Earnings Per Share / Common Unit (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Basic Earnings:
Net income attributable to the company's common shareholders / unitholders									$ 511,034	$ 572,347	$ 451,939
Net income attributable to the company's common shareholders / unitholders (in shares / units)									154,582,000	154,427,000	154,190,000
Net income attributable to the company's common shareholders / unitholders (in dollars per share / unit)	$ 0.91	$ 0.70	$ 1.06	$ 0.63	$ 0.96	$ 0.77	$ 0.83	$ 1.14	$ 3.31	$ 3.71	$ 2.93
Allocation of undistributed earnings to participating securities										$ (101)
Allocation of undistributed earnings to participating securities (in shares / units)										0
Allocation of undistributed earnings to participating securities (in dollars per share / unit)										$ 0
Net income attributable to the company's common shareholders / unitholders, after allocation of undistributed earnings to participating securities										$ 572,246
Net income attributable to the company's common shareholders / unitholders, after allocation of undistributed earnings to participating securities (in shares / units)										154,427,000
Net income attributable to the company's common shareholders / unitholders, after allocation of undistributed earnings to participating securities (in dollars per share / unit)										$ 3.71
Effect of Dilutive Securities:
Stock Based Compensation									$ 0	$ 0	$ 0
Stock Based Compensation (in shares / units)									301,000	255,000	200,000
Weighted Average Number Diluted Shares Outstanding Adjustment (per share)									$ (0.01)	$ (0.01)	$ 0
Diluted Earnings:
Diluted Earnings: Net income attributable to the Company's common shareholders / unitholders									$ 511,034	$ 572,246	$ 451,939
Diluted Earnings: Net income attributable to the Company's common shareholders / unitholders (in shares / units)									154,883,000	154,682,000	154,390,000
Diluted Earnings: Net income, Per Share Amount (in dollars per share / unit)	0.91	0.70	1.06	0.63	0.96	0.77	0.83	1.14	$ 3.30	$ 3.70	$ 2.93
Boston Properties Limited Partnership
Redeemable Common Units									17,618,000	17,485,000	17,471,000
Basic Earnings:
Net income attributable to the company's common shareholders / unitholders									$ 580,102	$ 656,903	$ 512,866
Net income attributable to the company's common shareholders / unitholders (in shares / units)									172,200,000	171,912,000	171,661,000
Net income attributable to the company's common shareholders / unitholders (in dollars per share / unit)	0.92	0.71	1.08	0.66	1.01	0.79	0.85	1.17	$ 3.37	$ 3.82	$ 2.99
Allocation of undistributed earnings to participating securities										$ (113)
Allocation of undistributed earnings to participating securities (in shares / units)										0
Allocation of undistributed earnings to participating securities (in dollars per share / unit)										$ 0
Net income attributable to the company's common shareholders / unitholders, after allocation of undistributed earnings to participating securities										$ 656,790
Net income attributable to the company's common shareholders / unitholders, after allocation of undistributed earnings to participating securities (in shares / units)										171,912,000
Net income attributable to the company's common shareholders / unitholders, after allocation of undistributed earnings to participating securities (in dollars per share / unit)										$ 3.82
Effect of Dilutive Securities:
Stock Based Compensation									$ 0	$ 0	$ 0
Stock Based Compensation (in shares / units)									301,000	255,000	200,000
Weighted Average Number Diluted Shares Outstanding Adjustment (per share)									$ (0.01)	$ (0.01)	$ (0.01)
Diluted Earnings:
Diluted Earnings: Net income attributable to the Company's common shareholders / unitholders									$ 580,102	$ 656,790	$ 512,866
Diluted Earnings: Net income attributable to the Company's common shareholders / unitholders (in shares / units)									172,501,000	172,167,000	171,861,000
Diluted Earnings: Net income, Per Share Amount (in dollars per share / unit)	$ 0.92	$ 0.71	$ 1.08	$ 0.66	$ 1.01	$ 0.79	$ 0.85	$ 1.17	$ 3.36	$ 3.81	$ 2.98