Segment Information (Schedule Of Reconciliation Of Net Operating Income To Net Income) (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net income attributable to the Company's common shareholders / unitholders	$ 266,525	$ 164,318	$ 764,232	$ 262,431
Preferred dividends / distributions	(2,625)	(2,625)	(5,250)	(5,250)
Noncontrolling interest-common units of the Operating Partnership	(30,197)	(19,036)	(87,525)	(30,627)
Noncontrolling interest in property partnerships	767	(17,482)	(18,719)	(36,312)
Interest expense	(107,142)	(102,357)	(208,733)	(203,366)
Company's share of net operating income from joint ventures	(402,404)	(454,301)	(874,057)	(902,016)
Depreciation and amortization expense	(178,188)	(177,411)	(349,282)	(342,005)
Transaction costs	(332)	(417)	(947)	(877)
General and administrative expense	(37,743)	(35,071)	(74,197)	(76,833)
Gains (losses) from investments in securities	(4,552)	(1,165)	893	(4,134)
Interest and other income (loss)	(1,305)	(3,615)	(4,322)	(7,368)
Gains on sales of real estate	(203,767)	(1,686)	(613,932)	(781)
Income from unconsolidated joint ventures	(1,832)	(47,964)	(1,463)	(48,177)
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	266,525	164,318	764,232	262,431
Preferred dividends / distributions	2,625	2,625	5,250	5,250
Noncontrolling interest-common units of the Operating Partnership	30,197	19,036	87,525	30,627
Noncontrolling interest in property partnerships	(767)	17,482	18,719	36,312
Interest expense	107,142	102,357	208,733	203,366
Impairment losses	0	0	0	24,038
Depreciation and amortization expense	178,188	177,411	349,282	342,005
Transaction costs	332	417	947	877
Operating expense	2,484	2,403	5,721	5,798
General and administrative expense	37,743	35,071	74,197	76,833
Gains (losses) from investments in securities	4,552	1,165	(893)	4,134
Interest and other income (loss)	1,305	3,615	4,322	7,368
Gains on sales of real estate	203,767	1,686	613,932	781
Income from unconsolidated joint ventures	1,832	47,964	1,463	48,177
Other revenue	2,484	2,403	5,721	5,798
Net Operating Income	397,888	433,454	850,638	859,433
Unconsolidated Joint Ventures [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Interest expense	(23,306)	(20,803)	(45,889)	(41,560)
Company's share of net operating income from joint ventures	(27,911)	(24,715)	(56,669)	(50,064)
Depreciation and amortization expense	(37,390)	(24,818)	(69,425)	(53,464)
Gains on sales of real estate	(11,720)	(34,572)	(11,720)	(34,572)
Income from unconsolidated joint ventures	(1,832)	(47,964)	(1,463)	(48,177)
Unconsolidated Joint Ventures [Member] \| Business Intersegment, Eliminations [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Company's share of net operating income from joint ventures	27,911	24,715	56,669	50,064
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	301,975	185,715	868,308	299,097
Preferred dividends / distributions	(2,625)	(2,625)	(5,250)	(5,250)
Noncontrolling interest in property partnerships	767	(17,482)	(18,719)	(36,312)
Interest expense	(107,142)	(102,357)	(208,733)	(203,366)
Depreciation and amortization expense	(176,409)	(175,199)	(345,694)	(337,881)
Transaction costs	(332)	(417)	(947)	(877)
General and administrative expense	(37,743)	(35,071)	(74,197)	(76,833)
Gains (losses) from investments in securities	(4,552)	(1,165)	893	(4,134)
Interest and other income (loss)	(1,305)	(3,615)	(4,322)	(7,368)
Gains on sales of real estate	(207,241)	(1,835)	(626,895)	(930)
Income from unconsolidated joint ventures	(1,832)	(47,964)	(1,463)	(48,177)
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	301,975	185,715	868,308	299,097
Preferred dividends / distributions	2,625	2,625	5,250	5,250
Noncontrolling interest in property partnerships	(767)	17,482	18,719	36,312
Interest expense	107,142	102,357	208,733	203,366
Impairment losses	0	0	0	22,272
Depreciation and amortization expense	176,409	175,199	345,694	337,881
Transaction costs	332	417	947	877
Operating expense	2,484	2,403	5,721	5,798
General and administrative expense	37,743	35,071	74,197	76,833
Gains (losses) from investments in securities	4,552	1,165	(893)	4,134
Interest and other income (loss)	1,305	3,615	4,322	7,368
Gains on sales of real estate	207,241	1,835	626,895	930
Income from unconsolidated joint ventures	1,832	47,964	1,463	48,177
Other revenue	2,484	2,403	5,721	5,798
Net Operating Income	397,888	433,454	850,638	859,433
Management Service [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Other revenue	(8,125)	(9,986)	(16,004)	(19,263)
Management Service [Member] \| Business Intersegment, Eliminations [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Other revenue	8,125	9,986	16,004	19,263
Management Service [Member] \| Boston Properties Limited Partnership
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Operating expense	(2,484)	(2,403)	(5,721)	(5,798)
Other revenue	(8,125)	(9,986)	(16,004)	(19,263)
Management Service [Member] \| Boston Properties Limited Partnership \| Business Intersegment, Eliminations [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Other revenue	8,125	9,986	16,004	19,263
Noncontrolling interest - property partnerships [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Company's share of net operating income from joint ventures	32,427	45,562	80,088	92,647
Noncontrolling interest - property partnerships [Member] \| Business Intersegment, Eliminations [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Company's share of net operating income from joint ventures	32,427	45,562	80,088	92,647
Noncontrolling interest - property partnerships [Member] \| Boston Properties Limited Partnership \| Business Intersegment, Eliminations [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Company's share of net operating income from joint ventures	$ 32,427	$ 45,562	$ 80,088	$ 92,647

The net result for the period of deducting property operating expenses from property operating revenues.

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