Segment Information (Schedule Of Reconciliation Of Net Operating Income To Net Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net income attributable to the Company's common shareholders / unitholders	$ 451,939	$ 502,285	$ 572,606
Preferred dividends / distributions	(10,500)	(10,500)	(10,500)
Noncontrolling interest-common units of the Operating Partnership	(52,210)	(59,260)	(66,951)
Noncontrolling interest - redeemable preferred units	0	0	(6)
Noncontrolling interest in property partnerships	(47,832)	2,068	(149,855)
Losses from interest rate contracts	0	(140)	0
Interest expense	(374,481)	(412,849)	(432,196)
Depreciation and amortization expense	(617,547)	(694,403)	(639,542)
Impairment loss	0	(1,783)	0
Transaction costs	(668)	(2,387)	(1,259)
General and administrative expense	(113,715)	(105,229)	(96,319)
Gains (losses) from early extinguishments of debt	(496)	371	22,040
Gains (losses) from investments in securities	(3,678)	(2,273)	653
Interest and other income	(5,783)	(7,230)	(6,777)
Gain on sale of investment in unconsolidated joint venture	0	(59,370)	0
Income from unconsolidated joint ventures	(11,232)	(8,074)	(22,770)
Development and management services income	(34,605)	(28,284)	(22,554)
Business Intersegment, Eliminations [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net income attributable to the Company's common shareholders / unitholders	451,939	502,285	572,606
Preferred dividends / distributions	10,500	10,500	10,500
Noncontrolling interest-common units of the Operating Partnership	52,210	59,260	66,951
Noncontrolling interest - redeemable preferred units	0	0	6
Noncontrolling interest in property partnerships	47,832	(2,068)	149,855
Losses from interest rate contracts	0	140	0
Interest expense	374,481	412,849	432,196
Depreciation and amortization expense	617,547	694,403	639,542
Impairment loss	0	1,783	0
Transaction costs	668	2,387	1,259
General and administrative expense	113,715	105,229	96,319
Gains on sales of real estate	7,663	80,606	375,895
Gains (losses) from early extinguishments of debt	496	(371)	(22,040)
Gains (losses) from investments in securities	3,678	2,273	(653)
Interest and other income	5,783	7,230	6,777
Gain on sale of investment in unconsolidated joint venture	0	59,370	0
Income from unconsolidated joint ventures	11,232	8,074	22,770
Development and management services income	34,605	28,284	22,554
Net Operating Income	1,605,435	1,601,302	1,563,931
Boston Properties Limited Partnership
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net income attributable to the Company's common shareholders / unitholders	512,866	575,341	648,748
Preferred dividends / distributions	(10,500)	(10,500)	(10,500)
Noncontrolling interest - redeemable preferred units	0	0	(6)
Noncontrolling interest in property partnerships	(47,832)	2,068	(149,855)
Losses from interest rate contracts	0	(140)	0
Interest expense	(374,481)	(412,849)	(432,196)
Depreciation and amortization expense	(609,407)	(682,776)	(631,549)
Impairment loss	0	(1,783)	0
Transaction costs	(668)	(2,387)	(1,259)
General and administrative expense	(113,715)	(105,229)	(96,319)
Gains (losses) from early extinguishments of debt	(496)	371	22,040
Gains (losses) from investments in securities	(3,678)	(2,273)	653
Interest and other income	(5,783)	(7,230)	(6,777)
Gain on sale of investment in unconsolidated joint venture	0	(59,370)	0
Income from unconsolidated joint ventures	(11,232)	(8,074)	(22,770)
Development and management services income	(34,605)	(28,284)	(22,554)
Boston Properties Limited Partnership | Business Intersegment, Eliminations [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net income attributable to the Company's common shareholders / unitholders	512,866	575,341	648,748
Preferred dividends / distributions	10,500	10,500	10,500
Noncontrolling interest - redeemable preferred units	0	0	6
Noncontrolling interest in property partnerships	47,832	(2,068)	149,855
Losses from interest rate contracts	0	140	0
Interest expense	374,481	412,849	432,196
Depreciation and amortization expense	609,407	682,776	631,549
Impairment loss	0	1,783	0
Transaction costs	668	2,387	1,259
General and administrative expense	113,715	105,229	96,319
Gains on sales of real estate	8,240	82,775	377,093
Gains (losses) from early extinguishments of debt	496	(371)	(22,040)
Gains (losses) from investments in securities	3,678	2,273	(653)
Interest and other income	5,783	7,230	6,777
Gain on sale of investment in unconsolidated joint venture	0	59,370	0
Income from unconsolidated joint ventures	11,232	8,074	22,770
Development and management services income	34,605	28,284	22,554
Net Operating Income	$ 1,605,435	$ 1,601,302	$ 1,563,931