Receivable Type [Axis] Receivable Type [Axis] Intrinsic Value of stock options Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value Stock Option Awards Conversion Ratio Stock Option Awards Conversion Ratio Stock Option Awards Conversion Ratio Redemption of operating partnership units to common stock, shares Conversion of redeemable partnership units Stock Issued During Period, Shares, Conversion of Units Commitments And Contingencies Commitments and Contingencies Disclosure [Text Block] Real Estate Properties [Line Items] Real Estate Properties [Line Items] Noncontrolling Interest [Table] Noncontrolling Interest [Table] Stabilization as defined in the agreement [Member] Stabilization as defined in the agreement [Member] Stabilization as defined in the agreement [Member] Number of Additional Shares Authorized Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized 3.279% unsecured senior notes Three point two seven nine percent unsecured senior notes [Member] 3.279% unsecured senior notes Rental Expenses: Residential Rental Expenses Residential Rental Expenses Residential. Range [Domain] Statistical Measurement [Domain] LIABILITIES AND EQUITY LIABILITIES AND MEMBERS'/PARTNERS' EQUITY Liabilities and Equity [Abstract] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Amortization of right-of-use asset Finance Lease, Right-of-Use Asset, Amortization Preferred Stock [Member] Preferred Units [Member] Preferred Stock [Member] At Market Stock Offering Program Maximum Length Of Sale (in years) At Market Stock Offering Program Maximum Length Of Sale (in years) At Market Stock Offering Program Maximum Length Of Sale (in years) Cash and cash equivalents deconsolidated Payments for (Proceeds from) Other Real Estate Partnerships Security Exchange Name Security Exchange Name Total adjustments Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities Maximum Earned Awards Maximum Earned Awards Maximum Earned Awards Payment Award Discount From Market Price Based on Ten Business Day Average Payment Award Discount From Market Price Based on Ten Business Day Average Payment Award Discount From Market Price Based on Ten Business Day Average Redemption of operating partnership units to common stock, value Stock Issued During Period, Value, Conversion of Units Contributions, value Partners' Capital Account, Contributions Restriction on redemption of OP Unit to Common Stock (in years) Restriction On Redemption Restriction on redemption of OP unit to Common Stock Preferred stock redemption liability Preferred stock redemption liability Preferred stock redemption liability Conversions of noncontrolling interests to stockholders’ equity Conversions of noncontrolling interests to Stockholders' Equity Conversions of noncontrolling interests to Stockholders' Equity BP/CRF Metropolitan Square LLC [Member] BP/CRF Metropolitan Square LLC [Member] BP/CRF Metropolitan Square LLC [Member] Variable Rate [Domain] Variable Rate [Domain] Restriction on redemption of OP units from date of issuance (years) Restriction On Redemption Of OP Units From Date Of Issuance In Years Restriction On Redemption Of OP Units From Date Of Issuance In Years Real Estate, Type of Property [Axis] Real Estate, Type of Property [Axis] Total lease payments Finance Lease, Liability, Payment, Due ASSETS Assets [Abstract] Investment, Name [Axis] Investment, Name [Axis] Accounting Policies [Abstract] Accounting Policies [Abstract] Boston Properties Limited Partnership Subsidiaries [Member] Cash Held in Escrows Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block] Net activity from stock option and incentive plan, value Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture Lease liabilities - operating leases Operating Lease, Payments Operating Lease, Payments 2023 Long-Term Debt, Maturity, Year Three Rental Revenue Total Rental Revenue Total Rental Revenue Total Write-off for accrued rent and accounts receivables Allowance for Loan and Lease Losses, Write-offs Schedule Of Balance Sheets Of The Unconsolidated Joint Ventures [Text Block] Schedule Of Balance Sheets Of The Unconsolidated Joint Ventures [Text Block] Schedule Of Balance Sheets Of The Unconsolidated Joint Ventures [Text Block] General Partners' Capital Account, Units Outstanding (in units) General Partners' Capital Account, Units Outstanding Vested 2012 OPP units and MYLTIPS Conversion of 2012 OPP units and MYLTIPS [Member] Conversion of 2012 OPP units and MYLTIPS cumulative cumulative [Member] cumulative 181, 191 and 201 Spring Street 181, 191 and 201 Spring Street [Member] 181, 191 and 201 Spring Street Deductible in insurance as a percentage of the value of the affected property, San Francisco and Los Angeles Earthquake Deductible Insurance Percentage Of Value Of The Affected Property San Francisco and Los Angeles Earthquake Deductible Insurance Percentage Of Value Of The Affected Property San Francisco and Los Angeles 2022 Lessee, Operating Lease, Liability, to be Paid, Year One Beginning outstanding, shares Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number 901 New York Avenue LLC [Member] Bp Crf Nine Zero One New York Avenue Llc [Member] BP/CRF Nine Zero One New York Avenue LLC [Member] 2025 Lessee, Operating Lease, Liability, to be Paid, Year Four 2016 MYLTIP Units forfeited Stock Issued During Period, Shares, Share-based Compensation, Forfeited Shares Issued, Shares, Share-based Payment Arrangement, Forfeited Unrecognized compensation expenses Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount Hotel Tower Developer LLC [Member] Hotel Tower Developer LLC [Member] Hotel Tower Developer LLC [Member] Maximum funding obligation Guarantor Obligations, Maximum Exposure, Undiscounted 5.25% Series B cumulative redeemable preferred stock / units, liquidation preference $2,500 per share / unit, 80,000 shares / units issued and outstanding at December 31, 2020 Preferred Stock, Value, Issued Operating Expenses Operating Operating Expenses Other comprehensive income (loss): Other Comprehensive Income (Loss), Net of Tax [Abstract] Common Stock, Par or Stated Value Per Share Common Stock, Par or Stated Value Per Share Investments in securities Marketable Securities Annapolis Junction Building Seven and Eight [Member] Annapolis Junction building seven and eight [Member] Annapolis Junction building seven and eight [Member] Payments on finance lease obligations Finance Lease, Principal Payments Stock Option And Incentive Plan And Stock Repurchase Plan [Domain] Stock Option And Incentive Plan And Stock Repurchase Plan [Domain] Stock Option And Incentive Plan And Stock Repurchase Plan [Domain] Noncontrolling interest - Redeemable partnership units [Member] Noncontrolling interest - Redeemable partnership units [Member] Noncontrolling interest - Redeemable partnership units [Member] Segment Reconciling Items Segment Reconciling Items [Member] Schedule of Acquired Finite-Lived Intangible Asset by Major Class [Table] Schedule of Acquired Finite-Lived Intangible Asset by Major Class [Table] Dividends Payable [Line Items] Dividends / Distributions [Line Items] Dividends Payable [Line Items] 11251 Roger Bacon Drive 11251 Roger Bacon Drive [Member] 11251 Roger Bacon Drive Board of Directors Chairman [Member] Board of Directors Chairman [Member] Excess stock, $0.01 par value, 150,000,000 shares authorized, none issued or outstanding Excess Stock Value Excess Stock Value Statement [Line Items] Statement [Line Items] 3.954% unsecured senior notes Three point nine five four percent unsecured senior notes [Member] 3.954% unsecured senior notes Class of Stock [Domain] Class of Stock [Domain] Statements Of Operations Of The Joint Ventures Schedule Of Statements Of Operations Of The Unconsolidated Joint Ventures [Text Bock] Schedule Of Statements Of Operations Of The Unconsolidated Joint Ventures [Text Bock] Measurement Input Type [Domain] Measurement Input Type [Domain] Statement [Table] Statement [Table] Write-off for accounts receivable Accounts Receivable, Allowance for Credit Loss, Writeoff Amortization of interest rate contracts Other Comprehensive Income, Other, Net of Tax Range [Axis] Statistical Measurement [Axis] Series Four Preferred Units [Member] series four preferred units [Member] Series Four Preferred Units [Member] Text Block [Abstract] Title of 12(g) Security Title of 12(g) Security Competitive bid quote Competitive bid quote Competitive bid quote Weighted Average [Member] Weighted Average [Member] Entity Small Business Entity Small Business MYLTIP 2019 [Member] MYLTIP two thousand nineteen [Member] MYLTIP two thousand nineteen [Member] Impairment loss Impairment of Real Estate Impairment of Real Estate Variable lease payments Operating Lease, Variable Lease Income Unsecured Senior Notes Debt Disclosure [Text Block] Market Square North [Member] Market Square North [Member] Market Square North Liabilities for Contingent Guarantees Liabilities for Guarantees on Long-Duration Contracts, Guaranteed Benefit Liability, Gross Amendment Flag Amendment Flag Operating Lease, Liability Net Present Value and Operating Lease Liability Operating Lease, Liability (used for footnotes) Mortgage Loan Related to Property Sales Mortgage Loan Related to Property Sales Stock Option and Incentive Plan Disclosure of Share-based Compensation Arrangements by Share-based Payment Award [Table Text Block] Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Common stock available for issuance Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized Stockholders Equity / Partners Capital [Abstract] Stockholders Equity / Partners Capital [Abstract] Stockholders Equity / Partners Capital [Abstract] Real Estate Properties [Domain] Real Estate Properties [Domain] LTIP Unit [Member] LTIP Unit [Member] LTIP Unit BP-M 3HB Venture LLC [Member] Three Hudson Boulevard [Member] 3 Hudson Boulevard [Member] Related Party Note Receivable [Member] Financing Receivable [Member] Seattle Seattle [Member] Seattle Senior Notes Pricing Senior Notes Pricing Note Price Percentage Of Principal Amount Fair Value, by Balance Sheet Grouping [Table Text Block] Fair Value, by Balance Sheet Grouping [Table Text Block] Investments in Unconsolidated Joint Ventures Equity Method Investments [Policy Text Block] Conversion of redeemable partnership units, value Partners' Capital Account, Exchanges and Conversions Building and other capital improvements Payments for Capital Improvements Portion At Fair Value Fair Value Disclosure [Domain] Fair Value Measurement [Domain] Statement of Partners' Capital [Abstract] Statement of Partners' Capital [Abstract] Derivative Instruments and Hedging Activities Derivatives, Policy [Policy Text Block] Change in real estate included in accounts payable and accrued expenses Capital Expenditures Incurred but Not yet Paid Dividends [Domain] Dividends [Domain] Number of shares issued Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period 325 Main Street Three Two Five Main Street [Member] Three Two Five Main Street [Member] Redemption of unsecured senior notes Repayments of Unsecured Debt Repayments of Unsecured Debt Future Office Building [Member] Future Office Building [Member] Future Office Building [Member] Lessor, Leases Lessor, Leases [Policy Text Block] Employee Stock Employee Stock [Member] MYLTIP vesting 2021 MYLTIP vesting two thousand twenty one [Member] [Member] MYLTIP vesting 2021 [Member] [Member] Tenant improvements Payments for Tenant Improvements Noncontrolling interests in property partnerships Noncontrolling interest in property partnerships Noncontrolling Interest in Net Income (Loss) Limited Partnerships, Nonredeemable 2012 Stock Option and Incentive