CONSOLIDATED STATEMENTS OF CASH FLOWS OF ERP OPERATING LIMITED PARTNERSHIP (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 73,798	$ 60,364
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	229,961	199,962
Amortization of deferred financing costs	2,077	2,185
Amortization of above/below market lease intangibles		(18)
Amortization of discounts and premiums on debt	1,358	1,294
Amortization of deferred settlements on derivative instruments	2,422	2,301
Amortization of right-of-use assets	3,046	2,980
Write-off of pursuit costs	1,463	1,331
(Income) loss from investments in unconsolidated entities	1,261	1,611
Distributions from unconsolidated entities – return on capital	79
Net (gain) loss on sales of real estate properties	102	43
Net (gain) loss on sales of land parcels		(5)
Realized (gain) loss on sale of investment securities	(2,066)	133
Compensation paid with Company Common Shares	9,203	8,678
Changes in assets and liabilities:
(Increase) decrease in other assets	30,174	20,746
Increase (decrease) in accounts payable and accrued expenses	54,553	59,116
Increase (decrease) in accrued interest payable	(12,634)	(10,407)
Increase (decrease) in lease liabilities	(902)	(868)
Increase (decrease) in other liabilities	(27,213)	(3,852)
Increase (decrease) in security deposits	1,374	459
Net cash provided by operating activities	368,056	346,053
CASH FLOWS FROM INVESTING ACTIVITIES:
Investment in real estate – acquisitions	(113,046)
Investment in real estate – development/other	(24,255)	(64,599)
Capital expenditures to real estate	(35,285)	(28,679)
Non-real estate capital additions	(971)	(589)
Interest capitalized for real estate and unconsolidated entities under development	(1,017)	(3,769)
Investments in unconsolidated entities – other	(24,897)	(2,378)
Distributions from unconsolidated entities – return of capital	9	4
Purchase of investment securities and other investments	(1,009)	(26,335)
Proceeds from sale of investment securities	3,434
Net cash provided by (used for) investing activities	(197,037)	(126,345)
CASH FLOWS FROM FINANCING ACTIVITIES:
Debt financing costs		(318)
Mortgage notes payable, net:
Proceeds	2,689	37,492
Lump sum payoffs		(59,880)
Scheduled principal repayments	(1,933)	(1,871)
Line of credit and commercial paper:
Commercial paper proceeds	1,424,086	1,184,923
Commercial paper repayments	(1,609,121)	(1,170,000)
Finance ground lease principal payments	(140)	(116)
Proceeds from Employee Share Purchase Plan (ESPP)	969	1,731
Proceeds from exercise of EQR options	14,344	22,882
Payment of offering costs	(114)
Contributions – Noncontrolling Interests – Partially Owned Properties	446
Contributions – Limited Partners	1
Distributions:
OP Units – General Partner	(226,639)	(224,308)
Preference Units	(772)	(773)
OP Units – Limited Partners	(7,535)	(8,479)
Noncontrolling Interests – Partially Owned Properties	(15,836)	(2,883)
Net cash provided by (used for) financing activities	(419,555)	(221,600)
Net increase (decrease) in cash and cash equivalents and restricted deposits	(248,536)	(1,892)
Cash and cash equivalents and restricted deposits, beginning of period	360,236	99,728
Cash and cash equivalents and restricted deposits, end of period	111,700	97,836
Cash and cash equivalents	41,140	35,453
Restricted deposits	70,560	62,383
SUPPLEMENTAL INFORMATION:
Cash paid for interest, net of amounts capitalized	81,391	74,058
Net cash paid (received) for income and other taxes	350	752
Amortization of deferred financing costs:
Investment in real estate, net	(127)	(60)
Other assets	585	585
Mortgage notes payable, net	557	703
Notes, net	1,062	957
Amortization of discounts and premiums on debt:
Mortgage notes payable, net	685	684
Notes, net	673	610
Amortization of deferred settlements on derivative instruments:
Other liabilities	(3)	(2)
Accumulated other comprehensive income	2,425	2,303
Write-off of pursuit costs:
Investment in real estate, net	375	1,209
Investments in unconsolidated entities	1,070
Other assets	18	114
Accounts payable and accrued expenses		8
(Income) loss from investments in unconsolidated entities:
Investments in unconsolidated entities	946	1,282
Other liabilities	315	329
Interest capitalized for real estate and unconsolidated entities under development:
Investment in real estate, net	(307)	(3,769)
Investments in unconsolidated entities	710
Investments in unconsolidated entities – other:
Investments in unconsolidated entities	(24,897)	(1,778)
Other liabilities		(600)
Debt financing costs:
Mortgage notes payable, net		(318)
Right-of-use assets and lease liabilities initial measurement and reclassifications:
Right-of-use assets		11,308
Lease liabilities		(11,308)
Non-cash share distribution from unconsolidated entities:
Investments in unconsolidated entities	859
