Extension Option (in years)

No definition available.

Name:	bxp_ExtensionOptioninyears
Namespace Prefix:	bxp_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Leased percentage

+ References

No definition available.

+ Details

Name:	bxp_Leasedpercentage
Namespace Prefix:	bxp_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
-URI https://asc.fasb.org/extlink&oid=123466204&loc=SL6031897-161870

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI https://asc.fasb.org/extlink&oid=126734703&loc=d3e572229-122910

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI https://asc.fasb.org/extlink&oid=126897435&loc=d3e534808-122878

+ Details

Name:	us-gaap_DebtInstrumentCarryingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Description of reference rate used for variable rate of debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentDescriptionOfVariableRateBasis
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI https://asc.fasb.org/extlink&oid=114001798&loc=d3e33918-111571

+ Details

Name:	us-gaap_EquityMethodInvestmentOwnershipPercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Duration of a fiscal period, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Includes, but not limited to, weeks in a year or quarter.

+ References

No definition available.

+ Details

Name:	us-gaap_FiscalPeriodDuration
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Area of land subject to a ground lease.

+ References

No definition available.

+ Details

Name:	us-gaap_LandSubjectToGroundLeases
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:areaItemType
Balance Type:	na
Period Type:	instant

- Definition

Net rentable area for properties owned.

+ References

No definition available.

+ Details

Name:	us-gaap_NetRentableArea
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:areaItemType
Balance Type:	na
Period Type:	instant

- Definition

The cash outflow from repayment of borrowings to finance the cost of construction.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3291-108585

+ Details

Name:	us-gaap_RepaymentsOfConstructionLoansPayable
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

No definition available.

+ Details

Name:	us-gaap_SubsequentEventLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=bxp_OfficeTowerDeveloperLLCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=bxp_OneFourZeroKendrickStreetBuildingAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=bxp_OneHundredCausewayStreetMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RealEstatePropertiesAxis=us-gaap_UnconsolidatedPropertiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_ConstructionLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LoanRestructuringModificationAxis=us-gaap_ExtendedMaturityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=bxp_ThreeFourThreeMadisonAvenueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LeaseContractualTermAxis=bxp_GroundLeaseTermOfContractMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=bxp_UnconsolidatedJointVenturesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Subsequent Events (Details) $ in Thousands	Aug. 01, 2023 ft²	Jul. 28, 2023 USD ($) ft² Integer	Jul. 27, 2023 USD ($)	Jul. 20, 2023 ft²	Jun. 30, 2023
Office Tower Developer LLC
Subsequent Event [Line Items]
Ownership Percentage					50.00%
Subsequent Event [Member] \| 140 Kendrick Street - Building A
Subsequent Event [Line Items]
Net Rentable Area (in sf)				104,000
Subsequent Event [Member] \| 100 Causeway Street [Member] \| Unconsolidated Properties
Subsequent Event [Line Items]
Net Rentable Area (in sf)		634,000
Leased percentage		95.00%
Subsequent Event [Member] \| 100 Causeway Street [Member] \| Office Tower Developer LLC
Subsequent Event [Line Items]
Ownership Percentage		50.00%
Subsequent Event [Member] \| 100 Causeway Street [Member] \| Construction Loans
Subsequent Event [Line Items]
Debt \| $		$ 336,600	$ 340,600
Extension Option (in years) \| Integer		1
Repayments of Construction Loans Payable \| $		$ 4,000
Subsequent Event [Member] \| 100 Causeway Street [Member] \| Construction Loans \| Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Subsequent Event [Line Items]
Debt Instrument, Description of Variable Rate Basis		Term SOFR	Term SOFR
Debt Instrument, Basis Spread on Variable Rate		1.48%	1.60%
Subsequent Event [Member] \| 100 Causeway Street [Member] \| Extended Maturity \| Construction Loans
Subsequent Event [Line Items]
Fiscal Period Duration		1 year
Subsequent Event [Member] \| 343 Madison Avenue
Subsequent Event [Line Items]
Ownership Percentage		55.00%
Subsequent Event [Member] \| 343 Madison Avenue \| Unconsolidated Properties
Subsequent Event [Line Items]
Net Rentable Area (in sf)		900,000
Subsequent Event [Member] \| 343 Madison Avenue \| Ground Lease Term of Contract \| Unconsolidated Properties
Subsequent Event [Line Items]
Fiscal Period Duration	99 years
Land Subject to Ground Leases	25,000
Subsequent Event [Member] \| Unconsolidated Joint Ventures [Member] \| 343 Madison Avenue
Subsequent Event [Line Items]
Ownership Percentage		45.00%