(Common Units) (Narrative) (Details) $ / shares in Units, $ in Millions				12 Months Ended
	Feb. 03, 2017 USD ($) shares	Feb. 04, 2016 USD ($) shares	Feb. 06, 2015 USD ($) shares	Dec. 31, 2017 USD ($) yr shares	Dec. 31, 2016 shares	Dec. 29, 2017 $ / shares	May 02, 2016 shares
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Conversion of LTIP Units to OP Units (in units)							625,043
MYLTIP 2014
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Final awards percentage of target	27.70%
Value of MYLTIP Awards | $	$ 3.5
MYLTIP Units forfeited	447,386
2012 OPP and 2013 MYLTIP [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Conversion of LTIP Units to OP Units (in units)							32,349
OP Units [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
OP Units for redemption (in shares)				495,637	190,857
Redemption of OP units issued on conversion of LTIP Units (in shares)				36,486	103,847
MYLTIP Units distribution as percentage of OP Unit distribution prior to measurement date				10.00%
Restriction on redemption of OP Unit to Common Stock (in years) | yr				1
Redemption of OP Unit equivalence to Common Stock (in shares)				1
Common units of operating partnership if converted value | $				$ 2,300.0
Closing price of common stock (in dollars per share) | $ / shares						$ 130.03
MYLTIP 2013
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Final awards percentage of target		109.50%
Value of MYLTIP Awards | $		$ 13.5
MYLTIP Units forfeited		205,762
OPP Units 2012 [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Outperformance awards earned | $			$ 32.1
Potential maximum amount of Outperformance Awards earned (percent)			80.00%
Potential Awards Earned | $			$ 40.0
2012 OPP Units forfeited			174,549
Boston Properties Limited Partnership | MYLTIP 2014
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
2014 MYLTIP				25,107
Boston Properties Limited Partnership | MYLTIP 2016 [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
2016 MYLTIP				473,360
Boston Properties Limited Partnership | MYLTIP 2017 [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
2017 MYLTIP				400,000
Boston Properties Limited Partnership | MYLTIP 2015 [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
2015 MYLTIP				366,618