CONSOLIDATED STATEMENTS OF CHANGES IN CAPITAL OF ERP OPERATING LIMITED PARTNERSHIP (Unaudited) - USD ($) $ in Thousands	Total	ERPOP [Member]	Preferred Stock [Member] ERPOP [Member]	Preferred Stock [Member] ERPOP [Member] 8.29% Series K Cumulative Redeemable Preferred Stock	GENERAL PARTNER [Member] ERPOP [Member]	LIMITED PARTNERS [Member] ERPOP [Member]	ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) [Member] ERPOP [Member]	DISTRIBUTIONS [Member] ERPOP [Member]	PARTIALLY OWNED PROPERTIES [Member] ERPOP [Member]
Balance, beginning of year at Dec. 31, 2022			$ 37,280		$ 11,138,706	$ 209,961	$ (2,547)
Balance, beginning of year at Dec. 31, 2022									$ (721)
Conversion of OP Units held by Limited Partners into OP Units held by General Partner					3,673	(3,673)
Exercise of EQR share options					8,112
EQR's Employee Share Purchase Plan (ESPP)					1,452
EQR restricted shares					3,654
EQR share options					1,497
EQR ESPP discount					260
Net income available to Units - General Partner		$ 211,263			211,263
OP Units - General Partner distributions					(250,969)
Supplemental Executive Retirement Plan (SERP)					491
Change in market value of Redeemable Limited Partners					(5,946)
Adjustment for Limited Partners ownership in Operating Partnership					(953)	953
Equity compensation associated with Units - Limited Partners						4,654
Net income available to Units - Limited Partners		7,059				7,059
Units - Limited Partners distributions						(7,904)
Change in carrying value of Redeemable Limited Partners						668
Unrealized holding gains (losses) arising during the period	$ (9,780)	(9,780)					(9,780)
Losses reclassified into earnings from other comprehensive income	1,095	1,095					1,095
Distributions declared per Unit outstanding								$ 0.6625
Net income attributable to Noncontrolling Interests	220,071	220,071							977
Distributions to Noncontrolling Interests									(2,809)
Balance, end of period at Mar. 31, 2023			37,280		11,111,240	211,718	(11,232)
Balance, end of period at Mar. 31, 2023									(2,553)
Balance, beginning of year at Dec. 31, 2023			37,280		11,042,844	202,306	5,704
Balance, beginning of year at Dec. 31, 2023									994
Partial redemption				$ (20,125)
Conversion of OP Units held by Limited Partners into OP Units held by General Partner					254	(254)
Exercise of EQR share options					4,401
EQR's Employee Share Purchase Plan (ESPP)					1,644
EQR restricted shares					4,496	2
EQR share options					1,289
EQR ESPP discount					296
OP Units repurchased and retired	38,500				(38,474)
Net income available to Units - General Partner		293,796			293,796
OP Units - General Partner distributions					(255,843)
Supplemental Executive Retirement Plan (SERP)					(227)
Change in market value of Redeemable Limited Partners					(8,815)
Adjustment for Limited Partners ownership in Operating Partnership					(1,458)	1,458
Equity compensation associated with Units - Limited Partners						4,087
Net income available to Units - Limited Partners		8,275				8,275
Units - Limited Partners distributions						(8,446)
Change in carrying value of Redeemable Limited Partners						(156)
Losses reclassified into earnings from other comprehensive income	610	610					610
Distributions declared per Unit outstanding								$ 0.675
Net income attributable to Noncontrolling Interests	$ 305,032	$ 305,032							970
Contributions by Noncontrolling Interests									235
Distributions to Noncontrolling Interests									(2,330)
Other									(1,000)
Balance, end of period at Mar. 31, 2024			$ 17,155		$ 11,044,203	$ 207,272	$ 6,314
Balance, end of period at Mar. 31, 2024									$ (1,131)