Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended	21 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022	Sep. 30, 2023
Net income (loss)	$ (103,543)	$ 420,661	$ 138,269	$ 864,861
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization			618,746	551,445
Amortization of right of use assets - operating leases			1,502	1,843
Non-cash compensation expense			46,699	44,208
Loss (income) from unconsolidated joint ventures	247,556	3,524	261,793	1,389
Distributions of net cash flow from operations of unconsolidated joint ventures			21,871	20,511
Losses (gains) from investments in securities			(2,311)	8,549
Allowance for current expected credit losses			302	(476)
Non-cash portion of interest expense			22,541	19,704
Other Income - assignment fee	0	0	0	(6,624)
Gains on sales of real estate	(517)	(262,345)	(517)	(381,293)
Unrealized gain (loss) on non-real estate investment	51	0	(332)	0
Change in assets and liabilities:
Tenant and other receivables, net			(13,467)	4,133
Notes receivable, net			0	(152)
Accrued rental income, net			(72,190)	(76,268)
Prepaid expenses and other assets			(76,621)	(46,104)
Right of use assets - operating lease			(25,640)	0
Lease liabilities - operating leases			282	447
Accounts payable and accrued expenses			40,914	3,167
Accrued interest payable			24,648	(2,900)
Other liabilities			(6,254)	(35,490)
Tenant leasing costs			(65,863)	(58,547)
Total adjustments			776,103	47,542
Net cash provided by operating activities			914,372	912,403
Cash flows from investing activities:
Acquisitions of real estate			0	(1,320,273)
Construction in progress			(361,625)	(384,083)
Building and other capital improvements			(117,393)	(112,755)
Tenant improvements			(244,841)	(139,986)
Proceeds from sales of real estate			517	695,231
Proceeds from assignment fee			0	6,624
Capital contributions to unconsolidated joint ventures			(148,875)	(109,643)
Capital distributions from unconsolidated joint ventures			7,350	36,622
Investment in non-real estate investments			(1,990)	0
Issuance of related party note receivable			(10,500)	0
Proceeds from note receivable			0	10,000
Investments in securities, net			1,779	5,043
Net cash used in investing activities			(875,578)	(1,313,220)
Cash flows from financing activities:
Proceeds from unsecured senior notes			747,727	0
Redemption of unsecured senior notes			(500,000)	0
Borrowings on unsecured line of credit			0	885,000
Repayments of unsecured line of credit			0	(690,000)
Borrowings on unsecured term loan			1,200,000	730,000
Repayment of unsecured term loan			(730,000)	0
Deferred financing costs			(12,639)	(2,230)
Net activity from equity transactions			367	(359)
Dividends and distributions			(514,974)	(513,486)
Contributions from noncontrolling interests in property partnerships	5,116		12,671	849
Distributions to noncontrolling interests in property partnerships	(12,150)	(20,150)	(48,370)	(61,229)
Net cash provided by financing activities			154,782	348,545
Net increase (decrease) in cash and cash equivalents and cash held in escrows			193,576	(52,272)
Cash and cash equivalents and cash held in escrows, beginning of period			736,812	501,158	$ 501,158	$ 501,158
Cash and cash equivalents and cash held in escrows, end of period	930,388	448,886	930,388	448,886	736,812	930,388
Reconciliation of cash and cash equivalents and cash held in escrow
Cash and cash equivalents, beginning of period			690,333	452,692	452,692	452,692
Cash held in escrows, beginning of period			46,479	48,466	48,466	48,466
Cash and cash equivalents, end of period	882,647	375,774	882,647	375,774	690,333	882,647
Cash held in escrows,end of period	47,741	73,112	47,741	73,112	46,479	47,741
Supplemental disclosures:
Cash paid for interest			404,016	339,067
Interest capitalized			33,426	40,048
Non-cash investing and financing activities:
Write-off of fully depreciated real estate			(111,154)	(95,996)
Change in real estate included in accounts payable and accrued expenses			29,435	29,290
Construction in progress, net deconsolidated			0	(11,316)
Investment in unconsolidated joint ventures recorded upon deconsolidation			0	11,316
Right-of-use assets obtained in exchange for lease liabilities			134,509	0
Other Significant Noncash Transaction, Value of Consideration Received			17,519	0
Capitalized operating lease costs			5,031	0
Construction in progress from prepaid expenses and other assets			25,577	0
Dividends and distributions declared but not paid	171,916	170,952	171,916	170,952	170,643	171,916
Conversions of noncontrolling interests to stockholders’ equity			3,714	6,388
