Boston Properties (BXP) 10-Q10 May 242024 Q1 Quarterly reportFinancial data

Company Profile

Cover

Cover - $ / shares	3 Months Ended
Cover - $ / shares	Mar. 31, 2024	May 02, 2024
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2024
Document Transition Report	false
Entity File Number	1-13087
Entity Registrant Name	BOSTON PROPERTIES, INC.
Entity Central Index Key	0001037540
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q1
Amendment Flag	false
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	04-2473675
Entity Address, Address Line One	Prudential Center, 800 Boylston Street, Suite 1900
Entity Address, City or Town	Boston
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02199-8103
City Area Code	617
Local Phone Number	236-3300
Title of 12(b) Security	Common Stock, par value $0.01 per share
Entity Listing, Par Value Per Share	$ 0.01
Trading Symbol	BXP
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		157,058,652
Boston Properties Limited Partnership
Entity Information [Line Items]
Document Type	10-Q
Document Period End Date	Mar. 31, 2024
Entity File Number	0-50209
Entity Registrant Name	BOSTON PROPERTIES LIMITED PARTNERSHIP
Entity Central Index Key	0001043121
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q1
Amendment Flag	false
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	04-3372948
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands		Mar. 31, 2024	Dec. 31, 2023
ASSETS
Real estate, at cost (amounts related to variable interest entities (“VIEs”) of $7,376,175 and $7,054,075 at March 31, 2024 and December 31, 2023, respectively)		$ 27,063,048	$ 26,749,209
Right of use assets - finance leases (amounts related to VIEs of $21,000 and $21,000 at March 31, 2024 and December 31, 2023, respectively)		401,486	401,680
Right of use assets - operating leases (amounts related to VIEs of $154,217 and $158,885 at March 31, 2024 and December 31, 2023, respectively)	[1]	344,255	324,298
Less: accumulated depreciation (amounts related to VIEs of $(1,538,940) and $(1,501,483) at March 31, 2024 and December 31, 2023, respectively)		(7,040,501)	(6,881,728)
Total real estate		20,768,288	20,593,459
Cash and cash equivalents (amounts related to VIEs of $298,548 and $245,317 at March 31, 2024 and December 31, 2023, respectively)		701,695	1,531,477
Cash held in escrows (amounts related to VIEs of $4,839 and $22,160 at March 31, 2024 and December 31, 2023, respectively)		64,939	81,090
Investments in securities		37,184	36,337
Tenant and other receivables, net (amounts related to VIEs of $27,792 and $27,987 at March 31, 2024 and December 31, 2023, respectively)		94,115	122,407
Note receivable, net		2,274	1,714
Sales-type lease receivable, net		13,943	13,704
Accrued rental income, net (amounts related to VIEs of $409,628 and $401,159 at March 31, 2024 and December 31, 2023, respectively)		1,390,217	1,355,212
Deferred charges, net (amounts related to VIEs of $194,489 and $175,383 at March 31, 2024 and December 31, 2023, respectively)		818,424	760,421
Prepaid expenses and other assets (amounts related to VIEs of $45,672 and $11,824 at March 31, 2024 and December 31, 2023, respectively)		146,286	64,230
Investments in unconsolidated joint ventures		1,399,824	1,377,319
Total assets		25,525,978	26,026,149
Liabilities:
Mortgage notes payable, net (amounts related to VIEs of $3,278,396 and $3,277,185 at March 31, 2024 and December 31, 2023, respectively)		4,368,367	4,166,379
Unsecured senior notes, net		9,794,527	10,491,617
Unsecured line of credit		0	0
Unsecured term loan, net		1,199,430	1,198,301
Lease liabilities - finance leases (amounts related to VIEs of $20,831 and $20,794 at March 31, 2024 and December 31, 2023, respectively)		415,888	417,961
Lease liabilities - operating leases (amounts related to VIEs of $148,706 and $145,826 at March 31, 2024 and December 31, 2023, respectively)		377,667	350,391
Accounts payable and accrued expenses (amounts related to VIEs of $112,385 and $59,667 at March 31, 2024 and December 31, 2023, respectively)		374,681	458,329
Dividends and distributions payable		172,154	171,176
Accrued interest payable		119,573	133,684
Other liabilities (amounts related to VIEs of $105,786 and $115,275 at March 31, 2024 and December 31, 2023, respectively)		417,978	445,947
Total liabilities		17,240,265	17,833,785
Redeemable deferred stock units— 124,656 and 119,471 units outstanding at redemption value at March 31, 2024 and December 31, 2023, respectively		$ 8,141	$ 8,383
Excess stock, shares outstanding		0	0
Excess stock, shares issued		0	0
Preferred stock / units, shares / units issued (in shares / units)		0	0
Preferred stock / units, shares / units outstanding (in shares / units)		0	0
Equity / Capital:
Excess stock, $0.01 par value, 150,000,000 shares authorized, none issued or outstanding		$ 0	$ 0
Preferred stock, $0.01 par value, 50,000,000 shares authorized, none issued or outstanding		0	0
Common stock, $0.01 par value, 250,000,000 shares authorized, 157,128,071 and 157,019,766 issued and 157,049,171 and 156,940,866 outstanding at March 31, 2024 and December 31, 2023, respectively		1,570	1,569
Additional paid-in capital		6,752,648	6,715,149
Dividends in excess of earnings		$ (890,177)	$ (816,152)
Treasury common stock at cost, shares		78,900	78,900
Treasury common stock at cost, 78,900 shares at March 31, 2024 and December 31, 2023		$ (2,722)	$ (2,722)
Accumulated other comprehensive loss		(3,620)	(21,147)
Total stockholders' equity attributable to Boston Properties, Inc.		5,857,699	5,876,697
Noncontrolling interests:
Common units of the Operating Partnership		684,969	666,580
Property partnerships		1,734,904	1,640,704
Total equity / capital		8,277,572	8,183,981
Total liabilities and equity / capital		25,525,978	26,026,149
Related Party
ASSETS
Related party note receivable, net		88,789	88,779
Variable Interest Entity, Primary Beneficiary [Member]
ASSETS
Real estate, at cost (amounts related to variable interest entities (“VIEs”) of $7,376,175 and $7,054,075 at March 31, 2024 and December 31, 2023, respectively)		7,376,175	7,054,075
Right of use assets - finance leases (amounts related to VIEs of $21,000 and $21,000 at March 31, 2024 and December 31, 2023, respectively)		21,000	21,000
Right of use assets - operating leases (amounts related to VIEs of $154,217 and $158,885 at March 31, 2024 and December 31, 2023, respectively)		154,217	158,885
Less: accumulated depreciation (amounts related to VIEs of $(1,538,940) and $(1,501,483) at March 31, 2024 and December 31, 2023, respectively)		(1,538,940)	(1,501,483)
Cash and cash equivalents (amounts related to VIEs of $298,548 and $245,317 at March 31, 2024 and December 31, 2023, respectively)		298,548	245,317
Cash held in escrows (amounts related to VIEs of $4,839 and $22,160 at March 31, 2024 and December 31, 2023, respectively)		4,839	22,160
Tenant and other receivables, net (amounts related to VIEs of $27,792 and $27,987 at March 31, 2024 and December 31, 2023, respectively)		27,792	27,987
Accrued rental income, net (amounts related to VIEs of $409,628 and $401,159 at March 31, 2024 and December 31, 2023, respectively)		409,628	401,159
Deferred charges, net (amounts related to VIEs of $194,489 and $175,383 at March 31, 2024 and December 31, 2023, respectively)		194,489	175,383
Prepaid expenses and other assets (amounts related to VIEs of $45,672 and $11,824 at March 31, 2024 and December 31, 2023, respectively)		45,672	11,824
Liabilities:
Mortgage notes payable, net (amounts related to VIEs of $3,278,396 and $3,277,185 at March 31, 2024 and December 31, 2023, respectively)		3,278,396	3,277,185
Lease liabilities - finance leases (amounts related to VIEs of $20,831 and $20,794 at March 31, 2024 and December 31, 2023, respectively)		20,831	20,794
Lease liabilities - operating leases (amounts related to VIEs of $148,706 and $145,826 at March 31, 2024 and December 31, 2023, respectively)		148,706	145,826
Accounts payable and accrued expenses (amounts related to VIEs of $112,385 and $59,667 at March 31, 2024 and December 31, 2023, respectively)		112,385	59,667
Other liabilities (amounts related to VIEs of $105,786 and $115,275 at March 31, 2024 and December 31, 2023, respectively)		105,786	115,275
Boston Properties Limited Partnership
ASSETS
Real estate, at cost (amounts related to variable interest entities (“VIEs”) of $7,376,175 and $7,054,075 at March 31, 2024 and December 31, 2023, respectively)		26,696,783	26,382,944
Right of use assets - finance leases (amounts related to VIEs of $21,000 and $21,000 at March 31, 2024 and December 31, 2023, respectively)		401,486	401,680
Right of use assets - operating leases (amounts related to VIEs of $154,217 and $158,885 at March 31, 2024 and December 31, 2023, respectively)	[1]	344,255	324,298
Less: accumulated depreciation (amounts related to VIEs of $(1,538,940) and $(1,501,483) at March 31, 2024 and December 31, 2023, respectively)		(6,915,437)	(6,758,361)
Total real estate		20,527,087	20,350,561
Cash and cash equivalents (amounts related to VIEs of $298,548 and $245,317 at March 31, 2024 and December 31, 2023, respectively)		701,695	1,531,477
Cash held in escrows (amounts related to VIEs of $4,839 and $22,160 at March 31, 2024 and December 31, 2023, respectively)		64,939	81,090
Investments in securities		37,184	36,337
Tenant and other receivables, net (amounts related to VIEs of $27,792 and $27,987 at March 31, 2024 and December 31, 2023, respectively)		94,115	122,407
Note receivable, net		2,274	1,714
Sales-type lease receivable, net		13,943	13,704
Accrued rental income, net (amounts related to VIEs of $409,628 and $401,159 at March 31, 2024 and December 31, 2023, respectively)		1,390,217	1,355,212
Deferred charges, net (amounts related to VIEs of $194,489 and $175,383 at March 31, 2024 and December 31, 2023, respectively)		818,424	760,421
Prepaid expenses and other assets (amounts related to VIEs of $45,672 and $11,824 at March 31, 2024 and December 31, 2023, respectively)		146,286	64,230
Investments in unconsolidated joint ventures		1,399,824	1,377,319
Total assets		25,284,777	25,783,251
Liabilities:
Mortgage notes payable, net (amounts related to VIEs of $3,278,396 and $3,277,185 at March 31, 2024 and December 31, 2023, respectively)		4,368,367	4,166,379
Unsecured senior notes, net		9,794,527	10,491,617
Unsecured line of credit		0	0
Unsecured term loan, net		1,199,430	1,198,301
Lease liabilities - finance leases (amounts related to VIEs of $20,831 and $20,794 at March 31, 2024 and December 31, 2023, respectively)		415,888	417,961
Lease liabilities - operating leases (amounts related to VIEs of $148,706 and $145,826 at March 31, 2024 and December 31, 2023, respectively)		377,667	350,391
Accounts payable and accrued expenses (amounts related to VIEs of $112,385 and $59,667 at March 31, 2024 and December 31, 2023, respectively)		374,681	458,329
Dividends and distributions payable		172,154	171,176
Accrued interest payable		119,573	133,684
Other liabilities (amounts related to VIEs of $105,786 and $115,275 at March 31, 2024 and December 31, 2023, respectively)		417,978	445,947
Total liabilities		17,240,265	17,833,785
Redeemable deferred stock units— 124,656 and 119,471 units outstanding at redemption value at March 31, 2024 and December 31, 2023, respectively		8,141	8,383
Noncontrolling interest:
Redeemable partnership units— 16,492,171 and 16,508,277 common units and 2,666,636 and 2,065,861 long term incentive units outstanding at redemption value at March 31, 2024 and December 31, 2023, respectively		1,300,409	1,347,575
Equity / Capital:
Boston Properties Limited Partnership partners’ capital— 1,762,080 and 1,755,150 general partner units and 155,287,091 and 155,185,716 limited partner units outstanding at March 31, 2024 and December 31, 2023, respectively		5,004,678	4,973,951
Accumulated other comprehensive loss		(3,620)	(21,147)
Total partners’ capital		5,001,058	4,952,804
Noncontrolling interests in property partnerships		1,734,904	1,640,704
Noncontrolling interests:
Total equity / capital		6,735,962	6,593,508
Total liabilities and equity / capital		25,284,777	25,783,251
Boston Properties Limited Partnership \| Related Party
ASSETS
Related party note receivable, net		88,789	88,779
Boston Properties Limited Partnership \| Variable Interest Entity, Primary Beneficiary [Member]
ASSETS
Real estate, at cost (amounts related to variable interest entities (“VIEs”) of $7,376,175 and $7,054,075 at March 31, 2024 and December 31, 2023, respectively)		7,376,175	7,054,075
Right of use assets - finance leases (amounts related to VIEs of $21,000 and $21,000 at March 31, 2024 and December 31, 2023, respectively)		21,000	21,000
Right of use assets - operating leases (amounts related to VIEs of $154,217 and $158,885 at March 31, 2024 and December 31, 2023, respectively)		154,217	158,885
Less: accumulated depreciation (amounts related to VIEs of $(1,538,940) and $(1,501,483) at March 31, 2024 and December 31, 2023, respectively)		(1,538,940)	(1,501,483)
Cash and cash equivalents (amounts related to VIEs of $298,548 and $245,317 at March 31, 2024 and December 31, 2023, respectively)		298,548	245,317
Cash held in escrows (amounts related to VIEs of $4,839 and $22,160 at March 31, 2024 and December 31, 2023, respectively)		4,839	22,160
Tenant and other receivables, net (amounts related to VIEs of $27,792 and $27,987 at March 31, 2024 and December 31, 2023, respectively)		27,792	27,987
Accrued rental income, net (amounts related to VIEs of $409,628 and $401,159 at March 31, 2024 and December 31, 2023, respectively)		409,628	401,159
Deferred charges, net (amounts related to VIEs of $194,489 and $175,383 at March 31, 2024 and December 31, 2023, respectively)		194,489	175,383
Prepaid expenses and other assets (amounts related to VIEs of $45,672 and $11,824 at March 31, 2024 and December 31, 2023, respectively)		45,672	11,824
Liabilities:
Mortgage notes payable, net (amounts related to VIEs of $3,278,396 and $3,277,185 at March 31, 2024 and December 31, 2023, respectively)		3,278,396	3,277,185
Lease liabilities - finance leases (amounts related to VIEs of $20,831 and $20,794 at March 31, 2024 and December 31, 2023, respectively)		20,831	20,794
Lease liabilities - operating leases (amounts related to VIEs of $148,706 and $145,826 at March 31, 2024 and December 31, 2023, respectively)		148,706	145,826
Accounts payable and accrued expenses (amounts related to VIEs of $112,385 and $59,667 at March 31, 2024 and December 31, 2023, respectively)		112,385	59,667
Other liabilities (amounts related to VIEs of $105,786 and $115,275 at March 31, 2024 and December 31, 2023, respectively)		$ 105,786	$ 115,275

[1] See Note 4.

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands		Mar. 31, 2024	Dec. 31, 2023
Real estate, at cost (amounts related to variable interest entities (“VIEs”) of $7,376,175 and $7,054,075 at March 31, 2024 and December 31, 2023, respectively)		$ 27,063,048	$ 26,749,209
Right of use assets - finance leases (amounts related to VIEs of $21,000 and $21,000 at March 31, 2024 and December 31, 2023, respectively)		401,486	401,680
Right of use assets - operating leases (amounts related to VIEs of $154,217 and $158,885 at March 31, 2024 and December 31, 2023, respectively)	[1]	344,255	324,298
Less: accumulated depreciation (amounts related to VIEs of $(1,538,940) and $(1,501,483) at March 31, 2024 and December 31, 2023, respectively)		(7,040,501)	(6,881,728)
Cash and cash equivalents (amounts related to VIEs of $298,548 and $245,317 at March 31, 2024 and December 31, 2023, respectively)		701,695	1,531,477
Cash held in escrows (amounts related to VIEs of $4,839 and $22,160 at March 31, 2024 and December 31, 2023, respectively)		64,939	81,090
Tenant and other receivables, net (amounts related to VIEs of $27,792 and $27,987 at March 31, 2024 and December 31, 2023, respectively)		94,115	122,407
Accrued rental income, net (amounts related to VIEs of $409,628 and $401,159 at March 31, 2024 and December 31, 2023, respectively)		1,390,217	1,355,212
Deferred charges, net (amounts related to VIEs of $194,489 and $175,383 at March 31, 2024 and December 31, 2023, respectively)		818,424	760,421
Prepaid expenses and other assets (amounts related to VIEs of $45,672 and $11,824 at March 31, 2024 and December 31, 2023, respectively)		146,286	64,230
Mortgage notes payable, net (amounts related to VIEs of $3,278,396 and $3,277,185 at March 31, 2024 and December 31, 2023, respectively)		4,368,367	4,166,379
Lease liabilities - finance leases (amounts related to VIEs of $20,831 and $20,794 at March 31, 2024 and December 31, 2023, respectively)		415,888	417,961
Lease liabilities - operating leases (amounts related to VIEs of $148,706 and $145,826 at March 31, 2024 and December 31, 2023, respectively)		377,667	350,391
Accounts payable and accrued expenses (amounts related to VIEs of $112,385 and $59,667 at March 31, 2024 and December 31, 2023, respectively)		374,681	458,329
Other liabilities (amounts related to VIEs of $105,786 and $115,275 at March 31, 2024 and December 31, 2023, respectively)		$ 417,978	$ 445,947
Reedemable deferred stock units, units		124,656	119,471
Limited Partners' Capital Account, Units Outstanding (in units)		155,287,091
General Partners' Capital Account, Units Outstanding (in units)		1,762,080
Excess stock, par value		$ 0.01	$ 0.01
Excess stock, shares authorized		150,000,000	150,000,000
Excess stock, shares outstanding		0	0
Excess stock, shares issued		0	0
Preferred stock, par value		$ 0.01	$ 0.01
Preferred stock, shares authorized		50,000,000	50,000,000
Preferred stock / units, shares / units issued (in shares / units)		0	0
Preferred stock / units, shares / units outstanding (in shares / units)		0	0
Common Stock, Par or Stated Value Per Share		$ 0.01	$ 0.01
Common stock, shares authorized		250,000,000	250,000,000
Common stock, shares issued		157,128,071	157,019,766
Common Stock, Shares, Outstanding		157,049,171	156,940,866
Treasury common stock at cost, shares		78,900	78,900
Boston Properties Limited Partnership
Real estate, at cost (amounts related to variable interest entities (“VIEs”) of $7,376,175 and $7,054,075 at March 31, 2024 and December 31, 2023, respectively)		$ 26,696,783	$ 26,382,944
Right of use assets - finance leases (amounts related to VIEs of $21,000 and $21,000 at March 31, 2024 and December 31, 2023, respectively)		401,486	401,680
Right of use assets - operating leases (amounts related to VIEs of $154,217 and $158,885 at March 31, 2024 and December 31, 2023, respectively)	[1]	344,255	324,298
Less: accumulated depreciation (amounts related to VIEs of $(1,538,940) and $(1,501,483) at March 31, 2024 and December 31, 2023, respectively)		(6,915,437)	(6,758,361)
Cash and cash equivalents (amounts related to VIEs of $298,548 and $245,317 at March 31, 2024 and December 31, 2023, respectively)		701,695	1,531,477
Cash held in escrows (amounts related to VIEs of $4,839 and $22,160 at March 31, 2024 and December 31, 2023, respectively)		64,939	81,090
Tenant and other receivables, net (amounts related to VIEs of $27,792 and $27,987 at March 31, 2024 and December 31, 2023, respectively)		94,115	122,407
Accrued rental income, net (amounts related to VIEs of $409,628 and $401,159 at March 31, 2024 and December 31, 2023, respectively)		1,390,217	1,355,212
Deferred charges, net (amounts related to VIEs of $194,489 and $175,383 at March 31, 2024 and December 31, 2023, respectively)		818,424	760,421
Prepaid expenses and other assets (amounts related to VIEs of $45,672 and $11,824 at March 31, 2024 and December 31, 2023, respectively)		146,286	64,230
Mortgage notes payable, net (amounts related to VIEs of $3,278,396 and $3,277,185 at March 31, 2024 and December 31, 2023, respectively)		4,368,367	4,166,379
Lease liabilities - finance leases (amounts related to VIEs of $20,831 and $20,794 at March 31, 2024 and December 31, 2023, respectively)		415,888	417,961
Lease liabilities - operating leases (amounts related to VIEs of $148,706 and $145,826 at March 31, 2024 and December 31, 2023, respectively)		377,667	350,391
Accounts payable and accrued expenses (amounts related to VIEs of $112,385 and $59,667 at March 31, 2024 and December 31, 2023, respectively)		374,681	458,329
Other liabilities (amounts related to VIEs of $105,786 and $115,275 at March 31, 2024 and December 31, 2023, respectively)		$ 417,978	$ 445,947
Reedemable deferred stock units, units		124,656	119,471
Limited Partners' Capital Account, Units Outstanding (in units)		155,287,091	155,185,716
General Partners' Capital Account, Units Outstanding (in units)		1,762,080	1,755,150
NonControlling Interest Redeemable Partnership Units Common Units Shares Outstanding		16,492,171	16,508,277
NonControlling Interest Redeemable Partnership Units Common Units Long Term Incentive Units At Redemption Value Shares Outstanding		2,666,636	2,065,861
Variable Interest Entity, Primary Beneficiary [Member]
Real estate, at cost (amounts related to variable interest entities (“VIEs”) of $7,376,175 and $7,054,075 at March 31, 2024 and December 31, 2023, respectively)		$ 7,376,175	$ 7,054,075
Right of use assets - finance leases (amounts related to VIEs of $21,000 and $21,000 at March 31, 2024 and December 31, 2023, respectively)		21,000	21,000
Right of use assets - operating leases (amounts related to VIEs of $154,217 and $158,885 at March 31, 2024 and December 31, 2023, respectively)		154,217	158,885
Less: accumulated depreciation (amounts related to VIEs of $(1,538,940) and $(1,501,483) at March 31, 2024 and December 31, 2023, respectively)		(1,538,940)	(1,501,483)
Cash and cash equivalents (amounts related to VIEs of $298,548 and $245,317 at March 31, 2024 and December 31, 2023, respectively)		298,548	245,317
Cash held in escrows (amounts related to VIEs of $4,839 and $22,160 at March 31, 2024 and December 31, 2023, respectively)		4,839	22,160
Tenant and other receivables, net (amounts related to VIEs of $27,792 and $27,987 at March 31, 2024 and December 31, 2023, respectively)		27,792	27,987
Accrued rental income, net (amounts related to VIEs of $409,628 and $401,159 at March 31, 2024 and December 31, 2023, respectively)		409,628	401,159
Deferred charges, net (amounts related to VIEs of $194,489 and $175,383 at March 31, 2024 and December 31, 2023, respectively)		194,489	175,383
Prepaid expenses and other assets (amounts related to VIEs of $45,672 and $11,824 at March 31, 2024 and December 31, 2023, respectively)		45,672	11,824
Mortgage notes payable, net (amounts related to VIEs of $3,278,396 and $3,277,185 at March 31, 2024 and December 31, 2023, respectively)		3,278,396	3,277,185
Lease liabilities - finance leases (amounts related to VIEs of $20,831 and $20,794 at March 31, 2024 and December 31, 2023, respectively)		20,831	20,794
Lease liabilities - operating leases (amounts related to VIEs of $148,706 and $145,826 at March 31, 2024 and December 31, 2023, respectively)		148,706	145,826
Accounts payable and accrued expenses (amounts related to VIEs of $112,385 and $59,667 at March 31, 2024 and December 31, 2023, respectively)		112,385	59,667
Other liabilities (amounts related to VIEs of $105,786 and $115,275 at March 31, 2024 and December 31, 2023, respectively)		105,786	115,275
Variable Interest Entity, Primary Beneficiary [Member] \| Boston Properties Limited Partnership
Real estate, at cost (amounts related to variable interest entities (“VIEs”) of $7,376,175 and $7,054,075 at March 31, 2024 and December 31, 2023, respectively)		7,376,175	7,054,075
Right of use assets - finance leases (amounts related to VIEs of $21,000 and $21,000 at March 31, 2024 and December 31, 2023, respectively)		21,000	21,000
Right of use assets - operating leases (amounts related to VIEs of $154,217 and $158,885 at March 31, 2024 and December 31, 2023, respectively)		154,217	158,885
Less: accumulated depreciation (amounts related to VIEs of $(1,538,940) and $(1,501,483) at March 31, 2024 and December 31, 2023, respectively)		(1,538,940)	(1,501,483)
Cash and cash equivalents (amounts related to VIEs of $298,548 and $245,317 at March 31, 2024 and December 31, 2023, respectively)		298,548	245,317
Cash held in escrows (amounts related to VIEs of $4,839 and $22,160 at March 31, 2024 and December 31, 2023, respectively)		4,839	22,160
Tenant and other receivables, net (amounts related to VIEs of $27,792 and $27,987 at March 31, 2024 and December 31, 2023, respectively)		27,792	27,987
Accrued rental income, net (amounts related to VIEs of $409,628 and $401,159 at March 31, 2024 and December 31, 2023, respectively)		409,628	401,159
Deferred charges, net (amounts related to VIEs of $194,489 and $175,383 at March 31, 2024 and December 31, 2023, respectively)		194,489	175,383
Prepaid expenses and other assets (amounts related to VIEs of $45,672 and $11,824 at March 31, 2024 and December 31, 2023, respectively)		45,672	11,824
Mortgage notes payable, net (amounts related to VIEs of $3,278,396 and $3,277,185 at March 31, 2024 and December 31, 2023, respectively)		3,278,396	3,277,185
Lease liabilities - finance leases (amounts related to VIEs of $20,831 and $20,794 at March 31, 2024 and December 31, 2023, respectively)		20,831	20,794
Lease liabilities - operating leases (amounts related to VIEs of $148,706 and $145,826 at March 31, 2024 and December 31, 2023, respectively)		148,706	145,826
Accounts payable and accrued expenses (amounts related to VIEs of $112,385 and $59,667 at March 31, 2024 and December 31, 2023, respectively)		112,385	59,667
Other liabilities (amounts related to VIEs of $105,786 and $115,275 at March 31, 2024 and December 31, 2023, respectively)		$ 105,786	$ 115,275

[1] See Note 4.

