Consolidated Statements Of Cash Flows $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($)	Mar. 31, 2023 USD ($)
Net income (loss)	$ 106,604	$ 105,628
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	218,716	208,734
Impairment of Real Estate	13,615	0
Amortization of right of use assets - operating leases	1,441	652
Non-cash compensation expense	18,873	26,262
Loss (income) from unconsolidated joint ventures	(19,186)	7,569
Distributions of net cash flow from operations of unconsolidated joint ventures	8,643	5,996
Gains from investments in securities	(2,272)	(1,665)
Allowance for current expected credit losses (gains)	4	45
Non-cash portion of interest expense	12,109	7,387
Unrealized Gain (Loss) on non-real estate Investments	(396)	(259)
Change in assets and liabilities:
Tenant and other receivables, net	29,454	7,518
Accrued rental income, net	(35,945)	(18,619)
Prepaid expenses and other assets	(74,705)	(97,762)
Right of use assets - operating lease	(750)	0
Lease liabilities - operating leases	(1,241)	(251)
Accounts payable and accrued expenses	(20,725)	(8,505)
Accrued interest payable	(14,171)	10,626
Other liabilities	(12,846)	16,565
Tenant leasing costs	(29,627)	(35,911)
Total adjustments	90,991	128,382
Net cash provided by operating activities	197,595	234,010
Cash flows from investing activities:
Construction in progress	(181,636)	(119,682)
Building and other capital improvements	(32,087)	(39,100)
Tenant improvements	(53,377)	(67,175)
Acquisition of real estate (net of cash received upon consolidation)	6,086	0
Capital contributions to unconsolidated joint ventures	(26,457)	(60,745)
Investment in non-real estate investments	0	(733)
Issuance of note receivables (including related party)	(573)	0
Investments in securities, net	1,425	1,843
Net cash used in investing activities	(286,619)	(285,592)
Cash flows from financing activities:
Repayments of mortgage notes payable	(804)	0
Redemption of unsecured senior notes	(700,000)	0
Borrowings on unsecured term loan	0	1,200,000
Payments on finance lease obligations	(3,160)	0
Repayment of unsecured term loan	0	(730,000)
Deferred financing costs	(108)	(6,213)
Net activity from equity transactions	(2,136)	586
Dividends and distributions	(171,794)	(171,270)
Proceeds from sale of interest in property partnerships and contributions from noncontrolling interests in property partnerships	142,942	7,555
Distributions to noncontrolling interests in property partnerships	(20,025)	(21,606)
Net cash provided by (used in) financing activities	(756,909)	279,052
Net increase (decrease) in cash and cash equivalents and cash held in escrows	(845,933)	227,470
Cash and cash equivalents and cash held in escrows, beginning of period	1,612,567	736,812
Cash and cash equivalents and cash held in escrows, end of period	766,634	964,282
Reconciliation of cash and cash equivalents and cash held in escrow
Cash and cash equivalents, beginning of period	1,531,477	690,333
Cash held in escrows, beginning of period	81,090	46,479
Cash and cash equivalents, end of period	701,695	918,952
Cash held in escrows,end of period	64,939	45,330
Supplemental disclosures:
Cash paid for interest	180,717	125,698
Interest capitalized	9,381	10,589
Non-cash investing and financing activities:
Write-off of fully depreciated real estate	(27,993)	(56,391)
Change in real estate included in accounts payable and accrued expenses	(48,518)	11,692
Right of use assets obtained in exchange for lease liabilities - operating lease	25,637	0
Non-cash contributions from noncontrolling interest in property partnerhips	52,786	0
Capitalized operating lease costs	7,548	0
Investment in unconsolidated joint ventures eliminated upon consolidation	(11,834)	0
Mortgage notes payable recorded upon consolidation	207,093	0
Real estate and intangibles recorded upon consolidation	(220,015)	0
Dividends and distributions declared but not paid	172,154	171,427
Conversions of noncontrolling interests to stockholders’ equity	1,303	195
Issuance of restricted securities to employees and non-employee directors	41,989	46,516
Cash
Cash flows from financing activities:
