (details) - USD ($)
$ in Thousands

12 Months Ended

Dec. 31, 2014

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Encumbrances

^[1]

$ 4,309,484

Original Land

4,661,817

11,331,324

2,793,431

4,680,181

13,101,966

268,114

736,311

18,786,572

$ 18,523,277

$ 14,431,521

$ 12,922,967

Furniture, fixtures and equipment

3,458,640

3,081,040

$ 2,862,302

$ 2,577,118

27,986

$ 25,164

Accumulated depreciation, furniture, fixtures and equipment

17,681

Real Estate Aggregate Cost For Tax Purposes

16,000,000

Real Estate Aggregate Accumulated Depreciation For Tax Purposes

$ 2,900,000

Real Estate and Accumulated Depreciation, Life Used for Depreciation

40 years

Unamoritzed balance of histroical fair value adjustments

$ 138,711

767 5th Avenue (The General Motors Building) [Member]

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

767 Fifth Avenue (The General Motors Building)

Office

New York, NY

$ 1,421,083

1,796,252

1,532,654

19,627

1,796,252

1,552,281

3,348,533

$ 80,075

1968

Embarcadero Center [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

Embarcadero Center

Office

San Francisco, CA

$ 354,680

179,697

847,410

254,939

180,420

1,101,626

1,282,046

$ 495,091

1970/1989

Prudential Center [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

Prudential Center

Office

Boston, MA

$ 92,077

734,594

319,846

92,328

1,018,741

404

35,044

1,146,517

$ 411,161

1965/1993/2002

Real Estate and Accumulated Depreciation [Line Items]

^[2]

-1

399 Park Avenue [Member]

Real Estate And Accumulated Depreciation Name of Property

399 Park Avenue

Office

New York, NY

$ 339,200

700,358

50,022

339,200

750,380

1,089,580

$ 232,464

1961

The John Hancock Tower And Garage [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

The John Hancock Tower and Garage

Office

Boston, MA

$ 649,108

219,543

667,884

74,060

219,616

740,863

1,008

961,487

$ 104,888

1976

601 Lexington Avenue [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

601 Lexington Avenue

Office

New York, NY

$ 710,932

241,600

494,782

188,718

279,281

645,819

925,100

$ 221,412

1977/1997

250 West 55th Street [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

250 West 55th Street

Office

New York, NY

$ 285,263

603,167

285,263

603,167

888,430

$ 9,240

2014

Times Square Tower [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

Times Square Tower

Office

New York, NY

$ 165,413

380,438

46,509

159,694

432,666

592,360

$ 144,194

2004

100 Federal Street [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

100 Federal Street

Office

Boston, MA

$ 0

131,067

435,954

9,711

131,067

445,432

233

576,732

$ 44,931

1971-1975

Real Estate and Accumulated Depreciation [Line Items]

^[2]

-1

Carnegie Center [Member]

Real Estate And Accumulated Depreciation Name of Property

Carnegie Center

Office

Princeton, NJ

$ 105,107

377,259

65,735

98,733

437,666

2,350

9,352

548,101

$ 180,935

1983-1999

Real Estate and Accumulated Depreciation [Line Items]

^[2]

-1

Atlantic Wharf [Member]

Real Estate And Accumulated Depreciation Name of Property

Atlantic Wharf

Office

Boston, MA

$ 63,988

454,537

15,169

63,988

469,706

533,694

$ 55,070

2011

Real Estate and Accumulated Depreciation [Line Items]

^[2]

-1

Fountain Square [Member]

Real Estate And Accumulated Depreciation Name of Property

Fountain Square

Office

Reston, VA

$ 220,133

56,853

306,298

6,938

56,853

313,236

370,089

$ 27,645

1986-1990

510 Madison Avenue [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

510 Madison Avenue

Office

New York, NY

$ 0

103,000

253,665

12,912

103,000

266,577

369,577

$ 24,871

2012

680 Folsom Street [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

680 Folsom Street

Office

San Francisco, CA

$ 0

106,510

185,801

106,510

185,801

292,311

$ 4,161

2014

599 Lexington Avenue [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

599 Lexington Avenue

Office

New York, NY

$ 750,000

81,040

100,507

101,407

81,040

201,914

282,954

$ 148,356

1986

South of Market and Democracy Tower [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