Consolidated Statements Of Oper

Consolidated Statements Of Operations - USD ($) shares in Thousands, $ in Thousands		3 Months Ended
		Mar. 31, 2024	Mar. 31, 2023
Revenue
Lease		$ 788,590	$ 756,875
Total revenue		839,439	803,200
Expenses
Rental		314,157	291,308
General and administrative		50,018	55,802
Transaction costs		513	911
Depreciation and amortization		218,716	208,734
Total expenses		593,712	568,661
Other income (expense)
Income (loss) from unconsolidated joint ventures		19,186	(7,569)
Interest and other income (loss)		14,529	10,941
Gains from investments in securities		2,272	1,665
Unrealized gain on non-real estate investments		396	259
Impairment loss		(13,615)	0
Interest expense		(161,891)	(134,207)
Net Income (loss)		106,604	105,628
Net income attributable to noncontrolling interests
Noncontrolling interests in property partnerships		(17,221)	(18,660)
Noncontrolling interest - common units of the Operating Partnership		(9,500)	(9,078)
Net income attributable to Boston Properties, Inc.		79,883	77,890
Net income attributable to the Company		$ 79,883	$ 77,890
Basic earnings per common share / unit attributable to the Company common shareholders / unitholders
Earnings Per Share After Allocation of Undistributed Earnings to Participating Securities Basic (dollars per share)		$ 0.51	$ 0.50
Weighted average number of common shares / units outstanding (in shares / units)		156,983	156,803
Diluted earnings per common share / unit attributable to the Company common shareholders / unitholders
Diluted Earnings: Net income, Per Share Amount (in dollars per share / unit)		$ 0.51	$ 0.50
Weighted average number of common and common equivalent shares / units outstanding (in shares / units)		157,132	157,043
Boston Properties Limited Partnership
Revenue
Lease		$ 788,590	$ 756,875
Total revenue		839,439	803,200
Expenses
Rental		314,157	291,308
General and administrative		50,018	55,802
Transaction costs		513	911
Depreciation and amortization		217,019	206,872
Total expenses		592,015	566,799
Other income (expense)
Income (loss) from unconsolidated joint ventures		19,186	(7,569)
Interest and other income (loss)		14,529	10,941
Gains from investments in securities		2,272	1,665
Unrealized gain on non-real estate investments		396	259
Impairment loss		(13,615)	0
Interest expense		(161,891)	(134,207)
Net Income (loss)		108,301	107,490
Net income attributable to noncontrolling interests
Noncontrolling interests in property partnerships		(17,221)	(18,660)
Net income attributable to Boston Properties, Inc.		91,080	88,830
Net income attributable to the Company		$ 91,080	$ 88,830
Basic earnings per common share / unit attributable to the Company common shareholders / unitholders
Earnings Per Share After Allocation of Undistributed Earnings to Participating Securities Basic (dollars per share)		$ 0.52	$ 0.51
Weighted average number of common shares / units outstanding (in shares / units)		175,255	174,652
Diluted earnings per common share / unit attributable to the Company common shareholders / unitholders
Diluted Earnings: Net income, Per Share Amount (in dollars per share / unit)		$ 0.52	$ 0.51
Weighted average number of common and common equivalent shares / units outstanding (in shares / units)		175,404	174,892
Parking and Other [Member]
Revenue
Other revenue		$ 32,216	$ 24,009
Parking and Other [Member] \| Boston Properties Limited Partnership
Revenue
Other revenue		32,216	24,009
Hotel [Member]
Revenue
Other revenue	[1]	8,186	8,101
Expenses
Operating expense		6,015	6,671
Hotel [Member] \| Boston Properties Limited Partnership
Revenue
Other revenue		8,186	8,101
Expenses
Operating expense		6,015	6,671
Management Service [Member]
Revenue
Other revenue		6,154	8,980
Management Service [Member] \| Boston Properties Limited Partnership
Revenue
Other revenue		6,154	8,980
Real Estate, Other [Member]
Revenue
Other revenue		4,293	5,235
Expenses
Operating expense		4,293	5,235
Real Estate, Other [Member] \| Boston Properties Limited Partnership
Revenue
Other revenue		4,293	5,235
Expenses
Operating expense		$ 4,293	$ 5,235

[1] Rental Revenue is equal to Total Revenue per the Company’s Consolidated Statements of Operations, less Development and Management Services Revenue and Direct Reimbursements of Payroll and Related Costs from Management Services Contracts Revenue per the Consolidated Statements of Operations.

Consolidated Statements Of Comp

Consolidated Statements Of Comprehensive Income - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2024	Mar. 31, 2023
Net income (loss)		$ 106,604	$ 105,628
Other comprehensive income :
Effective portion of interest rate contracts		16,351	(6,538)
Amortization of interest rate contracts	[1]	3,360	1,675
Other comprehensive income (loss)		19,711	(4,863)
Comprehensive income		126,315	100,765
Net income attributable to noncontrolling interests		(26,721)	(27,738)
Other comprehensive (income) loss attributable to noncontrolling interest		(2,184)	368
Comprehensive income attributable to Boston Properties, Inc.		97,410	73,395
Boston Properties Limited Partnership
Net income (loss)		108,301	107,490
Other comprehensive income :
Effective portion of interest rate contracts		16,351	(6,538)
Amortization of interest rate contracts	[2]	3,360	1,675
Other comprehensive income (loss)		19,711	(4,863)
Comprehensive income		128,012	102,627
Net income attributable to noncontrolling interests		(17,365)	(18,804)
Comprehensive income attributable to Boston Properties, Inc.		$ 110,647	$ 83,823

[1]Amounts reclassified from comprehensive income primarily to interest expense within Boston Properties, Inc.’s Consolidated Statements of Operations[2] Amounts reclassified from comprehensive income primarily to interest expense within Boston Properties Limited Partnership’s Consolidated Statements of Operations.

Consolidated Statements Of Equi

Consolidated Statements Of Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Dividends In Excess Of Earnings [Member]	Treasury Stock, at cost [Member]	Accumulated Other Comprehensive Loss [Member]	Noncontrolling Interests [Member]	Noncontrolling interest - property partnerships [Member]
Equity, shares at Dec. 31, 2022		156,758,000
Equity, value at Dec. 31, 2022	$ 8,363,819	$ 1,568	$ 6,539,147	$ (391,356)	$ (2,722)	$ (13,718)	$ 683,583	$ 1,547,317
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Redemption of operating partnership units to common stock, shares		5,000
Redemption of operating partnership units to common stock, value	0	$ 0	195				(195)
Allocated net income for the period	105,628			77,890			9,078	18,660
Dividends declared	(172,054)			(153,693)			(18,361)
Shares issued pursuant to stock purchase plan, shares		9,000
Shares issued pursuant to stock purchase plan, value	586		586
Net activity from stock option and incentive plan, shares		58,000
Net activity from stock option and incentive plan, value	27,419		3,448				23,971
Proceeds from sale of interest in property partnerships and contributions from noncontrolling interests in property partnerships	7,555							7,555
Distributions to noncontrolling interests in property partnerships	(21,606)							(21,606)
Effective portion of interest rate contracts	(6,538)					(5,870)	(668)
Amortization of interest rate contracts	1,675					1,374	157	144
Reallocation of noncontrolling interest	0		5,938				(5,938)
Equity, shares at Mar. 31, 2023		156,830,000
Equity, value at Mar. 31, 2023	$ 8,306,484	$ 1,568	6,549,314	(467,159)	(2,722)	(18,214)	691,627	1,552,070
Equity, shares at Dec. 31, 2023	156,940,866	156,941,000
Equity, value at Dec. 31, 2023	$ 8,183,981	$ 1,569	6,715,149	(816,152)	(2,722)	(21,147)	666,580	1,640,704
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Redemption of operating partnership units to common stock, shares		36,000
Redemption of operating partnership units to common stock, value	0	$ 1	1,302				(1,303)
Allocated net income for the period	106,604			79,883			9,500	17,221
Dividends declared	(172,772)			(153,908)			(18,864)
Shares issued pursuant to stock purchase plan, shares		8,000
Shares issued pursuant to stock purchase plan, value	600		600
Net activity from stock option and incentive plan, shares		64,000
Net activity from stock option and incentive plan, value	16,531		2,262				14,269
Proceeds from sale of interest in property partnerships and contributions from noncontrolling interests in property partnerships	142,942		46,082					96,860
Distributions to noncontrolling interests in property partnerships	(20,025)							(20,025)
Effective portion of interest rate contracts	16,351					14,646	1,705
Amortization of interest rate contracts	3,360					2,881	335	144
Reallocation of noncontrolling interest	$ 0		(12,747)				12,747
Equity, shares at Mar. 31, 2024	157,049,171	157,049,000
Equity, value at Mar. 31, 2024	$ 8,277,572	$ 1,570	$ 6,752,648	$ (890,177)	$ (2,722)	$ (3,620)	$ 684,969	$ 1,734,904

Consolidated Statement of Capit

Consolidated Statement of Capital and Noncontrolling Interests - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023	Dec. 31, 2022
Common Stock, Shares, Outstanding	157,049,171		156,940,866
Effective portion of interest rate contracts	$ 16,351	$ (6,538)
Amortization of interest rate contracts	3,360	1,675
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)
General Partner [Member]
Common Stock, Shares, Outstanding	1,762,000	1,755,000	1,755,000	1,750,000
Net activity from contributions and unearned compensation	5,000	5,000
Conversion of redeemable partnership units	2,000
Limited Partner [Member]
Common Stock, Shares, Outstanding	155,287,000	155,075,000	155,185,000	155,008,000
Net activity from contributions and unearned compensation	68,000	62,000
Conversion of redeemable partnership units	34,000	5,000
Partners' Capital (General and Limited Partners)[Member]
Beginning Balance	$ 5,004,678	$ 5,449,936	$ 4,973,951	$ 5,299,428
Net activity from contributions and unearned compensation, value	2,862	4,032
Allocated net income for the period	81,580	79,752
Distributions	(153,908)	(153,693)
Conversion of redeemable partnership units, value	1,303	195
Adjustment to reflect redeemable partnership units at redemption value	52,808	220,222
Proceeds from sale of interest in property partnerships and contributions from noncontrolling interests in property partnerships	46,082
Accumulated Other Comprehensive Loss [Member]
Beginning Balance	(3,620)	(18,214)	(21,147)	(13,718)
Effective portion of interest rate contracts	14,646	(5,870)
Amortization of interest rate contracts	2,881	1,374
Noncontrolling interest - property partnerships [Member]
Beginning Balance	1,734,904	1,552,070	1,640,704	1,547,317
Allocated net income for the period	17,221	18,660
Amortization of interest rate contracts	144	144
Proceeds from sale of interest in property partnerships and contributions from noncontrolling interests in property partnerships	96,860	7,555
Distributions to noncontrolling interests in property partnerships	(20,025)	(21,606)
Total Capital [Member]
Beginning Balance	6,735,962	6,983,792	6,593,508	6,833,027
Net activity from contributions and unearned compensation, value	2,862	4,032
Allocated net income for the period	98,801	98,412
Distributions	(153,908)	(153,693)
Conversion of redeemable partnership units, value	1,303	195
Adjustment to reflect redeemable partnership units at redemption value	52,808	220,222
Effective portion of interest rate contracts	14,646	(5,870)
Amortization of interest rate contracts	3,025	1,518
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)
Noncontrolling interest - Redeemable partnership units [Member]
Beginning Balance	1,300,409	1,074,648	$ 1,347,575	$ 1,280,886
Net activity from contributions and unearned compensation, value	14,269	23,973
Allocated net income for the period	9,500	9,078
Distributions	(18,864)	(18,361)
Conversion of redeemable partnership units, value	(1,303)	(195)
Adjustment to reflect redeemable partnership units at redemption value	(52,808)	(220,222)
Effective portion of interest rate contracts	1,705	(668)
Amortization of interest rate contracts	$ 335	$ 157

Consolidated Statements Of Cash

Consolidated Statements Of Cash Flows $ in Thousands	3 Months Ended
Consolidated Statements Of Cash Flows $ in Thousands	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

Organization

Organization	3 Months Ended
Organization	Mar. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	1. Organization BXP is a fully integrated, self-administered and self-managed REIT. BXP is the sole general partner of BPLP, its operating partnership, and at March 31, 2024, owned an approximate 89.1% (89.4% at December 31, 2023) general and limited partnership interest in BPLP. Unless stated otherwise or the context requires, the “Company” refers to BXP and its subsidiaries, including BPLP and its consolidated subsidiaries. Partnership interests in BPLP include: • common units of partnership interest (also referred to as “OP Units”) and • long term incentive units of partnership interest (also referred to as “LTIP Units”) Unless specifically noted otherwise, all references to OP Units exclude units held by BXP. A holder of an OP Unit may present the OP Unit to BPLP for redemption at any time (subject to restrictions agreed upon at the time of issuance of OP Units to particular holders that may restrict such redemption right for a period of time, generally one year from issuance). Upon presentation of an OP Unit for redemption, BPLP is obligated to redeem the OP Unit for cash equal to the value of a share of common stock of BXP (“Common Stock”). In lieu of such cash redemption, BXP may elect to acquire the OP Unit for one share of Common Stock. Because the number of shares of Common Stock outstanding at all times equals the number of OP Units that BXP owns, one share of Common Stock is generally the economic equivalent of one OP Unit, and the quarterly distribution that may be paid to the holder of an OP Unit equals the quarterly dividend that may be paid to the holder of a share of Common Stock. The Company uses LTIP Units as a form of time-based, restricted equity compensation and as a form of performance-based equity compensation for employees, and has previously granted LTIP Units in the form of (1) 2012 outperformance plan awards (“2012 OPP Units”) and (2) 2013 - 2024 multi-year, long-term incentive program awards (also referred to as “MYLTIP Units”), each of which, upon the satisfaction of certain performance-based and time-based vesting conditions, is convertible into one OP Unit. The three Properties At March 31, 2024, the Company owned or had joint venture interests in a portfolio of 187 commercial real estate properties (the “Properties”) aggregating approximately 53.5 million net rentable square feet of primarily premier workplaces, including 11 properties under construction/redevelopment totaling approximately 3.2 million net rentable square feet. At March 31, 2024, the Properties consisted of: • 165 office and life sciences properties (including seven properties under construction/redevelopment); • 14 retail properties (including two properties under construction/redevelopment); • seven residential properties (including two properties under construction ) ; and • one hotel. The Company considers premier workplaces to be well-located buildings that are modern structures or have been modernized to compete with newer buildings and professionally managed and maintained. As such, these properties attract high-quality tenants and command upper-tier rental rates.

Summary Of Significant Accounti

Summary Of Significant Accounting Policies	3 Months Ended
Summary Of Significant Accounting Policies	Mar. 31, 2024
Accounting Policies [Abstract]
Summary Of Significant Accounting Policies	2. Summary of Significant Accounting Policies BXP does not have any other significant assets, liabilities or operations, other than its investment in BPLP, nor does it have employees of its own. BPLP, not BXP, generally executes all significant business relationships other than transactions involving securities of BXP. All majority-owned subsidiaries and joint ventures over which the Company has financial and operating control and variable interest entities (“VIEs”) in which the Company has determined it is the primary beneficiary are included in the consolidated financial statements. All significant intercompany balances and transactions have been eliminated in consolidation. The Company accounts for all other unconsolidated joint ventures using the equity method of accounting. Accordingly, the Company’s share of the earnings of these joint ventures and companies is included in consolidated net income. The accompanying interim financial statements are unaudited; however, the financial statements have been prepared in accordance with generally accepted accounting principles (“GAAP”) for interim financial information and in conjunction with the rules and regulations of the Securities and Exchange Commission (the “SEC”). Accordingly, they do not include all of the disclosures required by GAAP for complete financial statements. In the opinion of management, all adjustments (consisting solely of normal recurring matters) necessary for a fair statement of the financial statements for these interim periods have been included. The results of operations for the interim periods are not necessarily indicative of the results to be obtained for other interim periods or for the full fiscal year. The year-end consolidated balance sheet data was derived from audited financial statements, but does not include all disclosure required by GAAP. These financial statements should be read in conjunction with the Company’s financial statements and notes thereto contained in the Company’s Annual Report in the Company’s Form 10-K for its fiscal year ended December 31, 2023. The Company bases its estimates on historical experience and on various other assumptions that it considers to be reasonable under the circumstances, including the impact of extraordinary events such as a pandemic, the results of which form the basis for making significant judgments about the carrying values of assets and liabilities, assessments of future collectability, and other areas of the financial statements that are impacted by the use of estimates. Actual results may differ from these estimates under different assumptions or conditions. Variable Interest Entities (VIEs) Consolidated VIEs are those for which the Company is considered to be the primary beneficiary of a VIE. The primary beneficiary is the entity that has a controlling financial interest in the VIE, which is defined by the entity having both of the following characteristics: (1) the power to direct the activities that, when taken together, most significantly impact the VIE’s performance and (2) the obligation to absorb losses or the right to receive the returns from the VIE that could potentially be significant to the VIE. The assets of each VIE are only available to satisfy such VIE's respective liabilities. The Company has identified nine entities that are VIEs as of March 31, 2024 and has determined that it is the primary beneficiary for all of these entities as of March 31, 2024. Consolidated Variable Interest Entities As of March 31, 2024, BXP has identified nine consolidated VIEs, including BPLP. Excluding BPLP, the consolidated VIEs consisted of (i) the following five in-service properties: 767 Fifth Avenue (the General Motors Building), Times Square Tower, 601 Lexington Avenue, Atlantic Wharf Office Building and 100 Federal Street, (ii) 343 Madison Avenue, which is categorized as land held for future development and (iii) 290 Binney Street and 300 Binney Street which are currently under development / redevelopment. The Company consolidates these VIEs because it is the primary beneficiary. The third parties’ interests in these consolidated entities (excluding BPLP’s interest) are reflected as noncontrolling interests in property partnerships in the accompanying consolidated financial statements (See Note 9). In addition, BXP’s only significant asset is its investment in BPLP and, consequently, substantially all of BXP’s assets and liabilities are the assets and liabilities of BPLP. Variable Interest Entities Not Consolidated As of March 31, 2024, the Company does not have any unconsolidated joint ventures that are classified as VIEs. Fair Value Measurements The Company follows the authoritative guidance for fair value measurements when valuing its financial instruments for disclosure purposes. The table below presents for March 31, 2024 and December 31, 2023, the financial instruments that are being valued for disclosure purposes as well as the Level at which they are categorized as defined in Accounting Standards Codification (“ASC”) 820 “Fair Value Measurements and Disclosures” (“ASC 820”). Financial Instrument Level 3-Month United States Treasury Bills Level 1 Investment in securities Level 1 Unsecured senior notes (1) Level 1 Related party note receivable Level 3 Notes receivable Level 3 Sales-type lease receivable Level 3 Mortgage notes payable Level 3 Unsecured line of credit Level 3 Unsecured term loan Level 3 _______________ (1) If trading volume for the period is low, the valuation could be categorized as Level 2. Because the Company’s valuations of its financial instruments are based on the above Levels and involve the use of estimates, the actual fair values of its financial instruments may differ materially from those estimates. In addition, the Company’s estimated fair values for these instruments as of the end of the applicable reporting period are not projections of, nor necessarily indicative of, estimated or actual fair values in future reporting periods. At December 31, 2023, the Company had outstanding three The Company’s investment in non-real estate investments is shown within Prepaid and Other Assets on the Consolidated Balance Sheets and was approximately $5.1 million and $4.6 million at March 31, 2024 and December 31, 2023, respectively. The non-real estate investments utilize net asset value as the practical expedient. Non-Recurring Fair Value The following table presents the aggregate carrying value of the Company’s non-recurring fair value financial instruments and the Company’s corresponding estimate of fair value as of March 31, 2024 and December 31, 2023 (in thousands): March 31, 2024 December 31, 2023 Carrying Estimated Carrying Estimated 3-Month United States Treasury Bills (1) $ — $ — $ 302,746 $ 302,746 Related party note receivable, net $ 88,789 $ 90,582 $ 88,779 $ 90,593 Note receivable, net 2,274 2,249 1,714 1,677 Sales-type lease receivable, net 13,943 13,416 13,704 13,338 Total $ 105,006 $ 106,247 $ 104,197 $ 105,608 Mortgage notes payable, net $ 4,368,367 $ 3,935,382 $ 4,166,379 $ 3,705,513 Unsecured senior notes, net 9,794,527 8,979,934 10,491,617 9,697,393 Unsecured line of credit — — — — Unsecured term loan, net 1,199,430 1,198,951 1,198,301 1,196,945 Total $ 15,362,324 $ 14,114,267 $ 15,856,297 $ 14,599,851 _______________ (1) Per the guidance in ASC 326 “Financial Instruments — Credit Losses” (“ASC 326”), the Company concluded that the risk of nonpayment is nonexistent because the U.S. Government has a long history with no credit losses and therefore, no credit loss allowance was recorded. At March 31, 2024, the Company evaluated the expected hold period for a portion of its Shady Grove property located in Rockville, Maryland. Based on a shorter-than-expected hold period, the Company reduced the carrying value of a portion of the property that the Company anticipates selling to a third party developer to its estimated fair value at March 31, 2024. As a result, each of BXP and BPLP recognized an impairment loss of approximately $13.6 million. The Company’s estimated fair value utilized Level 3 inputs and was based on a pending offer from a third party. Recurring Fair Value Derivatives In addition to the financial instruments noted above, the Company uses interest rate swap agreements to manage its interest rate risk (See Note 7). The valuation of these instruments is determined using widely accepted valuation techniques, including discounted cash flow analysis on the expected cash flows of each derivative. This analysis reflects the contractual terms of the derivatives, including the period to maturity, and uses observable market-based inputs, including interest rate curves. To comply with the provisions of ASC 820, the Company incorporates credit valuation adjustments to appropriately reflect both its own nonperformance risk and the respective counterparty’s nonperformance risk in the fair value measurements. Although the Company has determined that the majority of the inputs used to value its derivatives fall within Level 2 of the fair value hierarchy, the credit valuation adjustments associated with its derivatives utilize Level 3 inputs, such as estimates of current credit spreads to evaluate the likelihood of default by the Company and its counterparties. The Company assessed the significance of the impact of the credit valuation adjustments on the overall valuation of its derivative positions and determined that the credit valuation adjustments were not significant to the overall valuation of its derivatives. As a result, the Company has determined that its derivative valuations in their entirety are classified in Level 2 of the fair value hierarchy. The following table presents the aggregate fair value of the Company’s interest rate swaps as of March 31, 2024 and December 31, 2023 (in thousands): Fair value March 31, 2024 December 31, 2023 Interest rate swaps $ 12,298 $ 1,976 Investments The Company accounts for investments in equity securities at fair value, with gains or losses resulting from changes in fair value recognized currently in earnings. The Company maintains deferred compensation plans that are designed to allow officers and non-employee directors of BXP to defer a portion of the officer’s current income or the non-employee director’s current compensation on a pre-tax basis and receive a tax-deferred return on these deferrals based on the performance of specific investments selected by the officer or non-employee director. The Company’s obligation under the plans is that of an unsecured promise to pay the deferred compensation to the plan participants in the future. At March 31, 2024 and December 31, 2023, the Company had maintained approximately $37.0 million and $36.1 million, respectively, in separate accounts, which are not restricted as to their use. The Company recognized gains of approximately $2.3 million and $1.7 million on its investments in the accounts associated with the Company’s deferred compensation plans during the three months ended March 31, 2024 and March 31, 2023, respectively primarily due to the observable change in fair value.

Real Estate

Real Estate	3 Months Ended
Real Estate	Mar. 31, 2024
Real Estate [Abstract]
Real Estate	3. Real Estate BXP Real estate consisted of the following at March 31, 2024 and December 31, 2023 (in thousands): March 31, 2024 December 31, 2023 Land $ 5,317,032 $ 5,251,224 Right of use assets - finance leases 401,486 401,680 Right of use assets - operating leases (1) 344,255 324,298 Land held for future development (2) 661,713 697,061 Buildings and improvements 16,689,571 16,607,756 Tenant improvements 3,654,576 3,592,172 Furniture, fixtures and equipment 54,691 53,716 Construction in progress 685,465 547,280 Total 27,808,789 27,475,187 Less: Accumulated depreciation (7,040,501) (6,881,728) $ 20,768,288 $ 20,593,459 _______________ (1) See Note 4. (2) Includes pre-development costs. BPLP Real estate consisted of the following at March 31, 2024 and December 31, 2023 (in thousands): March 31, 2024 December 31, 2023 Land $ 5,222,323 $ 5,156,515 Right of use assets - finance leases 401,486 401,680 Right of use assets - operating leases (1) 344,255 324,298 Land held for future development (2) 661,713 697,061 Buildings and improvements 16,418,015 16,336,200 Tenant improvements 3,654,576 3,592,172 Furniture, fixtures and equipment 54,691 53,716 Construction in progress 685,465 547,280 Total 27,442,524 27,108,922 Less: Accumulated depreciation (6,915,437) (6,758,361) $ 20,527,087 $ 20,350,561 _______________ (1) See Note 4. (2) Includes pre-development costs. Acquisition On January 8, 2024, the Company completed the acquisition of its joint venture partner’s 50% economic ownership interest in the joint venture that owns 901 New York Avenue, located in Washington, DC. At acquisition, the total net equity acquired was $20.0 million, which includes $10.0 million in cash that the Company paid for the joint venture partner's 50% economic ownership interest in the joint venture. The property is subject to existing mortgage indebtedness of approximately $207.1 million (See Note 6 ) . The acquisition resulted in the Company recording a gain upon consolidation of approximately $21.8 million, which is the difference between the fair value of the previously held equity method investment immediately prior to the consolidation of $10.0 million, less the Company’s costs basis of approximately $(11.8) million. The gain on consolidation is included within income (loss) from unconsolidated joint ventures in the Consolidated Statement of Operations. The total net assets acquired is equal to (1) the total net equity acquired of $20.0 million, which includes $10.0 million in cash that the Company paid for the joint venture partner's 50% economic ownership interest in the joint venture. plus (2) $207.1 million of debt assumed, less (3) net working capital acquired of approximately $7.1 million. The following table summarizes the allocation of the fair value of the net assets the Company received at the date of acquisition for 901 New York Avenue (in thousands): Land and site improvements $ 65,808 Building and improvements 56,882 Tenant improvements 16,088 In-place lease intangibles 72,621 Above-market lease intangibles 2,757 Below-market lease intangibles (2,515) Mortgage note payable adjustment 8,374 Net assets acquired $ 220,015 The following table summarizes the estimated annual amortization of the acquired in-place lease intangibles, and the acquired above- and below-market lease intangibles for 901 New York Avenue for the remainder of 2024 and each of the next five succeeding fiscal years (in thousands): Acquired In-Place Lease Intangibles Acquired Above-Market Lease Intangibles Acquired Below-Market Lease Intangibles Period from January 8, 2024 through December 31, 2024 $ 10,364 $ 607 $ 252 2025 9,030 454 257 2026 6,494 238 257 2027 6,265 201 257 2028 6,069 186 257 2029 6,076 186 251 The following table summarizes the weighted-average useful life of the acquired in-place lease intangibles and the acquired above- and below-market lease intangibles for 901 New York Avenue as of the acquisition date (in years): Acquired In-Place Lease Intangibles Acquired Above-Market Lease Intangibles Acquired Below-Market Lease Intangibles Weighted-average useful life 6.7 4.0 9.8 901 New York Avenue contributed approximately $7.9 million of revenue and $2.3 million of net loss to the Company for the period from January 8, 2024 through March 31, 2024. 901 New York Avenue is a premier workplace consisting of approximately 524,000 net rentable square feet. Development On February 12, 2024, the Company commenced the development of a residential project at 121 Broadway Street in Cambridge, Massachusetts that is adjacent to its development projects at 290 Binney Street and 300 Binney Street. 121 Broadway will consist of 439 residential units aggregating approximately 492,000 net rentable square feet. Impairment At March 31, 2024, the Company evaluated the expected hold period for a portion of its Shady Grove property located in Rockville, Maryland. Based on a shorter-than-expected hold period, the Company reduced the carrying value of a portion of the property that the Company anticipates selling to a third party developer to its estimated fair value at March 31, 2024. As a result, each of BXP and BPLP recognized an impairment loss of approximately

