(Common Units) (Narrative) (Details) (USD $)	0 Months Ended	3 Months Ended
	Jan. 29, 2014	Mar. 31, 2014 Y	Mar. 18, 2014
OP Units [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
OP Units for redemption (in shares)		18,528
Redemption of OP units issued on conversion of LTIP Units (in shares)		17,191
Outperformance Awards LTIP Units distribution as percentage of OP Unit distribution prior to measurement date		10.00%
Distributions made to OP and LTIP units per unit (in dollars per share)	$ 0.65
Distribution paid to outperformance awards, OPP Units (in dollars per share)	$ 0.065
Distribution declared to OP and LTIP units by Boston Properties, Inc. (in dollars per share)			$ 0.65
Distribution declared to outperformance awards OPP Units by Boston Properties, Inc. (in dollars per share)			$ 0.065
Restriction on redemption of OP Unit to Common Stock (in years)		1
Redemption of OP Unit equivalence to Common Stock (in shares)		1
Common units of operating partnership if converted value		$ 2,000,000,000
Value of Series Two Preferred Units assuming conversion		$ 100,100,000
Closing price of common stock (in dollars per share)		$ 114.53
OPP Units 2012 [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Outperformance awards in LTIP Units (in shares)		394,590
MYLTIP [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
2013 MYLTIP		314,974
MYLTIP 2014 [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Two thousand fourteen MYLTIP		483,555
Quarter 4 2013 [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Dividend payable date		Jan. 29, 2014
Quarter 4 2013 [Member] | OP Units [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Dividend payable date		Jan. 29, 2014
Holders of record date		Dec. 31, 2013
Quarter 1 2014 [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Dividend payable date		Apr. 30, 2014
Dividends payable, date declared		Mar. 18, 2014
Quarter 1 2014 [Member] | OP Units [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Dividend payable date		Apr. 30, 2014
Holders of record date		Mar. 31, 2014
Dividends payable, date declared		Mar. 18, 2014
special dividend [Member] | OP Units [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Distributions made to OP and LTIP units per unit (in dollars per share)	$ 2.25