Equity Residential (EQR) 10-Q 29 Oct 21 2021 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2021	Oct. 22, 2021
Document Information [Line Items]
Entity Registrant Name	EQUITY RESIDENTIAL
Entity Central Index Key	0000906107
Document Type	10-Q
Document Period End Date	Sep. 30, 2021
Amendment Flag	false
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Trading Symbol	EQR
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		375,016,222
Entity Current Reporting Status	Yes
Entity Shell Company	false
Entity File Number	1-12252
Entity Tax Identification Number	13-3675988
Entity Address, Address Line One	Two North Riverside Plaza
Entity Address, City or Town	Chicago
Entity Address, State or Province	IL
Entity Address, Postal Zip Code	60606
City Area Code	312
Local Phone Number	474-1300
Entity Incorporation, State or Country Code	MD
Title of 12(b) Security	Common Shares of Beneficial Interest,$0.01 Par Value (Equity Residential)
Security Exchange Name	NYSE
Document Quarterly Report	true
Document Transition Report	false
Entity Interactive Data Current	Yes
ERPOP [Member]
Document Information [Line Items]
Entity Registrant Name	ERP OPERATING LIMITED PARTNERSHIP
Entity Central Index Key	0000931182
Document Type	10-Q
Document Period End Date	Sep. 30, 2021
Amendment Flag	false
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
No Trading Symbol Flag	true
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Current Reporting Status	Yes
Entity Shell Company	false
Entity File Number	0-24920
Entity Tax Identification Number	36-3894853
Entity Address, Address Line One	Two North Riverside Plaza
Entity Address, City or Town	Chicago
Entity Address, State or Province	IL
Entity Address, Postal Zip Code	60606
City Area Code	312
Local Phone Number	474-1300
Entity Incorporation, State or Country Code	IL
Title of 12(b) Security	7.57% Notes due August 15, 2026(ERP Operating Limited Partnership)
Security Exchange Name	NYSE
Document Quarterly Report	true
Document Transition Report	false
Entity Interactive Data Current	Yes

CONSOLIDATED BALANCE SHEETS (Un

CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
ASSETS
Land	$ 5,779,686	$ 5,785,367
Depreciable property	21,840,344	20,920,654
Projects under development	163,659	411,134
Land held for development	82,026	86,170
Investment in real estate	27,865,715	27,203,325
Accumulated depreciation	(8,260,846)	(7,859,657)
Investment in real estate, net	19,604,869	19,343,668
Investments in unconsolidated entities	79,429	52,782
Cash and cash equivalents	39,707	42,591
Restricted deposits	187,042	57,137
Right-of-use assets	477,693	499,287
Other assets	274,275	291,426
Total assets	20,663,015	20,286,891
Liabilities:
Mortgage notes payable, net	2,281,165	2,293,890
Notes, net	5,833,483	5,335,536
Line of credit and commercial paper	30,000	414,830
Accounts payable and accrued expenses	166,522	107,366
Accrued interest payable	56,777	65,896
Lease liabilities	313,361	329,130
Other liabilities	350,201	345,064
Security deposits	64,617	60,480
Distributions payable	233,306	232,262
Total liabilities	9,329,432	9,184,454
Commitments and contingencies
Redeemable Noncontrolling Interests – Operating Partnership	459,933	338,951
Shareholders' equity:
Preferred Shares of beneficial interest, $0.01 par value; 100,000,000 shares authorized; 745,600 shares issued and outstanding as of September 30, 2021 and December 31, 2020	37,280	37,280
Common Shares of beneficial interest, $0.01 par value; 1,000,000,000 shares authorized; 375,002,588 shares issued and outstanding as of September 30, 2021 and 372,302,000 shares issued and outstanding as of December 31, 2020	3,750	3,723
Paid in capital	9,131,078	9,128,599
Retained earnings	1,527,115	1,399,715
Accumulated other comprehensive income (loss)	(36,666)	(43,666)
Total shareholders’ equity	10,662,557	10,525,651
Noncontrolling Interests:
Operating Partnership	208,955	233,162
Partially Owned Properties	2,138	4,673
Total Noncontrolling Interests	211,093	237,835
Total equity	10,873,650	10,763,486
Total liabilities and equity/capital	$ 20,663,015	$ 20,286,891

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) (Unaudited) - $ / shares	Sep. 30, 2021	Dec. 31, 2020
Statement Of Financial Position [Abstract]
Preferred Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Preferred Stock, Shares Authorized	100,000,000	100,000,000
Preferred Stock, Shares Issued	745,600	745,600
Preferred Stock, Shares Outstanding	745,600	745,600
Common Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Common Stock, Shares Authorized	1,000,000,000	1,000,000,000
Common Stock, Shares, Issued	375,002,588	372,302,000
Common Stock, Shares, Outstanding	375,002,588	372,302,000

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
REVENUES
Rental income	$ 623,206	$ 622,433	$ 1,818,867	$ 1,958,270
EXPENSES
Property and maintenance	116,461	113,065	341,261	333,333
Real estate taxes and insurance	96,909	95,273	297,780	288,043
Property management	23,772	20,196	74,357	71,513
General and administrative	13,041	10,859	43,102	37,212
Depreciation	215,397	200,605	616,032	619,003
Total expenses	465,580	439,998	1,372,532	1,349,104
Net gain (loss) on sales of real estate properties	363,928	(25)	587,623	352,218
Operating income	521,554	182,410	1,033,958	961,384
Interest and other income	973	535	25,293	4,006
Other expenses	(3,456)	(4,097)	(10,908)	(8,324)
Interest:
Expense incurred, net	(68,251)	(80,874)	(202,733)	(248,349)
Amortization of deferred financing costs	(2,048)	(2,101)	(6,172)	(6,253)
Income before income and other taxes, income (loss) from investments in unconsolidated entities and net gain (loss) on sales of land parcels	448,772	95,873	839,438	702,464
Income and other tax (expense) benefit	(284)	(262)	(679)	(502)
Income (loss) from investments in unconsolidated entities	(1,156)	(246)	(3,028)	(2,445)
Net gain (loss) on sales of land parcels			5
Net income	447,332	95,365	835,736	699,517
Net (income) loss attributable to Noncontrolling Interests:
Operating Partnership	(14,847)	(3,376)	(27,903)	(24,624)
Partially Owned Properties	(534)	(703)	(1,957)	(14,113)
Net income attributable to controlling interests	431,951	91,286	805,876	660,780
Preferred distributions	(773)	(773)	(2,318)	(2,318)
Net income available to Common Shares	$ 431,178	$ 90,513	$ 803,558	$ 658,462
Earnings per share – basic:
Net income available to Common Shares	$ 1.15	$ 0.24	$ 2.15	$ 1.77
Weighted average Common Shares outstanding	374,308	371,869	373,474	371,749
Earnings per share – diluted:
Net income available to Common Shares	$ 1.15	$ 0.24	$ 2.14	$ 1.77
Weighted average Common Shares outstanding	388,374	385,652	387,642	385,973

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Comprehensive income:
Net income	$ 447,332	$ 95,365	$ 835,736	$ 699,517
Other comprehensive income (loss) – derivative instruments:
Unrealized holding gains (losses) arising during the period				(1,190)
Losses reclassified into earnings from other comprehensive income	2,363	5,877	7,000	17,275
Other comprehensive income (loss)	2,363	5,877	7,000	16,085
Comprehensive income	449,695	101,242	842,736	715,602
Comprehensive (income) attributable to Noncontrolling Interests	(15,459)	(4,290)	(30,100)	(39,316)
Comprehensive income attributable to controlling interests	$ 434,236	$ 96,952	$ 812,636	$ 676,286

