CONSOLIDATED STATEMENTS OF CASH FLOWS OF ERP OPERATING LIMITED PARTNERSHIP - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 868,488	$ 806,995	$ 1,396,714
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	888,709	882,168	838,272
Amortization of deferred financing costs	8,941	8,729	8,737
Amortization of above/below market lease intangibles			(154)
Amortization of discounts and premiums on debt	4,091	5,004	5,302
Amortization of deferred settlements on derivative instruments	3,725	11,059	9,382
Amortization of right-of-use assets	12,795	12,157	13,266
Impairment			16,769
Write-off of pursuit costs	3,647	4,780	6,526
(Income) loss from investments in unconsolidated entities	5,378	5,031	3,398
Distributions from unconsolidated entities – return on capital	559	398	56
Net (gain) loss on sales of real estate properties	(282,539)	(304,325)	(1,072,183)
Net (gain) loss on sales of land parcels			(5)
Realized (gain) loss on investment securities	(1,504)	(2,061)	(23,432)
Unrealized (gain) loss on investment securities	(13,466)
Compensation paid with Company Common Shares	31,815	29,513	27,810
Changes in assets and liabilities:
(Increase) decrease in other assets	(10,203)	10,893	5,906
Increase (decrease) in accounts payable and accrued expenses	8,911	(266)	15,381
Increase (decrease) in accrued interest payable	(594)	(3,200)	3,614
Increase (decrease) in lease liabilities	(1,551)	(1,524)	(5,122)
Increase (decrease) in other liabilities	5,358	(13,394)	4,286
Increase (decrease) in security deposits	238	2,799	5,661
Net cash provided by operating activities	1,532,798	1,454,756	1,260,184
CASH FLOWS FROM INVESTING ACTIVITIES:
Investment in real estate – acquisitions	(324,497)	(113,046)	(1,712,131)
Investment in real estate – development/other	(78,197)	(109,345)	(206,421)
Capital expenditures to real estate	(319,342)	(221,086)	(151,019)
Non-real estate capital additions	(1,851)	(4,050)	(1,696)
Interest capitalized for real estate and unconsolidated entities under development	(12,347)	(7,105)	(15,932)
Proceeds from disposition of real estate, net	374,018	720,302	1,707,747
Investments in unconsolidated entities – acquisitions	(2,800)	(49,855)	(48,534)
Investments in unconsolidated entities - development/other	(47,180)	(109,846)	(31,257)
Distributions from unconsolidated entities – return of capital	42	300	1,516
Purchase of investment securities and other investments	(2,500)	(2,061)	(168,291)
Proceeds from sale of investment securities	3,042	3,584	191,398
Consolidation of previously unconsolidated entities	2,108
Net cash provided by (used for) investing activities	(409,504)	107,792	(434,620)
CASH FLOWS FROM FINANCING ACTIVITIES:
Debt financing costs	(4,106)	(9,894)	(6,446)
Mortgage notes payable, net:
Proceeds	572,896	48,054	58,428
Lump sum payoffs	(932,598)	(286,461)	(156,815)
Scheduled principal repayments	(3,354)	(3,392)	(7,465)
Notes, net:
Proceeds			497,470
Lump sum payoffs		(500,000)
Line of credit and commercial paper:
Line of credit proceeds			10,000
Line of credit repayments			(10,000)
Commercial paper proceeds	6,124,068	6,036,083	7,590,200
Commercial paper repayments	(5,844,892)	(6,221,158)	(7,690,000)
Proceeds from (payments on) settlement of derivative instruments	25,169
Finance ground lease principal payments	(2,662)	(2,463)	(365)
Proceeds from sale of OP Units		139,623
Proceeds from Employee Share Purchase Plan (ESPP)	3,517	4,178	4,265
Proceeds from exercise of EQR options	23,632	25,069	85,445
Payment of offering costs		(783)	(428)
Other financing activities, net	(75)	(63)	(63)
Acquisition of Noncontrolling Interests - Partially Owned Properties	(3,737)	(32,178)
Contributions – Noncontrolling Interests – Partially Owned Properties	9	603	1,394
Contributions – Limited Partners	1	1
Distributions:
OP Units – General Partner	(990,148)	(931,783)	(900,468)
Preference Units	(3,090)	(2,318)	(3,090)
OP Units – Limited Partners	(30,253)	(30,324)	(31,316)
Noncontrolling Interests – Partially Owned Properties	(5,743)	(18,406)	(5,802)
Net cash provided by (used for) financing activities	(1,120,471)	(1,785,612)	(565,056)
Net increase (decrease) in cash and cash equivalents and restricted deposits	2,823	(223,064)	260,508
Cash and cash equivalents and restricted deposits, beginning of year	137,172	360,236	99,728
Cash and cash equivalents and restricted deposits, end of year	139,995	137,172	360,236
Cash and cash equivalents	50,743	53,869	123,832
Restricted deposits	89,252	83,303	236,404
SUPPLEMENTAL INFORMATION:
Cash paid for interest, net of amounts capitalized	248,990	267,612	252,838
Net cash paid (received) for income and other taxes	1,091	748	1,179
Real estate acquisitions/dispositions/other:
Mortgage loans assumed	42,256
Amortization of deferred financing costs:
Investment in real estate, net	(211)	(506)	(353)
Other assets	2,785	2,768	2,338
Mortgage notes payable, net	2,527	2,080	2,743
Notes, net	3,840	4,387	4,009
Amortization of discounts and premiums on debt:
Mortgage notes payable, net	1,843	2,184	2,764
Notes, net	2,248	2,820	2,538
Amortization of deferred settlements on derivative instruments:
Other liabilities	(12)	(12)	(12)
Accumulated other comprehensive income	3,737	11,071	9,394
Write-off of pursuit costs:
Investment in real estate, net	527	1,150	5,918
Investments in unconsolidated entities	2,186	2,898
Other assets	934	732	582
Accounts payable and accrued expenses			26
(Income) loss from investments in unconsolidated entities:
Investments in unconsolidated entities	4,132	3,778	2,122
Other liabilities	1,246	1,253	1,276
Realized/unrealized (gain) loss on derivative instruments:
Other assets	(3,749)	(21,865)
Other liabilities	(765)	1,211
Accumulated other comprehensive income	4,514	20,654
Interest capitalized for real estate and unconsolidated entities under development:
Investment in real estate, net	4,010	2,365	15,318
Investments in unconsolidated entities	(8,337)	(4,740)	(614)
Investments in unconsolidated entities - development/other:
Investment in real estate, net			1,395
Investments in unconsolidated entities	(45,770)	(108,556)	(30,642)
Other liabilities	(1,410)	(1,290)	(2,010)
Consolidation of previously unconsolidated entities:
Investment in real estate, net	(50,315)
Investments in unconsolidated entities	46,327
Accounts payable and accrued expenses	75
Other liabilities	2,000
Noncontrolling Interests - Partially Owned Properties	4,021
Debt financing costs:
Other assets		(9,566)	229
Mortgage notes payable, net	(4,106)	(228)	(2,344)
Notes, net		(100)	(4,331)
Proceeds from (payments on) settlement of derivative instruments:
Other assets	25,613
Other liabilities	(444)
Right-of-use assets and lease liabilities initial measurement and reclassifications:
Right-of-use assets	(7,105)	(400)	11,308
Lease liabilities	7,105	400	(11,308)
Non-cash share distribution and other transfers from unconsolidated entities:
Investments in unconsolidated entities	636	4,201	1,430
Other assets	(636)	(4,201)	(1,430)
ERPOP [Member]
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	868,488	806,995	1,396,714
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	888,709	882,168	838,272
Amortization of deferred financing costs	8,941	8,729	8,737
Amortization of above/below market lease intangibles			(154)
Amortization of discounts and premiums on debt	4,091	5,004	5,302
Amortization of deferred settlements on derivative instruments	3,725	11,059	9,382
Amortization of right-of-use assets	12,795	12,157	13,266
Impairment			16,769
Write-off of pursuit costs	3,647	4,780	6,526
(Income) loss from investments in unconsolidated entities	5,378	5,031	3,398
Distributions from unconsolidated entities – return on capital	559	398	56
Net (gain) loss on sales of real estate properties	(282,539)	(304,325)	(1,072,183)
Net (gain) loss on sales of land parcels			(5)
Realized (gain) loss on investment securities	(1,504)	(2,061)	(23,432)
Unrealized (gain) loss on investment securities	(13,466)
Compensation paid with Company Common Shares	31,815	29,513	27,810
Changes in assets and liabilities:
(Increase) decrease in other assets	(10,203)	10,893	5,906
Increase (decrease) in accounts payable and accrued expenses	8,911	(266)	15,381
Increase (decrease) in accrued interest payable	(594)	(3,200)	3,614
Increase (decrease) in lease liabilities	(1,551)	(1,524)	(5,122)
Increase (decrease) in other liabilities	5,358	(13,394)	4,286
Increase (decrease) in security deposits	238	2,799	5,661
Net cash provided by operating activities	1,532,798	1,454,756	1,260,184
CASH FLOWS FROM INVESTING ACTIVITIES:
Investment in real estate – acquisitions	(324,497)	(113,046)	(1,712,131)
Investment in real estate – development/other	(78,197)	(109,345)	(206,421)
Capital expenditures to real estate	(319,342)	(221,086)	(151,019)
Non-real estate capital additions	(1,851)	(4,050)	(1,696)
Interest capitalized for real estate and unconsolidated entities under development	(12,347)	(7,105)	(15,932)
Proceeds from disposition of real estate, net	374,018	720,302	1,707,747
Investments in unconsolidated entities – acquisitions	(2,800)	(49,855)	(48,534)
Investments in unconsolidated entities - development/other	(47,180)	(109,846)	(31,257)
Distributions from unconsolidated entities – return of capital	42	300	1,516
Purchase of investment securities and other investments	(2,500)	(2,061)	(168,291)
Proceeds from sale of investment securities	3,042	3,584	191,398
Consolidation of previously unconsolidated entities	2,108
Net cash provided by (used for) investing activities	(409,504)	107,792	(434,620)
CASH FLOWS FROM FINANCING ACTIVITIES:
Debt financing costs	(4,106)	(9,894)	(6,446)
Mortgage notes payable, net:
Proceeds	572,896	48,054	58,428
Lump sum payoffs	(932,598)	(286,461)	(156,815)
Scheduled principal repayments	(3,354)	(3,392)	(7,465)
Notes, net:
Proceeds			497,470
Lump sum payoffs		(500,000)
Line of credit and commercial paper:
Line of credit proceeds			10,000
Line of credit repayments			(10,000)
Commercial paper proceeds	6,124,068	6,036,083	7,590,200
Commercial paper repayments	(5,844,892)	(6,221,158)	(7,690,000)
Proceeds from (payments on) settlement of derivative instruments	25,169
Finance ground lease principal payments	(2,662)	(2,463)	(365)
Proceeds from sale of OP Units		139,623
Proceeds from Employee Share Purchase Plan (ESPP)	3,517	4,178	4,265
Proceeds from exercise of EQR options	23,632	25,069	85,445
OP Units repurchased and retired	(49,105)
Payment of offering costs		(783)	(428)
Other financing activities, net	(75)	(63)	(63)
Acquisition of Noncontrolling Interests - Partially Owned Properties	(3,737)	(32,178)
Contributions – Noncontrolling Interests – Partially Owned Properties	9	603	1,394
Contributions – Limited Partners	1	1
Distributions:
OP Units – General Partner	(990,148)	(931,783)	(900,468)
Preference Units	(3,090)	(2,318)	(3,090)
OP Units – Limited Partners	(30,253)	(30,324)	(31,316)
Noncontrolling Interests – Partially Owned Properties	(5,743)	(18,406)	(5,802)
Net cash provided by (used for) financing activities	(1,120,471)	(1,785,612)	(565,056)
Net increase (decrease) in cash and cash equivalents and restricted deposits	2,823	(223,064)	260,508
Cash and cash equivalents and restricted deposits, beginning of year	137,172	360,236	99,728
Cash and cash equivalents and restricted deposits, end of year	139,995	137,172	360,236
Cash and cash equivalents	50,743	53,869	123,832
Restricted deposits	89,252	83,303	236,404
SUPPLEMENTAL INFORMATION:
Cash paid for interest, net of amounts capitalized	248,990	267,612	252,838
Net cash paid (received) for income and other taxes	1,091	748	1,179
Real estate acquisitions/dispositions/other:
Mortgage loans assumed	42,256
Amortization of deferred financing costs:
Investment in real estate, net	(211)	(506)	(353)
Other assets	2,785	2,768	2,338
Mortgage notes payable, net	2,527	2,080	2,743
Notes, net	3,840	4,387	4,009
Amortization of discounts and premiums on debt:
Mortgage notes payable, net	1,843	2,184	2,764
Notes, net	2,248	2,820	2,538
Amortization of deferred settlements on derivative instruments:
Other liabilities	(12)	(12)	(12)
Accumulated other comprehensive income	3,737	11,071	9,394
Write-off of pursuit costs:
Investment in real estate, net	527	1,150	5,918
Investments in unconsolidated entities	2,186	2,898
Other assets	934	732	582
Accounts payable and accrued expenses			26
(Income) loss from investments in unconsolidated entities:
Investments in unconsolidated entities	4,132	3,778	2,122
Other liabilities	1,246	1,253	1,276
Realized/unrealized (gain) loss on derivative instruments:
Other assets	(3,749)	(21,865)
Other liabilities	(765)	1,211
Accumulated other comprehensive income	4,514	20,654
Interest capitalized for real estate and unconsolidated entities under development:
Investment in real estate, net	(4,010)	(2,365)	(15,318)
Investments in unconsolidated entities	(8,337)	(4,740)	(614)
Investments in unconsolidated entities - development/other:
Investment in real estate, net			1,395
Investments in unconsolidated entities	(45,770)	(108,556)	(30,642)
Other liabilities	(1,410)	(1,290)	(2,010)
Consolidation of previously unconsolidated entities:
Investment in real estate, net	(50,315)
Investments in unconsolidated entities	46,327
Accounts payable and accrued expenses	75
Other liabilities	2,000
Noncontrolling Interests - Partially Owned Properties	4,021
Debt financing costs:
Other assets		(9,566)	229
Mortgage notes payable, net	(4,106)	(228)	(2,344)
Notes, net		(100)	(4,331)
Proceeds from (payments on) settlement of derivative instruments:
Other assets	25,613
Other liabilities	(444)
Right-of-use assets and lease liabilities initial measurement and reclassifications:
Right-of-use assets	(7,105)	(400)	11,308
Lease liabilities	7,105	400	(11,308)
Non-cash share distribution and other transfers from unconsolidated entities:
Investments in unconsolidated entities	636	4,201	1,430
Other assets	$ (636)	$ (4,201)	$ (1,430)