South of Market and Democracy Tower

Office

Reston, VA

$ 13,603

237,479

9,454

13,603

246,933

260,536

$ 60,626

2008-2009

Bay Colony Corporate Center [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

Bay Colony Corporate Center

Office

Waltham, MA

$ 18,789

148,451

58,126

18,789

206,577

225,366

$ 31,089

1985-1989

Real Estate and Accumulated Depreciation [Line Items]

^[2]

-1

Gateway Center [Member]

Real Estate And Accumulated Depreciation Name of Property

Gateway Center

Office

San Francisco, CA

$ 28,255

139,245

46,379

29,029

184,850

213,879

$ 86,679

1984/1986/2002

2200 Pennsylvania Avenue [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

2200 Pennsylvania Avenue

Office

Washington, DC

$ 183,541

5,141

188,682

188,682

$ 26,612

2011

Mountain View Research [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

Mountain View Research Park

Office

Mountain View, CA

$ 95,066

68,373

3,267

95,066

71,640

166,706

$ 6,044

1977-1981/2007-2013

3100-3130 Zanker Road (formerly 3200 Zanker Road) [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

3100-3130 Zanker Road (formerly 3200 Zanker Road)

Office

San Jose, CA

$ 36,705

82,863

27,751

36,705

106,861

3,753

147,319

$ 25,721

1988

Real Estate and Accumulated Depreciation [Line Items]

^[2]

-1

Reservoir Place [Member]

Real Estate And Accumulated Depreciation Name of Property

Reservoir Place

Office

Waltham, MA

$ 18,605

92,619

30,657

19,099

122,774

141,881

$ 56,766

1955/1987

Real Estate and Accumulated Depreciation [Line Items]

^[2]

-1

505 9th Street [Member]

Real Estate And Accumulated Depreciation Name of Property

505 9th Street

Office

Washington, DC

$ 118,919

38,885

83,719

5,409

42,011

86,002

128,013

$ 23,331

2007

Kingstowne Towne Center [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

Kingstowne Towne Center

Office

Alexandria, VA

$ 31,364

18,021

109,038

849

18,021

109,887

127,908

$ 29,800

2003-2006

1333 New Hampshire Avenue [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

1333 New Hampshire Avenue

Office

Washington, DC

$ 34,032

85,660

4,553

34,032

90,213

124,245

$ 32,028

1996

1330 Connecticut Avenue [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

1330 Connecticut Avenue

Office

Washington, DC

$ 25,982

82,311

11,766

25,982

94,077

120,059

$ 31,959

1984

Weston Corporate Center [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

Weston Corporate Center

Office

Weston, MA

$ 25,753

92,312

(123)

25,854

92,088

117,942

$ 13,972

2010

Real Estate and Accumulated Depreciation [Line Items]

^[2]

-1

Capital Gallery [Member]

Real Estate And Accumulated Depreciation Name of Property

Capital Gallery

Office

Washington, DC

$ 4,725

29,565

77,947

6,128

106,109

112,237

$ 51,604

1981/2006

One Freedom Square [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

One Freedom Square

Office

Reston, VA

$ 9,929

84,504

13,261

9,883

97,811

107,694

$ 35,957

2000

Two Freedom Square [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

Two Freedom Square

Office

Reston, VA

$ 13,930

77,739

13,351

13,866

91,154

105,020

$ 37,225

2001

One And Two Reston Overlook [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