Leases

Leases	3 Months Ended
Leases	Mar. 31, 2024
Leases [Abstract]
Lessor, Operating Leases [Text Block]	4. Leases Lessor The following table summarizes the components of lease revenue recognized under the Company’s operating and sales-type leases for the three months ended March 31, 2024 and 2023 and included within the Company's Consolidated Statements of Operations (in thousands): Three months ended March 31, Lease Revenue 2024 2023 Fixed contractual payments $ 648,890 $ 621,646 Variable lease payments 139,458 135,003 Sales-type lease revenue 242 226 $ 788,590 $ 756,875
Lessee, Operating Leases	Lessee On March 28, 2024, the Company entered into a 90-year air rights lease with the Massachusetts Department of Transportation for an approximately 61,000 square feet site at the parking garage located at 100 Clarendon Street and the concourse level of the Massachusetts Bay Transportation Authority’s Back Bay Station (the “Station”). The lease requires annual base rental payments of $250,000 until the commencement of construction, as defined in the lease. If the Company commences construction of a project on the site on or before August 1, 2028, then a final fixed rental payment is due in accordance with the lease at that time. After August 1, 2028, if the Company commences construction of a project on the site, then a final rental payment based on the then current fair market value will be due at that time. In addition, the lease requires annual payments of $500,000 through 2033 to fund maintenance and improvements to the Station. The Company has assumed that it will begin construction on the site on or before August 1, 2028. The incremental borrowing rate for this lease is 6.57% per annum. The net present value of the ground lease payments is approximately $23.2 million. The Company classifies this lease as an operating lease. As a result, the Company recorded a Right of Use Assets – Operating Leases and Lease Liabilities – Operating Leases of approximately $23.9 million and $23.2 million, respectively, on its Consolidated Balance Sheets as of March 31, 2024. There were no lease costs for the period from March 28, 2024 through March 31, 2024. The following table provides a maturity analysis for the air rights operating lease as of March 28, 2024 (in thousands): Operating Period from March 28, 2024 through December 31, 2024 $ — 2025 750 2026 750 2027 750 2028 25,826 2029 500 Thereafter 2,000 Total lease payments 30,576 Less: Interest portion 7,391 Present value of lease payments $ 23,185

Investments in Unconsolidated J

Investments in Unconsolidated Joint Ventures	3 Months Ended
Investments in Unconsolidated Joint Ventures	Mar. 31, 2024
Equity Method Investments and Joint Ventures [Abstract]
Investments In Unconsolidated Joint Ventures	5. Investments in Unconsolidated Joint Ventures The investments in unconsolidated joint ventures consist of the following at March 31, 2024 and December 31, 2023: Carrying Value of Investment (1) Entity Properties Nominal % Ownership March 31, 2024 December 31, 2023 (in thousands) Square 407 Limited Partnership Market Square North 50.00 % $ (6,103) $ (5,996) 901 New York, LLC 901 New York Avenue 25.00 % (2) — (11,764) WP Project Developer LLC Wisconsin Place Land and Infrastructure 33.33 % (3) 30,221 30,375 500 North Capitol Venture LLC 500 North Capitol Street, NW 30.00 % (10,773) (10,253) 501 K Street LLC 1001 6th Street 50.00 % 45,013 44,774 Podium Developer LLC The Hub on Causeway - Podium 50.00 % 45,068 45,201 Residential Tower Developer LLC Hub50House 50.00 % 42,250 40,235 Hotel Tower Developer LLC The Hub on Causeway - Hotel Air Rights 50.00 % 13,680 13,494 Office Tower Developer LLC 100 Causeway Street 50.00 % 57,079 57,660 1265 Main Office JV LLC 1265 Main Street 50.00 % 3,583 3,585 BNY Tower Holdings LLC Dock 72 50.00 % (4) (12,501) (11,890) CA-Colorado Center, LLC Colorado Center 50.00 % 235,143 237,815 7750 Wisconsin Avenue LLC 7750 Wisconsin Avenue 50.00 % 49,756 50,064 BP-M 3HB Venture LLC 3 Hudson Boulevard 25.00 % 114,331 115,103 Platform 16 Holdings LP Platform 16 55.00 % 51,349 45,564 Gateway Portfolio Holdings LLC Gateway Commons 50.00 % 385,568 376,834 Rosecrans-Sepulveda Partners 4, LLC Beach Cities Media Campus 50.00 % 27,042 27,034 Safeco Plaza REIT LLC Safeco Plaza 33.67 % (5) 43,860 44,734 360 PAS Holdco LLC 360 Park Avenue South 71.11 % (6) 49,888 42,988 PR II/BXP Reston Gateway LLC Skymark - Reston Next Residential 20.00 % 15,323 15,184 751 Gateway Holdings LLC 751 Gateway 49.00 % 95,863 93,411 200 Fifth Avenue JV LLC 200 Fifth Avenue 26.69 % 76,728 75,718 ABXP Worldgate Investments LLC 13100 and 13150 Worldgate Drive 50.00 % 18,079 17,546 $ 1,370,447 $ 1,337,416 _______________ (1) Investments with deficit balances aggregating approximately $29.4 million and $39.9 million at March 31, 2024 and December 31, 2023, respectively, are included within Other Liabilities in the Company’s Consolidated Balance Sheets. (2) At December 31, 2023, the Company’s economic ownership was approximately 50%. On January 8, 2024, the Company completed the acquisition of its joint venture partner’s 50% economic ownership interest for a gross purchase price of $10.0 million, as described in Note 3 and this Note 5. (3) The Company’s wholly-owned subsidiary that owns Wisconsin Place Office also owns a 33.33% interest in the joint venture entity that owns the land, parking garage and infrastructure of the project. (4) This property includes net equity balances from the amenity joint venture. (5) The Company’s ownership includes (1) a 33.0% direct interest in the joint venture, and (2) an additional 1% interest in each of the two entities through which each partner owns its interest in the joint venture. (6) The Company’s ownership includes (1) a 35.79% direct interest in the joint venture, (2) an additional 35.02% indirect ownership in the joint venture, and (3) an additional 1% interest in the entity through which the partner owns its interest in the joint venture. Certain of the Company’s unconsolidated joint venture agreements include provisions whereby, at certain specified times, each partner has the right to initiate a purchase or sale of its interest in the joint ventures. Under certain of the Company’s joint venture agreements, if certain return thresholds are achieved, the partners or the Company will be entitled to an additional promoted interest or payments. The combined summarized balance sheets of the Company’s unconsolidated joint ventures are as follows: March 31, 2024 December 31, 2023 (in thousands) ASSETS Real estate and development in process, net (1) $ 5,740,545 $ 5,811,763 Other assets (2) 619,559 682,291 Total assets $ 6,360,104 $ 6,494,054 LIABILITIES AND MEMBERS’/PARTNERS’ EQUITY Mortgage and notes payable, net $ 3,162,545 $ 3,351,873 Other liabilities (3) 318,708 361,357 Members’/Partners’ equity 2,878,851 2,780,824 Total liabilities and members’/partners’ equity $ 6,360,104 $ 6,494,054 Company’s share of equity $ 1,313,484 $ 1,278,483 Basis differentials (4) 56,963 58,933 Carrying value of the Company’s investments in unconsolidated joint ventures (5) $ 1,370,447 $ 1,337,416 _______________ (1) At March 31, 2024 and December 31, 2023, this amount included right of use assets - operating leases totaling approximately $19.8 million and $20.1 million, respectively. (2) At March 31, 2024 and December 31, 2023, this amount included sales-type lease receivable, net totaling approximately $14.0 million and $13.9 million, respectively. (3) At March 31, 2024 and December 31, 2023, this amount included lease liabilities - operating leases totaling approximately $30.5 million. (4) This amount represents the aggregate difference between the Company’s historical cost basis and the basis reflected at the joint venture level, which is typically amortized over the life of the related assets and liabilities. Basis differentials result from impairments of investments, acquisitions through joint ventures with no change in control and upon the transfer of assets that were previously owned by the Company into a joint venture. In addition, certain acquisition, transaction and other costs may not be reflected in the net assets at the joint venture level. The majority of the Company’s basis differences are as follows: March 31, 2024 December 31, 2023 Property (in thousands) Colorado Center $ 298,190 $ 298,906 200 Fifth Avenue 56,193 58,308 Gateway Commons 49,593 48,971 Safeco Plaza (29,432) (29,678) 360 Park Avenue South (116,188) (116,534) Dock 72 (94,586) (95,521) Platform 16 (142,671) (143,052) These basis differentials (excluding land) will be amortized over the remaining lives of the related assets and liabilities. (5) Investments with deficit balances aggregating approximately $29.4 million and $39.9 million at March 31, 2024 and December 31, 2023, respectively, are reflected within Other Liabilities in the Company’s Consolidated Balance Sheets. The combined summarized statements of operations of the Company’s unconsolidated joint ventures are as follows: Three months ended March 31, 2024 2023 (in thousands) Total revenue (1) $ 130,392 $ 151,423 Expenses Operating 49,194 57,206 Transaction costs 2 74 Depreciation and amortization 39,424 49,978 Total expenses 88,620 107,258 Other income (expense) Interest expense (43,563) (57,250) Unrealized gain (loss) on derivative instruments 10,112 (10,610) Net income (loss) $ 8,321 $ (23,695) Company’s share of net income (loss) $ 2,960 $ (6,902) Gain on sale / consolidation 21,696 — Basis differential (2) (5,470) (667) Income (loss) from unconsolidated joint ventures $ 19,186 $ (7,569) _______________ (1) Includes straight-line rent adjustments of approximately $7.7 million and $6.3 million for the three months ended March 31, 2024 and 2023, respectively. (2) Includes depreciation and amortization of approximately $2.9 million and $3.7 million for the three months ended March 31, 2024 and 2023, respectively. Includes unrealized gain (loss) on derivative instruments of approximately $2.7 million and $(2.8) million for the three months ended March 31, 2024 and 2023, respectively. Includes straight-line rent adjustments of approximately $0.3 million for the three months ended March 31, 2024 and 2023. Also includes net above-/below-market rent adjustments of approximately $0.2 million for the three months ended March 31, 2024 and 2023. On January 2, 2024, a joint venture in which the Company has a 50% interest partially placed in-service 651 Gateway, an approximately 327,000 net rentable square foot laboratory/life sciences project in South San Francisco, California. The property is approximately 21% pre-leased as of May 2, 2024. On January 8, 2024, the Company acquired its joint venture partner’s 50% economic ownership interest in the joint venture that owns 901 New York Avenue, located in Washington, DC, for a gross purchase price of $10.0 million in cash (See Note 3). Prior to the acquisition, the Company had a 50% economic ownership interest in the joint venture and accounted for it under the equity method of accounting. The acquisition resulted in the Company having full ownership of the joint venture such that the Company now accounts for the assets, liabilities, and operations of it on a consolidated basis in its financial statements instead of under the equity method of accounting and as a result recognized a gain on consolidation of approximately $21.8 million. On February 6, 2024, a joint venture in which the Company owns a 25% interest extended the maturity date of the loan collateralized by its 3 Hudson Boulevard property. The extended loan continues to bear interest at a variable rate equal to Term SOFR plus approximately 3.61% per annum and matures on May 9, 2024. At the time of the extension, the loan had an outstanding balance totaling $80.0 million and was scheduled to mature on February 9, 2024. 3 Hudson Boulevard consists of land and improvements held for future development located in New York, New York. On February 9, 2024, a joint venture in which the Company owns a 50% interest exercised an option to extend the maturity date of the construction loan collateralized by its 7750 Wisconsin Avenue property. The construction loan had a total commitment amount of approximately $252.6 million. The extended loan continues to bear interest at a variable rate equal to Term SOFR plus 1.35% per annum and matures on April 26, 2025. At the time of the extension, the loan had an outstanding balance totaling approximately $251.6 million and was scheduled to mature on April 26, 2024. 7750 Wisconsin Avenue is a premier workplace with approximately 736,000 net rentable square feet located in Bethesda, Maryland.

Debt

Debt	3 Months Ended
Debt	Mar. 31, 2024
Debt Disclosure [Abstract]
Debt Disclosure [Text Block]	6. Debt Mortgage Notes Payable On January 8, 2024, the Company acquired its joint venture partner’s 50% economic ownership interest in the joint venture that owns 901 New York Avenue located in Washington, DC (See Note 3). The property is subject to existing mortgage indebtedness. At acquisition, the mortgage loan had an outstanding principal balance of approximately $207.1 million, bore interest at 3.61% per annum and was scheduled to mature on January 5, 2025. The mortgage loan was recorded at a fair value of approximately $198.7 million. On January 11, 2024, the Company modified the mortgage loan to provide for two extension options totaling five years of additional term, each subject to certain conditions. Unsecured Senior Notes The following summarizes the unsecured senior notes outstanding as of March 31, 2024 (dollars in thousands): Coupon/Stated Rate Effective Rate(1) Principal Amount Maturity Date(2) 7 Year Unsecured Senior Notes 3.200 % 3.350 % $ 850,000 January 15, 2025 10 Year Unsecured Senior Notes 3.650 % 3.766 % 1,000,000 February 1, 2026 10 Year Unsecured Senior Notes 2.750 % 3.495 % 1,000,000 October 1, 2026 5 Year Unsecured Senior Notes 6.750 % 6.924 % 750,000 December 1, 2027 10 Year Unsecured Senior Notes 4.500 % 4.628 % 1,000,000 December 1, 2028 10 Year Unsecured Senior Notes 3.400 % 3.505 % 850,000 June 21, 2029 10.5 Year Unsecured Senior Notes 2.900 % 2.984 % 700,000 March 15, 2030 10.75 Year Unsecured Senior Notes 3.250 % 3.343 % 1,250,000 January 30, 2031 11 Year Unsecured Senior Notes 2.550 % 2.671 % 850,000 April 1, 2032 12 Year Unsecured Senior Notes 2.450 % 2.524 % 850,000 October 1, 2033 10.7 Year Unsecured Senior Notes 6.500 % 6.619 % 750,000 January 15, 2034 Total principal 9,850,000 Less: Net unamortized discount 12,611 Deferred financing costs, net 42,862 Total $ 9,794,527 _______________ (1) Yield on issuance date including the effects of discounts on the notes, settlements of interest rate contracts and the amortization of financing costs. (2) No principal amounts are due prior to maturity. On February 1, 2024, BPLP repaid $700.0 million in aggregate principal amount of its 3.800% senior notes due February 1, 2024. The repayment was completed with available cash and the $600.0 million proceeds from the mortgage loan entered into on October 26, 2023. The repayment price was approximately $713.3 million, which was equal to the stated principal plus approximately $13.3 million of accrued and unpaid interest to, but not including, the repayment date. Excluding the accrued and unpaid interest, the repayment price was equal to the principal amount being repaid. The indenture relating to the unsecured senior notes contains certain financial restrictions and requirements, including (1) a leverage ratio not to exceed 60%, (2) a secured debt leverage ratio not to exceed 50%, (3) an interest coverage ratio of greater than 1.50, and (4) an unencumbered asset value of not less than 150% of unsecured debt. At March 31, 2024, BPLP was in compliance with each of these financial restrictions and requirements.

Derivative Instruments and Hedg

Derivative Instruments and Hedging Activities	3 Months Ended
Derivative Instruments and Hedging Activities	Mar. 31, 2024
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments and Hedging Activities Disclosure	7. Derivative Instruments and Hedging Activities BPLP’s agreements with the swap derivative counterparties contain provisions whereby if BPLP defaults on the underlying indebtedness, including defaults where repayment of the indebtedness has not been accelerated by the lender, then BPLP could also be declared in default of the swap derivative obligation. As of March 31, 2024, the Company had not posted any collateral related to the agreements. Effective Hedge Instruments BPLP assesses the effectiveness of its hedges both at inception and on an ongoing basis. If the hedges are deemed to be effective, the fair value is recorded in “Accumulated other comprehensive income (loss)” in the Company’s Consolidated Balance Sheets and is subsequently reclassified into “Interest expense” in the Company’s Consolidated Statements of Operations in the period that the hedged forecasted transactions affect earnings. BPLP’s derivative financial instruments are cash flow hedges that are designated as effective hedges, and are carried at their estimated fair value on a recurring basis (See Note 2). The Company did not incur any ineffectiveness during the three months ended March 31, 2024. BPLP’s and SMBP LLC’s interest rate swap contracts consisted of the following at March 31, 2024 (dollars in thousands): Derivative Instrument Aggregate Notional Amount Strike Rate Range Balance Sheet Location Effective Date Maturity Date Low High Fair Value BPLP: Interest Rate Swaps $ 1,200,000 May 4, 2023 May 16, 2024 4.638 % — 4.646 % Prepaid expenses and other assets $ 1,006 Interest Rate Swaps 600,000 December 15, 2023 October 26, 2028 3.790 % — 3.798 % Prepaid expenses and other assets 4,646 1,800,000 5,652 SMBP LLC (1) Interest Rate Swaps 300,000 December 14, 2023 April 1, 2025 2.661 % — 2.688 % Prepaid expenses and other assets 6,646 $ 2,100,000 $ 12,298 _______________ (1) A subsidiary of the Company that is the borrower under the mortgage loan collateralized by its Santa Monica Business Park property. The following table presents the location in the financial statements of the gains or losses recognized related to the Company’s cash flow hedges for the three months ended March 31, 2024 and 2023 (in thousands): Three months ended March 31, 2024 2023 Amount of gain (loss) related to the effective portion recognized in other comprehensive income (1) $ 16,351 $ (6,538) Amount of gain (loss) related to the effective portion subsequently reclassified to earnings (2) $ 3,360 $ 1,675 Amount of gain (loss) relate do the ineffective portion and amount excluded from effectiveness testing $ — $ — _______________ (1) Includes the Company’s share of gain (loss) related to the effective portion of derivatives outstanding at its unconsolidated joint venture properties. (2) Includes amounts from previous interest rate programs. BPLP has formally documented all of its relationships between hedge instruments and hedging items, as well as its risk-management objectives and strategy for undertaking various hedge transactions. While management believes its judgments are reasonable, a change in a derivative's effectiveness as a hedge could materially affect expenses, net income (loss) and equity. Ineffective Hedging Instruments During the year ended December 31, 2023, to satisfy a lender requirement, the Company entered into two agreements with the same third-party to purchase and sell a $600.0 million interest rate cap. The Company did not elect hedge accounting, and as such, any change in market value will be recognized in Gain (losses) from interest rate contracts in the Consolidated Statement of Operations. For the three months ended March 31, 2024 and 2023, the Company recognized no impact to its Consolidated Statement of Operations from entering into these agreements.

Commitments And Contingencies

Commitments And Contingencies	3 Months Ended
Commitments And Contingencies	Mar. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Commitments And Contingencies	8. Commitments and Contingencies General In the normal course of business, the Company guarantees its performance of services or indemnifies third parties against its negligence. In addition, in the normal course of business, the Company guarantees to certain tenants the obligations of its subsidiaries for the payment of tenant improvement allowances and brokerage commissions in connection with their leases and limited costs arising from delays in delivery of their premises. The Company had letter of credit and performance obligations related to lender and development requirements that total approximately $21.6 million at March 31, 2024. Certain of the Company’s joint venture agreements include provisions whereby, at certain specified times, each partner has the right to initiate a purchase or sale of its interest in the joint ventures. From time to time, under certain of the Company’s joint venture agreements, if certain return thresholds are achieved, either the Company or its partners may be entitled to an additional promoted interest or payments. From time to time, the Company (or ventures in which the Company has an ownership interest) has agreed, and may in the future agree, to (1) guarantee portions of the principal, interest and other amounts in connection with their borrowings, (2) provide customary environmental indemnifications and nonrecourse carve-outs (e.g., guarantees against fraud, misrepresentation and bankruptcy) in connection with their borrowings and (3) provide guarantees to lenders, tenants and other third parties for the completion of development projects. The Company has agreements with its outside or joint venture partners whereby the partners agree to reimburse the joint venture for their share of any payments made under the guarantee. In some cases, the Company earns a fee from the applicable joint venture for providing the guarantee. In connection with the refinancing of 767 Fifth Avenue’s (the General Motors Building) secured loan by the Company’s consolidated joint venture entity, 767 Venture, LLC, the Company guaranteed the consolidated entity’s obligation to fund various reserves for tenant improvement costs and allowances, leasing commissions and free rent obligations in lieu of cash deposits. As of March 31, 2024, the maximum funding obligation under the guarantee was approximately $8.5 million. The Company earns a fee from the joint venture for providing the guarantee and has an agreement with the outside partners to reimburse the joint venture for their share of any payments made under the guarantee. As of March 31, 2024, no amounts related to the guarantee were recorded as liabilities in the Company’s consolidated financial statements. In connection with the sale of Metropolitan Square, in which the Company had a 20% equity interest, the Company agreed to become a co-lender of up to $20.0 million under a mezzanine loan. The mezzanine loan has a maximum principal amount of $100.0 million, and it is subordinate only to an existing senior loan. The mezzanine loan may be drawn upon for future lease-up, operating and other costs on an as needed basis, and amounts borrowed will bear interest at a per annum rate of 12%, compounded monthly. As of March 31, 2024, the Company has funded approximately $2.2 million. Legal Matters The Company is subject to various legal proceedings and claims that arise in the ordinary course of business. These matters are generally covered by insurance. Management believes that the final outcome of such matters will not have a material adverse effect on the financial position, results of operations or liquidity of the Company. In connection with the acquisition of a premier workplace in New York City in 2010, the Company entered into an agreement with the seller pursuant to which the seller could earn various fees based on the future leasing performance of the property. The Company initially accrued approximately $1.5 million as an estimate of the fees it would owe the seller. The seller filed suit against the Company claiming that consideration significantly in excess of the initial reserve amount is owed under the agreement in 2020. The disagreement between the Company and the seller involves material issues of contract interpretation and, more importantly, the method of calculating fees, including various inputs (both facts and assumptions) that drive the calculation. In February 2024, a summary judgment was issued interpreting certain sections of the agreement in favor of the seller’s claims. The Company believes it has meritorious defenses to the seller’s claims, is disputing the seller’s calculations and intends to continue defending itself vigorously. However, there can be no assurance that the Company will prevail in the lawsuit. If the court ultimately agrees with the seller’s calculations, then amounts due to the seller could theoretically be as high as the additional $31 million claimed in the seller’s complaint, plus interest. Although the Company rejects those calculations, there can be no assurance that the Company’s ultimate liability will not be significantly greater than its established accrual. On April 26, 2024, Brammer Bio MA, LLC (“Brammer”), a subsidiary of Thermo Fisher Scientific Inc. and an abutter to the Company’s 290 Binney Street development project located in Cambridge, Massachusetts, filed a complaint in Superior Court in Suffolk County, Massachusetts against the Company relating to certain ongoing construction activities. In the first quarter of 2023, the Company commenced development of 290 Binney Street, an approximately 566,000 net rentable square foot laboratory/life sciences property that is 100% pre-leased to AstraZeneca Pharmaceuticals (“AstraZeneca”). The Company has a 55% interest in the joint venture that owns 290 Binney Street. Brammer subleases the premises at 250 Binney Street, the Company’s approximately 67,000 net rentable square foot life sciences property that is adjacent to 290 Binney Street. Brammer alleges that, as a result of the Company’s construction of 290 Binney Street, it is threatened with irreparable harm due to intrusion onto the 250 Binney Street premises and the loss of its property rights. Brammer also alleges that the 290 Binney Street development project has caused and is causing major disruption to its manufacturing operations, and that it has suffered and will continue to suffer damages in the form of losses to its clients and customers. Brammer brought the action for quiet title, breach of contract, trespass and nuisance, and it is seeking declaratory and injunctive relief and specific performance purportedly to protect its property interests in the premises located at 250 Binney Street. The Company believes Brammer’s claims are without merit and intends to defend against them vigorously. However, there can be no assurance the Company will prevail in the litigation. If the Company is enjoined from further construction activities, it could suffer delays in construction that could result in its failure to deliver a completed building on the schedule contemplated by the Company’s lease with AstraZeneca or at all, and this could result in owing financial penalties to AstraZeneca and other third parties. Although the Company is unable to estimate a range of loss for all related matters for which losses are reasonably possible, if the court grants injunctive relief or awards monetary damages to Brammer, it could have a material adverse effect on the Company’s results of operations and financial condition. Insurance The Company’s property insurance program per occurrence limits are $1.0 billion for its portfolio insurance program, including coverage for acts of terrorism other than nuclear, biological, chemical or radiological terrorism (“Terrorism Coverage”). The Company also carries $1.35 billion of property insurance in excess of the $1.0 billion of coverage in the Company’s property insurance program for 601 Lexington Avenue, New York, New York, consisting of $750 million of property and Terrorism Coverage in excess of the Company’s property insurance program and $600 million of Terrorism Coverage only in excess of the $1.75 billion of coverage. Certain properties, including the General Motors Building located at 767 Fifth Avenue in New York, New York (“767 Fifth Avenue”), are currently insured in separate insurance programs. The property insurance program per occurrence limits for 767 Fifth Avenue are $1.625 billion, including Terrorism Coverage. The Company also currently carries nuclear, biological, chemical and radiological terrorism insurance coverage for acts of terrorism certified under the Federal Terrorism Risk Insurance Act (as amended, “TRIA”) (“NBCR Coverage”), which is provided by IXP as a direct insurer, for the properties in the Company’s portfolio, including 767 Fifth Avenue, but excluding certain other properties owned in joint ventures with third parties or which the Company manages. The per occurrence limit for NBCR Coverage is $1.0 billion. Under TRIA, after the payment of the required deductible and coinsurance, the NBCR Coverage provided by IXP is backstopped by the Federal Government if the aggregate industry insured losses resulting from a certified act of terrorism exceed a “program trigger.” The program trigger is $200 million, the coinsurance is 20% and the deductible is 20% of the premiums earned by the insurer for the year prior to a claim. If the Federal Government pays out for a loss under TRIA, it is mandatory that the Federal Government recoup the full amount of the loss from insurers offering TRIA coverage after the payment of the loss pursuant to a formula in TRIA. The Company may elect to terminate the NBCR Coverage if the Federal Government seeks recoupment for losses paid under TRIA, if TRIA is not extended after its expiration on December 31, 2027, if there is a change in its portfolio or for any other reason. The Company intends to continue to monitor the scope, nature and cost of available terrorism insurance. The Company also currently carries earthquake insurance on its properties located in areas known to be subject to earthquakes. Specifically, the Company currently carries earthquake insurance which covers its San Francisco and Los Angeles regions with a $330 million per occurrence limit, and a $330 million annual aggregate limit, $30 million of which is provided by IXP, as a direct insurer. This insurance is subject to a deductible in the amount of 5% of the value of the affected property. In addition, the Company currently carries earthquake insurance which covers its Seattle region with a $110 million per occurrence limit, and a $110 million annual aggregate limit. This insurance is subject to a deductible in the amount of 2% of the value of the affected property. The amount of the Company’s earthquake insurance coverage may not be sufficient to cover losses from earthquakes. In addition, the amount of earthquake coverage could impact the Company’s ability to finance properties subject to earthquake risk. The Company may discontinue earthquake insurance or change the structure of its earthquake insurance program on some or all of its properties in the future if the premiums exceed the Company’s estimation of the value of the coverage. IXP, a captive insurance company which is a wholly-owned subsidiary of the Company, acts as a direct insurer with respect to a portion of the Company’s earthquake insurance coverage for its Greater San Francisco and Los Angeles properties and the Company’s NBCR Coverage. Insofar as the Company owns IXP, it is responsible for its liquidity and capital resources, and the accounts of IXP are part of the Company’s consolidated financial statements. In particular, if a loss occurs which is covered by the Company’s NBCR Coverage but is less than the applicable program trigger under TRIA, IXP would be responsible for the full amount of the loss without any backstop by the Federal Government. IXP would also be responsible for any recoupment charges by the Federal Government in the event losses are paid out and its insurance policy is maintained after the payout by the Federal Government. If the Company experiences a loss and IXP is required to pay under its insurance policy, the Company would ultimately record the loss to the extent of the required payment. Therefore, insurance coverage provided by IXP should not be considered as the equivalent of third-party insurance, but rather as a modified form of self-insurance. In addition, BPLP has issued a guarantee to cover liabilities of IXP in the amount of $20.0 million. The Company continues to monitor the state of the insurance market in general, and the scope and costs of coverage for acts of terrorism, earthquakes, pandemics and cybersecurity incidents, in particular, but the Company cannot anticipate what coverage will be available on commercially reasonable terms in future policy years. There are other types of losses, such as from wars, for which the Company cannot obtain insurance at all or at a reasonable cost. With respect to such losses and losses from acts of terrorism, earthquakes, pandemics or other catastrophic events, if the Company experiences a loss that is uninsured or that exceeds policy limits, the Company could lose the capital invested in the damaged properties, as well as the anticipated future revenues from those properties. Depending on the specific circumstances of each affected property, it is possible that the Company could be liable for mortgage indebtedness or other obligations related to the property. Any such loss could materially and adversely affect the Company’s business, financial condition and results of operations.