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 835,736	$ 699,517
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	616,032	619,003
Amortization of deferred financing costs	6,172	6,253
Amortization of above/below market lease intangibles	(154)	(53)
Amortization of discounts and premiums on debt	3,934	3,834
Amortization of deferred settlements on derivative instruments	6,991	17,266
Amortization of right-of-use assets	10,286	8,785
Write-off of pursuit costs	3,557	4,864
(Income) loss from investments in unconsolidated entities	3,028	2,445
Distributions from unconsolidated entities – return on capital		100
Net (gain) loss on sales of real estate properties	(587,623)	(352,218)
Net (gain) loss on sales of land parcels	(5)
Realized/unrealized (gain) loss on derivative instruments		50
Realized (gain) loss on sale of investment securities	(23,432)
Compensation paid with Company Common Shares	21,919	18,275
Other operating activities, net		1,805
Changes in assets and liabilities:
(Increase) decrease in other assets	16,269	(30,197)
Increase (decrease) in accounts payable and accrued expenses	69,170	54,418
Increase (decrease) in accrued interest payable	(9,119)	(1,183)
Increase (decrease) in lease liabilities	(4,112)	(1,650)
Increase (decrease) in other liabilities	5,427	(8,381)
Increase (decrease) in security deposits	4,137	(8,609)
Net cash provided by operating activities	978,213	1,034,324
CASH FLOWS FROM INVESTING ACTIVITIES:
Investment in real estate – acquisitions	(1,022,275)	(48,898)
Investment in real estate – development/other	(172,850)	(157,778)
Capital expenditures to real estate	(107,706)	(92,123)
Non-real estate capital additions	(1,251)	(19,290)
Interest capitalized for real estate and unconsolidated entities under development	(12,365)	(6,880)
Proceeds from disposition of real estate, net	1,014,328	747,600
Investments in unconsolidated entities	(31,081)	(6,664)
Distributions from unconsolidated entities – return of capital	4	1,000
Purchase of investment securities and other investments	(167,791)	(509)
Proceeds from sale of investment securities	191,398
Net cash provided by (used for) investing activities	(309,589)	416,458
CASH FLOWS FROM FINANCING ACTIVITIES:
Debt financing costs	(6,447)	(2,923)
Mortgage notes payable, net:
Proceeds	51,298	505,375
Lump sum payoffs	(59,880)	(127,767)
Scheduled principal repayments	(5,570)	(5,821)
Proceeds	497,470
Line of credit and commercial paper:
Line of credit proceeds		1,870,000
Line of credit repayments		(1,890,000)
Commercial paper proceeds	4,305,170	6,726,167
Commercial paper repayments	(4,690,000)	(7,724,000)
Proceeds from (payments on) settlement of derivative instruments		(1,240)
Finance ground lease principal payments	(349)
Proceeds from Employee Share Purchase Plan (ESPP)	3,455	3,556
Proceeds from exercise of options	68,807	11,426
Payment of offering costs	(267)
Other financing activities, net	(31)	(31)
Contributions – Noncontrolling Interests – Partially Owned Properties		417
Contributions – Noncontrolling Interests – Operating Partnership		12
Distributions:
Common Shares	(674,531)	(659,668)
Preferred Shares	(2,318)	(2,318)
Noncontrolling Interests – Operating Partnership	(23,949)	(24,440)
Noncontrolling Interests – Partially Owned Properties	(4,461)	(11,312)
Net cash provided by (used for) financing activities	(541,603)	(1,332,567)
Net increase (decrease) in cash and cash equivalents and restricted deposits	127,021	118,215
Cash and cash equivalents and restricted deposits, beginning of period	99,728	116,999
Cash and cash equivalents and restricted deposits, end of period	226,749	235,214
Cash and cash equivalents	39,707	178,333
Restricted deposits	187,042	56,881
SUPPLEMENTAL INFORMATION:
Cash paid for interest, net of amounts capitalized	199,799	223,703
Net cash paid (received) for income and other taxes	1,040	(1,092)
Amortization of deferred financing costs:
Investment in real estate, net	(227)	(180)
Other assets	1,754	1,755
Mortgage notes payable, net	1,702	1,337
Notes, net	2,943	3,341
Amortization of discounts and premiums on debt:
Mortgage notes payable, net	2,069	1,791
Notes, net	1,865	2,043
Amortization of deferred settlements on derivative instruments:
Other liabilities	(9)	(9)
Accumulated other comprehensive income	7,000	17,275
Write-off of pursuit costs:
Investment in real estate, net	3,000	4,621
Other assets	533	219
Accounts payable and accrued expenses	24	24
(Income) loss from investments in unconsolidated entities:
Investments in unconsolidated entities	2,062	1,474
Other liabilities	966	971
Realized/unrealized (gain) loss on derivative instruments:
Other liabilities		1,240
Accumulated other comprehensive income		(1,190)
Interest capitalized for real estate and unconsolidated entities under development:
Investment in real estate, net	(12,260)	(6,880)
Investments in unconsolidated entities	(105)
Investments in unconsolidated entities:
Investment in real estate, net	967
Investments in unconsolidated entities	(30,038)	(5,164)
Other liabilities	(2,010)	(1,500)
Debt financing costs:
Other assets	228	(231)
Mortgage notes payable, net	(2,344)	$ (2,692)
Notes, net	(4,331)
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	1,430
Other assets	$ (1,430)

