Subsequent Events subsequent Events (Details)						3 Months Ended								12 Months Ended
	Feb. 04, 2016 USD ($)	Feb. 03, 2016 USD ($) ft²	Jan. 25, 2016 USD ($) yr tiers indices	Jan. 20, 2016 USD ($)	Jan. 06, 2016 USD ($) yr swaps	Dec. 31, 2015 USD ($) shares	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2014 USD ($) shares	Sep. 30, 2014 USD ($)	Jun. 30, 2014 USD ($)	Mar. 31, 2014 USD ($)	Dec. 31, 2015 USD ($) yr swaps shares	Dec. 31, 2014 USD ($) shares	Dec. 31, 2013 USD ($)	Feb. 08, 2016 shares	Feb. 01, 2016 USD ($) ft²	May. 20, 2014 shares
Subsequent Event [Line Items]
Common stock, shares issued | shares						153,658,866				153,192,845				153,658,866	153,192,845				7,542
Proceeds from unsecured senior notes														$ 0	$ 0	$ 1,194,753,000
Repayments of Unsecured Debt														0	548,016,000	0
Revenue from a terminated tenant						$ 624,240,000	$ 629,884,000	$ 618,221,000	$ 618,476,000	$ 613,707,000	$ 618,803,000	$ 589,794,000	$ 574,694,000	$ 2,490,821,000	2,396,998,000	2,135,539,000
Subsequent Event [Member]
Subsequent Event [Line Items]
LTIP units issued (in shares) | shares																	139,435
Subsequent Event [Member] | MYLTIP 2016 [Member]
Subsequent Event [Line Items]
Indices Used to Compare TSR | indices			2
Number of Tiers | tiers			3
Percentage of annualized TSR for Reduction of Earned Awards			0.00%
Percentage to Cause Some Awards to be Earned Even if on a Relative Basis it Would Not Result in any Earned Awards			12.00%
Distributions percent before measurement date			10.00%
Value of MYLTIP Awards			$ 17,300,000
MYLTIP Value Amortized Into Earnings, Years | yr			4
TSR measurement (in years) | yr			3
Subsequent Event [Member] | MYLTIP 2016 [Member] | Cohen & Steers Realty Majors Portfolio Index [Member]
Subsequent Event [Line Items]
Weighted Percentage of Index Used to Compare to TSR			50.00%
Subsequent Event [Member] | MYLTIP 2016 [Member] | NAREIT Office Index adjusted [Member]
Subsequent Event [Line Items]
Weighted Percentage of Index Used to Compare to TSR			50.00%
Subsequent Event [Member] | MYLTIP 2013 [Member]
Subsequent Event [Line Items]
Final awards percentage of target	109.50%
Value of MYLTIP Awards	$ 13,500,000
TSR performance on an annualized compounded basis	8.50%
Subsequent Event [Member] | MYLTIP 2013 [Member] | Cohen & Steers Realty Majors Portfolio Index [Member]
Subsequent Event [Line Items]
TSR performance on an annualized compounded basis	9.40%
Subsequent Event [Member] | MYLTIP 2013 [Member] | NAREIT Office Index adjusted [Member]
Subsequent Event [Line Items]
TSR performance on an annualized compounded basis	6.20%
Subsequent Event [Member] | High [Member] | MYLTIP 2016 [Member]
Subsequent Event [Line Items]
Amount of Each Tier			$ 49,300,000
Subsequent Event [Member] | Minimum [Member] | MYLTIP 2016 [Member]
Subsequent Event [Line Items]
Potential Awards Earned			0
Subsequent Event [Member] | Maximum [Member] | MYLTIP 2016 [Member]
Subsequent Event [Line Items]
Potential Awards Earned			49,300,000
Subsequent Event [Member] | Threshold [Member] | MYLTIP 2016 [Member]
Subsequent Event [Line Items]
Amount of Each Tier			9,900,000
Subsequent Event [Member] | Target [Member] | MYLTIP 2016 [Member]
Subsequent Event [Line Items]
Amount of Each Tier			$ 19,700,000
Subsequent Event [Member] | MYLTIP vesting 2019 | MYLTIP 2016 [Member]
Subsequent Event [Line Items]
Vesting Percentage			50.00%
Subsequent Event [Member] | MYLTIP vesting 2020 | MYLTIP 2016 [Member]
Subsequent Event [Line Items]
Vesting Percentage			50.00%
Subsequent Event [Member] | Restricted Stock [Member]
Subsequent Event [Line Items]
Common stock, shares issued | shares																	18,521
415 Main Street | Subsequent Event [Member]
Subsequent Event [Line Items]
Sale Price Of Sold Property																		$ 105,400,000
Net Rentable Area | ft²																		231,000
767 Fifth Partners LLC [Member]
Subsequent Event [Line Items]
Ownership Percentage by Parent						60.00%								60.00%
767 Fifth Partners LLC [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Ownership Percentage by Parent					60.00%
Interest Rate Swap [Member]
Subsequent Event [Line Items]
Derivative, Notional Amount						$ 950,000,000								$ 950,000,000
Interest Rate Swap [Member] | 767 Fifth Partners LLC [Member]
Subsequent Event [Line Items]
Number of interest rate swap agreements entered into | swaps														14
Maximum period of hedging exposure to the variability in future cash flows for forecasted transactions (in years) | yr														10
Derivative, Average Fixed Interest Rate						2.646%								2.646%
Derivative, Notional Amount						$ 400,000,000								$ 400,000,000
Interest Rate Swap [Member] | 767 Fifth Partners LLC [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Number of interest rate swap agreements entered into | swaps					2
Maximum period of hedging exposure to the variability in future cash flows for forecasted transactions (in years) | yr					10
Derivative, Average Fixed Interest Rate					2.403%
Derivative, Notional Amount					$ 50,000,000
Boston Properties Limited Partnership [Member]
Subsequent Event [Line Items]
Proceeds from unsecured senior notes														0	0	1,194,753,000
Repayments of Unsecured Debt														0	548,016,000	0
Revenue from a terminated tenant						624,240,000	$ 629,884,000	$ 618,221,000	$ 618,476,000	$ 613,707,000	$ 618,803,000	$ 589,794,000	$ 574,694,000	2,490,821,000	$ 2,396,998,000	$ 2,135,539,000
Senior Notes [Member] | Boston Properties Limited Partnership [Member]
Subsequent Event [Line Items]
Principal Amount						$ 5,300,000,000								$ 5,300,000,000
Senior Notes [Member] | Unsecured senior note 3.766% [Member] | Boston Properties Limited Partnership [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Coupon/Stated Rate				3.65%
Proceeds from unsecured senior notes				$ 988,900,000
Principal Amount				$ 1,000,000,000
Senior Notes Pricing				99.708%
Effective Rate				3.766%
Terminated lease at 250 West 55th Street in NYC [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Net Rentable Area | ft²		85,000
Revenue from a terminated tenant		$ 45,000,000