Plan [Member] Two Thousand Twelve Stock Option and Incentive Plan [Member] Two Thousand Twelve Stock Option and Incentive Plan [Member] 2023 Lessee, Operating Lease, Liability, to be Paid, Year Two Cash flows from financing activities: Net Cash Provided by (Used in) Financing Activities [Abstract] number of investors number of investors number of investors Future Retail Building [Member] Future Retail Building [Member] Future Retail Building [Member] Furniture, Fixtures and Equipment Furniture and Fixtures, Gross Lease, Cost Lease, Cost [Table Text Block] Lease liability - finance lease deconsolidated Lease liability - finance lease deconsolidation Lease liability - finance lease deconsolidation MYLTIP 2016 [Member] MYLTIP Two thousand sixteen [Member] MYLTIP 2016 [Member] 2024 Lessee, Operating Lease, Liability, to be Paid, Year Three Gains from investments in securities Gain (Loss) on Sale of Investments Total assets Total assets Assets Lessee Operating Lease Liability Payments Due, Next Five Years bxp_Lessee Operating Lease Liability Payments Due, Next Five Years bxp_Lessee Operating Lease Liability Payments Due, Next Five Years Promote entities Promote entities [Member] Promote entities Allocated net income for the year Equity Profit Loss Net Income. Finance Lease, Liability, Payment, Due [Abstract] Finance Lease, Liability, Payment, Due [Abstract] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Lessor, Lease, Description [Table] Lessor, Lease, Description [Table] LTIP and MYLTIP Units [Member] LTIP and 2014 MYLTIP Units [Member] LTIP and 2014 MYLTIP Units [Member]. Home Ownership Units [Member] home ownership units [Member] home ownership units [Member] Share-based Compensation Arrangement by Share-based Payment Award, Description Share-based Compensation Arrangement by Share-based Payment Award, Description Series Two Preferred Units [Member] Series Two Preferred Units [Member] Series Two Preferred Units [Member] Total liabilities Liabilities Expected price volatility Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate Less: Interest Portion Lessee, Operating Lease, Liability, Undiscounted Excess Amount Cash held in escrows Increase (Decrease) in Restricted Cash for Operating Activities Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] Safeco Partner Entity Two Safeco Partner Entity Two [Member] Safeco Partner Entity Two Allocation of undistributed earnings to participating securities (in dollars per share / unit) Allocation of undistributed earnings to participating securities ($ per shares) Allocation of undistributed earnings to participating securities ($ per share shares) MYLTIP Value Amortized Into Earnings, Years MYLTIP Value Amortized Into Earnings, Years MYLTIP Value Amortized Into Earnings, Years Allocation of undistributed earnings to participating securities (in shares / units) Allocation of undistributed earnings to participating securities (in shares) Allocation of undistributed earnings to participating securities (in shares) Real Estate [Abstract] Real Estate [Abstract] OP Units for redemption (in shares) Stock Redeemed or Called During Period, Shares Tenant improvements, net deconsolidated Transfer Of Tenant Improvements Real Estate Transfer Of Tenant Improvements Real Estate Total Capital [Member] Capital [Member] Capital [Member] Additional Paid-In Capital [Member] Additional Paid-in Capital [Member] Other assets Other Assets Residential Tower Developer LLC [Member] Residential Tower Developer LLC [Member] Residential Tower Developer LLC [Member] Common units of the Operating Partnership Noncontrolling Interest in Operating Partnerships Boston Properties Limited Partnership partners’ capital— 1,736,833 and 1,730,921 general partner units and 154,469,658 and 153,987,904 limited partner units outstanding at September 30, 2021 and December 31, 2020, respectively General And Limited Partners Capital Account General And Limited Partners Capital Account Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Granted Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Granted Total partners’ capital Partners' Capital Program trigger deductible Program trigger deductible Program trigger deductible Interest on lease liabilities Finance Lease, Interest Expense Fair Value of Financial Instruments Fair Value of Financial Instruments, Policy [Policy Text Block] Common Stock, Shares, Outstanding Equity, shares Equity, shares Common Stock, Shares, Outstanding Metropolitan Square Metropolitan Square Associates LLC [Member] The Metropolitan Square Associates LLC [Member] Revolving Credit Facility [Member] Revolving Credit Facility [Member] Debt Instrument, Covenant Compliance Debt Instrument, Covenant Compliance Minimum square footage to make a potential additional payment to joint venture partner (in sqft) Minimum square footage to make a potential additional payment to joint venture partner (in sqft) Minimum square footage to make a potential additional payment to joint venture partner (in sqft) Co-investment program Co-investment program [Member] Co-investment program Weighted Average Exercise Price Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price Common stock, shares authorized Common Stock, Shares Authorized Stock Based Compensation (in shares / units) Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements Mortgage Notes Payable Disclosure Mortgage Notes Payable Disclosure [Text Block] Schedule Of Segment Information By Geographic Area And Property Type Schedule of Segment Reporting Information, by Segment [Table Text Block] Cohen & Steers Realty Majors Portfolio Index [Member] Cohen & Steers Realty Majors Portfolio Index [Member] Cohen & Steers Realty Majors Portfolio Index [Member] ATM Program [Member] Atm Program [Member] Prior Atm Program [Member] Aggregate purchase price Aggregate purchase price Aggregate purchase price Income Statement [Abstract] Income Statement [Abstract] Accumulated Other Comprehensive Loss [Member] AOCI Attributable to Parent [Member] AOCI Attributable to Parent [Member] MYLTIP 2021 Two Thousand Twenty-One MYLTIPS [Member] Two Thousand Twenty-One MYLTIPS Entity Listing, Par Value Per Share Entity Listing, Par Value Per Share Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights Prepaid expenses and other assets Increase (Decrease) in Prepaid Expense and Other Assets Safeco Partner Entity One [Member] Safeco Partner Entity One [Member] Safeco Partner Entity One Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Variable Interest Entity, Primary Beneficiary [Member] Variable Interest Entity, Primary Beneficiary [Member] Name of Property [Domain] Name of Property [Domain] Deferred proceeds from sale of investment in unconsolidated joint venture Deferred proceeds from sale of investment in unconsolidated joint venture Deferred proceeds from sale of investment in unconsolidated joint venture Cash paid for interest Interest Paid, Including Capitalized Interest, Operating and Investing Activities Use of Estimates in the Preparation of Financial Statements Use of Estimates, Policy [Policy Text Block] Schedule of Finite-Lived Intangible Assets Acquired as Part of Business Combination Schedule of Finite-Lived Intangible Assets Acquired as Part of Business Combination [Table Text Block] 7750 Wisconsin Avenue [Member] Seven Seven Five Zero Wisconsin Avenue [Member] 7750 Wisconsin Avenue [Member] Repayments of mezzanine notes payable Repayments of Subordinated Debt Dividends/distributions declared Dividends Consolidated Entities [Axis] Consolidated Entities [Axis] Number Of series Of preferred units outstanding Number Of Series Of Preferred Units Outstanding Number Of Series Of Preferred Units Outstanding. Weighted Average Number Of Shares Outstanding After Allocation of Undistributed Earnings to Participating Securities Basic (in shares) Weighted Average Number Of Shares Outstanding After Allocation of Undistributed Earnings to Participating Securities Basic (in shares) Weighted Average Number Of Shares Outstanding After Allocation of Undistributed Earnings to Participating Securities Basic (in shares) 3.916% unsecured senior notes Three point nine one six percent unsecured senior notes [Member] 3.916% unsecured senior notes Scenario [Domain] Scenario [Domain] Consolidation Items [Domain] Consolidation Items [Domain] 153 & 211 Second Avenue [Member] 153 & 211 Second Avenue [Member] 153 & 211 Second Avenue Note receivable fixed interest rate Note receivable fixed interest rate Note receivable fixed interest rate Income (Loss) from Unconsolidated Joint Ventures Loss from unconsolidated joint ventures Income (Loss) from Equity Method Investments Income (loss) from unconsolidated joint ventures Income (Loss) from Equity Method Investments Rental Expenses: % Of Grand Totals Percentage Of Total Rental Expenses Percentage Of Total Rental Expenses. Extension Option (in years) Extension Option (in years) Extension Option (in years) Gateway Commons Complex prior to deferred contribution [Member] [Member] Gateway Commons Complex prior to deferred contribution [Member] [Member] Gateway Commons Complex prior to deferred contribution [Member] Net Operating Income: % of Grand Totals Percentage Of Total Net Operating Income Percentage Of Total Net Operating Income 6595 Springfield Center Drive [Member] Six Five Nine Five Springfield Center Drive [Member] Six Five Nine Five Springfield Center Drive Accrued interest payable Increase (Decrease) in Interest Payable, Net Entity [Domain] Entity [Domain] Dividends Dividend Policy [Policy Text Block] Dividend Policy Other comprehensive (income) loss attributable to noncontrolling interests Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest Redeemable Common Units Redeemable Common Units Redeemable Common Units Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Table] Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Table] Thereafter Operating Leases, Future Minimum Payments, Due Thereafter Lessee, Lease, Description [Line Items] Lessee, Lease, Description [Line Items] OPP Units 2012 [Member] Opp Units Two Thousand And Twelve [Member] Opp Units Two Thousand And Twelve [Member] Excess stock, par value Excess Stock Par Or Stated Value Per Share Excess Stock, Par or Stated Value Per Share Fair Value Disclosures [Abstract] Fair Value Disclosures [Abstract] Share-based Compensation Arrangement by Share-based Payment Award, Terms of Award Share-based Compensation Arrangement by Share-based Payment Award, Terms of Award Contractual Sales Price Contractual Sales Price Contractual Sales Price Net proceeds from equity transactions Proceeds from Issuance or Sale of Equity Restricted Stock [Member] Restricted Stock [Member] Deferred Charges Deferred Charges, Policy [Policy Text Block] MYLTIP units issued (in shares) MYLTIP units issued MYLTIP units issued Class A Office Properties [Member] Class A Office Properties [Member] Class A Office Properties [Member]. Disclosure of Compensation Related Costs, Share-based Payments [Abstract] Share-based Payment Arrangement [Abstract] Consolidated Entities [Domain] Consolidated Entities [Domain] Earthquake Deductible Insurance Percentage of Value of the Affected Property Seattle Earthquake Deductible Insurance Percentage of Value of the Affected Property Seattle Earthquake Deductible Insurance Percentage of Value of the Affected Property Seattle Earned awards - Target Earned wards - Target Earned wards - Target Noncontrolling Interest, Outstanding Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding, Number land parcel land parcel land parcel Salesforce Tower Salesforce Tower [Member] Salesforce Tower Net Rentable Area (in sf) Net