Other assets	(859)
ERPOP [Member]
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	73,798	60,364
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	229,961	199,962
Amortization of deferred financing costs	2,077	2,185
Amortization of above/below market lease intangibles		(18)
Amortization of discounts and premiums on debt	1,358	1,294
Amortization of deferred settlements on derivative instruments	2,422	2,301
Amortization of right-of-use assets	3,046	2,980
Write-off of pursuit costs	1,463	1,331
(Income) loss from investments in unconsolidated entities	1,261	1,611
Distributions from unconsolidated entities – return on capital	79
Net (gain) loss on sales of real estate properties	102	43
Net (gain) loss on sales of land parcels		(5)
Realized (gain) loss on sale of investment securities	(2,066)	133
Compensation paid with Company Common Shares	9,203	8,678
Changes in assets and liabilities:
(Increase) decrease in other assets	30,174	20,746
Increase (decrease) in accounts payable and accrued expenses	54,553	59,116
Increase (decrease) in accrued interest payable	(12,634)	(10,407)
Increase (decrease) in lease liabilities	(902)	(868)
Increase (decrease) in other liabilities	(27,213)	(3,852)
Increase (decrease) in security deposits	1,374	459
Net cash provided by operating activities	368,056	346,053
CASH FLOWS FROM INVESTING ACTIVITIES:
Investment in real estate – acquisitions	(113,046)
Investment in real estate – development/other	(24,255)	(64,599)
Capital expenditures to real estate	(35,285)	(28,679)
Non-real estate capital additions	(971)	(589)
Interest capitalized for real estate and unconsolidated entities under development	(1,017)	(3,769)
Investments in unconsolidated entities – other	(24,897)	(2,378)
Distributions from unconsolidated entities – return of capital	9	4
Purchase of investment securities and other investments	(1,009)	(26,335)
Proceeds from sale of investment securities	3,434
Net cash provided by (used for) investing activities	(197,037)	(126,345)
CASH FLOWS FROM FINANCING ACTIVITIES:
Debt financing costs		(318)
Mortgage notes payable, net:
Proceeds	2,689	37,492
Lump sum payoffs		(59,880)
Scheduled principal repayments	(1,933)	(1,871)
Line of credit and commercial paper:
Commercial paper proceeds	1,424,086	1,184,923
Commercial paper repayments	(1,609,121)	(1,170,000)
Finance ground lease principal payments	(140)	(116)
Proceeds from Employee Share Purchase Plan (ESPP)	969	1,731
Proceeds from exercise of EQR options	14,344	22,882
Payment of offering costs	(114)
Contributions – Noncontrolling Interests – Partially Owned Properties	446
Contributions – Limited Partners	1
Distributions:
OP Units – General Partner	(226,639)	(224,308)
Preference Units	(772)	(773)
OP Units – Limited Partners	(7,535)	(8,479)
Noncontrolling Interests – Partially Owned Properties	(15,836)	(2,883)
Net cash provided by (used for) financing activities	(419,555)	(221,600)
Net increase (decrease) in cash and cash equivalents and restricted deposits	(248,536)	(1,892)
Cash and cash equivalents and restricted deposits, beginning of period	360,236	99,728
Cash and cash equivalents and restricted deposits, end of period	111,700	97,836
Cash and cash equivalents	41,140	35,453
Restricted deposits	70,560	62,383
SUPPLEMENTAL INFORMATION:
Cash paid for interest, net of amounts capitalized	81,391	74,058
Net cash paid (received) for income and other taxes	350	752
Amortization of deferred financing costs:
Investment in real estate, net	(127)	(60)
Other assets	585	585
Mortgage notes payable, net	557	703
Notes, net	1,062	957
Amortization of discounts and premiums on debt:
Mortgage notes payable, net	685	684
Notes, net	673	610
Amortization of deferred settlements on derivative instruments:
Other liabilities	(3)	(2)
Accumulated other comprehensive income	2,425	2,303
Write-off of pursuit costs:
Investment in real estate, net	375	1,209
Investments in unconsolidated entities	1,070
Other assets	18	114
Accounts payable and accrued expenses		8
(Income) loss from investments in unconsolidated entities:
Investments in unconsolidated entities	946	1,282
Other liabilities	315	329
Interest capitalized for real estate and unconsolidated entities under development:
Investment in real estate, net	(307)	(3,769)
Investments in unconsolidated entities	(710)
Investments in unconsolidated entities – other:
Investments in unconsolidated entities	(24,897)	(1,778)
Other liabilities		(600)
Debt financing costs:
Mortgage notes payable, net		(318)
Right-of-use assets and lease liabilities initial measurement and reclassifications:
Right-of-use assets		11,308
Lease liabilities		$ (11,308)
Non-cash share distribution from unconsolidated entities:
Investments in unconsolidated entities	859
Other assets	$ (859)