Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2021		Dec. 31, 2020
ASSETS
Real estate, at cost (amounts related to variable interest entities (“VIEs”) of $6,702,830 and $6,592,019 at December 31, 2021 and December 31, 2020, respectively)	$ 23,752,630		$ 22,969,110
Right of use assets - finance leases (amounts related to VIEs of $21,000 and $21,000 at December 31, 2021 and December 31, 2020, respectively)	237,507		237,393
Right of use assets - operating leases	169,778	[1]	146,406
Less: accumulated depreciation (amounts related to VIEs of $(1,283,060) and $(1,158,548) at December 31, 2021 and December 31, 2020, respectively)	(5,883,961)		(5,534,102)
Real estate and development in process, net	18,275,954		17,818,807
Cash and cash equivalents (amounts related to VIEs of $300,937 and $340,642 at December 31, 2021 and December 31, 2020, respectively)	452,692		1,668,742
Cash held in escrows	48,466		50,587
Investments in securities	43,632		39,457
Tenant and other receivables, net (amounts related to VIEs of $6,824 and $10,911 at December 31, 2021 and December 31, 2020, respectively)	70,186		77,411
Related party note receivable, net	78,336		77,552
Notes receivable, net	9,641		18,729
Accrued rental income, net (amounts related to VIEs of $357,395 and $336,594 at December 31, 2021 and December 31, 2020, respectively)	1,226,745		1,122,502
Deferred charges, net (amounts related to VIEs of $174,637 and $183,306 at December 31, 2021 and December 31, 2020, respectively)	618,798		640,085
Prepaid expenses and other assets (amounts related to VIEs of $29,668 and $13,137 at December 31, 2021 and December 31, 2020, respectively)	57,811		33,840
Investments in unconsolidated joint ventures	1,482,997		1,310,478
Total assets	22,365,258		22,858,190
Liabilities:
Secured Debt	3,267,914		2,909,081
Unsecured senior notes, net	9,483,695		9,639,287
Unsecured line of credit	145,000		0
Unsecured term loan, net	0		499,390
Lease liabilities - finance leases (amounts related to VIEs of $20,458 and $20,306 at December 31, 2021 and December 31, 2020, respectively)	244,421		236,492
Lease liabilities - operating leases	204,561		201,713
Accounts payable and accrued expenses (amounts related to VIEs of $29,464 and $23,128 at December 31, 2021 and December 31, 2020, respectively)	320,775		336,264
Dividends and distributions payable	169,859		171,082
Accrued interest payable	94,796		106,288
Other liabilities (amounts related to VIEs of $150,131 and $158,805 at December 31, 2021 and December 31, 2020, respectively)	391,441		412,084
Total liabilities	14,322,462		14,511,681
Redeemable deferred stock units— 83,073 and 72,966 units outstanding at redemption value at December 31, 2021 and December 31, 2020, respectively	9,568		6,897
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;
5.25% Series B cumulative redeemable preferred stock / units, liquidation preference $2,500 per share / unit, 80,000 shares / units issued and outstanding at December 31, 2020	0		200,000
Common stock, $0.01 par value, 250,000,000 shares authorized, 156,623,749 and 155,797,725 issued and 156,544,849 and 155,718,825 outstanding at December 31, 2021 and December 31, 2020, respectively	1,565		1,557
Additional paid-in capital	6,497,730		6,356,791
Dividends in excess of earnings	(625,891)		(509,653)
Treasury common stock at cost, 78,900 shares at December 31, 2021 and December 31, 2020	(2,722)		(2,722)
Accumulated other comprehensive loss	(36,662)		(49,890)
Total stockholders' equity attributable to Boston Properties, Inc.	5,834,020		5,996,083
Noncontrolling interests:
Common units of the Operating Partnership	642,655		616,596
Property partnerships	1,556,553		1,726,933
Total equity / capital	8,033,228		8,339,612
Total liabilities and equity / capital	$ 22,365,258		$ 22,858,190
Preferred stock, shares authorized	50,000,000		50,000,000
Preferred stock, par value	$ 0.01		$ 0.01
Series B Cumulative Redeemable Preferred Stock / Unit [Member]
Noncontrolling interests:
Preferred stock, shares authorized			92,000
Preferred stock / units, shares / units issued (in shares / units)			80,000
Series B Dividend Rate Percentage			5.25%
Preferred stock, par value			$ 0.01
Series B Liquidation Preference Per Share/ Unit			$ 2,500
Preferred stock / units, shares / units outstanding (in shares / units)			80,000
Series B Cumulative Redeemable Preferred Stock / Unit [Member] | Boston Properties Limited Partnership
