Earnings Per Share / Common Unit (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Basic Earnings:
Net income attributable to the company's common shareholders / unitholders	$ 89,854	$ 107,771	$ 854,541	$ 370,200
Net income attributable to the company's common shareholders / unitholders (in shares / units)	155,645,000	154,577,000	155,349,000	154,553,000
Net income attributable to the company's common shareholders / unitholders (in dollars per share / unit)	$ 0.58	$ 0.70	$ 5.50	$ 2.40
Allocation of undistributed earnings to participating securities			$ (1,150)
Allocation of undistributed earnings to participating securities (in shares / units)			0
Allocation of undistributed earnings to participating securities (in dollars per share / unit)			$ (0.01)
Net Income Loss Available To Common Stockholders After Allocation of Undistributed Earnings to Participating Securities Basic			$ 853,391
Weighted Average Number Of Shares Outstanding After Allocation of Undistributed Earnings to Participating Securities Basic (in shares)			155,349,000
Earnings Per Share After Allccation of Undistributed Earnings to Particiapting Securities Basic (dollars per share)	$ 0.58		$ 5.49
Effect of Dilutive Securities:
Stock Based Compensation	$ 0	$ 0	$ 0	$ 0
Stock Based Compensation (in shares / units)	25,000	243,000	98,000	294,000
Weighted Average Number Diluted Shares Outstanding Adjustment (per share)	$ 0	$ 0	$ 0	$ (0.01)
Diluted Earnings:
Diluted Earnings: Net income attributable to the Company's common shareholders / unitholders	$ 89,854	$ 107,771	$ 853,391	$ 370,200
Diluted Earnings: Net income attributable to the Company's common shareholders / unitholders (in shares / units)	155,670,000	154,820,000	155,447,000	154,847,000
Diluted Earnings: Net income, Per Share Amount (in dollars per share / unit)	$ 0.58	$ 0.70	$ 5.49	$ 2.39
Boston Properties Limited Partnership
Redeemable Common Units	17,032,000	17,638,000	17,279,000	17,630,000
Basic Earnings:
Net income attributable to the company's common shareholders / unitholders	$ 101,624	$ 122,117	$ 969,932	$ 421,214
Net income attributable to the company's common shareholders / unitholders (in shares / units)	172,677,000	172,215,000	172,628,000	172,183,000
Net income attributable to the company's common shareholders / unitholders (in dollars per share / unit)	$ 0.59	$ 0.71	$ 5.62	$ 2.45
Allocation of undistributed earnings to participating securities			$ (1,278)
Allocation of undistributed earnings to participating securities (in shares / units)			0
Allocation of undistributed earnings to participating securities (in dollars per share / unit)			$ (0.01)
Net Income Loss Available To Common Stockholders After Allocation of Undistributed Earnings to Participating Securities Basic			$ 968,654
Weighted Average Number Of Shares Outstanding After Allocation of Undistributed Earnings to Participating Securities Basic (in shares)			172,628,000
Earnings Per Share After Allccation of Undistributed Earnings to Particiapting Securities Basic (dollars per share)			$ 5.61
Effect of Dilutive Securities:
Stock Based Compensation	$ 0	$ 0	$ 0	$ 0
Stock Based Compensation (in shares / units)	25,000	243,000	98,000	294,000
Weighted Average Number Diluted Shares Outstanding Adjustment (per share)	$ 0	$ 0	$ 0	$ (0.01)
Diluted Earnings:
Diluted Earnings: Net income attributable to the Company's common shareholders / unitholders	$ 101,624	$ 122,117	$ 968,654	$ 421,214
Diluted Earnings: Net income attributable to the Company's common shareholders / unitholders (in shares / units)	172,702,000	172,458,000	172,726,000	172,477,000
Diluted Earnings: Net income, Per Share Amount (in dollars per share / unit)	$ 0.59	$ 0.71	$ 5.61	$ 2.44