CONSOLIDATED STATEMENTS OF CASH FLOWS OF ERP OPERATING LIMITED PARTNERSHIP (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 388,404	$ 604,152
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	400,635	418,398
Amortization of deferred financing costs	4,124	4,152
Amortization of above/below market lease intangibles	(154)	(35)
Amortization of discounts and premiums on debt	2,593	2,553
Amortization of deferred settlements on derivative instruments	4,631	11,392
Amortization of right-of-use assets	7,308	5,892
Write-off of pursuit costs	2,647	3,278
(Income) loss from investments in unconsolidated entities	1,872	2,199
Distributions from unconsolidated entities – return on capital		100
Net (gain) loss on sales of real estate properties	(223,695)	(352,243)
Net (gain) loss on sales of land parcels	(5)
Realized/unrealized (gain) loss on derivative instruments		25
Realized (gain) loss on sale of investment securities	(23,432)
Compensation paid with Company Common Shares	16,077	13,475
Other operating activities, net		1,805
Changes in assets and liabilities:
(Increase) decrease in other assets	(4,462)	(61,422)
Increase (decrease) in accounts payable and accrued expenses	6,514	5,954
Increase (decrease) in accrued interest payable	(82)	737
Increase (decrease) in lease liabilities	(3,211)	(1,199)
Increase (decrease) in other liabilities	(5,387)	(18,070)
Increase (decrease) in security deposits	1,748	(6,057)
Net cash provided by operating activities	576,125	635,086
CASH FLOWS FROM INVESTING ACTIVITIES:
Investment in real estate – acquisitions	(281,426)
Investment in real estate – development/other	(125,156)	(95,215)
Capital expenditures to real estate	(66,443)	(61,265)
Non-real estate capital additions	(1,042)	(15,536)
Interest capitalized for real estate under development	(8,176)	(4,102)
Proceeds from disposition of real estate, net	406,922	747,600
Investments in unconsolidated entities	(4,491)	(5,626)
Distributions from unconsolidated entities – return of capital	4
Purchase of investment securities and other investments	(166,945)	(509)
Proceeds from sale of investment securities	191,398
Net cash provided by (used for) investing activities	(55,355)	565,347
CASH FLOWS FROM FINANCING ACTIVITIES:
Debt financing costs	(362)	(2,907)
Mortgage notes payable, net:
Proceeds	47,759	495,145
Lump sum payoffs	(59,880)	(91,500)
Scheduled principal repayments	(3,713)	(3,873)
Line of credit and commercial paper:
Line of credit proceeds		1,870,000
Line of credit repayments		(1,890,000)
Commercial paper proceeds	2,819,940	6,726,167
Commercial paper repayments	(2,603,000)	(7,724,000)
Proceeds from (payments on) settlement of derivative instruments		(1,215)
Finance ground lease principal payments	(232)
Proceeds from Employee Share Purchase Plan (ESPP)	2,667	2,359
Proceeds from exercise of EQR options	39,623	11,322
Other financing activities, net	(31)	(31)
Contributions – Noncontrolling Interests – Partially Owned Properties		341
Contributions – Limited Partners		12
Distributions:
OP Units – General Partner	(448,983)	(435,427)
Preference Units	(1,545)	(1,545)
OP Units – Limited Partners	(16,540)	(16,478)
Noncontrolling Interests – Partially Owned Properties	(3,700)	(10,269)
Net cash provided by (used for) financing activities	(227,997)	(1,071,899)
Net increase (decrease) in cash and cash equivalents and restricted deposits	292,773	128,534
Cash and cash equivalents and restricted deposits, beginning of period	99,728	116,999
Cash and cash equivalents and restricted deposits, end of period	392,501	245,533
Cash and cash equivalents	39,492	187,416
Restricted deposits	353,009	58,117
SUPPLEMENTAL INFORMATION:
Cash paid for interest, net of amounts capitalized	126,742	148,164
Net cash paid (received) for income and other taxes	888	428
Amortization of deferred financing costs:
Investment in real estate, net	(100)	(120)
Other assets	1,169	1,169
Mortgage notes payable, net	1,139	876
Notes, net	1,916	2,227
Amortization of discounts and premiums on debt:
Mortgage notes payable, net	1,374	1,191
Notes, net	1,219	1,362
Amortization of deferred settlements on derivative instruments:
Other liabilities	(6)	(6)
Accumulated other comprehensive income	4,637	11,398
Write-off of pursuit costs:
Investment in real estate, net	2,314	3,122
Other assets	317	140
Accounts payable and accrued expenses	16	16
(Income) loss from investments in unconsolidated entities:
Investments in unconsolidated entities	1,216	1,554
Other liabilities	656	645
Realized/unrealized (gain) loss on derivative instruments:
Other liabilities		1,215
Accumulated other comprehensive income		(1,190)
Investments in unconsolidated entities:
Investments in unconsolidated entities	(3,231)	(4,726)
Other liabilities	(1,260)	(900)
Debt financing costs:
Other assets	(44)	(215)
Mortgage notes payable, net	(318)	(2,692)
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	1,429
