XML 54 R32.htm IDEA: XBRL DOCUMENT
v3.25.4

Summary Of Significant Accounting Policies (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2025
Summary Of Significant Accounting Policies [Line Items] |
Property, Plant and Equipment | Depreciation is computed on a straight-line basis over the estimated useful lives of the assets as follows:
Land improvements |  | 25 to 40 years
Buildings and improvements |  | 10 to 40 years
Tenant improvements |  | Shorter of useful life or terms of related lease
Furniture, fixtures, and equipment |  | 3 to 10 years
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense | The following table summarizes the scheduled amortization of the Company’s acquired “above-” and “below-market” lease intangibles for each of the five succeeding years (in thousands).
|  | Acquired Above-Market Lease Intangibles |  | Acquired Below-Market Lease Intangibles
2026 |  | $ | 1,236 |  |  | $ | 8,847 |
2027 |  | 928 |  |  | 5,648 |
2028 |  | 781 |  |  | 2,419 |
2029 |  | 729 |  |  | 718 |
2030 |  | 473 |  |  | 441 |
Fair Value, by Balance Sheet Grouping [Table Text Block] | The following table presents the Level at which the Company’s non-recurring fair value financial instruments are categorized as defined in ASC 820 as well as the Company’s aggregate carrying value and corresponding estimate of fair value as of December 31, 2025 and December 31, 2024 (in thousands):
|  |  | December 31, 2025 |  | December 31, 2024
Level | Financial Instrument |  | Carrying Amount |  | Estimated Fair Value |  | Carrying Amount |  | Estimated Fair Value
Level 3 | Related party note receivable, net |  | $ | 28,346 |  |  | $ | 28,716 |  |  | $ | 88,779 |  |  | $ | 89,213 |
Level 3 | Note receivable, net |  | 9,373 |  |  | 9,858 |  |  | 4,947 |  |  | 6,187 |
Level 3 | Sales-type lease receivable, net |  | 15,672 |  |  | 13,911 |  |  | 14,657 |  |  | 13,632 |
| Total |  | $ | 53,391 |  |  | $ | 52,485 |  |  | $ | 108,383 |  |  | $ | 109,032 |
Level 1 | Unsecured senior notes, net (1) |  | $ | 9,806,100 |  |  | $ | 9,554,844 |  |  | $ | 10,645,077 |  |  | $ | 10,005,606 |
Level 1 | Unsecured exchangeable senior notes, net (1) |  | 976,263 |  |  | 958,745 |  |  | — |  |  | — |
Level 1 | Unsecured commercial paper |  | 750,000 |  |  | 750,000 |  |  | 500,000 |  |  | 500,000 |
| Subtotal |  | $ | 11,532,363 |  |  | $ | 11,263,589 |  |  | $ | 11,145,077 |  |  | $ | 10,505,606 |
Level 3 | Mortgage notes payable, net |  | $ | 4,280,067 |  |  | $ | 4,010,151 |  |  | $ | 4,276,609 |  |  | $ | 3,808,095 |
Level 3 | Unsecured line of credit |  | — |  |  | — |  |  | — |  |  | — |
Level 3 | Unsecured term loan, net |  | 797,053 |  |  | 805,687 |  |  | 798,813 |  |  | 799,580 |
| Subtotal |  | $ | 5,077,120 |  |  | $ | 4,815,838 |  |  | $ | 5,075,422 |  |  | $ | 4,607,675 |
| Total |  | $ | 16,609,483 |  |  | $ | 16,079,427 |  |  | $ | 16,220,499 |  |  | $ | 15,113,281 |
_______________ (1)If trading volume for the period is low, the valuation could be categorized as Level 2.
Schedule of Derivative Assets at Fair Value [Table Text Block] | The following table presents the aggregate fair value of the Company’s interest rate swaps as of December 31, 2025 and December 31, 2024 (in thousands):
Fair value |  | December 31, 2025 |  | December 31, 2024
Interest rate swaps |  | $ | (8,283) |  |  | $ | 5,252 |
Real Estate Investment Trust, Distribution, Tax Status | The tax treatment of common dividends per share for federal income tax purposes is as follows:
|  | For the year ended December 31,
|  | 2025 |  | 2024 |  | 2023
|  | Per Share |  | % |  | Per Share |  | % |  | Per Share |  | %
Ordinary income |  | $ | 2.35 |  |  | 64.52 | % |  | $ | 3.22 |  |  | 88.29 | % |  | $ | 3.04 |  |  | 72.98 | %
Capital gain income |  | 1.29 |  |  | 35.48 | % |  | 0.03 |  |  | 0.79 | % |  | 1.12 |  |  | 27.02 | %
Return of capital |  | — |  |  | — | % |  | 0.40 |  |  | 10.92 | % |  | — |  |  | — | %
Total |  | $ | 3.64 |  | (1) | 100.00 | % |  | $ | 3.65 |  | (2) | 100.00 | % |  | $ | 4.16 |  | (3) | 100.00 | %
_____________ (1)The fourth quarter 2025 regular quarterly dividend was $0.70 per common share, all of which was allocated to 2026. (2)The fourth quarter 2024 regular quarterly dividend was $0.98 per common share, all of which was allocated to 2025. (3)The fourth quarter 2023 regular quarterly dividend was $0.98 per common share, of which approximately $0.27 per common share was allocated to 2023 and approximately $0.71 per common share was allocated to 2024.

X
- Definition Real Estate Investment Trust, Distribution, Tax Status + References No definition available. + Details
Name: | bxp_RealEstateInvestmentTrustDistributionTaxStatusTableTextBlock
Namespace Prefix: | bxp_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Summary Of Significant Accounting Policies [Line Items] + References No definition available. + Details
Name: | bxp_SummaryOfSignificantAccountingPoliciesLineItems
Namespace Prefix: | bxp_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the fair value of financial instruments, including financial assets and financial liabilities, and the measurements of those instruments, assets, and liabilities. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Name Accounting Standards Codification -Section 55 -Paragraph 10 -SubTopic 10 -Topic 825 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482881/825-10-55-10 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 13 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482907/825-10-50-13 Reference 3: http://www.xbrl.org/2003/role/exampleRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 12 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482881/825-10-55-12 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 12 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482907/825-10-50-12 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 11 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482907/825-10-50-11 + Details
Name: | us-gaap_FairValueByBalanceSheetGroupingTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of physical assets used in the normal conduct of business and not intended for resale. Includes, but is not limited to, balances by class of assets, depreciation and depletion expense and method used, including composite depreciation, and accumulated deprecation. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 50 -Paragraph 1 -SubTopic 10 -Topic 360 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482099/360-10-50-1 + Details
Name: | us-gaap_PropertyPlantAndEquipmentTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of derivative assets at fair value. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 815 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 4E -Publisher FASB -URI https://asc.fasb.org/1943274/2147480434/815-10-50-4E Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 815 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 4A -Publisher FASB -URI https://asc.fasb.org/1943274/2147480434/815-10-50-4A Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 815 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 4B -Publisher FASB -URI https://asc.fasb.org/1943274/2147480434/815-10-50-4B + Details
Name: | us-gaap_ScheduleOfDerivativeAssetsAtFairValueTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the amount of amortization expense expected to be recorded in succeeding fiscal years for finite-lived intangible assets. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Name Accounting Standards Codification -Section 55 -Paragraph 40 -SubTopic 30 -Topic 350 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482640/350-30-55-40 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 350 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a)(3) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482665/350-30-50-2 + Details
Name: | us-gaap_ScheduleofFiniteLivedIntangibleAssetsFutureAmortizationExpenseTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration