CONSOLIDATED STATEMENTS OF CHANGES IN CAPITAL OF ERP OPERATING LIMITED PARTNERSHIP (Unaudited) - USD ($) $ in Thousands	Total	ERPOP [Member]	PREFERRED SHARES ERPOP [Member]	General Partner [Member] ERPOP [Member]	Limited Partner ERPOP [Member]	ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) ERPOP [Member]	DISTRIBUTIONS [Member] ERPOP [Member]	PARTIALLY OWNED PROPERTIES [Member] ERPOP [Member]
Balance, beginning of year at Dec. 31, 2020			$ 37,280	$ 10,532,037	$ 233,162	$ (43,666)
Balance, beginning of year at Dec. 31, 2020								$ 4,673
Exercise of EQR share options				22,882
EQR's Employee Share Purchase Plan (ESPP)				1,731
EQR restricted shares				2,274
EQR share options				988
EQR ESPP discount				444
Net income available to Units - General Partner		$ 56,766		56,766
OP Units General Partner distributions				(224,673)
Supplemental Executive Retirement Plan (SERP)				(1,229)
Change in market value of Redeemable Limited Partners				(72,956)
Adjustment for Limited Partners ownership in Operating Partnership				619	(619)
Equity compensation associated with Units - Limited Partners					6,488
Net income available to Units - Limited Partners		2,143			2,143
Units - Limited Partners distributions					(8,589)
Change in carrying value of Redeemable Limited Partners					2,384
Unrealized holding (losses) arising during the period	$ 682	682
Losses reclassified into earnings from other comprehensive income	(2,303)	(2,303)				2,303
Distributions declared per Unit outstanding							$ 0.6025
Net income attributable to Noncontrolling Interests	60,364	60,364						682
Distributions to Noncontrolling Interests								(2,883)
Balance, end of period at Mar. 31, 2021			37,280	10,318,883	234,969	(41,363)
Balance, end of period at Mar. 31, 2021								2,472
Balance, beginning of year at Dec. 31, 2021			37,280	10,951,940	214,094	(34,272)
Balance, beginning of year at Dec. 31, 2021								18,166
Conversion of OP Units held by Limited Partners into OP Units held by General Partner				174	(174)
Exercise of EQR share options				14,344
EQR's Employee Share Purchase Plan (ESPP)				969
EQR restricted shares				3,611	1
EQR share options				876
EQR ESPP discount				171
Net income available to Units - General Partner		69,993		69,993
OP Units General Partner distributions				(235,351)
Offering costs				(114)
Supplemental Executive Retirement Plan (SERP)				(163)
Change in market value of Redeemable Limited Partners				939
Adjustment for Limited Partners ownership in Operating Partnership				1,045	(1,045)
Equity compensation associated with Units - Limited Partners					7,798
Net income available to Units - Limited Partners		2,394			2,394
Units - Limited Partners distributions					(7,895)
Change in carrying value of Redeemable Limited Partners					2,278
Unrealized holding (losses) arising during the period	639	639
Losses reclassified into earnings from other comprehensive income	(2,425)	(2,425)				2,425
Distributions declared per Unit outstanding							$ 0.625
Net income attributable to Noncontrolling Interests	$ 73,798	$ 73,798						639
Contributions by Noncontrolling Interests								446
Distributions to Noncontrolling Interests								(15,836)
Balance, end of period at Mar. 31, 2022			$ 37,280	$ 10,808,434	$ 217,451	$ (31,847)
Balance, end of period at Mar. 31, 2022								$ 3,415