Rentable Area Tenant improvements Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Tenant Improvements Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Tenant Improvements Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items] Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items] Cumulative Effect, Period of Adoption, Adjustment Cumulative Effect, Period of Adoption, Adjustment [Member] Series B Preferred Units [Member] Series B Preferred Units [Member] Series B Preferred Units [Member] Entity Registrant Name Entity Registrant Name Subsequent Event Type [Domain] Subsequent Event Type [Domain] 751 Gateway Seven Five One Gateway [Member] Seven Five One Gateway Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] MYLTIP 2013 MYLTIP two thousand thirteen [Member] MYLTIP two thousand thirteen [Member] Operating leases, Weighted-average discount rate Operating Lease, Weighted Average Discount Rate, Percent Other liabilities Increase (Decrease) in Other Operating Liabilities Real estate, at cost (amounts related to variable interest entities (“VIEs”) of $6,688,647 and $6,592,019 at September 30, 2021 and December 31, 2020, respectively) Real Estate Investment Property, at Cost Impairment losses Impairment loss Asset Impairment Charges Schedule Of Reconciliation Of Net Operating Income To Net Income Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Table Text Block] Deferred financing costs, net Debt Issuance Costs, Net Debt Issuance Costs, Net Number of floors Number of floors Number of floors Less: Interest Portion Finance Lease, Liability, Undiscounted Excess Amount CA-Colorado Center Limited Partnership [Member] Colorado Center CA-Colorado Center Limited Partnership [Member] CA-Colorado Center Limited Partnership [Member] Gain on Sale of Investments Gain on Sale of Investments Company's share of equity Company Share Of Equity Company Share Of Equity Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Real Estate [Domain] Real Estate [Domain] Preferred dividends / distributions Preferred Stock Dividends, Income Statement Impact Depreciation and amortization Depreciation and amortization expense Depreciation, Depletion and Amortization, Nonproduction Adjustments for New Accounting Pronouncements [Axis] Accounting Standards Update [Axis] Gains (losses) on sales of real estate Gains on sales of real estate Gains on sales of real estate Gain (Loss) on Disposition of Property Plant Equipment, Excluding Oil and Gas Property and Timber Property Minimum earned awards Minimum earned awards Minimum earned awards Number of VIEs Number of VIEs Number of VIEs - consolidated Below Market Lease Intangible [Member] Below Market Leases [Member] Below Market Leases Noncontrolling interest: Temporary Equity [Abstract] Entity Address, Postal Zip Code Entity Address, Postal Zip Code Basis differential Income Statement Basis Differential Income Statement Basis Differential BNYA Amenity Operator LLC [Member] BNYA Amenity Operator LLC [Member] BNYA Amenity Operator LLC [Member] Series B Dividend Rate Percentage Series B Dividend Rate Percentage Series B Dividend Rate Percentage Rental Revenue: Residential Rental Revenue Residential Rental Revenue Residential. Company's share of Net Operating Income Net Operating Income The net result for the period of deducting property operating expenses from property operating revenues. OP Units [Member] Op Units [Member] OP Units [Member] Fair Value Measurement Inputs and Valuation Techniques [Table Text Block] Fair Value Measurement Inputs and Valuation Techniques [Table Text Block] Beach Cities Media Center [Member] Beach Cities Media Center [Member] Beach Cities Media Center Debt Instrument, Face Amount Debt Instrument, Face Amount Equity [Abstract] Equity [Abstract] Derivative, Cap Interest Rate Derivative, Cap Interest Rate Total Assets, Fair Value Disclosure Non-cash investing and financing activities: Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract] Accounting Standards Update [Extensible List] Accounting Standards Update [Extensible List] 7750 Wisconsin Avenue LLC [Member] Seven seven five zero Wisconsin Avenue LLC [Member] 7750 Wisconsin Avenue LLC [Member] Entities [Table] Entities [Table] Redemption of OP units issued on conversion of LTIP, OPP and MYLTIP units (in shares) Redemption Of OP Units Issued On Conversion Of LTIP and MYLTIP Units Redemption Of OP Units Issued On Conversion Of LTIP and MYLTIP Units Schedule of Finite-Lived Intangible Assets, Future Amortization Expense Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block] Weighted average number of common and common equivalent shares / units outstanding (in shares / units) Diluted Earnings: Net income attributable to the Company's common shareholders / unitholders (in shares / units) Weighted Average Number of Shares Outstanding, Diluted Other income (expense) Other Income and Expenses [Abstract] Depositary shares of Series B Cumulative Redeemable Preferred [Member] Depository shares of Series B Cumulative Redeemable Preferred [Member] Depository shares of Series B Cumulative Redeemable Preferred [Member] Debt Disclosure [Abstract] Debt Disclosure [Abstract] Write off of accounts receivable Accounts Receivable, Allowance for Credit Loss, Recovery Amortization of right of use assets - operating leases Amortization of right of use asset - operating leases Amortization of right of use asset - operating leases Unsecured Debt [Member] Unsecured Debt [Member] Net cash provided by (used in) financing activities Net Cash Provided by (Used in) Financing Activities Agreement with 1265 Main Office JV LLC partner [Member] Agreement with One Two Six Five Main Office JV LLC partner [Member] Agreement with One Two Six Five Main Office JV LLC partner 540 Madison Venture 540 Madison Avenue [Member] Five Four Zero Madison Venture Llc [Member] Five Four Zero Madison Venture LLC [Member]. Future payment to acquire interest in equity method investment Future payment to acquire interest in equity method investment Future payment to acquire interest in equity method investment Investments by Consolidated and Nonconsolidated Entities [Domain] Investments by Consolidated and Nonconsolidated Entities [Domain] Common stock, $0.01 par value, 250,000,000 shares authorized, 156,285,391 and 155,797,725 issued and 156,206,491 and 155,718,825 outstanding at September 30, 2021 and December 31, 2020, respectively Common Stock, Value, Issued Common Stock, Value, Issued Proceeds from Construction Loans Payable Proceeds from Construction Loans Payable Document Fiscal Year Focus Document Fiscal Year Focus 2023 Finite-Lived Intangible Asset, Expected Amortization, Year Two Coverage For Acts Of Terrorism Under TRIA Covered in Excess of Amount Covered by IXP Coverage For Acts Of Terrorism Under TRIA Covered in Excess of Amount Covered by IXP Coverage For Acts Of Terrorism Under TRIA Covered in Excess of Amount Covered by IXP Property partnerships Noncontrolling Interest in Limited Partnerships Noncontrolling Interest in Limited Partnerships LTIP units issued (in shares) LTIP units issued LTIP units issued Entity Current Reporting Status Entity Current Reporting Status MYLTIP vesting 2020 [Member] MYLTIP vesting two thousand twenty [Member] MYLTIP vesting 2020 [Member] Proceeds from sale of investment in unconsolidated joint venture Proceeds from Sale of Equity Method Investments Proceeds from Sale of Equity Method Investments Payments on capital lease obligations Repayments of Long-term Capital Lease Obligations Earnings Per Share and Earnings Per Common Unit Earnings Per Share, Policy [Policy Text Block] Comprehensive Income Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Other Income Other Income Los Angeles [Member] Los Angeles [Member] Los Angeles [Member] Common stock, shares issued Shares issued Common Stock, Shares, Issued Cash and cash equivalents (amounts related to VIEs of $288,186 and $340,642 at September 30, 2021 and December 31, 2020, respectively) Cash and cash equivalents, beginning of period Cash and cash equivalents, end of period Cash and Cash Equivalents, at Carrying Value Cash and Cash Equivalents, at Carrying Value Properties Name of Joint Venture Property Name of Joint Venture Property Operating partnership guarantee to cover liabilities of IXP Operating partnership guarantee to cover liabilities of subsidiary Operating partnership guarantee to cover liabilities of subsidiary Lease liabilities - operating leases Present value of lease payments Operating Lease, Liability Segment Reporting [Abstract] Segment Reporting [Abstract] Tenant and other receivables, net (amounts related to VIEs of $8,598 and $10,911 at September 30, 2021 and December 31, 2020, respectively) Tenant and other receivables, net (amounts related to VIEs of $8,598 and $10,911 at September 30, 2021 and December 31, 2020, respectively) Accounts Receivable, after Allowance for Credit Loss Basis Of Presentation And Summary Of Significant Accounting Policies Basis of Presentation and Significant Accounting Policies [Text Block] Debt Instrument [Line Items] Debt Instrument [Line Items] Total stockholders' equity attributable to Boston Properties, Inc. Members’/Partners’ equity Stockholders' Equity Attributable to Parent Area of Land Area of Land Rental Expenses: Class A Office Rental Expenses Class Office Rental Expenses Class Office Entity Address, City or Town Entity Address, City or Town Square 407 Limited Partnership [Member] Square Four Zero Seven Limited Partnership [Member] Square 407 Limited Partnership [Member]. 2026 Lessee, Operating Lease, Liability, to be Paid, Year Five Number of VIEs - Total Number of VIEs - Total Number of VIEs - Total Type of Adoption [Domain] Accounting Standards Update [Domain] Allocation of undistributed earnings to participating securities Participating Securities, Distributed and Undistributed Earnings (Loss), Basic MYLTIP 2018 MYLTIP Two thousand eighteen [Member] MYLTIP Two thousand eighteen Performance Index [Axis] Performance Index [Axis] Performance Index [Axis] Dividend Paid [Member] Dividend Paid [Member] Real Estate Real Estate, Policy [Policy Text Block] Preferred Stock Redemption Charge Preferred Stock Redemption Premium Preferred Stock Redemption Premium Employee discount Share-based Compensation Arrangement by Share-based Payment Award, Discount from Market Price, Offering Date Dividends and distributions Payments of Dividends Liabilities: Liabilities [Abstract] Line of Credit Facility, Covenant Compliance Line of Credit Facility, Covenant Compliance Real Estate Real Estate Disclosure [Text Block] 2024 Finite-Lived Intangible Asset, Expected Amortization, Year Three Construction in Progress Construction in Progress [Member] One OP unit is equivalent to one share of Common Stock (in shares) Common Stock Conversion Rate Common Stock Conversion Rate Other Liabilities, Current Other Liabilities, Current Period from May 19, 2021 through December 31, 2021 Lessee, Operating Lease, Liability, to be Paid, Remainder of Fiscal Year Investment, Name [Domain] Investment, Name [Domain] Other comprehensive income (loss) Other Comprehensive Income (Loss), Net of Tax MYLTIP vesting 2022 MYLTIP vesting two thousand twenty two [Member] MYLTIP vesting 2022 [Member] Distributions percent before measurement date Distributions Percent Before Measurement Date Distributions Percent Before Measurement Date Leases [Abstract] Leases [Abstract] Unsecured Credit Facility Unsecured line of Credit [Text Block] Unsecured line of Credit Safeco Plaza Safeco Plaza [Member] Safeco Plaza Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Comprehensive income attributable to noncontrolling