Noncontrolling Interests

Noncontrolling Interests	3 Months Ended
Noncontrolling Interests	Mar. 31, 2024
Noncontrolling Interest [Abstract]
Noncontrolling Interest Disclosure [Text Block]	9. Noncontrolling Interests Noncontrolling interests relate to the interests in BPLP not owned by BXP and interests in consolidated property partnerships not wholly-owned by the Company. As of March 31, 2024, the noncontrolling interests in BPLP consisted of the following: OP Units LTIP Units (1) 2022 MYLTIP Units 2023 MYLTIP Units 2024 MYLTIP Units 16,492,171 2,666,636 252,151 322,053 330,479 __________ (1) Includes 666,405 LTIP Units earned by employees under the Company’s multi-year long-term incentive awards granted between 2012 and 2021 (i.e., 2012 OPP and 2013 - 2021 MYLTIP awards). Noncontrolling Interest—Common Units During the three months ended March 31, 2024, 36,305 OP Units were presented by the holders for redemption (including an aggregate of 22,155 OP Units issued upon conversion of LTIP Units, 2012 OPP Units and MYLTIP Units) and were redeemed by BXP in exchange for an equal number of shares of Common Stock. At March 31, 2024, BPLP had outstanding the 2022 - 2024 MYLTIP Units. Prior to the end of the respective three On February 1, 2024, the measurement period for the Company’s 2021 MYLTIP awards ended and, based on BXP’s absolute and relative TSR performance, the final payout was determined to be 112% of target, or an aggregate of approximately $12.6 million (after giving effect to employee separations). As a result, an aggregate of 155,625 2021 MYLTIP Units that had been previously granted were automatically forfeited. The following table presents BPLP’s distributions on the OP Units and LTIP Units and MYLTIP Units paid or declared in 2024 and during the three months ended March 31, 2023: Record Date Payment Date Distributions per OP Unit and LTIP Unit Distributions per MYLTIP Unit March 28, 2024 April 30, 2024 $0.98 $0.098 December 29, 2023 January 30, 2024 $0.98 $0.098 March 31, 2023 April 28, 2023 $0.98 $0.098 December 30, 2022 January 30, 2023 $0.98 $0.098 A holder of an OP Unit may present the OP Unit to BPLP for redemption at any time (subject to restrictions agreed upon at the time of issuance of OP Units to particular holders that may restrict such redemption right for a period of time, generally one year from issuance). Upon presentation of an OP Unit for redemption, BPLP must redeem the OP Unit for cash equal to the then value of a share of Common Stock of BXP. BXP may, in its sole discretion, elect to assume and satisfy the redemption obligation by paying either cash or issuing one share of Common Stock. The value of the OP Units (other than OP Units owned by BXP), and LTIP Units (including the 2012 OPP Units and 2013 - 2021 MYLTIP Units), assuming in each case that all conditions had been met for the conversion thereof, had all of such units been redeemed at March 31, 2024 was approximately $1.3 billion based on the last reported price of a share of Common Stock on the New York Stock Exchange of $65.31 per share on March 28, 2024. Noncontrolling Interests—Property Partnerships The noncontrolling interests in property partnerships consist of the outside equity interests in ventures that are consolidated with the financial results of the Company because the Company exercises control over the entities that own the properties. The equity interests in these ventures that are not owned by the Company, totaling approximately $1.7 billion and $1.6 billion at March 31, 2024 and December 31, 2023, respectively, are included in Noncontrolling Interests—Property Partnerships on the accompanying Consolidated Balance Sheets. On March 21, 2024, the Company completed the sale of a 45% interest in 290 Binney Street in Cambridge, Massachusetts.  The institutional investor funded approximately $97.2 million in cash at closing, which is less than 45% of the agreed upon carrying value of the property immediately prior to the transaction.  The institutional investor will fund all construction costs until its equity balance is proportionate to its ownership percentage, after which the Company and the institutional investor will fund the development project based on their respective ownership interests.  The Company retains a 55% ownership interest in the joint venture.  The transaction did not qualify as a sale of real estate for financial reporting purposes as the Company continues to effectively control the property and thus will continue to account for the property on a consolidated basis in its financial statements and no gain was recognized in the Consolidated Statements of Operations.  The Company provides customary development, property management and leasing services to the joint venture.  The Company has accounted for the transaction as an equity transaction and as of March 21, 2024 has recognized noncontrolling interest in its Consolidated Balance Sheets totaling approximately $104.6 million, which is equal to 45% of the aggregate carrying value of the total equity of the property immediately prior to the transaction.  The difference between the cash proceeds received and the noncontrolling interest recognized, which was approximately $7.5 million, has been reflected as a decrease in additional paid-in capital in the Company’s Consolidated Balance Sheets.  At the end of each reporting period, there will be a reallocation of the partners’ equity balances such that the ending balance in each partners’ capital account reflects each partners’ claim on net assets. These adjustments will impact additional paid-in capital and noncontrolling interest in property partnerships in the Company’s Consolidated Balance Sheets. For the period ended March 31, 2024, the adjustment was approximately $50.7 million.

Stockholders' Equity _ Partners

Stockholders' Equity / Partners' Capital	3 Months Ended
Stockholders' Equity / Partners' Capital	Mar. 31, 2024
Equity [Abstract]
Stockholders' Equity / Partners' Capital	10. Stockholders’ Equity / Partners’ Capital As of March 31, 2024, BXP had 157,049,171 shares of Common Stock outstanding. As of March 31, 2024, BXP owned 1,762,080 general partnership units and 155,287,091 limited partnership units in BPLP. On May 17, 2023, BXP renewed its “at the market” (“ATM”) stock offering program through which it may sell from time to time up to an aggregate of $600.0 million of its Common Stock through sales agents over a three-year period. Under the ATM stock offering program, BXP may also engage in forward sale transactions with affiliates of certain sales agents for the sale of its Common Stock on a forward basis. This program replaced BXP’s prior $600.0 million ATM stock offering program that was scheduled to expire on May 22, 2023. BXP intends to use the net proceeds from any offering for general business purposes, which may include investment opportunities and debt reduction. No shares of Common Stock have been issued under this ATM stock offering program. During the three months ended March 31, 2024, BXP issued 36,305 shares of Common Stock in connection with the redemption of an equal number of redeemable OP Units from limited partners. The following table presents BXP’s dividends per share and BPLP’s distributions per OP Unit and LTIP Unit paid or declared in 2024 and during the three months ended March 31, 2023: Record Date Payment Date Dividend (Per Share) Distribution (Per Unit) March 28, 2024 April 30, 2024 $0.98 $0.98 December 29, 2023 January 30, 2024 $0.98 $0.98 March 31, 2023 April 28, 2023 $0.98 $0.98 December 30, 2022 January 30, 2023 $0.98 $0.98

Segment Information

Segment Information	3 Months Ended
Segment Information	Mar. 31, 2024
Segment Reporting [Abstract]
Segment Reporting Disclosure [Text Block]	11. Segment Information The following tables present reconciliations of Net Income Attributable to Boston Properties, Inc. to the Company’s share of Net Operating Income and Net Income Attributable to Boston Properties Limited Partnership to the Company’s share of Net Operating Income for the three months ended March 31, 2024 and 2023. BXP Three months ended March 31, 2024 2023 (in thousands) Net income attributable to Boston Properties, Inc. $ 79,883 $ 77,890 Add: Noncontrolling interest—common units of the Operating Partnership 9,500 9,078 Noncontrolling interests in property partnerships 17,221 18,660 Interest expense 161,891 134,207 Impairment loss 13,615 — Net operating income from unconsolidated joint ventures 35,430 40,756 Depreciation and amortization expense 218,716 208,734 Transaction costs 513 911 Payroll and related costs from management services contracts 4,293 5,235 General and administrative expense 50,018 55,802 Less: Net operating income attributable to noncontrolling interests in property partnerships 46,570 47,097 Unrealized gain on non-real estate investment 396 259 Gains from investments in securities 2,272 1,665 Interest and other income (loss) 14,529 10,941 Income (loss) from unconsolidated joint ventures 19,186 (7,569) Direct reimbursements of payroll and related costs from management services contracts 4,293 5,235 Development and management services revenue 6,154 8,980 Company’s share of Net Operating Income $ 497,680 $ 484,665 BPLP Three months ended March 31, 2024 2023 (in thousands) Net income attributable to Boston Properties Limited Partnership $ 91,080 $ 88,830 Add: Noncontrolling interests in property partnerships 17,221 18,660 Interest expense 161,891 134,207 Impairment loss 13,615 — Net operating income from unconsolidated joint ventures 35,430 40,756 Depreciation and amortization expense 217,019 206,872 Transaction costs 513 911 Payroll and related costs from management services contracts 4,293 5,235 General and administrative expense 50,018 55,802 Less: Net operating income attributable to noncontrolling interests in property partnerships 46,570 47,097 Unrealized gain on non-real estate investment 396 259 Gains from investments in securities 2,272 1,665 Interest and other income (loss) 14,529 10,941 Income (loss) from unconsolidated joint ventures 19,186 (7,569) Direct reimbursements of payroll and related costs from management services contracts 4,293 5,235 Development and management services revenue 6,154 8,980 Company’s share of Net Operating Income $ 497,680 $ 484,665 Net operating income (“NOI”) is a non-GAAP financial measure equal to net income attributable to Boston Properties, Inc. and net income attributable to Boston Properties Limited Partnership, as applicable, the most directly comparable GAAP financial measures, plus (1) net income attributable to noncontrolling interests, interest expense, impairment loss, depreciation and amortization expense, transaction costs, payroll and related costs from management services contracts and corporate general and administrative expense less (2) unrealized gain on non-real estate investment, gains from investments in securities, interest and other income (loss), income (loss) from unconsolidated joint ventures, direct reimbursements of payroll and related costs from management services contracts and development and management services revenue. The Company believes NOI is useful to investors as a performance measure and believes it provides useful information to investors regarding its results of operations and financial condition because, when compared across periods, it reflects the impact on operations from trends in occupancy rates, rental rates, operating costs and acquisition and development activity on an unleveraged basis, providing perspective not immediately apparent from net income attributable to Boston Properties, Inc. and net income attributable to Boston Properties Limited Partnership. For example, interest expense is not necessarily linked to the operating performance of a real estate asset and is often incurred at the corporate level as opposed to the property level. Similarly, interest expense may be incurred at the property level even though the financing proceeds may be used at the corporate level (e.g., used for other investment activity). In addition, depreciation and amortization expense, because of historical cost accounting and useful life estimates, may distort operating performance measures at the property level. NOI presented by the Company may not be comparable to NOI reported by other REITs or real estate companies that define NOI differently. The Company’s internal reporting utilizes its share of NOI, which includes its share of NOI from consolidated and unconsolidated joint ventures, which is a non-GAAP financial measure that is calculated as the consolidated amount, plus the Company’s share of the amount from the Company’s unconsolidated joint ventures (calculated based upon the Company’s economic percentage ownership interest and, in some cases, after priority allocations), less the Company’s partners’ share of the amount from the Company’s consolidated joint ventures (calculated based upon the partners’ economic percentage ownership interests and, in some cases, after priority allocations, income allocation to private REIT shareholders and their share of fees due to the Company). The Company’s share of NOI from unconsolidated joint ventures, as defined above, also does not include its share of unrealized gain (loss) on derivative instruments and gain on sale / consolidation, all of which are included within Income (Loss) from Unconsolidated Joint Ventures in the Company’s Consolidated Statements of Operations. Management utilizes its share of NOI in assessing its performance as the Company has several significant joint ventures and, in some cases, the Company exercises significant influence over, but does not control, the joint venture, in which case GAAP requires that the Company account for the joint venture entity using the equity method of accounting and the Company does not consolidate it for financial reporting purposes. In other cases, GAAP requires that the Company consolidate the venture even though the Company’s partner(s) owns a significant percentage interest. As a result, the presentations of the Company’s share of NOI should not be considered a substitute for, and should only be considered together with and as a supplement to, the Company’s financial information presented in accordance with GAAP. Asset information by segment is not reported because the Company does not use this measure to assess performance. Therefore, depreciation and amortization expense is not allocated among segments. Interest expense, impairment loss, depreciation and amortization expense, transaction costs, payroll and related costs from management services contracts, corporate general and administrative expense, unrealized gain on non-real estate investment, gains from investments in securities, interest and other income (loss), income (loss) from unconsolidated joint ventures, direct reimbursements of payroll and related costs from management services contracts and development and management services revenue are not included in NOI and are provided as reconciling items to the Company’s reconciliations of its share of NOI to net income. The Company’s segments are based on the Company’s method of internal reporting which classifies its operations by geographic area. The Company’s segments by geographic area are Boston, Los Angeles, New York, San Francisco, Seattle and Washington, DC. The Company also presents information for each segment by property type, including Premier Workplace (which includes office, life sciences and retail), Residential and Hotel. Information by geographic area and property type (dollars in thousands): For the three months ended March 31, 2024: Boston Los Angeles New York San Francisco Seattle Washington, DC Total Rental Revenue: (1) Premier Workplace $ 280,466 $ 20,401 $ 260,809 $ 132,614 $ 10,910 $ 102,922 $ 808,122 Residential 4,196 — — 3,958 — 4,530 12,684 Hotel 8,186 — — — — — 8,186 Total 292,848 20,401 260,809 136,572 10,910 107,452 828,992 % of Grand Totals 35.33 % 2.46 % 31.46 % 16.47 % 1.32 % 12.96 % 100.00 % Rental Expenses: Premier Workplace 105,171 6,567 107,481 46,942 3,081 39,229 308,471 Residential 1,593 — — 2,218 — 1,875 5,686 Hotel 6,015 — — — — — 6,015 Total 112,779 6,567 107,481 49,160 3,081 41,104 320,172 % of Grand Totals 35.23 % 2.05 % 33.57 % 15.35 % 0.96 % 12.84 % 100.00 % Net operating income $ 180,069 $ 13,834 $ 153,328 $ 87,412 $ 7,829 $ 66,348 $ 508,820 % of Grand Totals 35.39 % 2.72 % 30.13 % 17.18 % 1.54 % 13.04 % 100.00 % Less: Net operating income attributable to noncontrolling interests in property partnerships (11,056) — (35,514) — — — (46,570) Add: Company’s share of net operating income from unconsolidated joint ventures 8,757 7,248 5,984 5,154 1,876 6,411 35,430 Company’s share of net operating income $ 177,770 $ 21,082 $ 123,798 $ 92,566 $ 9,705 $ 72,759 $ 497,680 % of Grand Totals 35.71 % 4.24 % 24.88 % 18.60 % 1.95 % 14.62 % 100.00 % _______________ (1) Rental Revenue is equal to Total Revenue per the Company’s Consolidated Statements of Operations, less Development and Management Services Revenue and Direct Reimbursements of Payroll and Related Costs from Management Services Contracts Revenue per the Consolidated Statements of Operations. For the three months ended March 31, 2023: Boston Los Angeles New York San Francisco Seattle Washington, DC Total Rental Revenue: (1) Premier Workplace $ 269,951 $ — $ 258,192 $ 136,093 $ 14,258 $ 90,664 $ 769,158 Residential 4,049 — — 3,642 — 4,035 11,726 Hotel 8,101 — — — — — 8,101 Total 282,101 — 258,192 139,735 14,258 94,699 788,985 % of Grand Totals 35.76 % — % 32.72 % 17.71 % 1.81 % 12.00 % 100.00 % Rental Expenses: Premier Workplace 100,049 — 102,485 46,085 2,960 34,266 285,845 Residential 1,552 — — 2,173 — 1,738 5,463 Hotel 6,671 — — — — — 6,671 Total 108,272 — 102,485 48,258 2,960 36,004 297,979 % of Grand Totals 36.34 % — % 34.39 % 16.20 % 0.99 % 12.08 % 100.00 % Net operating income $ 173,829 $ — $ 155,707 $ 91,477 $ 11,298 $ 58,695 $ 491,006 % of Grand Totals 35.41 % — % 31.71 % 18.63 % 2.30 % 11.95 % 100.00 % Less: Net operating income attributable to noncontrolling interests in property partnerships (10,817) — (36,280) — — — (47,097) Add: Company’s share of net operating income from unconsolidated joint ventures 8,577 13,225 3,650 3,464 1,846 9,994 40,756 Company’s share of net operating income $ 171,589 $ 13,225 $ 123,077 $ 94,941 $ 13,144 $ 68,689 $ 484,665 % of Grand Totals 35.41 % 2.73 % 25.39 % 19.59 % 2.71 % 14.17 % 100.00 % _______________ (1) Rental Revenue is equal to Total Revenue per the Company’s Consolidated Statements of Operations, less Development and Management Services Revenue and Direct Reimbursements of Payroll and Related Costs from Management Services Contracts Revenue per the Consolidated Statements of Operations.

Earnings Per Share _ Common Uni

Earnings Per Share / Common Unit	3 Months Ended
Earnings Per Share / Common Unit	Mar. 31, 2024
Earnings Per Share [Abstract]
Earnings Per Share / Common Unit	12. Earnings Per Share / Common Unit BXP The following table provides a reconciliation of both the net income attributable to Boston Properties, Inc. and the number of common shares used in the computation of basic earnings per share (“EPS”), which is calculated by dividing net income attributable to Boston Properties, Inc. by the weighted-average number of common shares outstanding during the period. Unvested share-based payment awards that contain non-forfeitable rights to dividends or dividend equivalents (whether paid or unpaid) are also participating securities. As such, unvested restricted common stock of BXP and BPLP’s LTIP Units, 2012 OPP Units and MYLTIP Units are considered participating securities. Participating securities are included in the computation of basic EPS of BXP using the two-class method. Participating securities are included in the computation of diluted EPS of BXP using the if-converted method if the impact is dilutive. Because the 2012 OPP Units and 2013 - 2021 MYLTIP Units required, and the 2022 - 2024 MYLTIP Units require, BXP to outperform certain performance thresholds, unless such thresholds have been met by the end of the applicable reporting period, BXP excludes such units from the diluted EPS calculation. Other potentially dilutive common shares, including stock options, restricted stock and other securities of BPLP that are exchangeable for BXP’s Common Stock, and the related impact on earnings, are considered when calculating diluted EPS. Three months ended March 31, 2024 Income Shares Per Share (in thousands, except for per share amounts) Basic Earnings: Net income attributable to Boston Properties, Inc. $ 79,883 156,983 $ 0.51 Effect of Dilutive Securities: Stock Based Compensation — 149 — Diluted Earnings: Net income attributable to Boston Properties, Inc. $ 79,883 157,132 $ 0.51 Three months ended March 31, 2023 Income Shares Per Share (in thousands, except for per share amounts) Basic Earnings: Net income attributable to Boston Properties, Inc. $ 77,890 156,803 $ 0.50 Effect of Dilutive Securities: Stock Based Compensation — 240 — Diluted Earnings: Net income attributable to Boston Properties, Inc. $ 77,890 157,043 $ 0.50 BPLP The following table provides a reconciliation of both the net income attributable to Boston Properties Limited Partnership and the number of common units used in the computation of basic earnings per common unit, which is calculated by dividing net income attributable to Boston Properties Limited Partnership by the weighted-average number of common units outstanding during the period. Unvested share-based payment awards that contain non-forfeitable rights to dividends or dividend equivalents (whether paid or unpaid) are also participating securities. As such, unvested restricted common stock of BXP and BPLP’s LTIP Units, 2012 OPP Units and MYLTIP Units are considered participating securities. Participating securities are included in the computation of basic earnings per common unit using the two-class method. Participating securities are included in the computation of diluted earnings per common unit using the if-converted method if the impact is dilutive. Because the 2012 OPP Units and 2013 - 2021 MYLTIP Units required, and the 2022 - 2024 MYLTIP Units require, BXP to outperform certain performance thresholds, unless such thresholds have been met by the end of the applicable reporting period, BPLP excludes such units from the diluted earnings per common unit calculation. Other potentially dilutive common units and the related impact on earnings are considered when calculating diluted earnings per common unit. Included in the number of units (the denominator) below are approximately 18,272,000 and 17,849,000 redeemable common units for the three months ended March 31, 2024 and 2023, respectively. Three months ended March 31, 2024 Income Units Per Unit (in thousands, except for per unit amounts) Basic Earnings: Net income attributable to Boston Properties Limited Partnership $ 91,080 175,255 $ 0.52 Effect of Dilutive Securities: Stock Based Compensation — 149 — Diluted Earnings: Net income attributable to Boston Properties Limited Partnership $ 91,080 175,404 $ 0.52 Three months ended March 31, 2023 Income Units Per Unit (in thousands, except for per unit amounts) Basic Earnings: Net income attributable to Boston Properties Limited Partnership $ 88,830 174,652 $ 0.51 Effect of Dilutive Securities: Stock Based Compensation — 240 — Diluted Earnings: Net income attributable to Boston Properties Limited Partnership $ 88,830 174,892 $ 0.51

Stock Option and Incentive Plan

Stock Option and Incentive Plan	3 Months Ended
Stock Option and Incentive Plan	Mar. 31, 2024
Share-Based Payment Arrangement [Abstract]
Stock Option and Incentive Plan	13. Stock Option and Incentive Plan On January 25, 2024, the Compensation Committee of BXP’s Board of Directors approved the grant of 2024 Multi-Year Long-Term Incentive Program (the “2024 MYLTIP”) awards under the Boston Properties, Inc. 2021 Stock Incentive Plan (the “2021 Plan”) to certain executive officers of BXP. The 2024 MYLTIP awards consists of three components. Two of the components, each weighted 40%, utilize BXP’s TSR over a three year measurement period as the performance metrics and the third component utilizes a leverage ratio as the performance metric. Earned awards will range from zero to a maximum of 330,479 LTIP Units depending on BXP’s performance under the three components, with a target of approximately 165,240 LTIP Units. Under ASC 718 “Compensation - Stock Compensation,” the 2024 MYLTIP awards have an aggregate value of approximately $11.1 million. On February 1, 2024, the measurement period for the Company’s 2021 MYLTIP awards ended and, based on BXP’s absolute and relative TSR performance, the final payout was determined to be 112% of target, or an aggregate of approximately $12.6 million (after giving effect to employee separations). As a result, an aggregate of 155,625 2021 MYLTIP Units that had been previously granted were automatically forfeited. During the three months ended March 31, 2024, BXP issued 76,228 shares of restricted common stock and BPLP issued 431,123 LTIP Units and 330,479 2024 MYLTIP Units to employees and non-employee directors under the 2021 Plan. Employees and non-employee directors paid $0.01 per share of restricted common stock and $0.25 per LTIP Unit and 2024 MYLTIP Unit. When issued, LTIP Units are not economically equivalent in value to a share of Common Stock, but over time can increase in value to one-for-one parity with Common Stock if there is sufficient appreciation in the value of the Company’s assets. The aggregate value of the LTIP Units is included in noncontrolling interests in the Consolidated Balance Sheets of BXP and BPLP. A substantial majority of the grants of restricted common stock and LTIP Units to employees vest in four equal annual installments. Restricted common stock is measured at fair value on the date of grant based on the number of shares granted and the closing price of BXP’s Common Stock on the date of grant as quoted on the New York Stock Exchange. Such value is recognized as an expense ratably over the corresponding employee service period. The shares of restricted common stock granted during the three months ended March 31, 2024 were valued at approximately $4.9 million. The LTIP Units granted were valued at approximately $25.6 million using a Monte Carlo simulation method model. Because the 2012 OPP Units and 2013 - 2024 MYLTIP Units are subject to both a service condition and a market condition, the Company recognizes the related compensation expense under the graded vesting attribution method. Under the graded vesting attribution method, each portion of the award that vests at a different date is accounted for as a separate award and recognized over the period appropriate to that portion so that the compensation cost for each portion should be recognized in full by the time that portion vests. The Company recognizes forfeitures as they occur on its awards of stock-based compensation. Dividends paid on both vested and unvested shares of restricted stock are charged directly to Dividends in Excess of Earnings in Boston Properties, Inc.’s Consolidated Balance Sheets and Partners’ Capital in Boston Properties Limited Partnership’s Consolidated Balance Sheets. Aggregate stock-based compensation expense associated with restricted stock, LTIP Units and MYLTIP Units was approximately $18.5 million and $25.9 million for the three months ended March 31, 2024 and 2023, respectively. At March 31, 2024, there was (1) an aggregate of approximately $38.9 million of unrecognized compensation expense related to unvested restricted stock and LTIP Units and (2) an aggregate of approximately $5.8 million of unrecognized compensation expense related to unvested 2022 - 2024 MYLTIP Units that is expected to be recognized over a weighted-average period of approximately 2.7 years.