One and Two Reston Overlook

Office

Reston, VA

$ 16,456

66,192

20,902

15,074

88,476

103,550

$ 34,527

1999

415 Main Street (formerly Seven Cambridge Center) [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

415 Main Street (formerly Seven Cambridge Center)

Office

Cambridge, MA

$ 3,457

97,136

210

3,457

97,346

100,803

$ 53,022

2006

355 Main Street (formerly Five Cambridge Center) [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

355 Main Street (formerly Five Cambridge Center)

Office

Cambridge, MA

$ 18,863

53,346

25,601

21,098

76,712

97,810

$ 20,817

1981/1996/2013

Discovery Square [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

Discovery Square

Office

Reston, VA

$ 11,198

71,782

14,432

11,146

86,266

97,412

$ 31,385

2001

140 Kendrick Street [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

140 Kendrick Street

Office

Needham, MA

$ 18,095

66,905

10,880

18,095

77,785

95,880

$ 19,519

2000

90 Broadway (formerly Four Cambridge Center) [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

90 Broadway (formerly Four Cambridge Center)

Office

Cambridge, MA

$ 19,104

52,078

13,501

20,741

63,942

84,683

$ 12,401

1983/1998/2013

Real Estate and Accumulated Depreciation [Line Items]

^[2]

-1

77 CityPoint [Member]

Real Estate And Accumulated Depreciation Name of Property

77 CityPoint

Office

Waltham, MA

$ 13,847

60,383

3,058

13,847

63,441

77,288

$ 14,625

2008

Real Estate and Accumulated Depreciation [Line Items]

^[2]

-1

230 CityPoint [Member]

Real Estate And Accumulated Depreciation Name of Property

230 CityPoint

Office

Waltham, MA

$ 13,189

49,823

14,127

13,189

63,950

77,139

$ 18,760

1992

Waltham Weston Corporate Center [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

Waltham Weston Corporate Center

Office

Waltham, MA

$ 10,385

60,694

5,118

10,350

65,847

76,197

$ 21,645

2003

North First Business Park [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

North First Business Park

Office

San Jose, CA

$ 58,402

13,069

4,005

23,371

16,197

35,908

75,476

$ 12,174

1981

300 Binney Street (formerly Seventeen Cambridge Center) [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

300 Binney Street (Seventeen Cambridge Center)

Office

Cambridge, MA

$ 18,080

51,262

165

18,080

51,427

69,507

$ 2,938

2013

2440 West El Camino Real [Member]

(1)

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

2440 West El Camino Real

Office

Mountain View, CA

$ 16,741

51,285

716

16,741

52,001

68,742

$ 6,400

1987/2003

Real Estate and Accumulated Depreciation [Line Items]

^[2]

-1

Wisconsin Place [Member]

Real Estate And Accumulated Depreciation Name of Property

Wisconsin Place

Office

Chevy Chase, MD

$ 53,349

12,787

66,136

66,136

$ 14,300

2009

Reston Corporate Center [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

Reston Corporate Center

Office

Reston, VA

$ 9,135

50,857

2,750

9,496

53,246

62,742

$ 22,099

1984

New Dominion Technology Park, Bldg. Two [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

New Dominion Technology Park, Bldg. Two

Office

Herndon, VA

$ 5,584

51,868

166

5,574

52,044

57,618

$ 17,674

2004

Real Estate and Accumulated Depreciation [Line Items]

^[2]

-1

Sumner Square [Member]

Real Estate And Accumulated Depreciation Name of Property

Sumner Square

Office

Washington, DC

$ 624

28,745

22,924

958

51,335

52,293

$ 24,802

1985

Real Estate and Accumulated Depreciation [Line Items]

^[2]

-1

200 West Street [Member]

Real Estate And Accumulated Depreciation Name of Property

200 West Street

Office

Waltham, MA

$ 16,148

24,983

7,121

16,148

32,104

48,252

$ 15,987

1999

New Dominion Technology Park, Bldg. One [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

