Noncontrolling Interests (Common Units) (Narrative) (Details) (USD $)	3 Months Ended
	Mar. 31, 2012	Mar. 16, 2012	Jan. 27, 2012
OP Units [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
OP Units for redemption	199,526
Redemption of OP units issued on conversion of LTIP Units	54,472
Redemption of OP units issued on conversion of Series Two Preferred Units	108,000
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			$ 0.55
Distribution paid to outperformance awards, OPP Units			$ 0.055
Distribution declared to OP and LTIP units by Boston Properties, Inc.		$ 0.55
Distribution declared to outperformance awards OPP Units by Boston Properties, Inc.		$ 0.055
Restriction on redemption of OP Unit to Common Stock, years	1
Redemption of OP Unit equivalence to Common Stock	1
Common units of operating partnership if converted value	$ 1,910,000,000
Value of Series Two Preferred Units assuming conversion	$ 142,000,000
OPP Units 2011 [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Outperformance awards in LTIP Units	400,000
OPP Units 2012 [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Outperformance awards in LTIP Units	400,000
Series Two Preferred Units [Member] | Noncontrolling Interests [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Closing price of common stock	$ 104.99
Quarter 4 [Member] | OP Units [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Dividend payable date	Jan. 27, 2012
Holders of record date	December 31, 2011
Quarter 1 [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Dividends declared date	Mar. 16, 2012
Quarter 1 [Member] | OP Units [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Dividends declared date	Mar. 16, 2012
Dividend payable date	Apr. 30, 2012
Holders of record date	March 30, 2012