Subsequent Events

Subsequent Events	3 Months Ended
Subsequent Events	Mar. 31, 2024
Subsequent Events [Abstract]
Subsequent Events	14. Subsequent Events On April 5, 2024, the Company completed and fully placed in-service 760 Boylston Street, an approximately 118,000 net rentable square feet retail redevelopment located in Boston, Massachusetts. On April 16, 2024, BPLP provided notice to exercise its one On April 17, 2024, BPLP established an unsecured commercial paper program. Under the terms of the program, BPLP may issue, from time to time, unsecured commercial paper notes up to a maximum aggregate amount outstanding at any one time of $500 million with varying maturities of up to one year. The notes will be sold in private placements and will rank pari passu with all of BPLP’s other unsecured senior indebtedness, including its outstanding senior notes. The commercial paper program is backstopped by available capacity under BPLP's unsecured revolving credit facility (the “2021 Credit Facility”). As of May 2, 2024, BPLP had $500.0 million outstanding under its commercial paper program that bears interest at a weighted-average rate of 5.58% per annum. Proceeds from the commercial paper program were used to reduce BPLP’s 2023 Unsecured Term Loan to $700.0 million. On April 29, 2024, BPLP increased the current maximum borrowing amount under the 2021 Credit Facility from $1.815 billion to $2.0 billion. All other terms of the 2021 Credit Facility, including its maturity date of June 15, 2026, remain unchanged. BPLP had no borrowings under the 2021 Credit Facility as of May 2, 2024.

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended
Pay vs Performance Disclosure - USD ($) $ in Thousands	Mar. 31, 2024	Mar. 31, 2023
Pay vs Performance Disclosure
Net Income (Loss) Attributable to Parent	$ 79,883	$ 77,890

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
Insider Trading Arrangements	Mar. 31, 2024
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Summary Of Significant Accoun_2

Summary Of Significant Accounting Policies (Policies)	3 Months Ended
Summary Of Significant Accounting Policies (Policies)	Mar. 31, 2024
Accounting Policies [Abstract]
Basis of Presentation	BXP does not have any other significant assets, liabilities or operations, other than its investment in BPLP, nor does it have employees of its own. BPLP, not BXP, generally executes all significant business relationships other than transactions involving securities of BXP. All majority-owned subsidiaries and joint ventures over which the Company has financial and operating control and variable interest entities (“VIEs”) in which the Company has determined it is the primary beneficiary are included in the consolidated financial statements. All significant intercompany balances and transactions have been eliminated in consolidation. The Company accounts for all other unconsolidated joint ventures using the equity method of accounting. Accordingly, the Company’s share of the earnings of these joint ventures and companies is included in consolidated net income.
Use of Estimates in the Preparation of Financial Statements	The Company bases its estimates on historical experience and on various other assumptions that it considers to be reasonable under the circumstances, including the impact of extraordinary events such as a pandemic, the results of which form the basis for making significant judgments about the carrying values of assets and liabilities, assessments of future collectability, and other areas of the financial statements that are impacted by the use of estimates. Actual results may differ from these estimates under different assumptions or conditions.
Consolidation, Variable Interest Entity, Policy	Consolidated VIEs are those for which the Company is considered to be the primary beneficiary of a VIE. The primary beneficiary is the entity that has a controlling financial interest in the VIE, which is defined by the entity having both of the following characteristics: (1) the power to direct the activities that, when taken together, most significantly impact the VIE’s performance and (2) the obligation to absorb losses or the right to receive the returns from the VIE that could potentially be significant to the VIE. The assets of each VIE are only available to satisfy such VIE's respective liabilities.
Derivative Instruments and Hedging Activities	In addition to the financial instruments noted above, the Company uses interest rate swap agreements to manage its interest rate risk (See Note 7). The valuation of these instruments is determined using widely accepted valuation techniques, including discounted cash flow analysis on the expected cash flows of each derivative. This analysis reflects the contractual terms of the derivatives, including the period to maturity, and uses observable market-based inputs, including interest rate curves. To comply with the provisions of ASC 820, the Company incorporates credit valuation adjustments to appropriately reflect both its own nonperformance risk and the respective counterparty’s nonperformance risk in the fair value measurements. Although the Company has determined that the majority of the inputs used to value its derivatives fall within Level 2 of the fair value hierarchy, the credit valuation adjustments associated with its derivatives utilize Level 3 inputs, such as estimates of current credit spreads to evaluate the likelihood of default by the Company and its counterparties. The Company assessed the significance of the impact of the credit valuation adjustments on the overall valuation of its derivative positions and determined that the credit valuation adjustments were not significant to the overall valuation of its derivatives. As a result, the Company has determined that its derivative valuations in their entirety are classified in Level 2 of the fair value hierarchy.

Summary Of Significant Accoun_3

Summary Of Significant Accounting Policies (Tables)	3 Months Ended
Summary Of Significant Accounting Policies (Tables)	Mar. 31, 2024
Summary Of Significant Accounting Policies [Line Items]
Fair Value Measurement Inputs and Valuation Techniques [Table Text Block]	The Company follows the authoritative guidance for fair value measurements when valuing its financial instruments for disclosure purposes. The table below presents for March 31, 2024 and December 31, 2023, the financial instruments that are being valued for disclosure purposes as well as the Level at which they are categorized as defined in Accounting Standards Codification (“ASC”) 820 “Fair Value Measurements and Disclosures” (“ASC 820”). Financial Instrument Level 3-Month United States Treasury Bills Level 1 Investment in securities Level 1 Unsecured senior notes (1) Level 1 Related party note receivable Level 3 Notes receivable Level 3 Sales-type lease receivable Level 3 Mortgage notes payable Level 3 Unsecured line of credit Level 3 Unsecured term loan Level 3 _______________ (1)
Fair Value, by Balance Sheet Grouping [Table Text Block]	The following table presents the aggregate carrying value of the Company’s non-recurring fair value financial instruments and the Company’s corresponding estimate of fair value as of March 31, 2024 and December 31, 2023 (in thousands): March 31, 2024 December 31, 2023 Carrying Estimated Carrying Estimated 3-Month United States Treasury Bills (1) $ — $ — $ 302,746 $ 302,746 Related party note receivable, net $ 88,789 $ 90,582 $ 88,779 $ 90,593 Note receivable, net 2,274 2,249 1,714 1,677 Sales-type lease receivable, net 13,943 13,416 13,704 13,338 Total $ 105,006 $ 106,247 $ 104,197 $ 105,608 Mortgage notes payable, net $ 4,368,367 $ 3,935,382 $ 4,166,379 $ 3,705,513 Unsecured senior notes, net 9,794,527 8,979,934 10,491,617 9,697,393 Unsecured line of credit — — — — Unsecured term loan, net 1,199,430 1,198,951 1,198,301 1,196,945 Total $ 15,362,324 $ 14,114,267 $ 15,856,297 $ 14,599,851 _______________
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 March 31, 2024 and December 31, 2023 (in thousands): Fair value March 31, 2024 December 31, 2023 Interest rate swaps $ 12,298 $ 1,976

Real Estate (Tables)

Real Estate (Tables)	3 Months Ended
Real Estate (Tables)	Mar. 31, 2024
Real Estate Properties [Line Items]
Schedule of Real Estate Properties	BXP Real estate consisted of the following at March 31, 2024 and December 31, 2023 (in thousands): March 31, 2024 December 31, 2023 Land $ 5,317,032 $ 5,251,224 Right of use assets - finance leases 401,486 401,680 Right of use assets - operating leases (1) 344,255 324,298 Land held for future development (2) 661,713 697,061 Buildings and improvements 16,689,571 16,607,756 Tenant improvements 3,654,576 3,592,172 Furniture, fixtures and equipment 54,691 53,716 Construction in progress 685,465 547,280 Total 27,808,789 27,475,187 Less: Accumulated depreciation (7,040,501) (6,881,728) $ 20,768,288 $ 20,593,459 _______________ (1) See Note 4. (2) Includes pre-development costs.
901 New York Avenue
Real Estate Properties [Line Items]
Asset Acquisition	The following table summarizes the allocation of the fair value of the net assets the Company received at the date of acquisition for 901 New York Avenue (in thousands): Land and site improvements $ 65,808 Building and improvements 56,882 Tenant improvements 16,088 In-place lease intangibles 72,621 Above-market lease intangibles 2,757 Below-market lease intangibles (2,515) Mortgage note payable adjustment 8,374 Net assets acquired $ 220,015
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense	The following table summarizes the estimated annual amortization of the acquired in-place lease intangibles, and the acquired above- and below-market lease intangibles for 901 New York Avenue for the remainder of 2024 and each of the next five succeeding fiscal years (in thousands): Acquired In-Place Lease Intangibles Acquired Above-Market Lease Intangibles Acquired Below-Market Lease Intangibles Period from January 8, 2024 through December 31, 2024 $ 10,364 $ 607 $ 252 2025 9,030 454 257 2026 6,494 238 257 2027 6,265 201 257 2028 6,069 186 257 2029 6,076 186 251
Schedule of Acquired Finite-Lived Intangible Assets by Major Class	The following table summarizes the weighted-average useful life of the acquired in-place lease intangibles and the acquired above- and below-market lease intangibles for 901 New York Avenue as of the acquisition date (in years): Acquired In-Place Lease Intangibles Acquired Above-Market Lease Intangibles Acquired Below-Market Lease Intangibles Weighted-average useful life 6.7 4.0 9.8
Boston Properties Limited Partnership
Real Estate Properties [Line Items]
Schedule of Real Estate Properties	BPLP Real estate consisted of the following at March 31, 2024 and December 31, 2023 (in thousands): March 31, 2024 December 31, 2023 Land $ 5,222,323 $ 5,156,515 Right of use assets - finance leases 401,486 401,680 Right of use assets - operating leases (1) 344,255 324,298 Land held for future development (2) 661,713 697,061 Buildings and improvements 16,418,015 16,336,200 Tenant improvements 3,654,576 3,592,172 Furniture, fixtures and equipment 54,691 53,716 Construction in progress 685,465 547,280 Total 27,442,524 27,108,922 Less: Accumulated depreciation (6,915,437) (6,758,361) $ 20,527,087 $ 20,350,561 _______________ (1) See Note 4. (2) Includes pre-development costs.

Leases (Tables)

Leases (Tables)	3 Months Ended
Leases (Tables)	Mar. 31, 2024
Lessor, Lease, Description [Line Items]
Operating Lease, Lease Income [Table Text Block]	The following table summarizes the components of lease revenue recognized under the Company’s operating and sales-type leases for the three months ended March 31, 2024 and 2023 and included within the Company's Consolidated Statements of Operations (in thousands): Three months ended March 31, Lease Revenue 2024 2023 Fixed contractual payments $ 648,890 $ 621,646 Variable lease payments 139,458 135,003 Sales-type lease revenue 242 226 $ 788,590 $ 756,875
Sales-type Lease, Lease Income	The following table summarizes the components of lease revenue recognized under the Company’s operating and sales-type leases for the three months ended March 31, 2024 and 2023 and included within the Company's Consolidated Statements of Operations (in thousands): Three months ended March 31, Lease Revenue 2024 2023 Fixed contractual payments $ 648,890 $ 621,646 Variable lease payments 139,458 135,003 Sales-type lease revenue 242 226 $ 788,590 $ 756,875
171 Dartmouth Street air rights [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Liability, Maturity	The following table provides a maturity analysis for the air rights operating lease as of March 28, 2024 (in thousands): Operating Period from March 28, 2024 through December 31, 2024 $ — 2025 750 2026 750 2027 750 2028 25,826 2029 500 Thereafter 2,000 Total lease payments 30,576 Less: Interest portion 7,391 Present value of lease payments $ 23,185

Investments in Unconsolidated_2

Investments in Unconsolidated Joint Ventures (Tables)	3 Months Ended
Investments in Unconsolidated Joint Ventures (Tables)	Mar. 31, 2024
Schedule of Equity Method Investments [Line Items]
Investments In Unconsolidated Joint Ventures	The investments in unconsolidated joint ventures consist of the following at March 31, 2024 and December 31, 2023: Carrying Value of Investment (1) Entity Properties Nominal % Ownership March 31, 2024 December 31, 2023 (in thousands) Square 407 Limited Partnership Market Square North 50.00 % $ (6,103) $ (5,996) 901 New York, LLC 901 New York Avenue 25.00 % (2) — (11,764) WP Project Developer LLC Wisconsin Place Land and Infrastructure 33.33 % (3) 30,221 30,375 500 North Capitol Venture LLC 500 North Capitol Street, NW 30.00 % (10,773) (10,253) 501 K Street LLC 1001 6th Street 50.00 % 45,013 44,774 Podium Developer LLC The Hub on Causeway - Podium 50.00 % 45,068 45,201 Residential Tower Developer LLC Hub50House 50.00 % 42,250 40,235 Hotel Tower Developer LLC The Hub on Causeway - Hotel Air Rights 50.00 % 13,680 13,494 Office Tower Developer LLC 100 Causeway Street 50.00 % 57,079 57,660 1265 Main Office JV LLC 1265 Main Street 50.00 % 3,583 3,585 BNY Tower Holdings LLC Dock 72 50.00 % (4) (12,501) (11,890) CA-Colorado Center, LLC Colorado Center 50.00 % 235,143 237,815 7750 Wisconsin Avenue LLC 7750 Wisconsin Avenue 50.00 % 49,756 50,064 BP-M 3HB Venture LLC 3 Hudson Boulevard 25.00 % 114,331 115,103 Platform 16 Holdings LP Platform 16 55.00 % 51,349 45,564 Gateway Portfolio Holdings LLC Gateway Commons 50.00 % 385,568 376,834 Rosecrans-Sepulveda Partners 4, LLC Beach Cities Media Campus 50.00 % 27,042 27,034 Safeco Plaza REIT LLC Safeco Plaza 33.67 % (5) 43,860 44,734 360 PAS Holdco LLC 360 Park Avenue South 71.11 % (6) 49,888 42,988 PR II/BXP Reston Gateway LLC Skymark - Reston Next Residential 20.00 % 15,323 15,184 751 Gateway Holdings LLC 751 Gateway 49.00 % 95,863 93,411 200 Fifth Avenue JV LLC 200 Fifth Avenue 26.69 % 76,728 75,718 ABXP Worldgate Investments LLC 13100 and 13150 Worldgate Drive 50.00 % 18,079 17,546 $ 1,370,447 $ 1,337,416 _______________ (1) Investments with deficit balances aggregating approximately $29.4 million and $39.9 million at March 31, 2024 and December 31, 2023, respectively, are included within Other Liabilities in the Company’s Consolidated Balance Sheets. (2) At December 31, 2023, the Company’s economic ownership was approximately 50%. On January 8, 2024, the Company completed the acquisition of its joint venture partner’s 50% economic ownership interest for a gross purchase price of $10.0 million, as described in Note 3 and this Note 5. (3) The Company’s wholly-owned subsidiary that owns Wisconsin Place Office also owns a 33.33% interest in the joint venture entity that owns the land, parking garage and infrastructure of the project. (4) This property includes net equity balances from the amenity joint venture. (5) The Company’s ownership includes (1) a 33.0% direct interest in the joint venture, and (2) an additional 1% interest in each of the two entities through which each partner owns its interest in the joint venture. (6)
Schedule Of Balance Sheets Of The Unconsolidated Joint Ventures [Text Block]	The combined summarized balance sheets of the Company’s unconsolidated joint ventures are as follows: March 31, 2024 December 31, 2023 (in thousands) ASSETS Real estate and development in process, net (1) $ 5,740,545 $ 5,811,763 Other assets (2) 619,559 682,291 Total assets $ 6,360,104 $ 6,494,054 LIABILITIES AND MEMBERS’/PARTNERS’ EQUITY Mortgage and notes payable, net $ 3,162,545 $ 3,351,873 Other liabilities (3) 318,708 361,357 Members’/Partners’ equity 2,878,851 2,780,824 Total liabilities and members’/partners’ equity $ 6,360,104 $ 6,494,054 Company’s share of equity $ 1,313,484 $ 1,278,483 Basis differentials (4) 56,963 58,933 Carrying value of the Company’s investments in unconsolidated joint ventures (5) $ 1,370,447 $ 1,337,416 _______________ (1) At March 31, 2024 and December 31, 2023, this amount included right of use assets - operating leases totaling approximately $19.8 million and $20.1 million, respectively. (2) At March 31, 2024 and December 31, 2023, this amount included sales-type lease receivable, net totaling approximately $14.0 million and $13.9 million, respectively. (3) At March 31, 2024 and December 31, 2023, this amount included lease liabilities - operating leases totaling approximately $30.5 million. (4) This amount represents the aggregate difference between the Company’s historical cost basis and the basis reflected at the joint venture level, which is typically amortized over the life of the related assets and liabilities. Basis differentials result from impairments of investments, acquisitions through joint ventures with no change in control and upon the transfer of assets that were previously owned by the Company into a joint venture. In addition, certain acquisition, transaction and other costs may not be reflected in the net assets at the joint venture level. The majority of the Company’s basis differences are as follows: March 31, 2024 December 31, 2023 Property (in thousands) Colorado Center $ 298,190 $ 298,906 200 Fifth Avenue 56,193 58,308 Gateway Commons 49,593 48,971 Safeco Plaza (29,432) (29,678) 360 Park Avenue South (116,188) (116,534) Dock 72 (94,586) (95,521) Platform 16 (142,671) (143,052) These basis differentials (excluding land) will be amortized over the remaining lives of the related assets and liabilities. (5) Investments with deficit balances aggregating approximately $29.4 million and $39.9 million at March 31, 2024 and December 31, 2023, respectively, are reflected within Other Liabilities in the Company’s Consolidated Balance Sheets.
Statements Of Operations Of The Joint Ventures	The combined summarized statements of operations of the Company’s unconsolidated joint ventures are as follows: Three months ended March 31, 2024 2023 (in thousands) Total revenue (1) $ 130,392 $ 151,423 Expenses Operating 49,194 57,206 Transaction costs 2 74 Depreciation and amortization 39,424 49,978 Total expenses 88,620 107,258 Other income (expense) Interest expense (43,563) (57,250) Unrealized gain (loss) on derivative instruments 10,112 (10,610) Net income (loss) $ 8,321 $ (23,695) Company’s share of net income (loss) $ 2,960 $ (6,902) Gain on sale / consolidation 21,696 — Basis differential (2) (5,470) (667) Income (loss) from unconsolidated joint ventures $ 19,186 $ (7,569) _______________ (1) Includes straight-line rent adjustments of approximately $7.7 million and $6.3 million for the three months ended March 31, 2024 and 2023, respectively. (2) Includes depreciation and amortization of approximately $2.9 million and $3.7 million for the three months ended March 31, 2024 and 2023, respectively. Includes unrealized gain (loss) on derivative instruments of approximately $2.7 million and $(2.8) million for the three months ended March 31, 2024 and 2023, respectively. Includes straight-line rent adjustments of approximately $0.3 million for the three months ended March 31, 2024 and 2023. Also includes net above-/below-market rent adjustments of approximately $0.2 million for the three months ended March 31, 2024 and 2023.

Debt (Tables)

Debt (Tables)	3 Months Ended
Debt (Tables)	Mar. 31, 2024
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments	The following summarizes the unsecured senior notes outstanding as of March 31, 2024 (dollars in thousands): Coupon/Stated Rate Effective Rate(1) Principal Amount Maturity Date(2) 7 Year Unsecured Senior Notes 3.200 % 3.350 % $ 850,000 January 15, 2025 10 Year Unsecured Senior Notes 3.650 % 3.766 % 1,000,000 February 1, 2026 10 Year Unsecured Senior Notes 2.750 % 3.495 % 1,000,000 October 1, 2026 5 Year Unsecured Senior Notes 6.750 % 6.924 % 750,000 December 1, 2027 10 Year Unsecured Senior Notes 4.500 % 4.628 % 1,000,000 December 1, 2028 10 Year Unsecured Senior Notes 3.400 % 3.505 % 850,000 June 21, 2029 10.5 Year Unsecured Senior Notes 2.900 % 2.984 % 700,000 March 15, 2030 10.75 Year Unsecured Senior Notes 3.250 % 3.343 % 1,250,000 January 30, 2031 11 Year Unsecured Senior Notes 2.550 % 2.671 % 850,000 April 1, 2032 12 Year Unsecured Senior Notes 2.450 % 2.524 % 850,000 October 1, 2033 10.7 Year Unsecured Senior Notes 6.500 % 6.619 % 750,000 January 15, 2034 Total principal 9,850,000 Less: Net unamortized discount 12,611 Deferred financing costs, net 42,862 Total $ 9,794,527 _______________ (1) Yield on issuance date including the effects of discounts on the notes, settlements of interest rate contracts and the amortization of financing costs. (2) No principal amounts are due prior to maturity.

Derivative Instruments and He_2

Derivative Instruments and Hedging Activities (Tables)	3 Months Ended
Derivative Instruments and Hedging Activities (Tables)	Mar. 31, 2024
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Interest Rate Derivatives	BPLP’s and SMBP LLC’s interest rate swap contracts consisted of the following at March 31, 2024 (dollars in thousands): Derivative Instrument Aggregate Notional Amount Strike Rate Range Balance Sheet Location Effective Date Maturity Date Low High Fair Value BPLP: Interest Rate Swaps $ 1,200,000 May 4, 2023 May 16, 2024 4.638 % — 4.646 % Prepaid expenses and other assets $ 1,006 Interest Rate Swaps 600,000 December 15, 2023 October 26, 2028 3.790 % — 3.798 % Prepaid expenses and other assets 4,646 1,800,000 5,652 SMBP LLC (1) Interest Rate Swaps 300,000 December 14, 2023 April 1, 2025 2.661 % — 2.688 % Prepaid expenses and other assets 6,646 $ 2,100,000 $ 12,298 _______________ (1) A subsidiary of the Company that is the borrower under the mortgage loan collateralized by its Santa Monica Business Park property.
Derivative Instruments, Gain (Loss)	The following table presents the location in the financial statements of the gains or losses recognized related to the Company’s cash flow hedges for the three months ended March 31, 2024 and 2023 (in thousands): Three months ended March 31, 2024 2023 Amount of gain (loss) related to the effective portion recognized in other comprehensive income (1) $ 16,351 $ (6,538) Amount of gain (loss) related to the effective portion subsequently reclassified to earnings (2) $ 3,360 $ 1,675 Amount of gain (loss) relate do the ineffective portion and amount excluded from effectiveness testing $ — $ — _______________ (1) Includes the Company’s share of gain (loss) related to the effective portion of derivatives outstanding at its unconsolidated joint venture properties. (2) Includes amounts from previous interest rate programs.

Noncontrolling Interests (Table

Noncontrolling Interests (Tables)	3 Months Ended
Noncontrolling Interests (Tables)	Mar. 31, 2024
Noncontrolling Interest [Line Items]
Distribution Declared to OP, LTIP, OPP and MYLTIP Units [Table Text Block]	The following table presents BXP’s dividends per share and BPLP’s distributions per OP Unit and LTIP Unit paid or declared in 2024 and during the three months ended March 31, 2023: Record Date Payment Date Dividend (Per Share) Distribution (Per Unit) March 28, 2024 April 30, 2024 $0.98 $0.98 December 29, 2023 January 30, 2024 $0.98 $0.98 March 31, 2023 April 28, 2023 $0.98 $0.98 December 30, 2022 January 30, 2023 $0.98 $0.98
Schedule of Noncontrolling Interest [Table Text Block]	Noncontrolling interests relate to the interests in BPLP not owned by BXP and interests in consolidated property partnerships not wholly-owned by the Company. As of March 31, 2024, the noncontrolling interests in BPLP consisted of the following: OP Units LTIP Units (1) 2022 MYLTIP Units 2023 MYLTIP Units 2024 MYLTIP Units 16,492,171 2,666,636 252,151 322,053 330,479 __________ (1) Includes 666,405 LTIP Units earned by employees under the Company’s multi-year long-term incentive awards granted between 2012 and 2021 (i.e., 2012 OPP and 2013 - 2021 MYLTIP awards).
Noncontrolling Interests [Member]
Noncontrolling Interest [Line Items]
Distribution Declared to OP, LTIP, OPP and MYLTIP Units [Table Text Block]	The following table presents BPLP’s distributions on the OP Units and LTIP Units and MYLTIP Units paid or declared in 2024 and during the three months ended March 31, 2023: Record Date Payment Date Distributions per OP Unit and LTIP Unit Distributions per MYLTIP Unit March 28, 2024 April 30, 2024 $0.98 $0.098 December 29, 2023 January 30, 2024 $0.98 $0.098 March 31, 2023 April 28, 2023 $0.98 $0.098 December 30, 2022 January 30, 2023 $0.98 $0.098

Stockholders' Equity _ Partne_2

Stockholders' Equity / Partners' Capital (Tables)	3 Months Ended
Stockholders' Equity / Partners' Capital (Tables)	Mar. 31, 2024
Class of Stock [Line Items]
Dividends Declared [Table Text Block]	The following table presents BXP’s dividends per share and BPLP’s distributions per OP Unit and LTIP Unit paid or declared in 2024 and during the three months ended March 31, 2023: Record Date Payment Date Dividend (Per Share) Distribution (Per Unit) March 28, 2024 April 30, 2024 $0.98 $0.98 December 29, 2023 January 30, 2024 $0.98 $0.98 March 31, 2023 April 28, 2023 $0.98 $0.98 December 30, 2022 January 30, 2023 $0.98 $0.98

Segment Information (Tables)