New Dominion Technology Park, Bldg. One

Office

Herndon, VA

$ 40,975

3,880

43,227

1,073

3,880

44,300

48,180

$ 20,681

2001

191 Spring Street [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

191 Spring Street

Office

Lexington, MA

$ 2,850

27,166

17,359

2,850

44,525

47,375

$ 30,882

1971/1995

255 Main Street (formerly One Cambridge Center) [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

255 Main Street (formerly One Cambridge Center)

Office

Cambridge, MA

$ 134

25,110

18,940

134

44,050

44,184

$ 26,889

1987

University Place [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

University Place

Office

Cambridge, MA

$ 12,290

37,091

5,344

42,408

42,435

$ 21,913

1985

2600 Tower Oaks Boulevard [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

2600 Tower Oaks Boulevard

Office

Rockville, MD

$ 4,243

31,125

5,761

4,244

36,885

41,129

$ 16,625

2001

Quorum Office Park [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

Quorum Office Park

Office

Chelmsford, MA

$ 3,750

32,454

4,116

4,762

35,558

40,320

$ 13,423

2001

150 Broadway (formerly Eight Cambridge Center) [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

150 Broadway (formerly Eight Cambridge Center)

Office

Cambridge, MA

$ 850

25,042

6,502

822

31,572

32,394

$ 12,264

1999

Real Estate and Accumulated Depreciation [Line Items]

^[2]

-1

500 E Street [Member]

Real Estate And Accumulated Depreciation Name of Property

500 E Street

Office

Washington, DC

$ 109

22,420

9,780

1,569

30,740

32,309

$ 21,054

1987

325 Main Street (formerly Three Cambridge Center) [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

325 Main Street (formerly Three Cambridge Center)

Office

Cambridge, MA

$ 174

12,200

11,003

772

22,605

23,377

$ 10,364

1987/2013

105 Broadway (formerly Ten Cambridge Center) [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

105 Broadway (formerly Ten Cambridge Center)

Office

Cambridge, MA

$ 1,299

12,943

4,745

1,868

17,119

18,987

$ 11,590

1990

40 Shattuck Road [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

40 Shattuck Road

Office

Andover, MA

$ 709

14,740

1,961

709

16,701

17,410

$ 6,046

2001

201 Spring Street [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

201 Spring Street

Office

Lexington, MA

$ 2,849

15,303

(1,253)

2,849

14,050

16,899

$ 6,324

1997

Lexington Office Park [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

Lexington Office Park

Office

Lexington, MA

$ 998

1,426

13,177

1,073

14,528

15,601

$ 11,219

1982

92 - 100 Hayden Avenue [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

92-100 Hayden Avenue

Office

Lexington, MA

$ 594

6,748

7,090

619

13,813

14,432

$ 10,541

1985

91 Hartwell Avenue [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

91 Hartwell Avenue

Office

Lexington, MA

$ 784

6,464

6,120

784

12,584

13,368

$ 7,547

1985

181 Spring Street [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

181 Spring Street

Office

Lexington, MA

$ 1,066

9,520

1,573

1,066

11,093

12,159

$ 4,242

1999

33 Hayden Avenue [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

33 Hayden Avenue

Office

Lexington, MA

$ 266

3,234

8,150

266

11,384

11,650

$ 5,450

1979

Real Estate and Accumulated Depreciation [Line Items]

^[2]