interests Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest Earnings Per Share [Abstract] Earnings Per Share [Abstract] Outside members’ notes payable contributed to noncontrolling interests in property partnerships Debt Conversion, Original Debt, Amount Dividends [Axis] Dividends [Axis] Above Market Lease Intangibles [Member] Above Market Leases [Member] Reallocation of noncontrolling interest Noncontrolling Interest, Increase from Subsidiary Equity Issuance 2026 Finite-Lived Intangible Asset, Expected Amortization, Year Five Document Fiscal Period Focus Document Fiscal Period Focus stock option stock option exercised [Member] Stock Option Exercised Retail Properties [ Member] Retail Properties [Member] Retail Properties [Member]. Diluted Earnings: Net income attributable to the Company's common shareholders / unitholders Net Income (Loss) Available to Common Stockholders, Diluted Mortgages [Member] Mortgages [Member] Company's Share of Net Operating Income: % of Grand Totals Percentage of Company's Share of Net Operating Income Percentage of Company's Share of Net Operating Income Entity Filer Category Entity Filer Category Common Stock [Member] Common Stock [Member] Number of extensions Number of extensions Number of extensions Product and Service [Domain] Product and Service [Domain] Lessee, Operating Lease, Discount Rate Lessee, Operating Lease, Discount Rate Noncontrolling interests in property partnerships Temporary Equity, Carrying Amount Redeemable Interest in Property Partnerships Temporary Equity, Carrying Amount Redeemable Interest in Property Partnerships Capital distributions from unconsolidated joint ventures Proceeds from Equity Method Investment, Distribution, Return of Capital Related party note receivable, net Notes Receivable, Related Parties Notes Receivable, Related Parties Above and below market rent adjustments, net Above And Below Market Rent Adjustments Above And Below Market Rent Adjustments Future Residential Building [Member] Future Residential Building [Member] Future Residential Building [Member] Finance leases, Weighted-average discount rate Finance Lease, Weighted Average Discount Rate, Percent Op units and LTIP units Op units and LTIP units [Member] Op units and LTIP units Mortgage Notes [Member] Secured Debt [Member] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Acquisition of noncontrolling interest in property partnership Proceeds from (Payments to) Noncontrolling Interests Schedule of Equity Method Investments [Line Items] Schedule of Equity Method Investments [Line Items] Unsecured senior notes, net Senior Notes Senior Notes Debt Instrument, Interest Rate, Stated Percentage Debt Instrument, Interest Rate, Stated Percentage Lease Obligation Incurred Lease Obligation Incurred 3.766% unsecured senior notes Three point seven six six percent unsecured senior notes [Member] 3.766% unsecured senior notes Notes receivable, net Financing Receivable, before Allowance for Credit Loss Name of Property [Axis] Name of Property [Axis] Company's Share [Member] Company's Share [Member] Company's Share [Member] Diluted earnings per common share / unit attributable to the Company Diluted Earnings: Earnings Per Share, Diluted [Abstract] Options exercised Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Limited Partners' Capital Account, Units Outstanding (in units) Limited Partners' Capital Account, Units Outstanding Commitments And Contingencies Disclosure [Table] Commitments And Contingencies Disclosure [Table] Commitments and Contingencies Disclosure [Table] Net increase (decrease) in cash and cash equivalents and cash held in escrows Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect Employee and director payment per share (in dollars per share) Employee and director payment per share Employee and director payment per share Tenant leasing costs, net deconsolidated Transfer Of Tenant Lease Costs Real Estate Transfer Of Tenant Lease Costs Real Estate Noncontrolling interests: Noncontrolling Interest Items [Abstract] Preferred stock, $0.01 par value, 50,000,000 shares authorized; Preferred Stock, Number of Shares, Par Value and Other Disclosures [Abstract] Expenses Costs and Expenses [Abstract] Subsequent Events [Abstract] Subsequent Events [Abstract] Treasury common stock at cost, shares Treasury Stock, Shares Impairment loss on investment Impairment loss on investment Other than Temporary Impairment Losses, Investments 2025 Long-Term Debt, Maturity, Year Five Ownership [Domain] Ownership [Domain] Final awards percentage of target Final awards percentage of target Final awards percentage of target Right of use assets - finance leases Right of use assets - finance leases Right of use assets - finance leases Hotel Property [ Member] Hotel Property [Member] Hotel Property [Member]. Total equity / capital Equity, value Equity, value Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Organization Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Additional paid-in capital Additional Paid in Capital 2022 Finite-Lived Intangible Asset, Expected Amortization, Year One Total revenue Total revenue Revenues Class of Stock [Axis] Class of Stock [Axis] Construction in progress Payments to Acquire Other Productive Assets Gateway Portfolio Holdings LLC [Member] Gateway Commons Complex [Member] Gateway Commons Complex [Member] Gateway Commons Complex [Member] Diluted Earnings: Net income, Per Share Amount (in dollars per share / unit) Earnings Per Share, Diluted Schedule of Stock by Class [Table] Schedule of Stock by Class [Table] Earnings Per Share After Allocation of Undistributed Earnings to Participating Securities Basic (dollars per share) Earnings Per Share After Allocation of Undistributed Earnings to Participating Securities Basic (dollars per share) Earnings Per Share After Allocation of Undistributed Earnings to Participating Securities Basic (dollars per share) Earnings Per Share After Allocation of Undistributed Earnings to Participating Securities Basic (dollars per share) Noncontrolling Interest [Line Items] Noncontrolling Interest [Line Items] Prepaid rent reclassified to right of use asset Prepaid rent reclassified to right of use asset Prepaid rent reclassified to right of use asset Equity to be transferred as part of acquisition Business Combination, Consideration Transferred, Including Equity Interest in Acquiree Held Prior to Combination Schedule of Long-term Debt Instruments Schedule of Long-term Debt Instruments [Table Text Block] Unconsolidated Properties Unconsolidated Properties [Member] Entity Address, Address Line One Entity Address, Address Line One Entity Emerging Growth Company Entity Emerging Growth Company Line of Credit Facility, Covenant Terms Line of Credit Facility, Covenant Terms Maximum [Member] Maximum [Member] Preferred stock, shares authorized Preferred Stock, Shares Authorized Noncontrolling Interests [Member] Noncontrolling Interest [Member] Noncontrolling Interest [Member] Vesting Period [Axis] Vesting Period [Axis] Vesting Period [Axis] Gains (losses) from investments in securities Gains (losses) from investments in securities Gain (Loss) on Investments Dividends, Common Stock, Cash Dividends, Common Stock, Cash Stock Option and Incentive Plan Term Period Stock Option and Incentive Plan Term Period Stock Option and Incentive Plan Term Period Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] OP unit conversion rate (in shares) OP Unit Conversion Rate OP Unit Conversion Rate. Trading Symbol Trading Symbol 3625 - 3635 Peterson Way Three Six Two Five Three Six Three Five Peterson Way [Member] Three Six Two Five Three Six Three Five Peterson Way Redeemable partnership units— 15,989,304 and 16,037,121 common units and 1,487,492 and 1,336,115 long term incentive units outstanding at redemption value at September 30, 2021 and December 31, 2020, respectively NonControlling Interest Redeemable Partnership Units Common Units Value Amount of Noncontrolling interest redeemable partnership common units. Organization, Consolidation and Presentation of Financial Statements [Abstract] Organization, Consolidation and Presentation of Financial Statements [Abstract] Debt Instrument, Increase, Accrued Interest Debt Instrument, Increase, Accrued Interest Entity Shell Company Entity Shell Company Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Fair Value Measurement Inputs and Valuation Techniques [Line Items] 2022 Finance Lease, Liability, to be Paid, Year Two Acquisition of noncontrolling interest in property partnership Difference Between Purchase Price And Carrying Value Difference Between Purchase Price And Carrying Value Real estate and development in process, net Total real estate Real Estate Investment Property, Net Investment in unconsolidated joint venture recorded upon deconsolidation Transfer to Investments Entity Public Float Entity Public Float 3.350% unsecured senior notes Three point three five zero percent unsecured senior notes [Member] 3.350% unsecured senior notes Payments to Acquire Real Estate Payments to Acquire Real Estate Document Type Document Type ICFR Auditor Attestation Flag ICFR Auditor Attestation Flag Accounts payable and accrued expenses Increase (Decrease) in Accounts Payable and Accrued Liabilities Treasury Stock, at cost [Member] Treasury Stock [Member] Management Service [Member] Management Service [Member] Series B Cumulative Redeemable Preferred Stock / Unit [Member] Series B Preferred Stock [Member] Series B Cumulative Redeemable Preferred Stock / Unit [Member] Series B Cumulative Redeemable Preferred Stock / Unit [Member] Statement, Business Segments [Axis] Segments [Axis] Effective portion of interest rate contracts Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax Effective portion of interest rate contracts Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax One Five Nine East 53rd Street One Five Nine East Five Three Street [Member] One Five Nine East Five Three Street Lessee, Leases Lessee, Leases [Policy Text Block] Allocated net income for the period Net income allocable to general and limited partner units Net Income Allocable To General And Limited Partner Units Debt instrument, borrowing capacity Debt instrument, borrowing capacity Debt instrument, borrowing capacity Accounting Standards Update 2018-09 Accounting Standards Update 2018-09 [Member] Construction Loan Facility Borrowing Capacity Construction Loan Facility Borrowing Capacity Construction Loan Facility Borrowing Capacity Limited Partner [Member] Limited Partner [Member] Reddemable deferred stock units, units Temporary Equity, Shares Subscribed but Unissued Commitments And Contingencies [Line Items] Commitments And Contingencies [Line Items] Commitments And Contingencies [Line Items] Line of Credit [Member] Line of Credit [Member] Office Technical Properties [Member] Office Technical Properties [Member] Office/Technical Properties [Member]. Proceeds from noncontrolling interest including a contribution related to the repayment of a members' note payable Proceeds from noncontrolling interest including a contribution related to the repayment of a members' note payable Proceeds from noncontrolling interestt including a contribution reltaed to the repayment of a members' note payable Value of MYLTIP Awards Value of MYLTIP Awards Value of MYLTIP Awards Unconsolidated Joint Ventures [Member] Unconsolidated Joint Ventures [Member] Unconsolidated Joint Ventures [Member] Annual Aggregate Limit of Earthquake Insurance Seattle Annual Aggregate Limit of Earthquake Insurance Seattle Annual Aggregate Limit of Earthquake Insurance Seattle Operating Income (Loss) Operating Income (Loss) Noncontrolling Interests Noncontrolling Interest Disclosure [Text Block] Noncash or Part Noncash Acquisition, Debt Assumed Noncash or Part Noncash Acquisition, Debt Assumed Investments by Consolidated and Nonconsolidated Entities [Axis] Investments by Consolidated and Nonconsolidated Entities [Axis] Boston Properties Limited Partnership Partners' Capital (General and Limited Partners)[Member] Boston Properties Limited Partnership [Member] Boston Properties Limited Partnership Variable Rate [Axis] Variable Rate [Axis] MYLTIP Units distribution as percentage of OP Unit distribution prior to measurement date Outperformance Awards Long Term Incentive Plan Units Distribution As Percentage Of Op Unit Distribution Prior To Measurement Date Prior to the measurement date on February 5, 2011, 2008 OPP 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. Commitments and contingencies (See Note 9) Commitments and Contingencies Vesting Period Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period TSR measurement (in years) TSR Measurement, Years TSR Measurement, Years. MYLTIP 2018 two thousand eighteen MYLTIP [Member] 2018 MYLTIP [Member] Entity Address, State or Province Entity Address, State or Province Debt Instrument, Description of Variable Rate Basis Debt Instrument, Description of Variable Rate Basis Institutional investor number two Institutional investor number two [Member] Institutional investor number two Dividends in excess of earnings Retained Earnings (Accumulated Deficit) Mortgage notes payable, net (amounts related to VIEs of $2,898,699 and $2,907,590 at September 30, 2021 and December 31, 2020, respectively) Mortgage notes payable, net Mortgage and notes payable, net Secured Debt Colorado Center [Member] Colorado Center [Member] Colorado Center [Member] Repayments of unsecured line of credit Repayments of Lines of Credit Right of use assets - operating leases Right of use assets - operating leases Operating Lease, Right-of-Use Asset Reconciliation of cash and cash equivalents and cash held in escrow Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract] Debt Instrument, Unamortized Discount Debt Instrument, Unamortized Discount Loss from early extinguishment of debt Loss from early extinguishment of debt Loss from early extinguishment of debt Gain (Loss) on Extinguishment of Debt Weighted Average Price of Shares Purchased Share-based Compensation Arrangement by Share-based Payment Award, Per Share Weighted Average Price of Shares Purchased Land held for future development Land Available for Development Hotel [Member] Hotel [Member] 2021 Finance Lease, Liability, to be Paid, Year One Equity / Capital: Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract] Residential Properties Under Construction [Member] Residential Properties Under Construction [Member] Residential Properties Under Construction [Member] Schedule of Stock Options Outstanding Schedule of Stock Options Outstanding [Table Text Block] Schedule of Stock Options Outstanding Annual aggregate limit of the earthquake insurance which covers San Francisco and Los Angeles regions Annual Aggregate Limit Of Earth Quake Insurance San Francisco and Los Angeles Annual Aggregate Limit Of Earth Quake Insurance San Francisco and Los Angeles Stock Based Compensation Dilutive Securities, Effect on Basic Earnings Per Share Income Taxes Income Tax, Policy [Policy Text Block] Tenant leasing costs Lease, Cost Capital contributions to unconsolidated joint ventures Payments to Acquire Equity Method Investments Payments to Acquire Equity Method Investments Number Exercisable Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number Debt prepayment and extinguishment costs Payment for Debt Extinguishment or Debt Prepayment Cost Deferred financing costs Payments of Financing Costs NAREIT Office Index adjusted [Member] NAREIT Office Index adjusted [Member] NAREIT Office Index adjusted [Member] Deposit on capital lease Payments for (Proceeds from) Other Investing Activities Noncontrolling interests in property partnerships Partners' Capital Attributable to Noncontrolling Interest Acquired Finite-Lived Intangible Assets [Line Items] Acquired Finite-Lived Intangible Assets [Line Items] Number Of Days Used In Calculation, Average Closing Prices Of Common Stock Number Of Days Used In Calculation, Average Closing Prices Of Common Stock Number Of Days Used In Calculation, Average Closing Prices Of Common Stock Origination of Notes Receivable from Related Parties Origination of Notes Receivable from Related Parties Noncontrolling interest - redeemable preferred units Noncontrolling Interest in Net Income (Loss) Preferred Unit Holders, Redeemable Land Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Land Construction in progress Construction in Progress, Gross Thereafter Long-Term Debt, Maturity, after Year Five Hub50House [Member] Hub50House [Member] Hub50House Gain Contingencies, Nature [Axis] Gain Contingencies, Nature [Axis] Closing price of common stock (in dollars per share) Share Price Investment in Securities Investment, Policy [Policy Text Block] Performance Index [Domain] Performance Index [Domain] Performance Index [Domain] Preferred Stock Redemption Price Per Share, plus accrued and unpaid dividends Preferred Stock Redemption Price Per Share, plus accrued and unpaid dividends Preferred Stock Redemption Price Per Share, plus accrued and unpaid dividends Geographical [Domain] Geographical [Domain] Distributions Payable, Amount Per Unit Dividends Payable, Amount Per Share / Unit Dividends Payable, Amount Per Share Sale of an interest in property partnerships sale of an interest in property partnerships sale of an interest in property partnerships San Francisco [Member] San Francisco [Member] San Francisco [Member] Net (income) loss attributable to noncontrolling interests Net Income (Loss) Attributable to Noncontrolling Interest [Abstract] Entity Voluntary Filers Entity Voluntary Filers Credit Facility [Axis] Credit Facility [Axis] Preferred stock / units, shares / units issued (in shares / units) Preferred Stock, Shares Issued Land Land Long-term Debt, Maturity Date Long-term Debt, Maturity Date Lessee, Operating Lease, Liability, Payment, Due [Abstract] Lessee, Operating Lease, Liability, Payment, Due [Abstract] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Gain Contingency, Nature [Domain] Gain Contingency, Nature [Domain] Value of program trigger Program Trigger Value Program Trigger Value Dock 72 [Member] Dock Seven Two [Member] Dock Seven Two Safeco Plaza REIT LLC Safeco Plaza REIT LLC [Member] Safeco Plaza REIT LLC Operating Lease, Lease Income [Table Text Block] Operating Lease, Lease Income [Table Text Block] Boston [Member] Boston [Member] Boston [Member] Computation Of Basic And Diluted Earnings Per Share / Unit Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] 360 Park South Avenue 360 Park South Avenue [Member] 360 Park South Avenue Line of Credit Facility, Expiration Date Line of Credit Facility, Expiration Date Company's share of net income Companys share of net income (loss) Company's share of net income (loss) MYLTIP 2015 [Member] MYLTIP two thousand fifteen [Member] MYLTIP 2015 [Member] Settlement of accreted debt discount on redemption of unsecured senior notes Accretion Expense Unsecured line of credit Long-term Line of Credit Long-term Line of Credit Repayments of Debt Repayments of Debt Investments In Unconsolidated Joint Ventures Equity Method Investments [Table Text Block] Net cash provided by operating activities Net Cash Provided by (Used in) Operating Activities Entity Central Index Key Entity Central Index Key Noncash or Part Noncash Acquisition, Other Assets Acquired Noncash or Part Noncash Acquisition, Other Assets Acquired Rental Expenses: Total Rental Expenses Operating Expenses Total Rental Expenses Operating Expenses Total. Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets by Major Class [Axis] Senior Notes Senior Notes [Member] Lessee, Finance Lease, Term of Contract Lessee, Finance Lease, Term of Contract Annapolis Junction NFM, LLC [Member] Annapolis Junction Nfm Llc [Member] Annapolis Junction NFM LLC [Member] Geographical [Axis] Geographical [Axis] Number of Units in Real Estate Property Number of Units in Real Estate Property Segment [Domain] Segments [Domain] 4.628% unsecured senior notes Four point six two eight percent unsecured senior notes [Member] 4.628% unsecured senior notes Potential additonal payments to joint venture partner Potential additonal payments to joint venture partner Potential additonal payments to joint venture partner unvested MYLTIP distributions as compared to total distributions (percentage) unvested MYLTIP distributions as compared to total distributions (percentage) unvested MYLTIP distributions as compared to total distributions (percentage) Podium Developer LLC [Member] Podium Developer LLC [Member] Podium Developer LLC [Member] Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Line of Credit Facility [Abstract] Weighted average price (per unit) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instrument Other than Option, Nonvested, Intrinsic Value 2024 Long-Term Debt, Maturity, Year Four Interest capitalized Interest Costs Capitalized Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Dividends Payable [Table] Dividends Payable [Table] Tenant and Other Receivables and Notes Receivable Receivable [Policy Text Block] Letter of credit and performance obligations Letter Of Credit And Performance Obligation Letter Of Credit And Performance Obligation Derivative, Notional Amount Derivative, Notional Amount Line of Credit Facility [Table] Line of Credit Facility [Table] Increase (decrease) in parking and other revenue primarily related to COVID-19 Increase (decrease) in parking and other revenue primarily related to COVID-19 Increase (decrease) in parking and other revenue primarily related to COVID-19 Buildings and improvements Investment Building and Building Improvements Interest and other income (loss) Interest and other income (loss) Interest and Other Income Investments In Unconsolidated Joint Ventures Equity Method Investments and Joint Ventures Disclosure [Text Block] Other liabilities (amounts related to VIEs of $124,615 and $158,805 at September 30, 2021 and December 31, 2020, respectively) Other Liabilities Other Liabilities Other Liabilities Segment Reporting Disclosure [Text Block] Segment Reporting Disclosure [Text Block] 901 New York Avenue LLC (economic ownership) [Member] Bp Crf Nine Zero One New York Avenue Llc (economic percentage)[Member] [Member] Bp Crf Nine Zero One New York Avenue Llc (economic percentage)[Member] [Member] Finance Lease, Interest Payment on Liability Finance Lease, Interest Payment on Liability Scenario [Axis] Scenario [Axis] Title of 12(b) Security Title of 12(b) Security Schedule of Real Estate Properties [Table] Schedule of Real Estate Properties [Table] MYLTIP 2020 [Member] two thousand twenty MYLTIPS [Member] [Member] two thousand twenty MYLTIPS [Member] [Member] Number of Vehicles Number of Vehicles Number of Vehicles Shares of Common Stock issued in connection with redemption of an equal number of OP Units (in shares) Conversion of Stock, Shares Issued 2.984% unsecured senior notes Two point nine eight four percent unsecured senior notes [Member] 2.984% unsecured senior notes Platform 16 Holdings LP [Member] Platform 16 Platform Sixteen [Member] Platform Sixteen [Member] Unearned compensation Partners' Capital Account, Deferred Compensation Vesting [Domain] Vesting [Domain] Finance Lease, Liability, Maturity Finance Lease, Liability, Fiscal Year Maturity [Table Text