Segment Information (Tables)	3 Months Ended
Segment Information (Tables)	Mar. 31, 2024
Segment Reporting [Abstract]
Schedule Of Reconciliation Of Net Operating Income To Net Income	BXP Three months ended March 31, 2024 2023 (in thousands) Net income attributable to Boston Properties, Inc. $ 79,883 $ 77,890 Add: Noncontrolling interest—common units of the Operating Partnership 9,500 9,078 Noncontrolling interests in property partnerships 17,221 18,660 Interest expense 161,891 134,207 Impairment loss 13,615 — Net operating income from unconsolidated joint ventures 35,430 40,756 Depreciation and amortization expense 218,716 208,734 Transaction costs 513 911 Payroll and related costs from management services contracts 4,293 5,235 General and administrative expense 50,018 55,802 Less: Net operating income attributable to noncontrolling interests in property partnerships 46,570 47,097 Unrealized gain on non-real estate investment 396 259 Gains from investments in securities 2,272 1,665 Interest and other income (loss) 14,529 10,941 Income (loss) from unconsolidated joint ventures 19,186 (7,569) Direct reimbursements of payroll and related costs from management services contracts 4,293 5,235 Development and management services revenue 6,154 8,980 Company’s share of Net Operating Income $ 497,680 $ 484,665 BPLP Three months ended March 31, 2024 2023 (in thousands) Net income attributable to Boston Properties Limited Partnership $ 91,080 $ 88,830 Add: Noncontrolling interests in property partnerships 17,221 18,660 Interest expense 161,891 134,207 Impairment loss 13,615 — Net operating income from unconsolidated joint ventures 35,430 40,756 Depreciation and amortization expense 217,019 206,872 Transaction costs 513 911 Payroll and related costs from management services contracts 4,293 5,235 General and administrative expense 50,018 55,802 Less: Net operating income attributable to noncontrolling interests in property partnerships 46,570 47,097 Unrealized gain on non-real estate investment 396 259 Gains from investments in securities 2,272 1,665 Interest and other income (loss) 14,529 10,941 Income (loss) from unconsolidated joint ventures 19,186 (7,569) Direct reimbursements of payroll and related costs from management services contracts 4,293 5,235 Development and management services revenue 6,154 8,980 Company’s share of Net Operating Income $ 497,680 $ 484,665
Schedule Of Segment Information By Geographic Area And Property Type	Information by geographic area and property type (dollars in thousands): For the three months ended March 31, 2024: Boston Los Angeles New York San Francisco Seattle Washington, DC Total Rental Revenue: (1) Premier Workplace $ 280,466 $ 20,401 $ 260,809 $ 132,614 $ 10,910 $ 102,922 $ 808,122 Residential 4,196 — — 3,958 — 4,530 12,684 Hotel 8,186 — — — — — 8,186 Total 292,848 20,401 260,809 136,572 10,910 107,452 828,992 % of Grand Totals 35.33 % 2.46 % 31.46 % 16.47 % 1.32 % 12.96 % 100.00 % Rental Expenses: Premier Workplace 105,171 6,567 107,481 46,942 3,081 39,229 308,471 Residential 1,593 — — 2,218 — 1,875 5,686 Hotel 6,015 — — — — — 6,015 Total 112,779 6,567 107,481 49,160 3,081 41,104 320,172 % of Grand Totals 35.23 % 2.05 % 33.57 % 15.35 % 0.96 % 12.84 % 100.00 % Net operating income $ 180,069 $ 13,834 $ 153,328 $ 87,412 $ 7,829 $ 66,348 $ 508,820 % of Grand Totals 35.39 % 2.72 % 30.13 % 17.18 % 1.54 % 13.04 % 100.00 % Less: Net operating income attributable to noncontrolling interests in property partnerships (11,056) — (35,514) — — — (46,570) Add: Company’s share of net operating income from unconsolidated joint ventures 8,757 7,248 5,984 5,154 1,876 6,411 35,430 Company’s share of net operating income $ 177,770 $ 21,082 $ 123,798 $ 92,566 $ 9,705 $ 72,759 $ 497,680 % of Grand Totals 35.71 % 4.24 % 24.88 % 18.60 % 1.95 % 14.62 % 100.00 % _______________ (1) Rental Revenue is equal to Total Revenue per the Company’s Consolidated Statements of Operations, less Development and Management Services Revenue and Direct Reimbursements of Payroll and Related Costs from Management Services Contracts Revenue per the Consolidated Statements of Operations. For the three months ended March 31, 2023: Boston Los Angeles New York San Francisco Seattle Washington, DC Total Rental Revenue: (1) Premier Workplace $ 269,951 $ — $ 258,192 $ 136,093 $ 14,258 $ 90,664 $ 769,158 Residential 4,049 — — 3,642 — 4,035 11,726 Hotel 8,101 — — — — — 8,101 Total 282,101 — 258,192 139,735 14,258 94,699 788,985 % of Grand Totals 35.76 % — % 32.72 % 17.71 % 1.81 % 12.00 % 100.00 % Rental Expenses: Premier Workplace 100,049 — 102,485 46,085 2,960 34,266 285,845 Residential 1,552 — — 2,173 — 1,738 5,463 Hotel 6,671 — — — — — 6,671 Total 108,272 — 102,485 48,258 2,960 36,004 297,979 % of Grand Totals 36.34 % — % 34.39 % 16.20 % 0.99 % 12.08 % 100.00 % Net operating income $ 173,829 $ — $ 155,707 $ 91,477 $ 11,298 $ 58,695 $ 491,006 % of Grand Totals 35.41 % — % 31.71 % 18.63 % 2.30 % 11.95 % 100.00 % Less: Net operating income attributable to noncontrolling interests in property partnerships (10,817) — (36,280) — — — (47,097) Add: Company’s share of net operating income from unconsolidated joint ventures 8,577 13,225 3,650 3,464 1,846 9,994 40,756 Company’s share of net operating income $ 171,589 $ 13,225 $ 123,077 $ 94,941 $ 13,144 $ 68,689 $ 484,665 % of Grand Totals 35.41 % 2.73 % 25.39 % 19.59 % 2.71 % 14.17 % 100.00 % _______________ (1) Rental Revenue is equal to Total Revenue per the Company’s Consolidated Statements of Operations, less Development and Management Services Revenue and Direct Reimbursements of Payroll and Related Costs from Management Services Contracts Revenue per the Consolidated Statements of Operations.

Earnings Per Share _ Common U_2

Earnings Per Share / Common Unit (Tables)	3 Months Ended
Earnings Per Share / Common Unit (Tables)	Mar. 31, 2024
Entity Information [Line Items]
Computation Of Basic And Diluted Earnings Per Share / Unit	Three months ended March 31, 2024 Income Shares Per Share (in thousands, except for per share amounts) Basic Earnings: Net income attributable to Boston Properties, Inc. $ 79,883 156,983 $ 0.51 Effect of Dilutive Securities: Stock Based Compensation — 149 — Diluted Earnings: Net income attributable to Boston Properties, Inc. $ 79,883 157,132 $ 0.51 Three months ended March 31, 2023 Income Shares Per Share (in thousands, except for per share amounts) Basic Earnings: Net income attributable to Boston Properties, Inc. $ 77,890 156,803 $ 0.50 Effect of Dilutive Securities: Stock Based Compensation — 240 — Diluted Earnings: Net income attributable to Boston Properties, Inc. $ 77,890 157,043 $ 0.50
Boston Properties Limited Partnership
Entity Information [Line Items]
Computation Of Basic And Diluted Earnings Per Share / Unit	Three months ended March 31, 2024 Income Units Per Unit (in thousands, except for per unit amounts) Basic Earnings: Net income attributable to Boston Properties Limited Partnership $ 91,080 175,255 $ 0.52 Effect of Dilutive Securities: Stock Based Compensation — 149 — Diluted Earnings: Net income attributable to Boston Properties Limited Partnership $ 91,080 175,404 $ 0.52 Three months ended March 31, 2023 Income Units Per Unit (in thousands, except for per unit amounts) Basic Earnings: Net income attributable to Boston Properties Limited Partnership $ 88,830 174,652 $ 0.51 Effect of Dilutive Securities: Stock Based Compensation — 240 — Diluted Earnings: Net income attributable to Boston Properties Limited Partnership $ 88,830 174,892 $ 0.51

Organization (Details)

Organization (Details) ft² in Millions		3 Months Ended
Organization (Details) ft² in Millions	Dec. 31, 2023	Mar. 31, 2024 ft² Real_Estate_Properties yr shares
Real Estate Properties [Line Items]
Restriction on redemption of OP units from date of issuance (years) \| yr		1
One OP unit is equivalent to one share of Common Stock (in shares) \| shares		1
OP unit conversion rate (in shares) \| shares		1
2012 OPP Units and Vested MYLTIPs
Real Estate Properties [Line Items]
Vesting Period		3 years
Construction in Progress
Real Estate Properties [Line Items]
Number of real estate properties		11
Net Rentable Area (in sf) \| ft²		3.2
Commercial Real Estate Properties [Member]
Real Estate Properties [Line Items]
Number of real estate properties		187
Net Rentable Area (in sf) \| ft²		53.5
Office and Life Sciences Building [Member]
Real Estate Properties [Line Items]
Number of real estate properties		165
Office and Life Sciences Building [Member] \| Construction in Progress
Real Estate Properties [Line Items]
Number of real estate properties		7
Retail Site [Member]
Real Estate Properties [Line Items]
Number of real estate properties		14
Retail Site [Member] \| Construction in Progress
Real Estate Properties [Line Items]
Number of real estate properties		2
Residential Building
Real Estate Properties [Line Items]
Number of real estate properties		7
Residential Building \| Construction in Progress
Real Estate Properties [Line Items]
Number of real estate properties		2
Hotel [Member]
Real Estate Properties [Line Items]
Number of real estate properties		1
Boston Properties Limited Partnership
Real Estate Properties [Line Items]
General and limited partnership interest in the operating partnership (percent)	89.40%	89.10%

Summary Of Significant Accoun_4

Summary Of Significant Accounting Policies (Narrative) (Details) $ in Thousands			3 Months Ended
	Mar. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Mar. 31, 2024 USD ($)	Mar. 31, 2023 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Number of VIEs	9		9
Separate Unrestricted Cash For Deferred Compensation Plan.	$ 37,000	$ 36,100	$ 37,000
Impairment loss			13,615	$ 0
Gains from investments in securities			2,272	1,665
Prepaid expenses and other assets (amounts related to VIEs of $45,672 and $11,824 at March 31, 2024 and December 31, 2023, respectively)	$ 146,286	64,230	$ 146,286
Unconsolidated Joint Ventures [Member]
Summary Of Significant Accounting Policies [Line Items]
Number of VIEs	0		0
Deferred Compensation, Excluding Share-Based Payments and Retirement Benefits
Summary Of Significant Accounting Policies [Line Items]
Gains from investments in securities			$ 2,300	$ 1,700
Shady Grove Innovation District [Member]
Summary Of Significant Accounting Policies [Line Items]
Impairment loss	$ 13,600
Environmental Focused Investment Fund
Summary Of Significant Accounting Policies [Line Items]
Prepaid expenses and other assets (amounts related to VIEs of $45,672 and $11,824 at March 31, 2024 and December 31, 2023, respectively)	5,100	$ 4,600	5,100
US Treasury Bill Securities
Summary Of Significant Accounting Policies [Line Items]
U.S. Treasury Bill, Term of Contract		3 months
3-Month United States Treasury Bills	$ 0	$ 302,700	$ 0
Variable Interest Entity, Primary Beneficiary [Member]
Summary Of Significant Accounting Policies [Line Items]
Number of VIEs	9		9
Prepaid expenses and other assets (amounts related to VIEs of $45,672 and $11,824 at March 31, 2024 and December 31, 2023, respectively)	$ 45,672	$ 11,824	$ 45,672
Commercial Real Estate Properties [Member] \| Variable Interest Entity, Primary Beneficiary [Member]
Summary Of Significant Accounting Policies [Line Items]
Number of VIEs	5		5

Summary Of Significant Accoun_5

Summary Of Significant Accounting Policies (Carrying Value Of Indebtedness And Corresponding Estimate Of Fair Value) (Details) - USD ($) $ in Thousands		Mar. 31, 2024	Dec. 31, 2023
Summary Of Significant Accounting Policies [Line Items]
Note receivable, net		$ 2,274	$ 1,714
Sales-type lease receivable, net		13,943	13,704
Mortgage notes payable, net		4,368,367	4,166,379
Unsecured senior notes, net		9,794,527	10,491,617
Unsecured line of credit		0	0
Unsecured term loan, net		1,199,430	1,198,301
Related Party
Summary Of Significant Accounting Policies [Line Items]
Related party note receivable, net		88,789	88,779
Carrying Amount [Member]
Summary Of Significant Accounting Policies [Line Items]
3-Month United States Treasury Bills	[1]	0	302,746
Sales-type lease receivable, net		13,943	13,704
Total		105,006	104,197
Mortgage notes payable, net		4,368,367	4,166,379
Unsecured senior notes, net		9,794,527	10,491,617
Unsecured line of credit		0	0
Unsecured term loan, net		1,199,430	1,198,301
Total		15,362,324	15,856,297
Carrying Amount [Member] \| Related Party
Summary Of Significant Accounting Policies [Line Items]
Related party note receivable, net		88,789	88,779
Carrying Amount [Member] \| Nonrelated Party
Summary Of Significant Accounting Policies [Line Items]
Note receivable, net		2,274	1,714
Estimated Fair Value [Member]
Summary Of Significant Accounting Policies [Line Items]
3-Month United States Treasury Bills	[1]	0	302,746
Sales-type lease receivable, net		13,416	13,338
Total		106,247	105,608
Mortgage notes payable, net		3,935,382	3,705,513
Unsecured senior notes, net		8,979,934	9,697,393
Unsecured line of credit		0	0
Unsecured term loan, net		1,198,951	1,196,945
Total		14,114,267	14,599,851
Estimated Fair Value [Member] \| Related Party
Summary Of Significant Accounting Policies [Line Items]
Related party note receivable, net		90,582	90,593
Estimated Fair Value [Member] \| Nonrelated Party
Summary Of Significant Accounting Policies [Line Items]
Note receivable, net		$ 2,249	$ 1,677

[1]Per the guidance in ASC 326 “Financial Instruments — Credit Losses” (“ASC 326”), the Company concluded that the risk of nonpayment is nonexistent because the U.S. Government has a long history with no credit losses and therefore, no credit loss allowance was recorded.

Summary Of Significant Accoun_6

Summary Of Significant Accounting Policies Fair Value of Derivatives (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Interest Rate Swap
Derivatives, Fair Value [Line Items]
Interest rate swaps	$ 12,298	$ 1,976

Real Estate Schedule of Real Es

Real Estate Schedule of Real Estate Properties (Details) - USD ($) $ in Thousands		Mar. 31, 2024	Dec. 31, 2023
Real Estate Properties [Line Items]
Land		$ 5,317,032	$ 5,251,224
Right-of-use assets - finance leases		401,486	401,680
Operating Lease, Right-of-Use Asset	[1]	344,255	324,298
Land held for future development	[2]	661,713	697,061
Buildings and improvements		16,689,571	16,607,756
Tenant improvements		3,654,576	3,592,172
Furniture, Fixtures and Equipment		54,691	53,716
Construction in progress		685,465	547,280
Total		27,808,789	27,475,187
Less: accumulated depreciation		(7,040,501)	(6,881,728)
Total real estate		20,768,288	20,593,459
Boston Properties Limited Partnership
Real Estate Properties [Line Items]
Land		5,222,323	5,156,515
Right-of-use assets - finance leases		401,486	401,680
Operating Lease, Right-of-Use Asset	[1]	344,255	324,298
Land held for future development	[2]	661,713	697,061
Buildings and improvements		16,418,015	16,336,200
Tenant improvements		3,654,576	3,592,172
Furniture, Fixtures and Equipment		54,691	53,716
Construction in progress		685,465	547,280
Total		27,442,524	27,108,922
Less: accumulated depreciation		(6,915,437)	(6,758,361)
Total real estate		$ 20,527,087	$ 20,350,561

[1] See Note 4. Includes pre-development costs.

Real Estate Asset Acquisition (

Real Estate Asset Acquisition (Details) - 901 New York Avenue $ in Thousands	Jan. 08, 2024 USD ($)
Asset Acquisition [Line Items]
Land	$ 65,808
Building and improvements	56,882
Tenant Improvements	16,088
Net Assets Acquired	220,015
Mortgages [Member]
Asset Acquisition [Line Items]
Liabilities, Fair Value Adjustment	8,374
In-Place Lease Intangibles
Asset Acquisition [Line Items]
Lease Intangibles	72,621
Above Market Lease Intangibles [Member]
Asset Acquisition [Line Items]
Lease Intangibles	2,757
Below Market Lease [Member]
Asset Acquisition [Line Items]
Lease Intangibles	$ (2,515)

Real Estate Amortization of Fin

Real Estate Amortization of Finite Lived Intangible Assets by Major Class (Details) - 901 New York Avenue $ in Thousands	Jan. 08, 2024 USD ($)
In-Place Lease Intangibles
Acquired Finite-Lived Intangible Assets [Line Items]
Period from acquisition through December 31, 2024	$ 10,364
2025	9,030
2026	6,494
2027	6,265
2028	6,069
2029	6,076
Above Market Lease Intangibles [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Period from acquisition through December 31, 2024	607
2025	454
2026	238
2027	201
2028	186
2029	186
Below Market Lease [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Period from acquisition through December 31, 2024	252
2025	257
2026	257
2027	257
2028	257
2029	$ 251

Real Estate Weighted-Average Us

Real Estate Weighted-Average Useful Life of Intangible Assets by Major Class (Details) - 901 New York Avenue	Jan. 08, 2024
In-Place Lease Intangibles
Real Estate Properties [Line Items]
Acquired Finite-Lived Intangible Assets, Weighted Average Useful Life	6 years 8 months 12 days
Above Market Lease Intangibles [Member]
Real Estate Properties [Line Items]
Acquired Finite-Lived Intangible Assets, Weighted Average Useful Life	4 years
Below Market Lease [Member]
Real Estate Properties [Line Items]
Acquired Finite-Lived Intangible Assets, Weighted Average Useful Life	9 years 9 months 18 days

Real Estate (Narrative) (Detail

Real Estate (Narrative) (Details) $ in Thousands				3 Months Ended
Real Estate (Narrative) (Details) $ in Thousands		Mar. 31, 2024 USD ($) ft² Real_Estate_Properties	Jan. 08, 2024 USD ($) ft²	Mar. 31, 2024 USD ($) ft² Real_Estate_Properties	Mar. 31, 2024 USD ($) ft² Real_Estate_Properties	Mar. 31, 2023 USD ($)	Feb. 12, 2024 ft² apartments	Jan. 07, 2024 USD ($)	Dec. 31, 2023 USD ($)
Real Estate Properties [Line Items]
Total revenue				$ 839,439		$ 803,200
Net Income (Loss)				79,883		77,890
Depreciation and amortization				218,716		208,734
Carying value of the Company's investment in unconsolidated joint ventures		$ 1,399,824		1,399,824	$ 1,399,824				$ 1,377,319
Impairment loss				$ 13,615		$ 0
901 New York Avenue LLC [Member]
Real Estate Properties [Line Items]
Ownership Percentage	[1]	25%		25%	25%
Construction in Progress
Real Estate Properties [Line Items]
Net Rentable Area (in sf) \| ft²		3,200,000		3,200,000	3,200,000
Number of real estate properties \| Real_Estate_Properties		11		11	11
Construction in Progress \| Residential Properties [Member]
Real Estate Properties [Line Items]
Net Rentable Area (in sf) \| ft²							492,000
Number of Units in Real Estate Property \| apartments							439
901 New York Avenue
Real Estate Properties [Line Items]
Net Rentable Area (in sf) \| ft²			524,000
Payments to Acquire Investments			$ 10,000
Net Working Capital, Including Cash Acquired from Acquisition			7,100
Gain (loss) on sale / consolidation			21,800
Total revenue					$ 7,900
Net Income (Loss)					$ (2,300)
Asset Acquisition, Consideration Transferred			20,000
901 New York Avenue \| Unconsolidated Properties
Real Estate Properties [Line Items]
Gain (loss) on sale / consolidation			21,800
901 New York Avenue \| 901 New York Avenue LLC [Member]
Real Estate Properties [Line Items]
Carying value of the Company's investment in unconsolidated joint ventures								$ (11,800)
Investments in Affiliates, Subsidiaries, Associates, and Joint Ventures, Fair Value Disclosure			10,000
901 New York Avenue \| 901 New York Avenue LLC [Member] \| Unconsolidated Properties
Real Estate Properties [Line Items]
Ownership Percentage								50%
901 New York Avenue \| Mortgages [Member]
Real Estate Properties [Line Items]
Debt			207,100
Assumption of mortgage notes payable			$ 207,100
901 New York Avenue \| Joint Venture Partner [Member]
Real Estate Properties [Line Items]
Ownership Percentage			50%
901 New York Avenue \| Joint Venture Partner [Member] \| 901 New York Avenue LLC [Member] \| Unconsolidated Properties
Real Estate Properties [Line Items]
Ownership Percentage			50%
Shady Grove Innovation District [Member]
Real Estate Properties [Line Items]
Impairment loss		$ 13,600

[1] At December 31, 2023, the Company’s economic ownership was approximately 50%. On January 8, 2024, the Company completed the acquisition of its joint venture partner’s 50% economic ownership interest for a gross purchase price of $10.0 million, as described in Note 3 and this Note 5.

Leases (Details)

Leases (Details) - USD ($) $ in Thousands	3 Months Ended
Leases (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Mar. 31, 2023
Leases [Abstract]
Fixed contractual payments	$ 648,890	$ 621,646
Variable lease payments	139,458	135,003
Sales-type lease revenue	242	226
Lease	$ 788,590	$ 756,875

Lessee - Leases Narrative (Deta

Lessee - Leases Narrative (Details) $ in Thousands			3 Months Ended
Lessee - Leases Narrative (Details) $ in Thousands		Mar. 31, 2024 USD ($)	Mar. 31, 2024 USD ($)	Mar. 31, 2023 USD ($)	Mar. 28, 2024 USD ($) ft²	Dec. 31, 2023 USD ($)
Lessee, Lease, Description [Line Items]
Operating Lease, Payments			$ 1,241	$ 251
Operating Lease, Right-of-Use Asset	[1]	$ 344,255	$ 344,255			$ 324,298
171 Dartmouth Street air rights [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Term of Contract					90 years
Lessee, Operating Lease, Discount Rate					6.57%
Net Present Value and Operating Lease Liability					$ 23,200
Operating Lease, Right-of-Use Asset					$ 23,900
Operating lease costs		$ 0
Land Subject to Ground Leases \| ft²					61,000
171 Dartmouth Street air rights [Member] \| Base Rental Payment [Member]
Lessee, Lease, Description [Line Items]
Operating Leases, Future Minimum Payments Due					$ 250
171 Dartmouth Street air rights [Member] \| Additional Rental Payment
Lessee, Lease, Description [Line Items]
Operating Leases, Future Minimum Payments Due					$ 500

[1] See Note 4.

Lease Liability Maturity Schedu

Lease Liability Maturity Schedule 171 Dartmouth Street (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Mar. 28, 2024	Dec. 31, 2023
Lessee, Lease, Description [Line Items]
Operating Lease, Liability	$ 377,667		$ 350,391
171 Dartmouth Street air rights [Member]
Lessee, Lease, Description [Line Items]
Period from March 28, 2024 - December 31, 2024		$ 0
2025		750
2026		750
2027		750
2028		25,826
2029		500
Thereafter		2,000
Total lease payments		30,576
Less: Interest Portion		7,391
Operating Lease, Liability		$ 23,185

Investments in Unconsolidated_3

Investments in Unconsolidated Joint Ventures (Investments in Unconsolidated Joint Ventures) (Details) - USD ($) $ in Thousands			3 Months Ended
		Jan. 08, 2024	Mar. 31, 2024	Dec. 31, 2023
Schedule of Equity Method Investments [Line Items]
Other Liabilities			$ (417,978)	$ (445,947)
Investments in unconsolidated joint ventures			1,399,824	1,377,319
Investments In Affiliates Subsidiaries Associates And Joint Ventures net	[1]		1,370,447	1,337,416
Unconsolidated Joint Ventures [Member]
Schedule of Equity Method Investments [Line Items]
Other Liabilities			$ (29,400)	(39,900)
Square 407 Limited Partnership [Member]
Schedule of Equity Method Investments [Line Items]
Properties			Market Square North
Ownership Percentage			50%
Other Liabilities	[1]		$ (6,103)	(5,996)
901 New York Avenue LLC [Member]
Schedule of Equity Method Investments [Line Items]
Properties			901 New York Avenue
Ownership Percentage	[2]		25%
Other Liabilities	[1]			$ (11,764)
901 New York Avenue LLC (economic ownership) [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Percentage				50%
Payments to Acquire Real Estate and Real Estate Joint Ventures		$ 10,000
901 New York Avenue LLC (economic ownership) [Member] \| Joint Venture Partner [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Percentage		50%
WP Project Developer LLC [Member]
Schedule of Equity Method Investments [Line Items]
Properties			Wisconsin Place Land and Infrastructure
Ownership Percentage	[3]		33.33%
Investments in unconsolidated joint ventures	[1]		$ 30,221	$ 30,375
500 North Capitol Venture LLC [Member]
Schedule of Equity Method Investments [Line Items]
Properties			500 North Capitol Street, NW
Ownership Percentage			30%
Other Liabilities	[1]		$ (10,773)	(10,253)
501 K Street LLC [Member]
Schedule of Equity Method Investments [Line Items]
Properties			1001 6th Street
Ownership Percentage			50%
Investments in unconsolidated joint ventures	[1]		$ 45,013	44,774
Podium Developer LLC [Member]
Schedule of Equity Method Investments [Line Items]
Properties			The Hub on Causeway - Podium
Ownership Percentage			50%
Investments in unconsolidated joint ventures	[1]		$ 45,068	45,201
Residential Tower Developer LLC [Member]
Schedule of Equity Method Investments [Line Items]
Properties			Hub50House
Ownership Percentage			50%
Investments in unconsolidated joint ventures	[1]		$ 42,250	40,235
Hotel Tower Developer LLC [Member]
Schedule of Equity Method Investments [Line Items]
Properties			The Hub on Causeway - Hotel Air Rights
Ownership Percentage			50%
Investments in unconsolidated joint ventures	[1]		$ 13,680	13,494
Office Tower Developer LLC
Schedule of Equity Method Investments [Line Items]
Properties			100 Causeway Street
Ownership Percentage			50%
Investments in unconsolidated joint ventures	[1]		$ 57,079	57,660
1265 Main Office JV LLC [Member]
Schedule of Equity Method Investments [Line Items]
Properties			1265 Main Street
Ownership Percentage			50%
Investments in unconsolidated joint ventures	[1]		$ 3,583	3,585
BNY Tower Holdings LLC [Member]
Schedule of Equity Method Investments [Line Items]
Properties			Dock 72
Ownership Percentage	[4]		50%
Other Liabilities	[1]		$ (12,501)	(11,890)
CA-Colorado Center LLC[Member]
Schedule of Equity Method Investments [Line Items]
Properties			Colorado Center
Ownership Percentage			50%
Investments in unconsolidated joint ventures	[1]		$ 235,143	237,815
7750 Wisconsin Avenue LLC [Member]
Schedule of Equity Method Investments [Line Items]
Properties			7750 Wisconsin Avenue
Ownership Percentage			50%
Investments in unconsolidated joint ventures	[1]		$ 49,756	50,064
BP-M 3HB Venture LLC [Member]
Schedule of Equity Method Investments [Line Items]
Properties			3 Hudson Boulevard
Ownership Percentage			25%
Investments in unconsolidated joint ventures	[1]		$ 114,331	115,103
Platform 16 Holdings LP [Member]
Schedule of Equity Method Investments [Line Items]
Properties			Platform 16
Ownership Percentage			55%
Investments in unconsolidated joint ventures	[1]		$ 51,349	45,564
Gateway Portfolio Holdings LLC [Member]
Schedule of Equity Method Investments [Line Items]
Properties			Gateway Commons
Ownership Percentage			50%
Investments in unconsolidated joint ventures	[1]		$ 385,568	376,834
Rosecrans-Sepulveda Partners 4, LLC
Schedule of Equity Method Investments [Line Items]
Properties			Beach Cities Media Campus
Ownership Percentage			50%
Investments in unconsolidated joint ventures	[1]		$ 27,042	27,034
Safeco Plaza REIT LLC
Schedule of Equity Method Investments [Line Items]
Properties			Safeco Plaza
Ownership Percentage	[5]		33.67%
Investments in unconsolidated joint ventures	[1]		$ 43,860	44,734
Safeco Plaza REIT LLC \| Company's Share [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Percentage			33%
360 PAS Holdco LLC
Schedule of Equity Method Investments [Line Items]
Properties			360 Park Avenue South
Ownership Percentage	[6]		71.11%
Investments in unconsolidated joint ventures	[1]		$ 49,888	42,988
360 PAS Holdco LLC \| Company's Share [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Percentage			35.79%
PR II BXP Reston Gateway LLC
Schedule of Equity Method Investments [Line Items]
Properties			Skymark - Reston Next Residential
Ownership Percentage			20%
Investments in unconsolidated joint ventures	[1]		$ 15,323	15,184
751 Gateway Holdings LLC
Schedule of Equity Method Investments [Line Items]
Properties			751 Gateway
Ownership Percentage			49%
Investments in unconsolidated joint ventures	[1]		$ 95,863	93,411
200 Fifth Avenue JV LLC
Schedule of Equity Method Investments [Line Items]
Properties			200 Fifth Avenue
Ownership Percentage			26.69%
Investments in unconsolidated joint ventures	[1]		$ 76,728	75,718
ABXP Worldgate Investments LLC
Schedule of Equity Method Investments [Line Items]
Properties			13100 and 13150 Worldgate Drive
Ownership Percentage			50%
Investments in unconsolidated joint ventures	[1]		$ 18,079	$ 17,546
Entity Owning Land And Infrastructure Of Project [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Percentage			33.33%
Safeco Partner Entity One [Member] \| Company's Share [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Percentage			1%
Safeco Partner Entity Two \| Company's Share [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Percentage			1%
360 Park Avenue South Partners Entity \| Company's Share [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Percentage			1%
360 PAS Holdco LLC (indirect ownership) \| Company's Share [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Percentage			35.02%

[1] Investments with deficit balances aggregating approximately $29.4 million and $39.9 million at March 31, 2024 and December 31, 2023, respectively, are included within Other Liabilities in the Company’s Consolidated Balance Sheets. At December 31, 2023, the Company’s economic ownership was approximately 50%. On January 8, 2024, the Company completed the acquisition of its joint venture partner’s 50% economic ownership interest for a gross purchase price of $10.0 million, as described in Note 3 and this Note 5. The Company’s wholly-owned subsidiary that owns Wisconsin Place Office also owns a 33.33% interest in the joint venture entity that owns the land, parking garage and infrastructure of the project. This property includes net equity balances from the amenity joint venture. The Company’s ownership includes (1) a 33.0% direct interest in the joint venture, and (2) an additional 1% interest in each of the two entities through which each partner owns its interest in the joint venture. The Company’s ownership includes (1) a 35.79% direct interest in the joint venture, (2) an additional 35.02% indirect ownership in the joint venture, and (3) an additional 1% interest in the entity through which the partner owns its interest in the joint venture.