-1

195 West Street [Member]

Real Estate And Accumulated Depreciation Name of Property

195 West Street

Office

Waltham, MA

$ 1,611

6,652

3,278

1,611

9,930

11,541

$ 6,456

1990

145 Broadway (formerly Eleven Cambridge Center) [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

145 Broadway (formerly Eleven Cambridge Center)

Office

Cambridge, MA

$ 121

5,535

4,465

121

10,000

10,121

$ 7,430

1984

7501 Boston Boulevard, Building Seven [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

7501 Boston Boulevard, Building Seven

Office

Springfield, VA

$ 665

9,273

665

9,288

9,953

$ 4,027

1997

7435 Boston Boulevard, Building One [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

7435 Boston Boulevard, Building One

Office

Springfield, VA

$ 392

3,822

3,105

486

6,833

7,319

$ 5,677

1982

7450 Boston Boulevard, Building Three [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

7450 Boston Boulevard, Building Three

Office

Springfield, VA

$ 1,165

4,681

1,466

1,327

5,985

7,312

$ 2,983

1987

453 Ravendale Drive [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

453 Ravendale Drive

Office

Mountain View, CA

$ 0

5,477

1,090

230

5,477

1,320

6,797

$ 213

1977

8000 Grainger Court, Building Five [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

8000 Grainger Court, Building Five

Office

Springfield, VA

$ 366

4,282

2,090

453

6,285

6,738

$ 5,042

1984

7500 Boston Boulevard, Building Six [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

7500 Boston Boulevard, Building Six

Office

Springfield, VA

$ 138

3,749

2,005

273

5,619

5,892

$ 4,175

1985

7300 Boston Boulevard, Building Thirteen [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

7300 Boston Boulevard, Building Thirteen

Office

Springfield, VA

$ 608

4,773

608

4,791

5,399

$ 4,193

2002

7601 Boston Boulevard, Building Eight [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

7601 Boston Boulevard, Building Eight

Office

Springfield, VA

$ 200

878

4,133

378

4,833

5,211

$ 3,571

1986

250 Binney Street (formerly Fourteen Cambridge Center) [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

250 Binney Street (formerly Fourteen Cambridge Center)

Office

Cambridge, MA

$ 110

4,483

569

110

5,052

5,162

$ 3,835

1983

8000 Corporate Court, Building Eleven [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

8000 Corporate Court, Building Eleven

Office

Springfield, VA

$ 136

3,071

1,260

687

3,780

4,467

$ 2,432

1989

7375 Boston Boulevard, Building Ten [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

7375 Boston Boulevard, Building Ten

Office

Springfield, VA

$ 23

2,685

822

3,483

3,530

$ 2,333

1988

7374 Boston Boulevard, Building Four [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

7374 Boston Boulevard, Building Four

Office

Springfield, VA

$ 241

1,605

1,346

303

2,889

3,192

$ 2,172

1984

7451 Boston Boulevard, Building Two [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

7451 Boston Boulevard, Building Two

Office

Springfield, VA

$ 249

1,542

1,348

535

2,604

3,139

$ 2,081

1982

32 Hartwell Avenue [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

32 Hartwell Avenue

Office

Lexington, MA

$ 168

1,943

223

168

2,166

2,334

$ 1,584

1968-1979/1987

164 Lexington Road [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

164 Lexington Road

Office

Billerica, MA

$ 592

1,370

117

592

1,487

2,079

$ 708

1982

17 Hartwell Avenue [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

17 Hartwell Avenue

Office

Lexington, MA

$ 26

150

861

995

1,037

$ 687

1968

Residences on The Avenue, 2221 I St., NW [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

Residences on The Avenue, 2221 I St., NW

Residential

Washington, DC

$ 119,874

(28)

119,846

119,846

$ 11,039

2011

The Avant at Reston Town Center Residential [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

The Avant at Reston Town Center

Residential

Reston, VA

$ 20,350

91,995

20,350

91,995

112,345

$ 2,397

2014

The Lofts At Atlantic Wharf [Member]

(1)

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

The Lofts at Atlantic Wharf

Residential

Boston, MA

$ 3,529

54,891

1,543

3,529

56,434

59,963

$ 5,093

2011

Boston Marriott Cambridge (formerly Cambridge Center Marriott) [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

Boston Marriott Cambridge (formerly Cambridge Center Marriott)

Hotel

Cambridge, MA

$ 478

37,918

33,269

478

71,187

71,665

$ 46,709

1986

Cambridge Center East Garage [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

Cambridge Center East Garage

Garage

Cambridge, MA

$ 35,035

1,147

36,182

36,182

$ 7,579

1984

Cambridge Center West Garage [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

Cambridge Center West Garage

Garage

Cambridge, MA

$ 1,256

15,697

859

1,256

16,556

17,812

$ 3,700

2006

Cambridge Center North Garage [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

Cambridge Center North Garage

Garage

Cambridge, MA

$ 1,163

11,633

1,105

1,163

12,738

13,901

$ 8,252

1990

Salesforce Tower [Member]

^[2]