Issuance of restricted securities to employees and non-employee directors			48,121	48,605
Boston Properties Limited Partnership
Net income (loss)	(101,787)	422,379	143,569	874,091
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization			613,446	546,271
Amortization of right of use assets - operating leases			1,502	1,843
Non-cash compensation expense			46,699	44,208
Loss (income) from unconsolidated joint ventures	247,556	3,524	261,793	1,389
Distributions of net cash flow from operations of unconsolidated joint ventures			21,871	20,511
Losses (gains) from investments in securities			(2,311)	8,549
Allowance for current expected credit losses			302	(476)
Non-cash portion of interest expense			22,541	19,704
Other Income - assignment fee	0	0	0	(6,624)
Gains on sales of real estate	(517)	(262,357)	(517)	(385,349)
Unrealized gain (loss) on non-real estate investment	51	0	(332)	0
Change in assets and liabilities:
Tenant and other receivables, net			(13,467)	4,133
Notes receivable, net			0	(152)
Accrued rental income, net			(72,190)	(76,268)
Prepaid expenses and other assets			(76,621)	(46,104)
Right of use assets - operating lease			(25,640)	0
Lease liabilities - operating leases			282	447
Accounts payable and accrued expenses			40,914	3,167
Accrued interest payable			24,648	(2,900)
Other liabilities			(6,254)	(35,490)
Tenant leasing costs			(65,863)	(58,547)
Total adjustments			770,803	38,312
Net cash provided by operating activities			914,372	912,403
Cash flows from investing activities:
Acquisitions of real estate			0	(1,320,273)
Construction in progress			(361,625)	(384,083)
Building and other capital improvements			(117,393)	(112,755)
Tenant improvements			(244,841)	(139,986)
Proceeds from sales of real estate			517	695,231
Proceeds from assignment fee			0	6,624
Capital contributions to unconsolidated joint ventures			(148,875)	(109,643)
Capital distributions from unconsolidated joint ventures			7,350	36,622
Investment in non-real estate investments			(1,990)	0
Issuance of related party note receivable			(10,500)	0
Proceeds from note receivable			0	10,000
Investments in securities, net			1,779	5,043
Net cash used in investing activities			(875,578)	(1,313,220)
Cash flows from financing activities:
Proceeds from unsecured senior notes			747,727	0
Redemption of unsecured senior notes			(500,000)	0
Borrowings on unsecured line of credit			0	885,000
Repayments of unsecured line of credit			0	(690,000)
Borrowings on unsecured term loan			1,200,000	730,000
Repayment of unsecured term loan			(730,000)	0
Deferred financing costs			(12,639)	(2,230)
Net activity from equity transactions			367	(359)
Dividends and distributions			(514,974)	(513,486)
Contributions from noncontrolling interests in property partnerships			12,671	849
Distributions to noncontrolling interests in property partnerships			(48,370)	(61,229)
Net cash provided by financing activities			154,782	348,545
Net increase (decrease) in cash and cash equivalents and cash held in escrows			193,576	(52,272)
Cash and cash equivalents and cash held in escrows, beginning of period			736,812	501,158	501,158	501,158
Cash and cash equivalents and cash held in escrows, end of period	930,388	448,886	930,388	448,886	736,812	930,388
Reconciliation of cash and cash equivalents and cash held in escrow
Cash and cash equivalents, beginning of period			690,333	452,692	452,692	452,692
Cash held in escrows, beginning of period			46,479	48,466	48,466	48,466
Cash and cash equivalents, end of period	882,647	375,774	882,647	375,774	690,333	882,647
Cash held in escrows,end of period	47,741	73,112	47,741	73,112	46,479	47,741
Supplemental disclosures:
Cash paid for interest			404,016	339,067
Interest capitalized			33,426	40,048
Non-cash investing and financing activities:
Write-off of fully depreciated real estate			(109,905)	(95,996)
Change in real estate included in accounts payable and accrued expenses			29,435	29,290
Construction in progress, net deconsolidated			0	(11,316)
Investment in unconsolidated joint ventures recorded upon deconsolidation			0	11,316
Right-of-use assets obtained in exchange for lease liabilities			134,509	0
Other Significant Noncash Transaction, Value of Consideration Received			17,519	0
Capitalized operating lease costs			5,031	0
Construction in progress from prepaid expenses and other assets			25,577	0
Dividends and distributions declared but not paid	$ 171,916	$ 170,952	171,916	170,952	$ 170,643	$ 171,916
Conversions of noncontrolling interests to stockholders’ equity			3,714	6,388
Issuance of restricted securities to employees and non-employee directors			$ 48,121	$ 48,605