Investments in Unconsolidated_4

Investments in Unconsolidated Joint Ventures (Balance Sheets of the Unconsolidated Joint Ventures) (Details) - USD ($) $ in Thousands		Mar. 31, 2024	Dec. 31, 2023
ASSETS
Total real estate		$ 20,768,288	$ 20,593,459
Total assets		25,525,978	26,026,149
LIABILITIES AND MEMBERS'/PARTNERS' EQUITY
Mortgage and notes payable, net		4,368,367	4,166,379
Other Liabilities		417,978	445,947
Members’/Partners’ equity		5,857,699	5,876,697
Total liabilities and equity / capital		25,525,978	26,026,149
Carying value of the Company's investment in unconsolidated joint ventures		1,399,824	1,377,319
Right-of-use assets - finance leases		401,486	401,680
Operating Lease, Right-of-Use Asset	[1]	344,255	324,298
Lease liabilities - finance leases		415,888	417,961
Lease Liabilities - Operating Leases		377,667	350,391
Unconsolidated Joint Ventures [Member]
ASSETS
Total real estate	[2]	5,740,545	5,811,763
Other assets	[3]	619,559	682,291
Total assets		6,360,104	6,494,054
LIABILITIES AND MEMBERS'/PARTNERS' EQUITY
Mortgage and notes payable, net		3,162,545	3,351,873
Other Liabilities	[4]	318,708	361,357
Members’/Partners’ equity		2,878,851	2,780,824
Total liabilities and equity / capital		6,360,104	6,494,054
Company's share of equity		1,313,484	1,278,483
Basis differentials	[5]	56,963	58,933
Carying value of the Company's investment in unconsolidated joint ventures	[6]	1,370,447	1,337,416
Operating Lease, Right-of-Use Asset		19,800	20,100
Sales-type lease receivable, net		14,000	13,900
Lease Liabilities - Operating Leases		30,500	30,500
Unconsolidated Joint Ventures [Member]
LIABILITIES AND MEMBERS'/PARTNERS' EQUITY
Other Liabilities		29,400	39,900
Colorado Center
LIABILITIES AND MEMBERS'/PARTNERS' EQUITY
Basis differentials		298,190	298,906
Carying value of the Company's investment in unconsolidated joint ventures	[7]	235,143	237,815
200 Fifth Avenue JV LLC
LIABILITIES AND MEMBERS'/PARTNERS' EQUITY
Basis differentials		56,193	58,308
Carying value of the Company's investment in unconsolidated joint ventures	[7]	76,728	75,718
Gateway Commons Complex [Member]
LIABILITIES AND MEMBERS'/PARTNERS' EQUITY
Basis differentials		49,593	48,971
Carying value of the Company's investment in unconsolidated joint ventures	[7]	385,568	376,834
Safeco Plaza REIT LLC
LIABILITIES AND MEMBERS'/PARTNERS' EQUITY
Basis differentials		(29,432)	(29,678)
Carying value of the Company's investment in unconsolidated joint ventures	[7]	43,860	44,734
360 PAS Holdco LLC
LIABILITIES AND MEMBERS'/PARTNERS' EQUITY
Basis differentials		(116,188)	(116,534)
Carying value of the Company's investment in unconsolidated joint ventures	[7]	49,888	42,988
Dock 72
LIABILITIES AND MEMBERS'/PARTNERS' EQUITY
Other Liabilities	[7]	12,501	11,890
Basis differentials		(94,586)	(95,521)
Platform 16
LIABILITIES AND MEMBERS'/PARTNERS' EQUITY
Basis differentials		(142,671)	(143,052)
Carying value of the Company's investment in unconsolidated joint ventures	[7]	$ 51,349	$ 45,564

[1] See Note 4. At March 31, 2024 and December 31, 2023, this amount included right of use assets - operating leases totaling approximately $19.8 million and $20.1 million, respectively. At March 31, 2024 and December 31, 2023, this amount included sales-type lease receivable, net totaling approximately $14.0 million and $13.9 million, respectively. At March 31, 2024 and December 31, 2023, this amount included lease liabilities - operating leases totaling approximately $30.5 million. This amount represents the aggregate difference between the Company’s historical cost basis and the basis reflected at the joint venture level, which is typically amortized over the life of the related assets and liabilities. Basis differentials result from impairments of investments, acquisitions through joint ventures with no change in control and upon the transfer of assets that were previously owned by the Company into a joint venture. In addition, certain acquisition, transaction and other costs may not be reflected in the net assets at the joint venture level. The majority of the Company’s basis differences are as follows: March 31, 2024 December 31, 2023 Property (in thousands) Colorado Center $ 298,190 $ 298,906 200 Fifth Avenue 56,193 58,308 Gateway Commons 49,593 48,971 Safeco Plaza (29,432) (29,678) 360 Park Avenue South (116,188) (116,534) Dock 72 (94,586) (95,521) Platform 16 (142,671) (143,052) These basis differentials (excluding land) will be amortized over the remaining lives of the related assets and liabilities. Investments with deficit balances aggregating approximately $29.4 million and $39.9 million at March 31, 2024 and December 31, 2023, respectively, are reflected within Other Liabilities in the Company’s Consolidated Balance Sheets. Investments with deficit balances aggregating approximately $29.4 million and $39.9 million at March 31, 2024 and December 31, 2023, respectively, are included within Other Liabilities in the Company’s Consolidated Balance Sheets.

Investments in Unconsolidated_5

Investments in Unconsolidated Joint Ventures (Statements of Operations of the Joint Ventures) (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2024	Mar. 31, 2023
Schedule of Equity Method Investments [Line Items]
Total revenue		$ 839,439	$ 803,200
Expenses
Transaction costs		513	911
Depreciation and amortization		218,716	208,734
Total expenses		593,712	568,661
Other income (expense)
Interest expense		(161,891)	(134,207)
Net Loss		106,604	105,628
Income (Loss) from Equity Method Investments		19,186	(7,569)
Unconsolidated Joint Ventures [Member]
Schedule of Equity Method Investments [Line Items]
Total revenue	[1]	130,392	151,423
Expenses
Operating		49,194	57,206
Transaction costs		2	74
Depreciation and amortization		39,424	49,978
Total expenses		88,620	107,258
Other income (expense)
Interest expense		(43,563)	(57,250)
Unrealized gain (loss) on derivative instruments		10,112	10,610
Net Loss		8,321	(23,695)
Company's share of net income (loss)		2,960	(6,902)
Gain (loss) on sale / consolidation		21,696	0
Basis differential	[2]	(5,470)	(667)
Income (Loss) from Equity Method Investments		19,186	(7,569)
Straight Line Rent Adjustments		7,700	6,300
Unconsolidated Joint Ventures [Member] \| Basis Differential
Expenses
Depreciation and amortization		2,900	3,700
Other income (expense)
Straight Line Rent Adjustments		300	300
Above and below market rent adjustments, net		200	200
Derivative, Gain (Loss) on Derivative, Net		$ 2,700	$ (2,800)

[1]Includes straight-line rent adjustments of approximately $7.7 million and $6.3 million for the three months ended March 31, 2024 and 2023, respectively.[2] Includes depreciation and amortization of approximately $2.9 million and $3.7 million for the three months ended March 31, 2024 and 2023, respectively. Includes unrealized gain (loss) on derivative instruments of approximately $2.7 million and $(2.8) million for the three months ended March 31, 2024 and 2023, respectively. Includes straight-line rent adjustments of approximately $0.3 million for the three months ended March 31, 2024 and 2023. Also includes net above-/below-market rent adjustments of approximately $0.2 million for the three months ended March 31, 2024 and 2023.

Investment in Unconsolidated Jo

Investment in Unconsolidated Joint Ventures (Narrative) (Details) $ in Thousands						3 Months Ended
		Feb. 09, 2024 USD ($) ft²	Feb. 06, 2024 USD ($)	Jan. 11, 2024	Jan. 08, 2024 USD ($) ft²	Mar. 31, 2024 USD ($)	Mar. 31, 2023 USD ($)	Jan. 07, 2024	Jan. 02, 2024 ft²
Schedule of Equity Method Investments [Line Items]
Interest and Other Income						$ 14,529	$ 10,941
3 Hudson Boulevard [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Percentage						25%
901 New York Avenue LLC [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Percentage	[1]					25%
Gateway Commons Complex [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Percentage						50%
Unconsolidated Joint Ventures [Member]
Schedule of Equity Method Investments [Line Items]
Gain (loss) on sale / consolidation						$ 21,696	$ 0
Unconsolidated Properties \| 651 Gateway \| Office and Life Sciences Building [Member]
Schedule of Equity Method Investments [Line Items]
Net Rentable Area (in sf) \| ft²									327,000
Leased percentage									21%
Unconsolidated Properties \| Gateway Commons Complex [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Percentage									50%
3 Hudson Boulevard [Member] \| Extended Maturity
Schedule of Equity Method Investments [Line Items]
Debt Instrument, Maturity Date			May 09, 2024
3 Hudson Boulevard [Member] \| Unconsolidated Properties
Schedule of Equity Method Investments [Line Items]
Ownership Percentage			25%
Debt			$ 80,000
3 Hudson Boulevard [Member] \| Unconsolidated Properties \| Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Schedule of Equity Method Investments [Line Items]
Debt Instrument, Basis Spread on Variable Rate			3.61%
7750 Wisconsin Avenue [Member] \| Extended Maturity
Schedule of Equity Method Investments [Line Items]
Debt Instrument, Maturity Date		Apr. 26, 2025
7750 Wisconsin Avenue [Member] \| Unconsolidated Properties
Schedule of Equity Method Investments [Line Items]
Ownership Percentage		50%
Net Rentable Area (in sf) \| ft²		736,000
Construction Loan		$ 252,600
Long-Term Debt		$ 251,600
7750 Wisconsin Avenue [Member] \| Unconsolidated Properties \| Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Schedule of Equity Method Investments [Line Items]
Debt Instrument, Basis Spread on Variable Rate		1.35%
901 New York Avenue
Schedule of Equity Method Investments [Line Items]
Net Rentable Area (in sf) \| ft²					524,000
Payments to Acquire Investments					$ 10,000
Gain (loss) on sale / consolidation					$ 21,800
901 New York Avenue \| Joint Venture Partner [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Percentage					50%
901 New York Avenue \| Mortgages [Member]
Schedule of Equity Method Investments [Line Items]
Debt					$ 207,100
Number of extensions				2
Debt Instrument, Interest Rate, Stated Percentage					3.61%
Debt Instrument, Maturity Date					Jan. 05, 2025
901 New York Avenue \| Unconsolidated Properties
Schedule of Equity Method Investments [Line Items]
Gain (loss) on sale / consolidation					$ 21,800
901 New York Avenue \| Unconsolidated Properties \| 901 New York Avenue LLC [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Percentage								50%
901 New York Avenue \| Unconsolidated Properties \| 901 New York Avenue LLC [Member] \| Joint Venture Partner [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Percentage					50%

[1] At December 31, 2023, the Company’s economic ownership was approximately 50%. On January 8, 2024, the Company completed the acquisition of its joint venture partner’s 50% economic ownership interest for a gross purchase price of $10.0 million, as described in Note 3 and this Note 5.

Mortgage Notes Payable, Net (De

Mortgage Notes Payable, Net (Details) - 901 New York Avenue $ in Thousands	Jan. 11, 2024	Jan. 08, 2024 USD ($) ft²
Debt Instrument [Line Items]
Net Rentable Area (in sf) \| ft²		524,000
Joint Venture Partner [Member]
Debt Instrument [Line Items]
Ownership Percentage		50%
Mortgages [Member]
Debt Instrument [Line Items]
Debt		$ 207,100
Debt Instrument, Interest Rate, Stated Percentage		3.61%
Long-Term Debt, Fair Value		$ 198,700
Debt Instrument, Maturity Date		Jan. 05, 2025
Number of extensions	2
Long Term Debt, Renewal Term	5

Schedule of Unsecured Senior No

Schedule of Unsecured Senior Notes (Details) - USD ($) $ in Thousands		Mar. 31, 2024	Dec. 31, 2023
Debt Instrument [Line Items]
Senior Notes		$ 9,794,527	$ 10,491,617
Boston Properties Limited Partnership
Debt Instrument [Line Items]
Senior Notes		9,794,527	$ 10,491,617
Boston Properties Limited Partnership \| Senior Notes
Debt Instrument [Line Items]
Debt		9,850,000
Debt Instrument, Unamortized Discount		12,611
Debt Issuance Costs, Net		$ 42,862
Boston Properties Limited Partnership \| Senior Notes \| 3.350% unsecured senior notes
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		3.20%
Debt Instrument, Interest Rate, Effective Percentage	[1]	3.35%
Debt		$ 850,000
Long-term Debt, Maturity Date	[2]	Jan. 15, 2025
Boston Properties Limited Partnership \| Senior Notes \| 3.766% unsecured senior notes
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		3.65%
Debt Instrument, Interest Rate, Effective Percentage	[1]	3.766%
Debt		$ 1,000,000
Long-term Debt, Maturity Date	[2]	Feb. 01, 2026
Boston Properties Limited Partnership \| Senior Notes \| 3.495% unsecured senior notes
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		2.75%
Debt Instrument, Interest Rate, Effective Percentage	[1]	3.495%
Debt		$ 1,000,000
Long-term Debt, Maturity Date	[2]	Oct. 01, 2026
Boston Properties Limited Partnership \| Senior Notes \| 6.924% unsecured senior notes
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		6.75%
Debt Instrument, Interest Rate, Effective Percentage	[1]	6.924%
Debt		$ 750,000
Long-term Debt, Maturity Date	[2]	Dec. 01, 2027
Boston Properties Limited Partnership \| Senior Notes \| 4.628% unsecured senior notes
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		4.50%
Debt Instrument, Interest Rate, Effective Percentage	[1]	4.628%
Debt		$ 1,000,000
Long-term Debt, Maturity Date	[2]	Dec. 01, 2028
Boston Properties Limited Partnership \| Senior Notes \| 3.505% unsecured senior notes
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		3.40%
Debt Instrument, Interest Rate, Effective Percentage	[1]	3.505%
Debt		$ 850,000
Long-term Debt, Maturity Date	[2]	Jun. 21, 2029
Boston Properties Limited Partnership \| Senior Notes \| 2.984% unsecured senior notes
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		2.90%
Debt Instrument, Interest Rate, Effective Percentage	[1]	2.984%
Debt		$ 700,000
Long-term Debt, Maturity Date	[2]	Mar. 15, 2030
Boston Properties Limited Partnership \| Senior Notes \| 3.343 % unsecured senior notes
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		3.25%
Debt Instrument, Interest Rate, Effective Percentage	[1]	3.343%
Debt		$ 1,250,000
Long-term Debt, Maturity Date	[2]	Jan. 30, 2031
Boston Properties Limited Partnership \| Senior Notes \| 2.671% unsecured senior notes
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		2.55%
Debt Instrument, Interest Rate, Effective Percentage	[1]	2.671%
Debt		$ 850,000
Long-term Debt, Maturity Date	[2]	Apr. 01, 2032
Boston Properties Limited Partnership \| Senior Notes \| 2.524% unsecured senior notes
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		2.45%
Debt Instrument, Interest Rate, Effective Percentage	[1]	2.524%
Debt		$ 850,000
Long-term Debt, Maturity Date	[2]	Oct. 01, 2033
Boston Properties Limited Partnership \| Senior Notes \| 6.619% unsecured senior notes
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		6.50%
Debt Instrument, Interest Rate, Effective Percentage	[1]	6.619%
Debt		$ 750,000
Long-term Debt, Maturity Date	[2]	Jan. 15, 2034

[1] Yield on issuance date including the effects of discounts on the notes, settlements of interest rate contracts and the amortization of financing costs. No principal amounts are due prior to maturity.

Unsecured Senior Notes (Narrati

Unsecured Senior Notes (Narrative) (Details) - USD ($) $ in Thousands			3 Months Ended
	Feb. 01, 2024	Oct. 26, 2023	Mar. 31, 2024	Mar. 31, 2023
Debt Instrument [Line Items]
Proceeds from Secured Notes Payable		$ 600,000
Repayments of Unsecured Debt			$ 700,000	$ 0
Boston Properties Limited Partnership
Debt Instrument [Line Items]
Repayments of Unsecured Debt			700,000	$ 0
Senior Notes \| Boston Properties Limited Partnership
Debt Instrument [Line Items]
Debt			$ 9,850,000
Debt Instrument, Covenant Description			The indenture relating to the unsecured senior notes contains certain financial restrictions and requirements, including (1) a leverage ratio not to exceed 60%, (2) a secured debt leverage ratio not to exceed 50%, (3) an interest coverage ratio of greater than 1.50, and (4) an unencumbered asset value of not less than 150% of unsecured debt.
Leverage ratio			60%
Secured debt leverage ratio - maximum			50%
Interest Coverage - Minimum			1.50
Unencumbered Asset Value - Minimum			150%
Debt Instrument, Covenant Compliance			At March 31, 2024, BPLP was in compliance with each of these financial restrictions and requirements.
3.916% unsecured senior notes \| Senior Notes \| Boston Properties Limited Partnership
Debt Instrument [Line Items]
Debt	$ 700,000
Debt Instrument, Interest Rate, Stated Percentage	3.80%
Repayments of Unsecured Debt	$ 713,300
Debt Instrument, Increase, Accrued Interest	$ 13,300

Derivative Instruments and He_3

Derivative Instruments and Hedging Activities (Details) - Interest Rate Swap - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Derivative [Line Items]
Derivative, Notional Amount	$ 2,100,000
Fair Value Hedge Assets	$ 12,298	$ 1,976
325 Main Street, 355 Main Street, 90 Broadway and Kendall Center Green Garage Properties [Member]
Derivative [Line Items]
Derivative, Swap Type	Interest Rate Swaps
Derivative, Notional Amount	$ 600,000
Derivative, Maturity Date	Oct. 26, 2028
Fair Value Hedge Assets	$ 4,646
Santa Monica Business Park [Member]
Derivative [Line Items]
Derivative, Swap Type	Interest Rate Swaps
Derivative, Notional Amount	$ 300,000
Derivative, Maturity Date	Apr. 01, 2025
Fair Value Hedge Assets	$ 6,646
Three Two Five Main Street, Three Five Five Main Street, Ninety Broadway and Kendall Center Green Garage Properties and Unsecured Term Loan
Derivative [Line Items]
Derivative, Notional Amount	1,800,000
Fair Value Hedge Assets	$ 5,652
2023 Unsecured Term Loan
Derivative [Line Items]
Derivative, Swap Type	Interest Rate Swaps
Derivative, Notional Amount	$ 1,200,000
Derivative, Maturity Date	May 16, 2024
Fair Value Hedge Assets	$ 1,006
Minimum [Member] \| 325 Main Street, 355 Main Street, 90 Broadway and Kendall Center Green Garage Properties [Member]
Derivative [Line Items]
Derivative, Fixed Interest Rate	3.79%
Minimum [Member] \| Santa Monica Business Park [Member]
Derivative [Line Items]
Derivative, Fixed Interest Rate	2.661%
Minimum [Member] \| 2023 Unsecured Term Loan
Derivative [Line Items]
Derivative, Fixed Interest Rate	4.638%
Maximum [Member] \| 325 Main Street, 355 Main Street, 90 Broadway and Kendall Center Green Garage Properties [Member]
Derivative [Line Items]
Derivative, Fixed Interest Rate	3.798%
Maximum [Member] \| Santa Monica Business Park [Member]
Derivative [Line Items]
Derivative, Fixed Interest Rate	2.688%
Maximum [Member] \| 2023 Unsecured Term Loan
Derivative [Line Items]
Derivative, Fixed Interest Rate	4.646%

Derivative Instruments and He_4

Derivative Instruments and Hedging Activities Gain (Loss) (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2024	Mar. 31, 2023
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain (loss) related to the effective portion recognized in other comprehensive income	[1]	$ 16,351	$ (6,538)
Amount of gain (loss) related to the effective portion subsequently reclassified to earnings	[2]	3,360	1,675
Amount of gain (loss) relate do the ineffective portion and amount excluded from effectiveness testing		$ 0	$ 0

[1] Includes the Company’s share of gain (loss) related to the effective portion of derivatives outstanding at its unconsolidated joint venture properties. Includes amounts from previous interest rate programs.

Derivative Instruments and He_5

Derivative Instruments and Hedging Activities (Narrative) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)
Derivative [Line Items]
Gain (Loss) from interest rate contracts	$ 0
Interest Rate Cap
Derivative [Line Items]
Derivative, Notional Amount	$ 600,000	$ 600,000
Derivative, Number of Instruments Held	2	2

Commitments And Contingencies (

Commitments And Contingencies (Details) $ in Thousands	3 Months Ended
Commitments And Contingencies (Details) $ in Thousands	Mar. 31, 2024 USD ($) ft² Real_Estate_Properties	Dec. 31, 2023 USD ($)	Oct. 02, 2023 USD ($)	Jan. 05, 2023 ft²
Commitments And Contingencies [Line Items]
Letter of credit and performance obligations	$ 21,600
Note receivable, net	2,274	$ 1,714
Accrued Liabilities	1,500
Loss Contingency, Portion Not Accrued	31,000
Property insurance program per occurrence limits	1,000,000
Per occurrence limit for NBCR Coverage	1,000,000
Value of program trigger	$ 200,000
Coinsurance of program trigger	20%
Program trigger deductible	20%
Per occurrence limit of the earthquake insurance which covers San Francisco and Los Angeles regions	$ 330,000
Annual aggregate limit of the earthquake insurance which covers San Francisco and Los Angeles regions	330,000
Amount of earthquake insurance provided by IXP, LLC as direct insurer San Francisco and Los Angeles	$ 30,000
Deductible in insurance as a percentage of the value of the affected property, San Francisco and Los Angeles	5%
Per Occurrence Limit of Earthquake Insurance Seattle	$ 110,000
Annual Aggregate Limit of Earthquake Insurance Seattle	$ 110,000
Earthquake Deductible Insurance Percentage of Value of the Affected Property Seattle	2%
Construction in Progress
Commitments And Contingencies [Line Items]
Net Rentable Area (in sf) \| ft²	3,200,000
Number of real estate properties \| Real_Estate_Properties	11
Boston Properties Limited Partnership
Commitments And Contingencies [Line Items]
Note receivable, net	$ 2,274	$ 1,714
Operating partnership guarantee to cover liabilities of IXP	20,000
767 Venture, LLC [Member]
Commitments And Contingencies [Line Items]
Maximum funding obligation	8,500
Property insurance program per occurrence limits	1,625,000
Metropolitan Square
Commitments And Contingencies [Line Items]
Ownership Percentage			20%
Metropolitan Square \| Affiliated Entity
Commitments And Contingencies [Line Items]
Note receivable, net	2,200
Metropolitan Square \| Subordinated Debt
Commitments And Contingencies [Line Items]
Debt Instrument, Unused Borrowing Capacity, Amount			$ 100,000
Debt Instrument, Interest Rate, Stated Percentage			12%
Metropolitan Square \| Scenario, Plan \| Subordinated Debt \| Affiliated Entity
Commitments And Contingencies [Line Items]
Loans and Leases Receivable, Loans in Process			$ 20,000
601 Lexington Avenue
Commitments And Contingencies [Line Items]
Coverage For Acts Of Terrorism Under TRIA Covered in Excess of Amount Covered by IXP	1,350,000
Coverage For Acts Of Terrorism Under TRIA Covered in Excess of Amount Covered by IXP - Property and Terrorism	750,000
Coverage For Acts Of Terrorism Under TRIA Covered in Excess of Amount Covered by IXP - Terrorism	600,000
Sum of Coverage Covered by IXP and Excess Coverage for Property and Terrorism	$ 1,750,000
Office and Life Sciences Building [Member]
Commitments And Contingencies [Line Items]
Number of real estate properties \| Real_Estate_Properties	165
Office and Life Sciences Building [Member] \| Construction in Progress
Commitments And Contingencies [Line Items]
Number of real estate properties \| Real_Estate_Properties	7
Office and Life Sciences Building [Member] \| 290 Binney \| Construction in Progress
Commitments And Contingencies [Line Items]
Net Rentable Area (in sf) \| ft²	566,000			566,000
Consolidated Entities, Ownership Percentage	55%
Leased percentage	100%			100%
Office and Life Sciences Building [Member] \| 250 Binney Street
Commitments And Contingencies [Line Items]
Net Rentable Area (in sf) \| ft²	67,000

Schedule of Noncontrolling Inte

Schedule of Noncontrolling Interests (Details) - Boston Properties Limited Partnership	Mar. 31, 2024 shares
OP Units [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Noncontrolling Interest, Outstanding	16,492,171
LTIP Units [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Noncontrolling Interest, Outstanding	2,666,636	[1]
MYLTIP 2022
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Noncontrolling Interest, Outstanding	252,151
MYLTIP 2023
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Noncontrolling Interest, Outstanding	322,053
MYLTIP 2024
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Noncontrolling Interest, Outstanding	330,479
2012 OPP and 2013-2021 MYLTIP [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Noncontrolling Interest, Outstanding	666,405

[1] Includes 666,405 LTIP Units earned by employees under the Company’s multi-year long-term incentive awards granted between 2012 and 2021 (i.e., 2012 OPP and 2013 - 2021 MYLTIP awards).

