Noncontrolling Interests Common units distributions (Details) - Boston Properties Limited Partnership - $ / shares	Jul. 31, 2019	Apr. 30, 2019	Jan. 30, 2019	Oct. 31, 2018	Jul. 31, 2018	Apr. 30, 2018	Jan. 30, 2018	Sep. 17, 2019
Dividends Payable [Line Items]
Distributions Declared To OP And LTIP Units Per Unit								$ 0.95
Distributions Declared To MYLTIP Units Per Unit (in dollars per unit)								$ 0.095
Distributions made to OP and LTIP units per unit (in dollars per unit)	$ 0.95	$ 0.95	$ 0.95	$ 0.95	$ 0.80	$ 0.80	$ 0.80
Distribution paid to MYLTIP Units (in dollars per unit)	$ 0.095	$ 0.095	$ 0.095	$ 0.095	$ 0.080	$ 0.080	$ 0.080