CONSOLIDATED STATEMENTS OF CHAN

CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (Unaudited) - USD ($) $ in Thousands	Total	PREFERRED SHARES	COMMON SHARES, $0.01 PAR VALUE	PAID IN CAPITAL	RETAINED EARNINGS	ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)	DISTRIBUTIONS	OPERATING PARTNERSHIP	PARTIALLY OWNED PROPERTIES
Balance, beginning of year at Dec. 31, 2019		$ 37,280	$ 3,717	$ 8,965,577	$ 1,386,495	$ (77,563)
Balance, beginning of year at Dec. 31, 2019								$ 227,837	$ 1,183
COMMON SHARES, $0.01 PAR VALUE
Conversion of OP Units into Common Shares			1	3,912
Exercise of share options			2	11,424
Employee Share Purchase Plan (ESPP)				3,556
Share-based employee compensation expense:
Issuance of restricted units/shares			2	9,236				12
Share options				1,819
ESPP discount				626
Supplemental Executive Retirement Plan (SERP)				(395)
Change in market value of Redeemable Noncontrolling Interests –Operating Partnership	$ (169,825)			169,825
Adjustment for Noncontrolling Interests ownership in Operating Partnership				438				(438)
PAID IN CAPITAL
Conversion of OP Units into Common Shares			1	3,912
Exercise of share options			2	11,424
Employee Share Purchase Plan (ESPP)				3,556
RETAINED EARNINGS
Net income attributable to controlling interests	660,780				660,780
Common Share distributions					(673,019)
Preferred Share distributions					(2,318)
Accumulated other comprehensive income (loss) - derivative instruments:
Unrealized holding gains (losses) arising during the period	(1,190)					(1,190)
Losses reclassified into earnings from other comprehensive income	(17,275)					17,275
DISTRIBUTIONS
Distributions declared per Common Share outstanding							$ 1.8075
NONCONTROLLING INTERESTS
Issuance of restricted units/shares			2	9,236				12
Conversion of OP Units held by Noncontrolling Interests into OP Units held by General Partner								(3,913)
Equity compensation associated with Noncontrolling Interests								9,525
Net income attributable to Noncontrolling Interests	24,624							24,624	14,113
Distributions to Noncontrolling Interests								(25,000)	(11,343)
Change in carrying value of Redeemable Noncontrolling Interests - Operating Partnership	131							(131)
Adjustment for Noncontrolling Interests ownership in Operating Partnership				438				(438)
PARTIALLY OWNED PROPERTIES
Net income attributable to Noncontrolling Interests	24,624							24,624	14,113
Contributions by Noncontrolling Interests									417
Distributions to Noncontrolling Interests								(25,000)	(11,343)
Balance, end of period at Sep. 30, 2020		37,280	3,722	9,166,018	1,371,938	(61,478)
Balance, end of period at Sep. 30, 2020								232,516	4,370
Balance, beginning of year at Jun. 30, 2020		37,280	3,722	9,118,332	1,505,694	(67,355)
Balance, beginning of year at Jun. 30, 2020								235,169	4,634
COMMON SHARES, $0.01 PAR VALUE
Conversion of OP Units into Common Shares				57
Exercise of share options				104
Employee Share Purchase Plan (ESPP)				1,197
Share-based employee compensation expense:
Issuance of restricted units/shares				1,984
Share options				526
ESPP discount				210
Supplemental Executive Retirement Plan (SERP)				111
Change in market value of Redeemable Noncontrolling Interests –Operating Partnership				41,072
Adjustment for Noncontrolling Interests ownership in Operating Partnership				2,425				(2,425)
PAID IN CAPITAL
Conversion of OP Units into Common Shares				57
Exercise of share options				104
Employee Share Purchase Plan (ESPP)				1,197
RETAINED EARNINGS
Net income attributable to controlling interests	91,286				91,286
Common Share distributions					(224,269)
Preferred Share distributions					(773)
Accumulated other comprehensive income (loss) - derivative instruments:
Losses reclassified into earnings from other comprehensive income	(5,877)					5,877
DISTRIBUTIONS
Distributions declared per Common Share outstanding							0.6025
NONCONTROLLING INTERESTS
Issuance of restricted units/shares				1,984
Conversion of OP Units held by Noncontrolling Interests into OP Units held by General Partner								(57)
Equity compensation associated with Noncontrolling Interests								2,499
Net income attributable to Noncontrolling Interests	3,376							3,376	703
Distributions to Noncontrolling Interests								(7,963)	(1,043)
Change in carrying value of Redeemable Noncontrolling Interests - Operating Partnership								1,917
Adjustment for Noncontrolling Interests ownership in Operating Partnership				2,425				(2,425)
PARTIALLY OWNED PROPERTIES
Net income attributable to Noncontrolling Interests	3,376							3,376	703
Contributions by Noncontrolling Interests									76
