Real Estate (Summary Of The Discontinued Operations (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total revenue	$ 613,707	$ 618,803	$ 589,794	$ 574,694	$ 576,199	$ 571,481	$ 510,033	$ 477,826	$ 2,396,998	$ 2,135,539	$ 1,847,186
Expenses
Depreciation and amortization									628,573	560,637	445,875
Total expenses									1,595,176	1,457,419	1,206,865
Operating income									801,822	678,120	640,321
Other Expenses
Interest expense									455,743	446,880	410,970
Noncontrolling interest in income from discontinued operations – common units of the Operating Partnership									0	(14,151)	(5,075)
Income from discontinued operations attributable to Boston Properties, Inc.										123,641	41,608
Gains on sales of real estate from discontinued operations									0	112,829	36,877
Gain on forgiveness of debt from discontinued operations									0	20,182	0
Impairment loss from discontinued operations									0	(3,241)	0
10 & 20 Burlington Mall Road, One Preserve Parkway, 1301 New York Avenue, 303 Almaden Blvd, Montvale Center and Bedford Business Park [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total revenue											32,607
Expenses
Operating											12,038
Depreciation and amortization											8,169
Total expenses											20,207
Operating income											12,400
Other Expenses
Interest expense											2,594
Income from discontinued operations											9,806
Noncontrolling interest in income from discontinued operations – common units of the Operating Partnership											(1,031)
Income from discontinued operations attributable to Boston Properties, Inc.											8,775
Gains on sales of real estate from discontinued operations											36,877
Gain on forgiveness of debt from discontinued operations											0
Impairment loss from discontinued operations											0
Noncontrolling interest in gains on sales of real estate, gain on forgiveness of debt and impairment loss from discontinued operations – common units of the Operating Partnership											(4,044)
Gain on the Slae of Real Estate, Gain On Forgiveness of Debt and Impairment Losses from Discontinued Operations Attributable to Company											32,833
Montvale Center, 303 Almaden Blvd, 1301 New York Avenue, One Preserve Parkway and 10 & 20 Burlington Mall Road [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total revenue										20,138
Expenses
Operating										6,996
Depreciation and amortization										4,760
Total expenses										11,756
Operating income										8,382
Other Expenses
Interest expense										360
Income from discontinued operations										8,022
Noncontrolling interest in income from discontinued operations – common units of the Operating Partnership										(803)
Income from discontinued operations attributable to Boston Properties, Inc.										7,219
Gains on sales of real estate from discontinued operations										112,829
Gain on forgiveness of debt from discontinued operations										20,182
Impairment loss from discontinued operations										(3,241)
Noncontrolling interest in gains on sales of real estate, gain on forgiveness of debt and impairment loss from discontinued operations – common units of the Operating Partnership										(13,348)
Gain on the Slae of Real Estate, Gain On Forgiveness of Debt and Impairment Losses from Discontinued Operations Attributable to Company										$ 116,422