Segment Information (Schedule Of Reconciliation Of Net Operating Income To Net Income) (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net income attributable to the Company's common shareholders / unitholders	$ 111,703,000	$ 266,525,000	$ 203,372,000	$ 764,232,000
Preferred Stock Redemption Charge	0	0	(6,412,000)	0
Preferred dividends / distributions	0	(2,625,000)	(2,560,000)	(5,250,000)
Noncontrolling interest-common units of the Operating Partnership	(12,383,000)	(30,197,000)	(23,422,000)	(87,525,000)
Noncontrolling interest in property partnerships	(17,164,000)	767,000	(33,631,000)	(18,719,000)
Interest expense	(106,319,000)	(107,142,000)	(214,221,000)	(208,733,000)
Loss from early extinguishment of debt	0	0	898,000	0
Company's share of net operating income from joint ventures	(453,169,000)	(402,404,000)	(897,116,000)	(874,057,000)
Depreciation and amortization expense	(183,838,000)	(178,188,000)	(360,403,000)	(349,282,000)
Transaction costs	(751,000)	(332,000)	(1,082,000)	(947,000)
General and administrative expense	(38,405,000)	(37,743,000)	(83,364,000)	(74,197,000)
Gains (losses) from investments in securities	(2,275,000)	(4,552,000)	(3,934,000)	893,000
Interest and other income (loss)	(1,452,000)	(1,305,000)	(2,620,000)	(4,322,000)
Gains on sales of real estate	(7,756,000)	(203,767,000)	(7,756,000)	(613,932,000)
Income (loss) from unconsolidated joint ventures	1,373,000	(1,832,000)	(3,852,000)	(1,463,000)
Segment Reconciling Items
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net income attributable to the Company's common shareholders / unitholders	111,703,000	266,525,000	203,372,000	764,232,000
Preferred Stock Redemption Charge	0	0	6,412,000	0
Preferred dividends / distributions	0	2,625,000	2,560,000	5,250,000
Noncontrolling interest-common units of the Operating Partnership	12,383,000	30,197,000	23,422,000	87,525,000
Noncontrolling interest in property partnerships	17,164,000	(767,000)	33,631,000	18,719,000
Interest expense	106,319,000	107,142,000	214,221,000	208,733,000
Loss from early extinguishment of debt	0	0	898,000	0
Depreciation and amortization expense	183,838,000	178,188,000	360,403,000	349,282,000
Transaction costs	751,000	332,000	1,082,000	947,000
Operating expense	2,655,000	2,484,000	6,160,000	5,721,000
General and administrative expense	38,405,000	37,743,000	83,364,000	74,197,000
Gains (losses) from investments in securities	2,275,000	4,552,000	3,934,000	(893,000)
Interest and other income (loss)	1,452,000	1,305,000	2,620,000	4,322,000
Gains on sales of real estate	7,756,000	203,767,000	7,756,000	613,932,000
Income (loss) from unconsolidated joint ventures	(1,373,000)	1,832,000	3,852,000	1,463,000
Other revenue	2,655,000	2,484,000	6,160,000	5,721,000
Company's share of Net Operating Income	432,299,000	397,888,000	856,665,000	850,638,000
Unconsolidated Joint Ventures [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Interest expense	(25,636,000)	(23,306,000)	(51,192,000)	(45,889,000)
Depreciation and amortization expense	(33,627,000)	(37,390,000)	(67,730,000)	(69,425,000)
Transaction costs	0	0	(7,000)	0
Gains on sales of real estate		(11,720,000)	0	(11,720,000)
Income (loss) from unconsolidated joint ventures	1,373,000	(1,832,000)	(3,852,000)	(1,463,000)
Unconsolidated Joint Ventures [Member] | Segment Reconciling Items
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Company's share of net operating income from joint ventures	25,417,000	27,911,000	50,212,000	56,669,000
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	125,846,000	301,975,000	231,619,000	868,308,000
Preferred Stock Redemption Charge	0	0	(6,412,000)	0
Preferred dividends / distributions	0	(2,625,000)	(2,560,000)	(5,250,000)
Noncontrolling interest in property partnerships	(17,164,000)	767,000	(33,631,000)	(18,719,000)
Interest expense	(106,319,000)	(107,142,000)	(214,221,000)	(208,733,000)
Loss from early extinguishment of debt	0	0	898,000	0
Depreciation and amortization expense	(182,078,000)	(176,409,000)	(355,578,000)	(345,694,000)
Transaction costs	(751,000)	(332,000)	(1,082,000)	(947,000)
General and administrative expense	(38,405,000)	(37,743,000)	(83,364,000)	(74,197,000)
Gains (losses) from investments in securities	(2,275,000)	(4,552,000)	(3,934,000)	893,000
Interest and other income (loss)	(1,452,000)	(1,305,000)	(2,620,000)	(4,322,000)
Gains on sales of real estate	(7,756,000)	(207,241,000)	(7,756,000)	(626,895,000)
Income (loss) from unconsolidated joint ventures	1,373,000	(1,832,000)	(3,852,000)	(1,463,000)
Boston Properties Limited Partnership | Segment Reconciling Items
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net income attributable to the Company's common shareholders / unitholders	125,846,000	301,975,000	231,619,000	868,308,000
Preferred Stock Redemption Charge	0	0	6,412,000	0
Preferred dividends / distributions	0	2,625,000	2,560,000	5,250,000
Noncontrolling interest in property partnerships	17,164,000	(767,000)	33,631,000	18,719,000
Interest expense	106,319,000	107,142,000	214,221,000	208,733,000
Loss from early extinguishment of debt	0	0	898,000	0
Depreciation and amortization expense	182,078,000	176,409,000	355,578,000	345,694,000
Transaction costs	751,000	332,000	1,082,000	947,000
Operating expense	2,655,000	2,484,000	6,160,000	5,721,000
General and administrative expense	38,405,000	37,743,000	83,364,000	74,197,000
Gains (losses) from investments in securities	2,275,000	4,552,000	3,934,000	(893,000)
Interest and other income (loss)	1,452,000	1,305,000	2,620,000	4,322,000
Gains on sales of real estate	7,756,000	207,241,000	7,756,000	626,895,000
Income (loss) from unconsolidated joint ventures	(1,373,000)	1,832,000	3,852,000	1,463,000
Other revenue	2,655,000	2,484,000	6,160,000	5,721,000
Company's share of Net Operating Income	432,299,000	397,888,000	856,665,000	850,638,000
Management Service [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Other revenue	(7,284,000)	(8,125,000)	(14,087,000)	(16,004,000)
Management Service [Member] | Segment Reconciling Items
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Other revenue	7,284,000	8,125,000	14,087,000	16,004,000
Management Service [Member] | Boston Properties Limited Partnership
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Other revenue	(7,284,000)	(8,125,000)	(14,087,000)	(16,004,000)
Management Service [Member] | Boston Properties Limited Partnership | Segment Reconciling Items
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Other revenue	7,284,000	8,125,000	14,087,000	16,004,000
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	46,287,000	32,427,000	90,663,000	80,088,000
Noncontrolling interest - property partnerships [Member] | Segment Reconciling Items
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Company's share of net operating income from joint ventures	46,287,000	32,427,000	90,663,000	80,088,000
Noncontrolling interest - property partnerships [Member] | Boston Properties Limited Partnership | Segment Reconciling Items
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Company's share of net operating income from joint ventures	$ 46,287,000	$ 32,427,000	$ 90,663,000	$ 80,088,000