Distributions to Noncontrolling Interests								(7,963)	(1,043)
Balance, end of period at Sep. 30, 2020		37,280	3,722	9,166,018	1,371,938	(61,478)
Balance, end of period at Sep. 30, 2020								232,516	4,370
Balance, beginning of year at Dec. 31, 2020	10,525,651	37,280	3,723	9,128,599	1,399,715	(43,666)
Balance, beginning of year at Dec. 31, 2020	237,835							233,162	4,673
COMMON SHARES, $0.01 PAR VALUE
Conversion of OP Units into Common Shares			11	68,246
Exercise of share options			14	68,793
Employee Share Purchase Plan (ESPP)			1	3,454
Share-based employee compensation expense:
Issuance of restricted units/shares			1	6,571
Share options				2,541
ESPP discount				798
Offering costs				(267)
Supplemental Executive Retirement Plan (SERP)				(1,335)
Change in market value of Redeemable Noncontrolling Interests –Operating Partnership	119,237			(119,237)
Adjustment for Noncontrolling Interests ownership in Operating Partnership				(27,085)				27,085
PAID IN CAPITAL
Conversion of OP Units into Common Shares			11	68,246
Exercise of share options			14	68,793
Employee Share Purchase Plan (ESPP)			1	3,454
RETAINED EARNINGS
Net income attributable to controlling interests	805,876				805,876
Common Share distributions					(676,158)
Preferred Share distributions					(2,318)
Accumulated other comprehensive income (loss) - derivative instruments:
Losses reclassified into earnings from other comprehensive income	(7,000)					7,000
DISTRIBUTIONS
Distributions declared per Common Share outstanding							1.8075
NONCONTROLLING INTERESTS
Issuance of restricted units/shares			1	6,571
Conversion of OP Units held by Noncontrolling Interests into OP Units held by General Partner								(68,257)
Equity compensation associated with Noncontrolling Interests								14,173
Net income attributable to Noncontrolling Interests	27,903							27,903	1,957
Distributions to Noncontrolling Interests								(23,366)	(4,492)
Change in carrying value of Redeemable Noncontrolling Interests - Operating Partnership	1,745							(1,745)
Adjustment for Noncontrolling Interests ownership in Operating Partnership				(27,085)				27,085
PARTIALLY OWNED PROPERTIES
Net income attributable to Noncontrolling Interests	27,903							27,903	1,957
Distributions to Noncontrolling Interests								(23,366)	(4,492)
Balance, end of period at Sep. 30, 2021	10,662,557	37,280	3,750	9,131,078	1,527,115	(36,666)
Balance, end of period at Sep. 30, 2021	211,093							208,955	2,138
Balance, beginning of year at Jun. 30, 2021		37,280	3,744	9,110,121	1,321,875	(39,029)
Balance, beginning of year at Jun. 30, 2021								205,691	2,365
COMMON SHARES, $0.01 PAR VALUE
Conversion of OP Units into Common Shares				1,597
Exercise of share options			6	29,178
Employee Share Purchase Plan (ESPP)				788
Share-based employee compensation expense:
Issuance of restricted units/shares				1,758
Share options				565
ESPP discount				165
Offering costs				(267)
Supplemental Executive Retirement Plan (SERP)				722
Change in market value of Redeemable Noncontrolling Interests –Operating Partnership				(17,271)
Adjustment for Noncontrolling Interests ownership in Operating Partnership				3,722				(3,722)
PAID IN CAPITAL
Conversion of OP Units into Common Shares				1,597
Exercise of share options			6	29,178
Employee Share Purchase Plan (ESPP)				788
RETAINED EARNINGS
Net income attributable to controlling interests	431,951				431,951
Common Share distributions					(225,938)
Preferred Share distributions					(773)
Accumulated other comprehensive income (loss) - derivative instruments:
Losses reclassified into earnings from other comprehensive income	(2,363)					2,363
DISTRIBUTIONS
Distributions declared per Common Share outstanding							$ 0.6025
NONCONTROLLING INTERESTS
Issuance of restricted units/shares				1,758
Conversion of OP Units held by Noncontrolling Interests into OP Units held by General Partner								(1,597)
Equity compensation associated with Noncontrolling Interests								3,642
Net income attributable to Noncontrolling Interests	14,847							14,847	534
Distributions to Noncontrolling Interests								(7,367)	(761)
Change in carrying value of Redeemable Noncontrolling Interests - Operating Partnership								(2,539)
Adjustment for Noncontrolling Interests ownership in Operating Partnership				3,722				(3,722)
PARTIALLY OWNED PROPERTIES
Net income attributable to Noncontrolling Interests	14,847							14,847	534
Distributions to Noncontrolling Interests								(7,367)	(761)
Balance, end of period at Sep. 30, 2021	10,662,557	$ 37,280	$ 3,750	$ 9,131,078	$ 1,527,115	$ (36,666)
Balance, end of period at Sep. 30, 2021	$ 211,093							$ 208,955	$ 2,138