Noncontrolling interests:
Preferred stock / units, shares / units issued (in shares / units)			80,000
Series B Dividend Rate Percentage			5.25%
Series B Liquidation Preference Per Share/ Unit			$ 2,500
Preferred stock / units, shares / units outstanding (in shares / units)			80,000
Boston Properties Limited Partnership
ASSETS
Real estate, at cost (amounts related to variable interest entities (“VIEs”) of $6,702,830 and $6,592,019 at December 31, 2021 and December 31, 2020, respectively)	$ 23,379,243		$ 22,592,301
Right of use assets - finance leases (amounts related to VIEs of $21,000 and $21,000 at December 31, 2021 and December 31, 2020, respectively)	237,507		237,393
Right of use assets - operating leases	169,778	[1]	146,406
Less: accumulated depreciation (amounts related to VIEs of $(1,283,060) and $(1,158,548) at December 31, 2021 and December 31, 2020, respectively)	(5,772,018)		(5,428,576)
Real estate and development in process, net	18,014,510		17,547,524
Cash and cash equivalents (amounts related to VIEs of $300,937 and $340,642 at December 31, 2021 and December 31, 2020, respectively)	452,692		1,668,742
Cash held in escrows	48,466		50,587
Investments in securities	43,632		39,457
Tenant and other receivables, net (amounts related to VIEs of $6,824 and $10,911 at December 31, 2021 and December 31, 2020, respectively)	70,186		77,411
Related party note receivable, net	78,336		77,552
Notes receivable, net	9,641		18,729
Accrued rental income, net (amounts related to VIEs of $357,395 and $336,594 at December 31, 2021 and December 31, 2020, respectively)	1,226,745		1,122,502
Deferred charges, net (amounts related to VIEs of $174,637 and $183,306 at December 31, 2021 and December 31, 2020, respectively)	618,798		640,085
Prepaid expenses and other assets (amounts related to VIEs of $29,668 and $13,137 at December 31, 2021 and December 31, 2020, respectively)	57,811		33,840
Investments in unconsolidated joint ventures	1,482,997		1,310,478
Total assets	22,103,814		22,586,907
Liabilities:
Secured Debt	3,267,914		2,909,081
Unsecured senior notes, net	9,483,695		9,639,287
Unsecured line of credit	145,000		0
Unsecured term loan, net	0		499,390
Lease liabilities - finance leases (amounts related to VIEs of $20,458 and $20,306 at December 31, 2021 and December 31, 2020, respectively)	244,421		236,492
Lease liabilities - operating leases	204,561		201,713
Accounts payable and accrued expenses (amounts related to VIEs of $29,464 and $23,128 at December 31, 2021 and December 31, 2020, respectively)	320,775		336,264
Dividends and distributions payable	169,859		171,082
Accrued interest payable	94,796		106,288
Other liabilities (amounts related to VIEs of $150,131 and $158,805 at December 31, 2021 and December 31, 2020, respectively)	391,441		412,084
Total liabilities	14,322,462		14,511,681
Redeemable deferred stock units— 83,073 and 72,966 units outstanding at redemption value at December 31, 2021 and December 31, 2020, respectively	9,568		6,897
Noncontrolling interest:
Redeemable partnership units— 16,561,186 and 16,037,121 common units and 1,485,376 and 1,336,115 long term incentive units outstanding at redemption value at December 31, 2021 and December 31, 2020, respectively	2,078,603		1,643,024
Preferred stock, $0.01 par value, 50,000,000 shares authorized;
5.25% Series B cumulative redeemable preferred stock / units, liquidation preference $2,500 per share / unit, 80,000 shares / units issued and outstanding at December 31, 2020	0		193,623
Boston Properties Limited Partnership partners’ capital— 1,745,914 and 1,730,921 general partner units and 154,798,935 and 153,987,904 limited partner units outstanding at December 31, 2021 and December 31, 2020, respectively	4,173,290		4,554,639
Accumulated other comprehensive loss	(36,662)		(49,890)
Total partners’ capital	4,136,628		4,698,372
Noncontrolling interests in property partnerships	1,556,553		1,726,933
Noncontrolling interests:
Total equity / capital	5,693,181		6,425,305
Total liabilities and equity / capital	$ 22,103,814		$ 22,586,907
NonControlling Interest Redeemable Partnership Units Common Units Shares Outstanding	16,561,186		16,037,121
NonControlling Interest Redeemable Partnership Units Common Units Long Term Incentive Units At Redemption Value Shares Outstanding	1,485,376		1,336,115

[1] See Note 4.