Block] Allowance for current expected credit losses Provision for Loan and Lease Losses Interest expense Interest expense Interest Expense Accrued interest payable Interest Payable 3.343 % unsecured senior notes Three point three four three percent unsecured senior notes [Member] 3.343% unsecured senior notes [Member] Leases of Lessor Disclosure [Text Block] Leases of Lessor Disclosure [Text Block] Depreciation and amortization Depreciation, Depletion and Amortization Series B Liquidation Preference Per Share/ Unit Series B, Liquidation Preference Per Share (dollars per share) Preferred Stock, Liquidation Preference Per Share Product and Service [Axis] Product and Service [Axis] Lessee Disclosure [Abstract] Lessee Disclosure [Abstract] Parking and Other [Member] Parking and Other [Member] Parking and Other [Member] Entity Owning Land And Infrastructure Of Project [Member] Entity Owning Land And Infrastructure Of Project [Member] Entity Owning Land And Infrastructure Of Project [Member] Proceeds from unsecured senior notes Proceeds from Issuance of Unsecured Debt Weighted-average period (years) Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition 2025 Finance Lease, Liability, to be Paid, Year Five 2022 Long-Term Debt, Maturity, Year Two Basis differentials Equity Method Investment, Difference Between Carrying Amount and Underlying Equity Annapolis Junction Building Six [Member] Annapolis Junction Building Six [Member] Annapolis Junction Building Six [Member] Net income attributable to the Company's common shareholders / unitholders Net income attributable to the company's common shareholders / unitholders Net Income (Loss) Available to Common Stockholders, Basic Target Target [Member] Target Affordable Housing requirement Affordable Housing requirement Affordable Housing requirement Ltips (including vested MYLTIPS) And Restricted Stock [Member] Ltips (including vested MYLTIPS) And Restricted Stock [Member] LTIPs (including vested MYLTIPS) and Restricted Stock [Member]. 500 North Capitol Venture LLC [Member] Five Zero Zero North Capitol Llc [Member] Five Zero Zero North Capitol LLC [Member]. Noncash or Part Noncash Acquisition, Value of Assets Acquired Noncash or Part Noncash Acquisition, Value of Assets Acquired Dividends, Per Unit, Cash Paid Common Stock / Unit, Dividends / Distributions, Per Share / Unit, Cash Paid Common Stock, Dividends, Per Share, Cash Paid Number of buildings number of buildings number of buildings Debt Instrument [Axis] Debt Instrument [Axis] Schedule of Business Acquisitions, by Acquisition Schedule of Business Acquisitions, by Acquisition [Table Text Block] Class of Stock [Line Items] Class of Stock [Line Items] Amortization of interest rate contracts Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax Gains (Losses) on Sales of Investment Real Estate Gains (Losses) on Sales of Investment Real Estate Adjustments to reconcile net income to net cash provided by operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Entity Information [Line Items] Entity Information [Line Items] Recoveries from tenants Other Operating Income Deposit on mortgage note payable interest rate lock Payments for (Proceeds from) Deposit on Loan Subsequent Event [Member] Subsequent Event [Member] Line of credit facility, maximum percent for loan advances Line of credit facility, maximum percent for loan advances Line of credit facility, maximum borrowing percentage for loan advances Leased percentage Leased percentage Leased percentage Revenue Recognition Revenue [Policy Text Block] New York [Member] NEW YORK 4.289% unsecured senior notes Four point two eight nine percent unsecured senior notes [Member] 4.289% unsecured senior notes Summary Of Significant Accounting Policies [Line Items] Summary Of Significant Accounting Policies [Line Items] Summary Of Significant Accounting Policies [Line Items] Estimated Fair Value [Member] Estimate of Fair Value Measurement [Member] At The Market Stock Offering Program Aggregate Value Of Common Stock At The Market Stock Offering Program Aggregate Value Of Common Stock At The Market Stock Offering Program, Aggregate Value Of Common Stock number of promoted interest number of promoted interest number of promoted interest 2025 Finite-Lived Intangible Asset, Expected Amortization, Year Four Lease Intangibles Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles Weighted Average Per Unit Fair Value (in dollars per share) Weighted Average Per Unit Fair Value Weighted Average Per Unit Fair Value Other Than Stock Options Awards Conversion Ratio Other Than Stock Options Awards Conversion Ratio Other Than Stock Options Awards Conversion Ratio Base rent Operating Leases, Income Statement, Lease Revenue Rental Direct Costs of Leased and Rented Property or Equipment Comprehensive income attributable to the Company Comprehensive Income (Loss), Net of Tax, Attributable to Parent 2023 Finance Lease, Liability, to be Paid, Year Three Potential Increase to Line of Credit Potential Increase to Line of Credit Potential Increase to Line of Credit Preferred stock, par value Preferred Stock, Par or Stated Value Per Share Documents Incorporated by Reference Documents Incorporated by Reference [Text Block] 2021 Long-Term Debt, Maturity, Year One City Area Code City Area Code Legal Entity [Axis] Legal Entity [Axis] MYLTIP Units forfeited MYLTIPUnitsForfeited MYLTIP Units Forfeited Lehman [Member] Lehman [Member] Lehman [Member] Per occurrence limit for NBCR Coverage Per occurrence limit for NBCR Coverage Per occurrence limit for NBCR Coverage Redeemable partnership units— 15,989,304 and 16,037,121 common units and 1,487,492 and 1,336,115 long term incentive units outstanding at redemption value at September 30, 2021 and December 31, 2020, respectively Redeemable Noncontrolling Interest, Equity, Preferred, Carrying Amount Redeemable Noncontrolling Interest, Equity, Preferred, Carrying Amount Document Period End Date Document Period End Date Reston Next Reston Next [Member] Reston Next Distributions Partners' Capital Account, Distributions 2021 Stock Incentive Plan 2021 Stock Incentive Plan [Member] 2021 Stock Incentive Plan Preferred Stock, Redemption Price Per Share Preferred Stock, Redemption Price Per Share Distribution Declared to OP, LTIP, OPP and MYLTIP Units [Table Text Block] Dividends Declared [Table Text Block] Dividends Declared [Table Text Block] Partners' Capital (General and Limited Partners) [Member] Boston Properties Limited Parntership [Member] Boston Properties Limited Parntership [Member] Losses from interest rate contracts Gain (Loss) on Derivative Instruments, Net, Pretax Rosecrans-Sepulveda Partners 4, LLC Rosecrans-Sepulveda Partners Four, LLC [Member] Rosecrans-Sepulveda Partners Four, LLC MYLTIP 2014 MYLTIP Two thousand fourteen [Member] MYLTIP Two thousand fourteen [Member] Net income Net income Net income Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Redeemable Preferred Stock Dividends Redeemable Preferred Stock Dividends Notes receivable, net Increase (Decrease) in Finance Receivables Non-Qualified Employee Stock Purchase Plan [Member] Non-Qualified Employee Stock Purchase Plan [Member] Non-Qualified Employee Stock Purchase Plan [Member] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Non-cash compensation expense Share-based Payment Arrangement, Noncash Expense Unvested MYLTIP Units [Member] Unvested MYLTIP Units [Member] Unvested 2018-2020 MYLTIPS[Member] Return of deposit on mortgage note payable interest rate lock Proceeds from (Payments for) Other Financing Activities Cover [Abstract] Cover [Abstract] Base Rate [Member] Base Rate [Member] Measurement Input Type [Axis] Measurement Input Type [Axis] Redemption of OP Unit equivalent to Common Stock (in shares) OP Unit Equivalence To Common Stock One OP Unit is equivalent to one common stock (share). Line of Credit, Additional Borrowing Capacity Line of Credit, Additional Borrowing Capacity Line of Credit, Additional Borrowing Capacity Distributions of net cash flow from operations of unconsolidated joint ventures Proceeds from Equity Method Investment, Distribution Debt instrument, total commitment Debt instrument, total commitment Debt instrument, total commitment Lessor Disclosure [Abstract] Lessor Disclosure [Abstract] Total Properties Under Construction [ Member] Properties Under Construction [Member] Properties Under Construction [Member]. Net Income Available To Common Stockholders After Allocation of Undistributed Earnings to Participating Securities Basic Net Income Loss Available To Common Stockholders After Allocation of Undistributed Earnings to Participating Securities Basic Net Income Loss Available To Common Stockholders After Allocation of Undistributed Earnings to Participating Securities Basic Total Total Long-term Debt Lessee, Operating Leases Lessee, Operating Leases [Text Block] In-Place Lease Intangibles Leases, Acquired-in-Place [Member] Operating expense Operating expense Operating expense Cost of Goods and Services Sold Lease, Cost [Abstract] Loans Assumed Loans Assumed Total expenses Total expenses Costs and Expenses Equity Components [Axis] Equity Components [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Minimum [Member] Minimum [Member] Real Estate Properties [Axis] Real Estate Property Ownership [Axis] Net assets acquired Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets Repayments of outside members’ notes payable Repayments of Notes Payable Significant unobservable inputs used in other than temporary impairment analysis Significant unobservable inputs used in other than temporary impairment analysis Significant unobservable inputs used in other than temporary impairment analysis NonControlling Interest Redeemable Partnership Units Common Units Shares Outstanding NonControlling Interest Redeemable Partnership Units Common Units Shares Outstanding NonControlling Interest Redeemable Partnership Units Common Units Shares Outstanding Entity Interactive Data Current Entity Interactive Data Current Revenue Revenues [Abstract] 180 CityPoint One Eight Zero CityPoint [Member] One Eight Zero CityPoint Cash flows from operating activities: Net Cash Provided by (Used in) Operating Activities [Abstract] Stockholders' Equity / Partners' Capital Stockholders' Equity Note Disclosure [Text Block] Share-based Payment Arrangement, Option, Activity Share-based Payment Arrangement, Option, Activity [Table Text Block] Equity Offering Costs Equity Offering Costs Policy [Policy Text Block] Equity Offering Costs Policy Issuance of notes receivable, net Payments to Acquire Loans Receivable Line of Credit Facility, Commitment Fee Percentage Line of Credit Facility, Commitment Fee Percentage 767 Venture, LLC [Member] Seven Six Seven Venture Llc [Member] Seven Six Seven Venture LLC [Member] Equity Method Investment, Description of Principal Activities Equity Method Investment, Description of Principal Activities Remainder of 2021 Finite-Lived Intangible Asset, Expected Amortization, Remainder of Fiscal Year Stock-Based Employee Compensation Plans Share-based Payment Arrangement [Policy Text Block] Unvested 2017 - 2019 MYLTIP Units [Member] Unvested Two Thousand Seventeen, Eighteen and Nineteen MYLTIP Units [Member] Unvested Two Thousand Seventeen, Eighteen and Nineteen MYLTIP Units [Member] BNY Tower Holdings LLC [Member] Dock 72 BNY Tower Holdings LLC [Member] BNY Tower Holdings LLC [Member] Noncontrolling interest - common units of the Operating Partnership Noncontrolling interest-common units of the Operating Partnership Noncontrolling Interest in Net Income (Loss) Operating Partnerships, Redeemable Unsecured term loan, net Other