Other assets	(1,429)
ERPOP [Member]
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	388,404	604,152
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	400,635	418,398
Amortization of deferred financing costs	4,124	4,152
Amortization of above/below market lease intangibles	(154)	(35)
Amortization of discounts and premiums on debt	2,593	2,553
Amortization of deferred settlements on derivative instruments	4,631	11,392
Amortization of right-of-use assets	7,308	5,892
Write-off of pursuit costs	2,647	3,278
(Income) loss from investments in unconsolidated entities	1,872	2,199
Distributions from unconsolidated entities – return on capital		100
Net (gain) loss on sales of real estate properties	(223,695)	(352,243)
Net (gain) loss on sales of land parcels	(5)
Realized/unrealized (gain) loss on derivative instruments		25
Realized (gain) loss on sale of investment securities	(23,432)
Compensation paid with Company Common Shares	16,077	13,475
Other operating activities, net		1,805
Changes in assets and liabilities:
(Increase) decrease in other assets	(4,462)	(61,422)
Increase (decrease) in accounts payable and accrued expenses	6,514	5,954
Increase (decrease) in accrued interest payable	(82)	737
Increase (decrease) in lease liabilities	(3,211)	(1,199)
Increase (decrease) in other liabilities	(5,387)	(18,070)
Increase (decrease) in security deposits	1,748	(6,057)
Net cash provided by operating activities	576,125	635,086
CASH FLOWS FROM INVESTING ACTIVITIES:
Investment in real estate – acquisitions	(281,426)
Investment in real estate – development/other	(125,156)	(95,215)
Capital expenditures to real estate	(66,443)	(61,265)
Non-real estate capital additions	(1,042)	(15,536)
Interest capitalized for real estate under development	(8,176)	(4,102)
Proceeds from disposition of real estate, net	406,922	747,600
Investments in unconsolidated entities	(4,491)	(5,626)
Distributions from unconsolidated entities – return of capital	4
Purchase of investment securities and other investments	(166,945)	(509)
Proceeds from sale of investment securities	191,398
Net cash provided by (used for) investing activities	(55,355)	565,347
CASH FLOWS FROM FINANCING ACTIVITIES:
Debt financing costs	(362)	(2,907)
Mortgage notes payable, net:
Proceeds	47,759	495,145
Lump sum payoffs	(59,880)	(91,500)
Scheduled principal repayments	(3,713)	(3,873)
Line of credit and commercial paper:
Line of credit proceeds		1,870,000
Line of credit repayments		(1,890,000)
Commercial paper proceeds	2,819,940	6,726,167
Commercial paper repayments	(2,603,000)	(7,724,000)
Proceeds from (payments on) settlement of derivative instruments		(1,215)
Finance ground lease principal payments	(232)
Proceeds from Employee Share Purchase Plan (ESPP)	2,667	2,359
Proceeds from exercise of EQR options	39,623	11,322
Other financing activities, net	(31)	(31)
Contributions – Noncontrolling Interests – Partially Owned Properties		341
Contributions – Limited Partners		12
Distributions:
OP Units – General Partner	(448,983)	(435,427)
Preference Units	(1,545)	(1,545)
OP Units – Limited Partners	(16,540)	(16,478)
Noncontrolling Interests – Partially Owned Properties	(3,700)	(10,269)
Net cash provided by (used for) financing activities	(227,997)	(1,071,899)
Net increase (decrease) in cash and cash equivalents and restricted deposits	292,773	128,534
Cash and cash equivalents and restricted deposits, beginning of period	99,728	116,999
Cash and cash equivalents and restricted deposits, end of period	392,501	245,533
Cash and cash equivalents	39,492	187,416
Restricted deposits	353,009	58,117
SUPPLEMENTAL INFORMATION:
Cash paid for interest, net of amounts capitalized	126,742	148,164
Net cash paid (received) for income and other taxes	888	428
Amortization of deferred financing costs:
Investment in real estate, net	(100)	(120)
Other assets	1,169	1,169
Mortgage notes payable, net	1,139	876
Notes, net	1,916	2,227
Amortization of discounts and premiums on debt:
Mortgage notes payable, net	1,374	1,191
Notes, net	1,219	1,362
Amortization of deferred settlements on derivative instruments:
Other liabilities	(6)	(6)
Accumulated other comprehensive income	4,637	11,398
Write-off of pursuit costs:
Investment in real estate, net	2,314	3,122
Other assets	317	140
Accounts payable and accrued expenses	16	16
(Income) loss from investments in unconsolidated entities:
Investments in unconsolidated entities	1,216	1,554
Other liabilities	656	645
Realized/unrealized (gain) loss on derivative instruments:
Other liabilities		1,215
Accumulated other comprehensive income		(1,190)
Investments in unconsolidated entities:
Investments in unconsolidated entities	(3,231)	(4,726)
Other liabilities	(1,260)	(900)
Debt financing costs:
Other assets	(44)	(215)
Mortgage notes payable, net	(318)	$ (2,692)
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	1,429
Other assets	$ (1,429)