(Common Units) (Narrative) (Det

(Common Units) (Narrative) (Details) $ / shares in Units, $ in Thousands		3 Months Ended
	Feb. 01, 2024 USD ($) shares	Mar. 31, 2024 USD ($) yr shares	Mar. 28, 2024 $ / shares	Dec. 31, 2023 USD ($)
Boston Properties Limited Partnership
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Redeemable Noncontrolling Interest, Equity, Preferred, Carrying Amount \| $		$ 1,300,409		$ 1,347,575
MYLTIP \| Boston Properties Limited Partnership
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Vesting Period		3 years
Unvested MYLTIP Units [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
unvested MYLTIP distributions as compared to total distributions (percentage)		10%
MYLTIP 2021
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Final awards percentage of target	112%
Value of MYLTIP Awards \| $	$ 12,600
Forfeitures, in units	155,625
OP Units [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
OP Units for redemption (in shares)		36,305
Restriction on redemption of OP Unit to Common Stock (in years) \| yr		1
Redemption of OP Unit equivalent to Common Stock (in shares)		1
Redeemable Noncontrolling Interest, Equity, Preferred, Carrying Amount \| $		$ 1,300,000
Closing price of common stock (in dollars per share) \| $ / shares			$ 65.31
Vested 2012 OPP units and MYLTIPS
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
OP Units for redemption (in shares)		22,155

Noncontrolling Interests Common

Noncontrolling Interests Common Units Distributions (Details) - $ / shares	Jan. 30, 2024	Apr. 28, 2023	Jan. 30, 2023	Mar. 18, 2024
Dividends Payable [Line Items]
Distributions Payable, Amount Per Unit				$ 0.98
Dividends, Per Unit, Cash Paid	$ 0.98	$ 0.98	$ 0.98
Boston Properties Limited Partnership
Dividends Payable [Line Items]
Distributions Payable, Amount Per Unit				0.98
Dividends, Per Unit, Cash Paid	0.98	0.98	0.98
Boston Properties Limited Partnership \| Op units and LTIP units
Dividends Payable [Line Items]
Distributions Payable, Amount Per Unit				0.98
Dividends, Per Unit, Cash Paid	0.98	0.98	0.98
Boston Properties Limited Partnership \| Unvested MYLTIP Units [Member]
Dividends Payable [Line Items]
Distributions Payable, Amount Per Unit				$ 0.098
Dividends, Per Unit, Cash Paid	$ 0.098	$ 0.098	$ 0.098

Noncontrolling Interests (Prope

Noncontrolling Interests (Property Partnerships) (Narrative) (Details) $ in Thousands			3 Months Ended
	Mar. 31, 2024 USD ($) ft²	Mar. 21, 2024 USD ($)	Mar. 31, 2024 USD ($) ft²	Mar. 31, 2023 USD ($)	Dec. 31, 2023 USD ($)	Jan. 05, 2023 ft²
Noncontrolling Interest [Line Items]
Noncontrolling Interest in Limited Partnerships	$ 1,734,904		$ 1,734,904		$ 1,640,704
Proceeds from sale of interest in property partnerships and contributions from noncontrolling interests in property partnerships			$ 142,942	$ 7,555
Construction in Progress
Noncontrolling Interest [Line Items]
Net Rentable Area (in sf) \| ft²	3,200,000		3,200,000
290 Binney
Noncontrolling Interest [Line Items]
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners		45%
Proceeds from sale of interest in property partnerships and contributions from noncontrolling interests in property partnerships		$ 97,200
Noncontrolling Interest, Increase from Sale of Parent Equity Interest	$ 50,700	104,600
Difference Between Proceeds from Sale and Noncontrolling Interest		$ 7,500
Percent of Carrying Value of Real Estate, Gross		45%
290 Binney \| Construction in Progress \| Office and Life Sciences Building [Member]
Noncontrolling Interest [Line Items]
Net Rentable Area (in sf) \| ft²	566,000		566,000			566,000
Leased percentage	100%		100%			100%
290 Binney \| Noncontrolling Interest [Member]
Noncontrolling Interest [Line Items]
Noncontrolling Interest, Ownership Percentage by Parent		55%

Stockholders' Equity _ Partne_3

Stockholders' Equity / Partners' Capital Narrative (Details) $ in Millions		3 Months Ended
	May 17, 2023 USD ($) yr	Mar. 31, 2024 shares	Dec. 31, 2023 shares	May 22, 2020 USD ($)
Class of Stock [Line Items]
Common Stock, Shares, Outstanding		157,049,171	156,940,866
General Partners' Capital Account, Units Outstanding (in units)		1,762,080
Limited Partners' Capital Account, Units Outstanding (in units)		155,287,091
Shares of Common Stock issued in connection with redemption of an equal number of OP Units (in shares)		36,305
ATM Program [Member]
Class of Stock [Line Items]
At The Market Stock Offering Program Aggregate Value Of Common Stock \| $	$ 600			$ 600
At Market Stock Offering Program Maximum Length Of Sale (in years) \| yr	3

Stockholders' Equity _ Partne_4

Stockholders' Equity / Partners' Capital Dividends / Distributions (Details) - $ / shares	Jan. 30, 2024	Apr. 28, 2023	Jan. 30, 2023	Mar. 18, 2024
Dividends / Distributions [Line Items]
Dividends Payable, Amount Per Share / Unit				$ 0.98
Common Stock / Unit, Dividends / Distributions, Per Share / Unit, Cash Paid	$ 0.98	$ 0.98	$ 0.98
Boston Properties Limited Partnership
Dividends / Distributions [Line Items]
Dividends Payable, Amount Per Share / Unit				0.98
Common Stock / Unit, Dividends / Distributions, Per Share / Unit, Cash Paid	0.98	0.98	0.98
Boston Properties Limited Partnership \| Op units and LTIP units
Dividends / Distributions [Line Items]
Dividends Payable, Amount Per Share / Unit				0.98
Common Stock / Unit, Dividends / Distributions, Per Share / Unit, Cash Paid	0.98	0.98	0.98
Boston Properties Limited Partnership \| Unvested MYLTIP Units [Member]
Dividends / Distributions [Line Items]
Dividends Payable, Amount Per Share / Unit				$ 0.098
Common Stock / Unit, Dividends / Distributions, Per Share / Unit, Cash Paid	$ 0.098	$ 0.098	$ 0.098

Segment Information (Schedule O

Segment Information (Schedule Of Reconciliation Of Net Operating Income To Net Income) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net income attributable to the Company	$ 79,883	$ 77,890
Noncontrolling interest-common units of the Operating Partnership	(9,500)	(9,078)
Noncontrolling interest in property partnerships	(17,221)	(18,660)
Interest expense	(161,891)	(134,207)
Gain (Loss) from interest rate contracts	0
Company's share of net operating income from joint ventures	(508,820)	(491,006)
Income (loss) from unconsolidated joint ventures	(19,186)	7,569
Depreciation and amortization expense	(218,716)	(208,734)
Transaction costs	(513)	(911)
General and administrative expense	(50,018)	(55,802)
Unrealized gain on non-real estate investments	(396)	(259)
Gains from investments in securities	(2,272)	(1,665)
Interest and other income (loss)	(14,529)	(10,941)
Segment Reconciling Items
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net income attributable to the Company	79,883	77,890
Noncontrolling interest-common units of the Operating Partnership	9,500	9,078
Noncontrolling interest in property partnerships	17,221	18,660
Interest expense	161,891	134,207
Impairment loss	13,615	0
Income (loss) from unconsolidated joint ventures	19,186	(7,569)
Depreciation and amortization expense	218,716	208,734
Transaction costs	513	911
Operating expense	4,293	5,235
General and administrative expense	50,018	55,802
Unrealized gain on non-real estate investments	396	259
Gains from investments in securities	2,272	1,665
Interest and other income (loss)	14,529	10,941
Other revenue	4,293	5,235
Company's share of Net Operating Income	497,680	484,665
Boston Properties Limited Partnership
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net income attributable to the Company	91,080	88,830
Noncontrolling interest in property partnerships	(17,221)	(18,660)
Interest expense	(161,891)	(134,207)
Income (loss) from unconsolidated joint ventures	(19,186)	7,569
Depreciation and amortization expense	(217,019)	(206,872)
Transaction costs	(513)	(911)
General and administrative expense	(50,018)	(55,802)
Unrealized gain on non-real estate investments	(396)	(259)
Gains from investments in securities	(2,272)	(1,665)
Interest and other income (loss)	(14,529)	(10,941)
Boston Properties Limited Partnership \| Segment Reconciling Items
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net income attributable to the Company	91,080	88,830
Noncontrolling interest in property partnerships	17,221	18,660
Interest expense	161,891	134,207
Impairment loss	13,615	0
Income (loss) from unconsolidated joint ventures	19,186	(7,569)
Depreciation and amortization expense	217,019	206,872
Transaction costs	513	911
Operating expense	4,293	5,235
General and administrative expense	50,018	55,802
Unrealized gain on non-real estate investments	396	259
Gains from investments in securities	2,272	1,665
Interest and other income (loss)	14,529	10,941
Other revenue	4,293	5,235
Company's share of Net Operating Income	497,680	484,665
Unconsolidated Joint Ventures [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Interest expense	(43,563)	(57,250)
Company's share of net operating income from joint ventures	(35,430)	(40,756)
Income (loss) from unconsolidated joint ventures	(19,186)	7,569
Depreciation and amortization expense	(39,424)	(49,978)
Transaction costs	(2)	(74)
Unconsolidated Joint Ventures [Member] \| Segment Reconciling Items
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Company's share of net operating income from joint ventures	35,430	40,756
Management Service [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Other revenue	(6,154)	(8,980)
Management Service [Member] \| Segment Reconciling Items
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Other revenue	6,154	8,980
Management Service [Member] \| Boston Properties Limited Partnership
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Other revenue	(6,154)	(8,980)
Management Service [Member] \| Boston Properties Limited Partnership \| Segment Reconciling Items
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Other revenue	6,154	8,980
Noncontrolling interest - property partnerships [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Company's share of net operating income from joint ventures	46,570	47,097
Noncontrolling interest - property partnerships [Member] \| Segment Reconciling Items
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Company's share of net operating income from joint ventures	46,570	47,097
Noncontrolling interest - property partnerships [Member] \| Boston Properties Limited Partnership \| Segment Reconciling Items
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Company's share of net operating income from joint ventures	$ 46,570	$ 47,097

Segment Information (Schedule_2

Segment Information (Schedule Of Segment Reporting By Geographic Area And Property Type) (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2024	Mar. 31, 2023
Segment Reporting Information [Line Items]
Rental Revenue: Class A Office	[1]	$ 808,122	$ 769,158
Rental Revenue: Residential	[1]	12,684	11,726
Rental Revenue Total	[1]	$ 828,992	$ 788,985
Rental Revenue: % of Grand Totals		100%	100%
Rental Expenses: Class A Office		$ 308,471	$ 285,845
Rental Expenses: Residential		5,686	5,463
Rental Expenses: Total		$ 320,172	$ 297,979
Rental Expenses: % Of Grand Totals		100%	100%
Net Operating Income		$ 508,820	$ 491,006
Net Operating Income: % of Grand Totals		100%	100%
Company's Share of Net Operating Income: % of Grand Totals		100%	100%
Boston [Member]
Segment Reporting Information [Line Items]
Rental Revenue: Class A Office	[1]	$ 280,466	$ 269,951
Rental Revenue: Residential	[1]	4,196	4,049
Rental Revenue Total	[1]	$ 292,848	$ 282,101
Rental Revenue: % of Grand Totals		35.33%	35.76%
Rental Expenses: Class A Office		$ 105,171	$ 100,049
Rental Expenses: Residential		1,593	1,552
Rental Expenses: Total		$ 112,779	$ 108,272
Rental Expenses: % Of Grand Totals		35.23%	36.34%
Net Operating Income		$ 180,069	$ 173,829
Net Operating Income: % of Grand Totals		35.39%	35.41%
Company's Share of Net Operating Income: % of Grand Totals		35.71%	35.41%
Los Angeles [Member]
Segment Reporting Information [Line Items]
Rental Revenue: Class A Office	[1]	$ 20,401	$ 0
Rental Revenue: Residential	[1]	0	0
Rental Revenue Total	[1]	$ 20,401	$ 0
Rental Revenue: % of Grand Totals		2.46%	0%
Rental Expenses: Class A Office		$ 6,567	$ 0
Rental Expenses: Residential		0	0
Rental Expenses: Total		$ 6,567	$ 0
Rental Expenses: % Of Grand Totals		2.05%	0%
Net Operating Income		$ 13,834	$ 0
Net Operating Income: % of Grand Totals		2.72%	0%
Company's Share of Net Operating Income: % of Grand Totals		4.24%	2.73%
New York [Member]
Segment Reporting Information [Line Items]
Rental Revenue: Class A Office	[1]	$ 260,809	$ 258,192
Rental Revenue: Residential	[1]	0	0
Rental Revenue Total	[1]	$ 260,809	$ 258,192
Rental Revenue: % of Grand Totals		31.46%	32.72%
Rental Expenses: Class A Office		$ 107,481	$ 102,485
Rental Expenses: Residential		0	0
Rental Expenses: Total		$ 107,481	$ 102,485
Rental Expenses: % Of Grand Totals		33.57%	34.39%
Net Operating Income		$ 153,328	$ 155,707
Net Operating Income: % of Grand Totals		30.13%	31.71%
Company's Share of Net Operating Income: % of Grand Totals		24.88%	25.39%
San Francisco [Member]
Segment Reporting Information [Line Items]
Rental Revenue: Class A Office	[1]	$ 132,614	$ 136,093
Rental Revenue: Residential	[1]	3,958	3,642
Rental Revenue Total	[1]	$ 136,572	$ 139,735
Rental Revenue: % of Grand Totals		16.47%	17.71%
Rental Expenses: Class A Office		$ 46,942	$ 46,085
Rental Expenses: Residential		2,218	2,173
Rental Expenses: Total		$ 49,160	$ 48,258
Rental Expenses: % Of Grand Totals		15.35%	16.20%
Net Operating Income		$ 87,412	$ 91,477
Net Operating Income: % of Grand Totals		17.18%	18.63%
Company's Share of Net Operating Income: % of Grand Totals		18.60%	19.59%
Seattle
Segment Reporting Information [Line Items]
Rental Revenue: Class A Office	[1]	$ 10,910	$ 14,258
Rental Revenue: Residential	[1]	0	0
Rental Revenue Total	[1]	$ 10,910	$ 14,258
Rental Revenue: % of Grand Totals		1.32%	1.81%
Rental Expenses: Class A Office		$ 3,081	$ 2,960
Rental Expenses: Residential		0	0
Rental Expenses: Total		$ 3,081	$ 2,960
Rental Expenses: % Of Grand Totals		0.96%	0.99%
Net Operating Income		$ 7,829	$ 11,298
Net Operating Income: % of Grand Totals		1.54%	2.30%
Company's Share of Net Operating Income: % of Grand Totals		1.95%	2.71%
Washington, DC [Member]
Segment Reporting Information [Line Items]
Rental Revenue: Class A Office	[1]	$ 102,922	$ 90,664
Rental Revenue: Residential	[1]	4,530	4,035
Rental Revenue Total	[1]	$ 107,452	$ 94,699
Rental Revenue: % of Grand Totals		12.96%	12%
Rental Expenses: Class A Office		$ 39,229	$ 34,266
Rental Expenses: Residential		1,875	1,738
Rental Expenses: Total		$ 41,104	$ 36,004
Rental Expenses: % Of Grand Totals		12.84%	12.08%
Net Operating Income		$ 66,348	$ 58,695
Net Operating Income: % of Grand Totals		13.04%	11.95%
Company's Share of Net Operating Income: % of Grand Totals		14.62%	14.17%
Hotel [Member]
Segment Reporting Information [Line Items]
Other revenue	[1]	$ 8,186	$ 8,101
Operating expense		6,015	6,671
Hotel [Member] \| Boston [Member]
Segment Reporting Information [Line Items]
Other revenue	[1]	8,186	8,101
Operating expense		6,015	6,671
Hotel [Member] \| Los Angeles [Member]
Segment Reporting Information [Line Items]
Other revenue	[1]	0	0
Operating expense		0	0
Hotel [Member] \| New York [Member]
Segment Reporting Information [Line Items]
Other revenue	[1]	0	0
Operating expense		0	0
Hotel [Member] \| San Francisco [Member]
Segment Reporting Information [Line Items]
Other revenue	[1]	0	0
Operating expense		0	0
Hotel [Member] \| Seattle
Segment Reporting Information [Line Items]
Other revenue	[1]	0	0
Operating expense		0	0
Hotel [Member] \| Washington, DC [Member]
Segment Reporting Information [Line Items]
Other revenue	[1]	0	0
Operating expense		0	0
Noncontrolling interest - property partnerships [Member]
Segment Reporting Information [Line Items]
Net Operating Income		(46,570)	(47,097)
Noncontrolling interest - property partnerships [Member] \| Boston [Member]
Segment Reporting Information [Line Items]
Net Operating Income		(11,056)	(10,817)
Noncontrolling interest - property partnerships [Member] \| Los Angeles [Member]
Segment Reporting Information [Line Items]
Net Operating Income		0	0
Noncontrolling interest - property partnerships [Member] \| New York [Member]
Segment Reporting Information [Line Items]
Net Operating Income		(35,514)	(36,280)
Noncontrolling interest - property partnerships [Member] \| San Francisco [Member]
Segment Reporting Information [Line Items]
Net Operating Income		0	0
Noncontrolling interest - property partnerships [Member] \| Seattle
Segment Reporting Information [Line Items]
Net Operating Income		0	0
Noncontrolling interest - property partnerships [Member] \| Washington, DC [Member]
Segment Reporting Information [Line Items]
Net Operating Income		0	0
Unconsolidated Joint Ventures [Member]
Segment Reporting Information [Line Items]
Net Operating Income		35,430	40,756
Unconsolidated Joint Ventures [Member] \| Boston [Member]
Segment Reporting Information [Line Items]
Net Operating Income		8,757	8,577
Unconsolidated Joint Ventures [Member] \| Los Angeles [Member]
Segment Reporting Information [Line Items]
Net Operating Income		7,248	13,225
Unconsolidated Joint Ventures [Member] \| New York [Member]
Segment Reporting Information [Line Items]
Net Operating Income		5,984	3,650
Unconsolidated Joint Ventures [Member] \| San Francisco [Member]
Segment Reporting Information [Line Items]
Net Operating Income		5,154	3,464
Unconsolidated Joint Ventures [Member] \| Seattle
Segment Reporting Information [Line Items]
Net Operating Income		1,876	1,846
Unconsolidated Joint Ventures [Member] \| Washington, DC [Member]
Segment Reporting Information [Line Items]
Net Operating Income		6,411	9,994
Company's Share [Member]
Segment Reporting Information [Line Items]
Net Operating Income		497,680	484,665
Company's Share [Member] \| Boston [Member]
Segment Reporting Information [Line Items]
Net Operating Income		177,770	171,589
Company's Share [Member] \| Los Angeles [Member]
Segment Reporting Information [Line Items]
Net Operating Income		21,082	13,225
Company's Share [Member] \| New York [Member]
Segment Reporting Information [Line Items]
Net Operating Income		123,798	123,077
Company's Share [Member] \| San Francisco [Member]
Segment Reporting Information [Line Items]
Net Operating Income		92,566	94,941
Company's Share [Member] \| Seattle
Segment Reporting Information [Line Items]
Net Operating Income		9,705	13,144
Company's Share [Member] \| Washington, DC [Member]
Segment Reporting Information [Line Items]
Net Operating Income		$ 72,759	$ 68,689

[1] Rental Revenue is equal to Total Revenue per the Company’s Consolidated Statements of Operations, less Development and Management Services Revenue and Direct Reimbursements of Payroll and Related Costs from Management Services Contracts Revenue per the Consolidated Statements of Operations.

Earnings Per Share _ Common U_3

Earnings Per Share / Common Unit (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Basic Earnings:
Net income attributable to the Company	$ 79,883	$ 77,890
Net income (loss) attributable to the company (in shares / units)	156,983,000	156,803,000
Net income (loss) attributable to the company (in dollars per share / unit)	$ 0.51	$ 0.50
Earnings Per Share After Allocation of Undistributed Earnings to Participating Securities Basic (dollars per share)	$ 0.51	$ 0.50
Effect of Dilutive Securities:
Stock Based Compensation	$ 0	$ 0
Stock Based Compensation (in shares / units)	149,000	240,000
Weighted Average Number Diluted Shares Outstanding Adjustment (per share)	$ 0	$ 0
Diluted Earnings:
Diluted Earnings: Net income attributable to the Company	$ 79,883	$ 77,890
Diluted Earnings: Net income attributable to the Company (in shares / units)	157,132,000	157,043,000
Diluted Earnings: Net income, Per Share Amount (in dollars per share / unit)	$ 0.51	$ 0.50
Boston Properties Limited Partnership
Redeemable Common Units	18,272,000	17,849,000
Basic Earnings:
Net income attributable to the Company	$ 91,080	$ 88,830
Net income (loss) attributable to the company (in shares / units)	175,255,000	174,652,000
Net income (loss) attributable to the company (in dollars per share / unit)	$ 0.52	$ 0.51
Earnings Per Share After Allocation of Undistributed Earnings to Participating Securities Basic (dollars per share)	$ 0.52	$ 0.51
Effect of Dilutive Securities:
Stock Based Compensation	$ 0	$ 0
Stock Based Compensation (in shares / units)	149,000	240,000
Weighted Average Number Diluted Shares Outstanding Adjustment (per share)	$ 0	$ 0
Diluted Earnings:
Diluted Earnings: Net income attributable to the Company	$ 91,080	$ 88,830
Diluted Earnings: Net income attributable to the Company (in shares / units)	175,404,000	174,892,000
Diluted Earnings: Net income, Per Share Amount (in dollars per share / unit)	$ 0.52	$ 0.51

Stock Option and Incentive Pl_2

Stock Option and Incentive Plan Stock and Units (Narrative) (Details) $ / shares in Units, $ in Thousands				3 Months Ended
		Feb. 01, 2024 USD ($) shares	Jan. 25, 2024 USD ($) shares	Mar. 31, 2024 USD ($) $ / shares shares	Mar. 31, 2023 USD ($)	Dec. 31, 2023 USD ($) shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued				157,128,071		157,019,766
Stock based compensation expense \| $				$ 18,500	$ 25,900
Common Stock, Value, Issued \| $				$ 1,570		$ 1,569
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued				76,228
LTIP Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Value Of LTIP Units Issued \| $				$ 25,600
MYLTIP 2024
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Value of MYLTIP Awards \| $			$ 11,100
MYLTIP 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Final awards percentage of target		112%
Value of MYLTIP Awards \| $		$ 12,600
Forfeitures, in units		155,625
Unvested Restricted stock and LTIP Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Annual Installments for Vesting				4
Boston Properties Limited Partnership \| LTIP Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares issued				431,123
Noncontrolling Interest, Outstanding	[1]			2,666,636
Boston Properties Limited Partnership \| MYLTIP 2024
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Noncontrolling Interest, Outstanding				330,479
Share-based Compensation Arrangement by Share-based Payment Award, Terms of Award			The 2024 MYLTIP awards consists of three components. Two of the components, each weighted 40%, utilize BXP’s TSR over a three year measurement period as the performance metrics and the third component utilizes a leverage ratio as the performance metric.
Boston Properties Limited Partnership \| MYLTIP 2024 \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock available for issuance			330,479
Boston Properties Limited Partnership \| MYLTIP 2024 \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock available for issuance			0
Boston Properties Limited Partnership \| MYLTIP 2024 \| Target
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock available for issuance			165,240
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee and director payment per share (in dollars per share) \| $ / shares				$ 0.01
Common Stock, Value, Issued \| $				$ 4,900
Ltips (including vested MYLTIPS) And Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expenses \| $				38,900
Unvested MYLTIP Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expenses \| $				$ 5,800
Weighted-average period (years)				2 years 8 months 12 days
LTIP and MYLTIP Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee and director payment per share (in dollars per share) \| $ / shares				$ 0.25

[1] Includes 666,405 LTIP Units earned by employees under the Company’s multi-year long-term incentive awards granted between 2012 and 2021 (i.e., 2012 OPP and 2013 - 2021 MYLTIP awards).

Subsequent Events (Details)

Subsequent Events (Details) $ in Thousands				3 Months Ended
Subsequent Events (Details) $ in Thousands	Apr. 29, 2024 USD ($)	Apr. 17, 2024 USD ($)	Apr. 16, 2024 USD ($)	Mar. 31, 2024 USD ($)	Mar. 31, 2023 USD ($)	May 02, 2024 USD ($)	Apr. 28, 2024 USD ($)	Apr. 05, 2024 ft²	Dec. 31, 2023 USD ($)
Subsequent Event [Line Items]
Repayments of Unsecured Debt				$ 700,000	$ 0
Long-term Line of Credit				$ 0					$ 0
Subsequent Event [Member] \| 2023 Unsecured Term Loan
Subsequent Event [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity			$ 1,200,000
Repayments of Unsecured Debt	$ 500,000
Debt						$ 700,000
Subsequent Event [Member] \| Extended Maturity \| 2023 Unsecured Term Loan
Subsequent Event [Line Items]
Fiscal Period Duration			1 year
Subsequent Event [Member] \| Commercial Paper
Subsequent Event [Line Items]
Commercial Paper, Maximum Borrowing Capacity		$ 500,000
Commercial Paper						$ 500,000
Debt, Weighted Average Interest Rate						5.58%
Debt Instrument, Term		1 year
Subsequent Event [Member] \| Revolving Credit Facility [Member]
Subsequent Event [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 2,000,000						$ 1,815,000
Long-term Line of Credit						$ 0
Subsequent Event [Member] \| 760 Boylston Street
Subsequent Event [Line Items]
Net Rentable Area (in sf) \| ft²								118,000