Borrowings Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] Segment Reporting Information, Revenue for Reportable Segment [Abstract] Segment Reporting Information, Revenue for Reportable Segment [Abstract] 6595 Springfield Center Drive 6595 Springfield Center Drive [Member] 6595 Springfield Center Drive Transaction costs Transaction costs Other Cost and Expense, Operating Building and other capital improvements, net deconsolidated Real Estate Owned, Transfer from Real Estate Owned Stockholders Equity / Partner Capital [Abstract] Stockholders Equity / Partner Capital [Abstract] Stockholders Equity / Partner Capital [Abstract] Schedule of Equity Method Investments [Table] Schedule of Equity Method Investments [Table] Issuance of restricted securities to employees and non-employee directors Issuance Of Restricted Units To Employees And Directors Issuance Of Restricted Units To Employees And Directors Debt Instrument, Interest Rate, Effective Percentage Debt Instrument, Interest Rate, Effective Percentage Effect of Dilutive Securities: Incremental Weighted Average Shares Attributable to Dilutive Effect [Abstract] Consolidation Items [Axis] Consolidation Items [Axis] Non-cash portion of interest expense Paid-in-Kind Interest Accrued rental income, net (amounts related to VIEs of $352,291 and $336,594 at September 30, 2021 and December 31, 2020, respectively) Accrued rental income, net (amounts related to VIEs of $352,291 and $336,594 at September 30, 2021 and December 31, 2020, respectively) Deferred Rent Receivables, Net Total lease payments Lessee, Operating Lease, Liability, to be Paid Noncontrolling Interest, Ownership Percentage by Parent Noncontrolling Interest, Ownership Percentage by Parent Joint Venture Partner [Member] Joint Venture Partner [Member] Joint Venture Partner [Member] Noncontrolling Interest [Abstract] Noncontrolling Interest [Abstract] Value Of LTIP Units Issued Value Of LTIP Units Issued Value Of LTIP Units Issued. 3.505% unsecured senior notes Three point five zero five percent unsecured senior notes [Member] 3.505% unsecured senior notes Lease Lease Operating Lease, Lease Income Accrued rental income, net Straight Line Rent MYLTIP MYLTIP [Member] MYLTIP Fixed contractual payments Operating Lease, Lease Income, Lease Payments Prepaid purchase price Other Prepaid Expense, Current Lessee, Operating Lease, Description Lessee, Operating Lease, Description LTIP Units [Member] LTIP Units [Member] LTIP Units [Member]. Investments In Affiliates Subsidiaries Associates And Joint Ventures net Investments In Affiliates Subsidiaries Associates And Joint Ventures net Total investments in (A) an entity in which the entity has significant influence, but does not have control, (B) subsidiaries that are not required to be consolidated and are accounted for using the equity and or cost method, and (C) an entity in which the reporting entity shares control of the entity with another party or group. Includes long-term advances receivable from a party that is affiliated with the reporting entity by means of direct or indirect ownership. Document Transition Report Document Transition Report Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits, by Title of Individual [Axis] Title of Individual [Axis] Accrued rental income, net deconsolidated Accrued rental income, net deconsolidated Accrued rental income, net deconsolidated General Partner [Member] General Partner [Member] Office Properties Under Construction [Member] Office Properties Under Construction [Member] Office Properties Under Construction [Member]. Cash held in escrows Cash held in escrows, beginning of period Cash held in escrows,end of period Restricted Cash and Cash Equivalents, Current Document Quarterly Report Document Quarterly Report Per occurrence limit of the earthquake insurance which covers San Francisco and Los Angeles regions Per Occurrence Limit Of Earth Quake Insurance San Francisco and Los Angeles Per Occurrence Limit Of Earth Quake Insurance San Francisco and Los Angeles Wholly-owned member [Member] Wholly-owned member [Member] Wholly-owned member 2.671% unsecured senior notes Two point six seven one percent unsecured senior notes [Member] Two point six seven one percent unsecured senior notes Institutional investor number one Institutional investor number one [Member] Institutional investor number one Subsequent Event [Line Items] Subsequent Event [Line Items] Cumulative Effect, Period of Adoption [Axis] Cumulative Effect, Period of Adoption [Axis] Credit Facility [Domain] Credit Facility [Domain] Proceeds from sales of real estate Proceeds from Sale of Real Estate Held-for-investment Net income attributable to the company's common shareholders / unitholders (in dollars per share / unit) Earnings Per Share, Basic Unvested Restricted stock and LTIP Units [Member] Unvested Restricted stock and LTIP Units [Member] Unvested Restricted stock and LTIP Units [Member] Expected life assumed to calculate per unit fair value per LTIP unit (in years) Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term Entity File Number Entity File Number Issuance of restricted securities to employees and non-employee directors Issuance of restricted securities to employees and directors Issuance of restricted securities to employees and directors Operating leases, Weighted-average remaining lease term Operating Lease, Weighted Average Remaining Lease Term Common Stock Weighted Average Price (in dollars per share) Common Stock Weighted Average Price Common Stock Weighted Average Price. Mortgage Notes Payable [Abstract] Mortgage Notes Payable Building and improvements Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Buildings Weighted Average Number Diluted Shares Outstanding Adjustment (per share) Weighted Average Number Diluted Shares Outstanding Adjustment (per share) Weighted Average Number Diluted Shares Outstanding Adjustment (per share) Preferred Stock, Redemption Amount Preferred Stock, Redemption Amount SMBP Venture LP [Member] Santa Monica Business Park [Member] Santa Monica Business Park [Member] Contributions from noncontrolling interests in property partnerships Proceeds from Noncontrolling Interests NonControlling Interest Redeemable Partnership Units Common Units Long Term Incentive Units At Redemption Value Shares Outstanding NonControlling Interest Redeemable Partnership Units Common Units Long Term Incentive Units At Redemption Value Shares Outstanding NonControlling Interest Redeemable Partnership Units Common Units Long Term Incentive Units At Redemption Value Shares Outstanding 880 Winter Street [Member] Eight Eight Zero Winter Street [Member] Eight Eight Zero Winter Street Stock based compensation expense Share-based Payment Arrangement, Expense Shares issued pursuant to stock purchase plan, value Stock Issued During Period, Value, Employee Stock Purchase Plan Other revenue Other revenue Revenue from Contract with Customer, Including Assessed Tax Straight-line rent adjustments Straight Line Rent Adjustments Document Annual Report Document Annual Report Commercial Real Estate Properties [Member] Commercial Real Estate [Member] 2024 Finance Lease, Liability, to be Paid, Year Four Summary Of Significant Accounting Policies [Table] Summary Of Significant Accounting Policies [Table] Summary Of Significant Accounting Policies [Table] Repayment of unsecured term loan Proceeds from Other Debt Receivable [Domain] Receivable [Domain] Subsequent Event [Table] Subsequent Event [Table] Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment [Abstract] Net activity from stock option and incentive plan, shares Net activity from stock option and incentive plan, shares Shares Issued, Shares, Share-based Payment Arrangement, after Forfeiture Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Debt Instrument, Covenant Description Debt Instrument, Covenant Description 2.524% unsecured senior notes Two point five two four percent unsecured senior notes [Member] Two point five two four percent unsecured senior notes Schedule Of Aggregate Principal Payments On Mortgage Notes bxp_ScheduleOfAggregatePrincipalPaymentsOnMortgageNotesTableTextBlock [Table Text Block] bxp_ScheduleOfAggregatePrincipalPaymentsOnMortgageNotesTableTextBlock Cash flows from investing activities: Net Cash Provided by (Used in) Investing Activities [Abstract] Shady Grove Bio+Tech Campus Shady Grove Bio+Tech Campus [Member] Shady Grove Bio+Tech Campus 2012 OPP and 2013-2018 MYLTIP 2012 OPP and 2013-2018 MYLTIP [Member] 2012 OPP and 2013-2018 MYLTIP Tenant and other receivables, net Increase (Decrease) in Accounts Receivable Preferred Stock, Redeemed Proceeds from (Repurchase of) Redeemable Preferred Stock Statement of Comprehensive Income [Abstract] Statement of Comprehensive Income [Abstract] Total liabilities and equity / capital Total liabilities and equity / capital Liabilities and Equity Washington, DC [Member] DISTRICT OF COLUMBIA Accounting Standards Update 2014-09 Accounting Standards Update 2014-09 [Member] Accumulated other comprehensive loss Accumulated Other Comprehensive Income (Loss), Net of Tax Portion at Fair Value Measurement [Member] Portion at Fair Value Measurement [Member] Increase (Decrease) in Operating Liabilities Increase (Decrease) in Operating Liabilities Operating lease costs Operating Lease, Cost General and administrative General and administrative expense General and Administrative Expense Line of Credit Facility [Line Items] Line of Credit Facility [Line Items] Beginning Balance Partners' Capital, Including Portion Attributable to Noncontrolling Interest Finance leases, Weighted-average remaining lease term Finance Lease, Weighted Average Remaining Lease Term Annapolis Junction Building Six and Seven Annapolis Junction Building Six and Seven [Member] Annapolis Junction Building Six and Seven Excess stock, shares outstanding Excess Stock, Shares Outstanding 601 Lexington Avenue Six Zero One Lexington Avenue [Member] Six Zero One Lexington Avenue [Member] Equity Component [Domain] Equity Component [Domain] Office Tower Developer LLC [Member] One Hundred Causeway Street [Member] One Hundred Causeway Street [Member] 100 Causeway Street [Member] Proceeds from note receivable Proceeds from Mortgage Deposits Company's share of net operating income from joint ventures Net Operating Income Gross Profit Write-off of fully depreciated real estate Write off of fully depreciated real estate Write off of fully depreciated real estate Entity Tax Identification Number Entity Tax Identification Number Lessee, Lease, Description [Table] Lessee, Lease, Description [Table] Finance leases under development Finance leases under development Finance leases under development Cash released from escrow for investing activities Increase (Decrease) in Restricted Cash Net income attributable to the Company Net Income (Loss) Attributable to Parent Delayed Draw Facility [Member] Delayed Draw Facility [Member] Delayed Draw Facility Excess stock, shares issued Excess Stock, Shares Issued Change in assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] Distributions to noncontrolling interests in property partnerships Payments to Noncontrolling Interests Tenant improvements Leasehold Improvements, Gross Total Real Estate Investment Property At Cost Including Right of Use Assets Real Estate Investment Property At Cost Including Right of Use Assets Finance Lease fixed purchase price Finance Lease fixed purchase price Finance Lease fixed purchase price Current Fiscal Year End Date Current Fiscal Year End Date Rental Revenue: Class A Office Rental Revenue Class A Office Rental Revenue Class A Office Lease liabilities - finance