Proceeds from sale of interest in property partnerships and contributions from noncontrolling interests in property partnerships	141,118	7,555
Boston Properties Limited Partnership
Net income (loss)	108,301	107,490
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	217,019	206,872
Impairment of Real Estate	13,615	0
Amortization of right of use assets - operating leases	1,441	652
Non-cash compensation expense	18,873	26,262
Loss (income) from unconsolidated joint ventures	(19,186)	7,569
Distributions of net cash flow from operations of unconsolidated joint ventures	8,643	5,996
Gains from investments in securities	(2,272)	(1,665)
Allowance for current expected credit losses (gains)	4	45
Non-cash portion of interest expense	12,109	7,387
Unrealized Gain (Loss) on non-real estate Investments	(396)	(259)
Change in assets and liabilities:
Tenant and other receivables, net	29,454	7,518
Accrued rental income, net	(35,945)	(18,619)
Prepaid expenses and other assets	(74,705)	(97,762)
Right of use assets - operating lease	(750)	0
Lease liabilities - operating leases	(1,241)	(251)
Accounts payable and accrued expenses	(20,725)	(8,505)
Accrued interest payable	(14,171)	10,626
Other liabilities	(12,846)	16,565
Tenant leasing costs	(29,627)	(35,911)
Total adjustments	89,294	126,520
Net cash provided by operating activities	197,595	234,010
Cash flows from investing activities:
Construction in progress	(181,636)	(119,682)
Building and other capital improvements	(32,087)	(39,100)
Tenant improvements	(53,377)	(67,175)
Acquisition of real estate (net of cash received upon consolidation)	6,086	0
Capital contributions to unconsolidated joint ventures	(26,457)	(60,745)
Investment in non-real estate investments	0	(733)
Issuance of note receivables (including related party)	(573)	0
Investments in securities, net	1,425	1,843
Net cash used in investing activities	(286,619)	(285,592)
Cash flows from financing activities:
Repayments of mortgage notes payable	(804)	0
Redemption of unsecured senior notes	(700,000)	0
Borrowings on unsecured term loan	0	1,200,000
Payments on finance lease obligations	(3,160)	0
Repayment of unsecured term loan	0	(730,000)
Deferred financing costs	(108)	(6,213)
Net activity from equity transactions	(2,136)	586
Dividends and distributions	(171,794)	(171,270)
Distributions to noncontrolling interests in property partnerships	(20,025)	(21,606)
Net cash provided by (used in) financing activities	(756,909)	279,052
Net increase (decrease) in cash and cash equivalents and cash held in escrows	(845,933)	227,470
Cash and cash equivalents and cash held in escrows, beginning of period	1,612,567	736,812
Cash and cash equivalents and cash held in escrows, end of period	766,634	964,282
Reconciliation of cash and cash equivalents and cash held in escrow
Cash and cash equivalents, beginning of period	1,531,477	690,333
Cash held in escrows, beginning of period	81,090	46,479
Cash and cash equivalents, end of period	701,695	918,952
Cash held in escrows,end of period	64,939	45,330
Supplemental disclosures:
Cash paid for interest	180,717	125,698
Interest capitalized	9,381	10,589
Non-cash investing and financing activities:
Write-off of fully depreciated real estate	(27,993)	(55,142)
Change in real estate included in accounts payable and accrued expenses	(48,518)	11,692
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	25,637	0
Non-cash contributions from noncontrolling interest in property partnerhips	52,786	0
Capitalized operating lease costs	7,548	0
Investment in unconsolidated joint ventures eliminated upon consolidation	(11,834)	0
Mortgage notes payable recorded upon consolidation	207,093	0
Real estate and intangibles recorded upon consolidation	(220,015)	0
Dividends and distributions declared but not paid	172,154	171,427
Conversions of noncontrolling interests to stockholders’ equity	1,303	195
Issuance of restricted securities to employees and non-employee directors	41,989	46,516
Boston Properties Limited Partnership | Cash
Cash flows from financing activities:
Proceeds from sale of interest in property partnerships and contributions from noncontrolling interests in property partnerships	$ 141,118	$ 7,555