-1

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

Salesforce Tower

Development

San Francisco, CA

$ 345,303

345,303

$ 345,303

N/A

601 Massachusetts Avenue [Member]

N/A

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

601 Massachusetts Avenue

Development

Washington, DC

$ 189,161

189,161

$ 189,161

N/A

535 Mission Street [Member]

N/A

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

535 Mission Street

Development

San Francisco, CA

$ 171,096

10,789

39,307

121,000

171,096

$ 225

N/A

Real Estate and Accumulated Depreciation [Line Items]

N/A

10 CityPoint [Member]

Real Estate And Accumulated Depreciation Name of Property

10 CityPoint

Development

Waltham, MA

$ 21,370

21,370

21,370

$ 0

N/A

690 Folsom Street [Member]

N/A

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

690 Folsom Street

Development

San Francisco, CA

$ 13,237

1,777

6,546

4,914

13,237

$ 11

N/A

Springfield Metro Center [Member]

N/A

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

Springfield Metro Center

Land

Springfield, VA

$ 32,445

32,445

$ 32,445

N/A

Reston Signature Site [Member]

N/A

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

Reston Signature Site

Land

Reston, VA

$ 30,256

30,256

$ 30,256

N/A

Plaza at Almaden [Member]

N/A

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

Plaza at Almaden

Land

San Jose, CA

$ 29,006

29,006

$ 29,006

N/A

Tower Oaks Master Plan [Member]

N/A

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

Tower Oaks Master Plan

Land

Rockville, MD

$ 28,919

28,919

$ 28,919

N/A

214 Third Avenue (formerly Prospect Hill) [Member]

N/A

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

214 Third Avenue (formerly Prospect Hill)

Land

Waltham, MA

$ 23,255

132

12,956

10,167

$ 23,255

N/A

Washingtonian North [Member]

N/A

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

Washingtonian North

Land

Gaithersburg, MD

$ 18,813

18,813

$ 18,813

N/A

6601 and 6605 Springfield Center Drive [Member]

N/A

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

6601 & 6605 Springfield Center Drive

Land

Springfield, VA

$ 13,866

13,866

$ 13,866

N/A

103 Fourth Avenue [Member]

^[2]

N/A

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

103 Fourth Avenue

Land

Waltham, MA

$ 11,920

11,920

$ 11,920

N/A

Real Estate and Accumulated Depreciation [Line Items]

N/A

Reston Gateway [Member]

Real Estate And Accumulated Depreciation Name of Property

Reston Gateway

Land

Reston, VA

$ 9,933

9,933

$ 9,933

N/A

Real Estate and Accumulated Depreciation [Line Items]

N/A

Reston Eastgate [Member]

Real Estate And Accumulated Depreciation Name of Property

Reston Eastgate

Land

Reston, VA

$ 8,817

8,817

$ 8,817

N/A

Real Estate and Accumulated Depreciation [Line Items]

N/A

Crane Meadow [Member]

Real Estate And Accumulated Depreciation Name of Property

Crane Meadow

Land

Marlborough, MA

$ 8,726

8,726

$ 8,726

N/A

Broad Run Business Park [Member]

N/A

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

Broad Run Business Park

Land

Loudoun County, VA

$ 6,311

6,311

$ 6,311

N/A

Real Estate and Accumulated Depreciation [Line Items]

N/A

20 CityPoint [Member]

Real Estate And Accumulated Depreciation Name of Property

20 CityPoint

Land

Waltham, MA

$ 4,801

4,801

$ 4,801

N/A

Cambridge Master Plan [Member]

N/A

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

Cambridge Master Plan

Land

Cambridge, MA

$ 3,527

3,527

$ 3,527

N/A

North First Master Plan [Member]

N/A

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

North First Master Plan

Land

San Jose, CA

$ 1,664

1,664

$ 1,664

N/A

425 Fourth Street [Member]

N/A

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

425 Fourth Street

Land

San Francisco, CA

$ 1,261

1,261

$ 1,261

N/A

30 Shattuck Road [Member]

N/A

Real Estate and Accumulated Depreciation [Line Items]

Real Estate And Accumulated Depreciation Name of Property

30 Shattuck Road

Land

Andover, MA

$ 1,213

1,213

$ 1,213

N/A