leases (amounts related to VIEs of $20,420 and $20,306 at September 30, 2021 and December 31, 2020, respectively) Present value of lease payments Lease liabilities - finance leases Finance Lease, Liability 1265 Main Office JV LLC [Member] One Two Six Five Main Office JV LLC [Member] 1265 Main Office JV LLC [Member] Rental Revenue: % of Grand Totals Percentage Of Total Revenue These are percentages not monetary value Property insurance program per occurrence limits Insurance Policy Limit Insurance Policy Limit Preferred Stock, Redemption Date Preferred Stock, Redemption Date University Place University Place [Member] University Place Notes Receivables [Member] Notes Receivable [Member] Boston Properties, Inc. [Member] Parent Company [Member] WP Project Developer LLC [Member] Wp Project Developer Llc [Member] WP Project Developer LLC [Member] Number of real estate properties Number of Real Estate Properties Redemption Premium Redemption Premium Thereafter Finance Lease, Liability, to be Paid, after Year Five Repayments of Construction Loans Payable Repayments of Construction Loans Payable Supplemental disclosures: Supplemental Cash Flow Information [Abstract] General and limited partnership interest in the operating partnership (percent) Limited Liability Company (LLC) or Limited Partnership (LP), Managing Member or General Partner, Ownership Interest Shares issued pursuant to stock purchase plan, shares Stock Issued During Period, Shares, Employee Stock Purchase Plans The Prudential Center Observatory The Prudential Center Observatory [Member] The Prudential Center Observatory Noncontrolling interest - property partnerships [Member] Noncontrolling interest - property partnerships [Member] Noncontrolling interest - property partnerships [Member] Deferred charges, net (amounts related to VIEs of $174,172 and $183,306 at September 30, 2021 and December 31, 2020, respectively) Deferred Costs, Noncurrent Property, Plant and Equipment Property, Plant and Equipment [Table Text Block] Preferred Stock, Dividend Rate, Percentage Series B, Dividend Rate, Percentage Preferred Stock, Dividend Rate, Percentage Acquisitions of real estate Payments to Acquire and Develop Real Estate Debt Instrument, Measurement Input Debt Instrument, Measurement Input Sumner Square Sumner Square [Member] Sumner Square MYLTIP 2017 [Member] MYLTIP two thousand seventeen [Member] 2017 MYLTIP [Member] Lessor, Lease, Description [Line Items] Lessor, Lease, Description [Line Items] Maximum proceeds from a state infrastructure development program Maximum proceeds from a state infrastructure development program Maximum proceeds from a state infrastructure development program Forfeitures, in units Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Forfeitures Stock Option And Incentive Plan And Stock Repurchase Plan [Axis] Stock Option And Incentive Plan And Stock Repurchase Plan [Axis] Stock Option And Incentive Plan And Stock Repurchase Plan [Axis] Schedule of Real Estate Properties Schedule of Property Subject to or Available for Operating Lease [Table Text Block] Parcels of undeveloped land Parcels of undeveloped land Parcels of undeveloped land Distributions to noncontrolling interests in property partnerships Noncontrolling Interest in Net Income (Loss) Joint Venture Partners, Nonredeemable Excess stock, shares authorized Excess Stock, Shares Authorized Redemption/repurchase of unsecured exchangeable senior notes Repayments of Convertible Debt Right of use assets - finance leases (amounts related to VIEs of $21,000 and $21,000 at September 30, 2021 and December 31, 2020, respectively) Right-of-use assets - finance leases Finance Lease, Right-of-Use Asset, after Accumulated Amortization Lessee, Operating Lease, Liability, Maturity Lessee, Operating Lease, Liability, Maturity [Table Text Block] Annapolis Junction Building Eight [Member] Annapolis Junction Building Eight [Member] Annapolis Junction Building Eight [Member] Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Weighted average number of common shares / units outstanding (in shares / units) Net income attributable to the company's common shareholders / unitholders (in shares / units) Weighted Average Number of Shares Outstanding, Basic Line of Credit Facility, Interest Rate Description Line of Credit Facility, Interest Rate Description Debt Instrument, Basis Spread on Variable Rate Debt Instrument, Basis Spread on Variable Rate Risk-free rate Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate Other Significant Noncash Transaction, Value of Consideration Given Other Significant Noncash Transaction, Value of Consideration Given Investments in unconsolidated joint ventures Carying value of the Company's investment in unconsolidated joint ventures Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures Ownership [Axis] Ownership [Axis] Entity Information [Line Items] Document Information [Line Items] Consolidation, Variable Interest Entity, Policy Consolidation, Variable Interest Entity, Policy [Policy Text Block] Scenario, Plan Scenario, Plan [Member] Annapolis Junction Building Seven [Member] Annapolis Junction Building Seven [Member] Annapolis Junction Building Seven [Member] Carrying Amount [Member] Reported Value Measurement [Member] Entity Well-known Seasoned Issuer Entity Well-known Seasoned Issuer Ownership Percentage Equity Method Investment, Ownership Percentage Dividends and distributions payable Dividends and distributions declared but not paid Dividends Payable Right-of-use assets obtained in exchange for operating lease liabilities Right-of-Use Asset Obtained in Exchange for Operating Lease Liability Per Occurrence Limit of Earthquake Insurance Seattle Per Occurrence Limit of Earthquake Insurance Seattle Per Occurrence Limit of Earthquake Insurance Seattle Cash and Cash Equivalents Cash and Cash Equivalents, Policy [Policy Text Block] Coinsurance of program trigger Program Trigger Coinsurance Program Trigger Coinsurance Real Estate, Other [Member] Real Estate, Other [Member] Residential Properties [Member] Residential Real Estate [Member] Cash and cash equivalents and cash held in escrows, beginning of period Cash and cash equivalents and cash held in escrows, end of period Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Affiliate of Bernstein Companies [Member] Affiliate of Bernstein Companies [Member] Affiliate of Bernstein Companies Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Table] Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Table] Investments in securities, net Payments to Acquire Marketable Securities Gain on sale of investment in unconsolidated joint venture Gain on sale of investment in unconsolidated joint venture Equity Method Investment, Realized Gain (Loss) on Disposal Title of Individual with Relationship to Entity [Domain] Title of Individual [Domain] Net proceeds from a state infrastructure development program Net proceeds from a state infrastructure development program Net proceeds from a state infrastructure development program Local Phone Number Local Phone Number Cumulative Effect, Period of Adoption [Domain] Cumulative Effect, Period of Adoption [Domain] Total Office Properties [Member] Total Office Properties [Member] Total Office Properties [Member]. Payments for Deposits on Real Estate Acquisitions Payments for Deposits on Real Estate Acquisitions Subsequent Events Schedule of Subsequent Events [Table Text Block] Debt Long-term Debt, Gross Payments on real estate transaction Payments on real estate transaction Payments on real estate transaction 3.495% unsecured senior notes Three point four nine five percent unsecured senior notes [Member] 3.495% unsecured senior notes Number of Promote Entities Number of Promote Entities Number of Promote Entities Line of Credit Facility, Maximum Borrowing Capacity Line of Credit Facility, Maximum Borrowing Capacity Award Type [Axis] Award Type [Axis] Prepaid expenses and other assets (amounts related to VIEs of $42,051 and $13,137 at September 30, 2021 and December 31, 2020, respectively) Prepaid Expense and Other Assets Repayments of mortgage notes payable Repayments of Secured Debt Repayments of Secured Debt Accounts payable and accrued expenses (amounts related to VIEs of $36,967 and $23,128 at September 30, 2021 and December 31, 2020, respectively) Accounts payable and accrued expenses (amounts related to VIEs of $36,967 and $23,128 at September 30, 2021 and December 31, 2020, respectively) Accounts Payable and Accrued Liabilities Dividends In Excess Of Earnings [Member] Dividends In Excess Of Earnings [Member] Retained Earnings [Member] Preferred stock / units, shares / units outstanding (in shares / units) Series B, Shares Outstanding (in shares) Preferred Stock, Shares Outstanding Fair Value, by Balance Sheet Grouping, Disclosure Item Amounts [Axis] Measurement Basis [Axis] Adjustment to reflect redeemable partnership units at redemption value Partners' Capital Account, Redemptions Net cash used in investing activities Net Cash Provided by (Used in) Investing Activities Deferred distributions from sale of investment in unconsolidated joint venture Deferred distributions from sale of investment in unconsolidated joint venture Deferred distributions from sale of investment in unconsolidated joint venture Award Type [Domain] Award Type [Domain] Lessor, Operating Lease, Payments to be Received, Maturity Lessor, Operating Lease, Payment to be Received, Fiscal Year Maturity [Table Text Block] Redemption of preferred stock Payments for Repurchase of Redeemable Preferred Stock Exercisable, Weighted Average Exercise Price Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price Vesting Percentage Vesting Percentage Vesting percentage Line of Credit Facility, Unused Capacity, Commitment Fee Percentage Line of Credit Facility, Unused Capacity, Commitment Fee Percentage Treasury common stock at cost, 78,900 shares at September 30, 2021 and December 31, 2020 Treasury Stock, Value Less: accumulated depreciation (amounts related to VIEs of $(1,266,516) and $(1,158,548) at September 30, 2021 and December 31, 2020, respectively) Less: accumulated depreciation Real Estate Investment Property, Accumulated Depreciation Earnings Per Share / Common Unit Earnings Per Share [Text Block] Investments In Unconsolidated Joint Ventures [Abstract] Investments In Unconsolidated Joint Ventures [Abstract] Investments In Unconsolidated Joint Ventures [Abstract] Redeemable deferred stock units— 80,989 and 72,966 units outstanding at redemption value at September 30, 2021 and December 31, 2020, respectively Redeemable Noncontrolling Interest, Equity, Carrying Amount Treasury Stock Treasury Stock [Policy Text Block] Treasury Stock Gateway Commons Complex Future Development[Member] [Member] Gateway Commons Complex Future Development[Member] [Member] Gateway Commons Complex Future Development[Member] [Member] New Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Borrowings on unsecured line of credit Proceeds from Lines of Credit 501 K Street LLC [Member] five zero one K Street LLC [Member] 501 K Street LLC [Member] Measurement Input, Discount Rate [Member] Measurement Input, Discount Rate [Member] Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Basic earnings per common share / unit attributable to the Company Basic Earnings: Earnings Per Share, Basic [Abstract] Amount of earthquake insurance provided by IXP, LLC as direct insurer San Francisco and Los Angeles Amount Of Earthquake Insurance Provided By IXP LLC As Direct Insurer San Francisco and Los Angeles Amount Of Earthquake Insurance Provided By IXP LLC As Direct Insurer San Francisco and Los Angeles