XML 65 R50.htm IDEA: XBRL DOCUMENT
v3.25.3

Unsecured Commercial Paper Program (Details) - USD ($) $ in Thousands | Sep. 30, 2025 | Mar. 28, 2025 | Mar. 27, 2025 | Dec. 31, 2024
--- | --- | --- | --- | ---
Short-Term Debt [Line Items] |  |  |  |
Unsecured commercial paper | $ 750,000 |  |  | $ 500,000
Commercial Paper |  |  |  |
Short-Term Debt [Line Items] |  |  |  |
Commercial Paper, Maximum Borrowing Capacity |  | $ 750,000 | $ 500,000 |
Unsecured commercial paper | $ 750,000 |  |  |
Debt, Weighted Average Interest Rate | 4.51% |  |  |
Commercial Paper | Weighted Average [Member] |  |  |  |
Short-Term Debt [Line Items] |  |  |  |
Debt Instrument, Term | 43 days |  |  |
Commercial Paper | Maximum [Member] |  |  |  |
Short-Term Debt [Line Items] |  |  |  |
Commercial Paper, Maximum Borrowing Capacity |  | $ 750,000 |  |
Debt Instrument, Term |  | 1 year |  |

X
- Definition Commercial Paper, Maximum Borrowing Capacity + References No definition available. + Details
Name: | bxp_CommercialPaperMaximumBorrowingCapacity
Namespace Prefix: | bxp_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Carrying value as of the balance sheet date of short-term borrowings using unsecured obligations issued by banks, corporations and other borrowers to investors. The maturities of these money market securities generally do not exceed 270 days. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 944 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(16)(a)(1)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 942 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(13)(2)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(19)(a)(3)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 + Details
Name: | us-gaap_CommercialPaper
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
Name: | us-gaap_DebtInstrumentTerm
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Weighted average interest rate of debt outstanding. + References No definition available. + Details
Name: | us-gaap_DebtWeightedAverageInterestRate
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_ShortTermDebtLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_CashAndCashEquivalentsAxis=us-gaap_CommercialPaperMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_WeightedAverageMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |