CONSOLIDATED STATEMENTS OF CASH FLOWS OF ERP OPERATING LIMITED PARTNERSHIP - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 806,995	$ 1,396,714	$ 962,501
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	882,168	838,272	820,832
Amortization of deferred financing costs	8,729	8,737	8,939
Amortization of above/below market lease intangibles		(154)	(71)
Amortization of discounts and premiums on debt	5,004	5,302	5,231
Amortization of deferred settlements on derivative instruments	11,059	9,382	35,075
Amortization of right-of-use assets	12,157	13,266	11,682
Impairment		16,769
Write-off of pursuit costs	4,780	6,526	6,869
(Income) loss from investments in unconsolidated entities	5,031	3,398	3,284
Distributions from unconsolidated entities – return on capital	398	56	100
Net (gain) loss on sales of real estate properties	(304,325)	(1,072,183)	(531,807)
Net (gain) loss on sales of land parcels		(5)	(34,234)
Net (gain) loss on debt extinguishment			26,150
Realized/unrealized (gain) loss on derivative instruments			50
Realized (gain) loss on sale of investment securities	(2,061)	(23,432)
Compensation paid with Company Common Shares	29,513	27,810	23,174
Other operating activities, net			1,805
Changes in assets and liabilities:
(Increase) decrease in other assets	10,893	5,906	(53,021)
Increase (decrease) in accounts payable and accrued expenses	(266)	15,381	470
Increase (decrease) in accrued interest payable	(3,200)	3,614	(956)
Increase (decrease) in lease liabilities	(1,524)	(5,122)	(2,204)
Increase (decrease) in other liabilities	(13,394)	4,286	(8,751)
Increase (decrease) in security deposits	2,799	5,661	(9,582)
Net cash provided by operating activities	1,454,756	1,260,184	1,265,536
CASH FLOWS FROM INVESTING ACTIVITIES:
Investment in real estate – acquisitions	(113,046)	(1,712,131)	(48,898)
Investment in real estate – development/other	(109,345)	(206,421)	(230,332)
Capital expenditures to real estate	(221,086)	(151,019)	(135,979)
Non-real estate capital additions	(4,050)	(1,696)	(20,100)
Interest capitalized for real estate and unconsolidated entities under development	(7,105)	(15,932)	(10,165)
Proceeds from disposition of real estate, net	720,302	1,707,747	1,113,972
Investments in unconsolidated entities – acquisitions	(49,855)	(48,534)
Investments in unconsolidated entities - development/other	(109,846)	(31,257)	(5,775)
Distributions from unconsolidated entities – return of capital	300	1,516	1,636
Purchase of investment securities and other investments	(2,061)	(168,291)	(773)
Proceeds from sale of investment securities	3,584	191,398
Net cash provided by (used for) investing activities	107,792	(434,620)	663,586
CASH FLOWS FROM FINANCING ACTIVITIES:
Debt financing costs	(9,894)	(6,446)	(2,923)
Mortgage notes payable, net:
Proceeds	48,054	58,428	519,204
Lump sum payoffs	(286,461)	(156,815)	(160,522)
Scheduled principal repayments	(3,392)	(7,465)	(7,759)
Notes, net:
Proceeds		497,470
Lump sum payoffs	(500,000)		(750,000)
Line of credit and commercial paper:
Line of credit proceeds		10,000	1,870,000
Line of credit repayments		(10,000)	(1,890,000)
Commercial paper proceeds	6,036,083	7,590,200	7,450,997
Commercial paper repayments	(6,221,158)	(7,690,000)	(8,034,000)
Proceeds from (payments on) settlement of derivative instruments			(1,240)
Finance ground lease principal payments	(2,463)	(365)
Proceeds from sale of OP Units	139,623
Proceeds from Employee Share Purchase Plan (ESPP)	4,178	4,265	4,508
Proceeds from exercise of EQR options	25,069	85,445	12,275
Payment of offering costs	(783)	(428)
Other financing activities, net	(63)	(63)	(63)
Acquisition of Noncontrolling Interests - Partially Owned Properties	(32,178)
Contributions – Noncontrolling Interests – Partially Owned Properties	603	1,394	417
Contributions – Limited Partners	1		13
Distributions:
OP Units – General Partner	(931,783)	(900,468)	(883,938)
Preference Units	(2,318)	(3,090)	(3,090)
OP Units – Limited Partners	(30,324)	(31,316)	(32,403)
Noncontrolling Interests – Partially Owned Properties	(18,406)	(5,802)	(11,719)
Net cash provided by (used for) financing activities	(1,785,612)	(565,056)	(1,946,393)
Net increase (decrease) in cash and cash equivalents and restricted deposits	(223,064)	260,508	(17,271)
Cash and cash equivalents and restricted deposits, beginning of year	360,236	99,728	116,999
Cash and cash equivalents and restricted deposits, end of year	137,172	360,236	99,728
Cash and cash equivalents	53,869	123,832	42,591
Restricted deposits	83,303	236,404	57,137
SUPPLEMENTAL INFORMATION:
Cash paid for interest, net of amounts capitalized	267,612	252,838	320,854
Net cash paid (received) for income and other taxes	748	1,179	(1,038)
Amortization of deferred financing costs:
Investment in real estate, net	(506)	(353)	(240)
Other assets	2,768	2,338	2,338
Mortgage notes payable, net	2,080	2,743	1,815
Notes, net	4,387	4,009	5,026
Amortization of discounts and premiums on debt:
Mortgage notes payable, net	2,184	2,764	2,234
Notes, net	2,820	2,538	2,997
Amortization of deferred settlements on derivative instruments:
Other liabilities	(12)	(12)	(12)
Accumulated other comprehensive income	11,071	9,394	35,087
Write-off of pursuit costs:
Investment in real estate, net	1,150	5,918	6,566
Investments in unconsolidated entities	2,898
Other assets	732	582	271
Accounts payable and accrued expenses		26	32
(Income) loss from investments in unconsolidated entities:
Investments in unconsolidated entities	3,778	2,122	1,995
Other liabilities	1,253	1,276	1,289
Realized/unrealized (gain) loss on derivative instruments:
Other assets	(21,865)
Other liabilities	1,211		1,240
Accumulated other comprehensive income	20,654		(1,190)
Interest capitalized for real estate and unconsolidated entities under development:
Investment in real estate, net	2,365	15,318	10,165
Investments in unconsolidated entities	4,740	614
Investments in unconsolidated entities - development/other:
Investments in unconsolidated entities	(108,556)	(30,642)	(4,275)
Debt financing costs:
Other assets	(9,566)	229	(231)
Mortgage notes payable, net	(228)	(2,344)	(2,692)
Notes, net	(100)	(4,331)
Right-of-use assets and lease liabilities initial measurement and reclassifications:
Right-of-use assets	(400)	11,308
Lease liabilities	400	(11,308)
Non-cash share distribution and other transfers from unconsolidated entities:
Investments in unconsolidated entities	4,201	1,430
Other assets	(4,201)	(1,430)
Mortgage Notes Payable, Net [Member]
Mortgage notes payable, net:
Net gain (loss) on debt extinguishment			(327)
Notes, net:
Net gain (loss) on debt extinguishment			(327)
Notes, Net [Member]
Mortgage notes payable, net:
Net gain (loss) on debt extinguishment			(25,823)
Notes, net:
Net gain (loss) on debt extinguishment			(25,823)
ERPOP [Member]
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	806,995	1,396,714	962,501
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	882,168	838,272	820,832
Amortization of deferred financing costs	8,729	8,737	8,939
Amortization of above/below market lease intangibles		(154)	(71)
Amortization of discounts and premiums on debt	5,004	5,302	5,231
Amortization of deferred settlements on derivative instruments	11,059	9,382	35,075
Amortization of right-of-use assets	12,157	13,266	11,682
Impairment		16,769
Write-off of pursuit costs	4,780	6,526	6,869
(Income) loss from investments in unconsolidated entities	5,031	3,398	3,284
Distributions from unconsolidated entities – return on capital	398	56	100
Net (gain) loss on sales of real estate properties	(304,325)	(1,072,183)	(531,807)
Net (gain) loss on sales of land parcels		(5)	(34,234)
Net (gain) loss on debt extinguishment			26,150
Realized/unrealized (gain) loss on derivative instruments			50
Realized (gain) loss on sale of investment securities	(2,061)	(23,432)
Compensation paid with Company Common Shares	29,513	27,810	23,174
Other operating activities, net			1,805
Changes in assets and liabilities:
(Increase) decrease in other assets	10,893	5,906	(53,021)
Increase (decrease) in accounts payable and accrued expenses	(266)	15,381	470
Increase (decrease) in accrued interest payable	(3,200)	3,614	(956)
Increase (decrease) in lease liabilities	(1,524)	(5,122)	(2,204)
Increase (decrease) in other liabilities	(13,394)	4,286	(8,751)
Increase (decrease) in security deposits	2,799	5,661	(9,582)
Net cash provided by operating activities	1,454,756	1,260,184	1,265,536
CASH FLOWS FROM INVESTING ACTIVITIES:
Investment in real estate – acquisitions	(113,046)	(1,712,131)	(48,898)
Investment in real estate – development/other	(109,345)	(206,421)	(230,332)
Capital expenditures to real estate	(221,086)	(151,019)	(135,979)
Non-real estate capital additions	(4,050)	(1,696)	(20,100)
Interest capitalized for real estate and unconsolidated entities under development	(7,105)	(15,932)	(10,165)
Proceeds from disposition of real estate, net	720,302	1,707,747	1,113,972
Investments in unconsolidated entities – acquisitions	(49,855)	(48,534)
Investments in unconsolidated entities - development/other	(109,846)	(31,257)	(5,775)
Distributions from unconsolidated entities – return of capital	300	1,516	1,636
Purchase of investment securities and other investments	(2,061)	(168,291)	(773)
Proceeds from sale of investment securities	3,584	191,398
Net cash provided by (used for) investing activities	107,792	(434,620)	663,586
CASH FLOWS FROM FINANCING ACTIVITIES:
Debt financing costs	(9,894)	(6,446)	(2,923)
Mortgage notes payable, net:
Proceeds	48,054	58,428	519,204
Lump sum payoffs	(286,461)	(156,815)	(160,522)
Scheduled principal repayments	(3,392)	(7,465)	(7,759)
Notes, net:
Proceeds		497,470
Lump sum payoffs	(500,000)		(750,000)
Line of credit and commercial paper:
Line of credit proceeds		10,000	1,870,000
Line of credit repayments		(10,000)	(1,890,000)
Commercial paper proceeds	6,036,083	7,590,200	7,450,997
Commercial paper repayments	(6,221,158)	(7,690,000)	(8,034,000)
Proceeds from (payments on) settlement of derivative instruments			(1,240)
Finance ground lease principal payments	(2,463)	(365)
Proceeds from sale of OP Units	139,623
Proceeds from Employee Share Purchase Plan (ESPP)	4,178	4,265	4,508
Proceeds from exercise of EQR options	25,069	85,445	12,275
Payment of offering costs	(783)	(428)
Other financing activities, net	(63)	(63)	(63)
Acquisition of Noncontrolling Interests - Partially Owned Properties	(32,178)
Contributions – Noncontrolling Interests – Partially Owned Properties	603	1,394	417
Contributions – Limited Partners	1		13
Distributions:
OP Units – General Partner	(931,783)	(900,468)	(883,938)
Preference Units	(2,318)	(3,090)	(3,090)
OP Units – Limited Partners	(30,324)	(31,316)	(32,403)
Noncontrolling Interests – Partially Owned Properties	(18,406)	(5,802)	(11,719)
Net cash provided by (used for) financing activities	(1,785,612)	(565,056)	(1,946,393)
Net increase (decrease) in cash and cash equivalents and restricted deposits	(223,064)	260,508	(17,271)
Cash and cash equivalents and restricted deposits, beginning of year	360,236	99,728	116,999
Cash and cash equivalents and restricted deposits, end of year	137,172	360,236	99,728
Cash and cash equivalents	53,869	123,832	42,591
Restricted deposits	83,303	236,404	57,137
SUPPLEMENTAL INFORMATION:
Cash paid for interest, net of amounts capitalized	267,612	252,838	320,854
Net cash paid (received) for income and other taxes	748	1,179	(1,038)
Amortization of deferred financing costs:
Investment in real estate, net	(506)	(353)	(240)
Other assets	2,768	2,338	2,338
Mortgage notes payable, net	2,080	2,743	1,815
Notes, net	4,387	4,009	5,026
Amortization of discounts and premiums on debt:
Mortgage notes payable, net	2,184	2,764	2,234
Notes, net	2,820	2,538	2,997
Amortization of deferred settlements on derivative instruments:
Other liabilities	(12)	(12)	(12)
Accumulated other comprehensive income	11,071	9,394	35,087
Write-off of pursuit costs:
Investment in real estate, net	1,150	5,918	6,566
Investments in unconsolidated entities	2,898
Other assets	732	582	271
Accounts payable and accrued expenses		26	32
(Income) loss from investments in unconsolidated entities:
Investments in unconsolidated entities	3,778	2,122	1,995
Other liabilities	1,253	1,276	1,289
Realized/unrealized (gain) loss on derivative instruments:
Other assets	(21,865)
Other liabilities	1,211		1,240
Accumulated other comprehensive income	20,654		(1,190)
Interest capitalized for real estate and unconsolidated entities under development:
Investment in real estate, net	(2,365)	(15,318)	(10,165)
Investments in unconsolidated entities	(4,740)	(614)
Investments in unconsolidated entities - development/other:
Investment in real estate, net		1,395
Investments in unconsolidated entities	(108,556)	(30,642)	(4,275)
Other liabilities	(1,290)	(2,010)	(1,500)
Debt financing costs:
Other assets	(9,566)	229	(231)
Mortgage notes payable, net	(228)	(2,344)	(2,692)
Notes, net	(100)	(4,331)
Right-of-use assets and lease liabilities initial measurement and reclassifications:
Right-of-use assets	400	(11,308)
Lease liabilities	400	(11,308)
Non-cash share distribution and other transfers from unconsolidated entities:
Investments in unconsolidated entities	4,201	1,430
Other assets	$ (4,201)	$ (1,430)
ERPOP [Member] | Mortgage Notes Payable, Net [Member]
Mortgage notes payable, net:
Net gain (loss) on debt extinguishment			(327)
Notes, net:
Net gain (loss) on debt extinguishment			(327)
ERPOP [Member] | Notes, Net [Member]
Mortgage notes payable, net:
Net gain (loss) on debt extinguishment			(25,823)
Notes, net:
Net gain (loss) on debt extinguishment			$ (25,823)