CONSOLIDATED STATEMENTS OF CH_2

CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (Parenthetical) - $ / shares	Sep. 30, 2021	Dec. 31, 2020	Sep. 30, 2020
Statement Of Stockholders Equity [Abstract]
Common Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01	$ 0.01

CONSOLIDATED BALANCE SHEETS OF

CONSOLIDATED BALANCE SHEETS OF ERP OPERATING LIMITED PARTNERSHIP (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
ASSETS
Land	$ 5,779,686	$ 5,785,367
Depreciable property	21,840,344	20,920,654
Projects under development	163,659	411,134
Land held for development	82,026	86,170
Investment in real estate	27,865,715	27,203,325
Accumulated depreciation	(8,260,846)	(7,859,657)
Investment in real estate, net	19,604,869	19,343,668
Investments in unconsolidated entities	79,429	52,782
Cash and cash equivalents	39,707	42,591
Restricted deposits	187,042	57,137
Right-of-use assets	477,693	499,287
Other assets	274,275	291,426
Total assets	20,663,015	20,286,891
Liabilities:
Mortgage notes payable, net	2,281,165	2,293,890
Notes, net	5,833,483	5,335,536
Line of credit and commercial paper	30,000	414,830
Accounts payable and accrued expenses	166,522	107,366
Accrued interest payable	56,777	65,896
Lease liabilities	313,361	329,130
Other liabilities	350,201	345,064
Security deposits	64,617	60,480
Distributions payable	233,306	232,262
Total liabilities	9,329,432	9,184,454
Commitments and contingencies
Redeemable Limited Partners	459,933	338,951
Partners’ Capital:
Accumulated other comprehensive income (loss)	(36,666)	(43,666)
Noncontrolling Interests – Partially Owned Properties	2,138	4,673
Total liabilities and equity/capital	20,663,015	20,286,891
ERPOP [Member]
ASSETS
Land	5,779,686	5,785,367
Depreciable property	21,840,344	20,920,654
Projects under development	163,659	411,134
Land held for development	82,026	86,170
Investment in real estate	27,865,715	27,203,325
Accumulated depreciation	(8,260,846)	(7,859,657)
Investment in real estate, net	19,604,869	19,343,668
Investments in unconsolidated entities	79,429	52,782
Cash and cash equivalents	39,707	42,591
Restricted deposits	187,042	57,137
Right-of-use assets	477,693	499,287
Other assets	274,275	291,426
Total assets	20,663,015	20,286,891
Liabilities:
Mortgage notes payable, net	2,281,165	2,293,890
Notes, net	5,833,483	5,335,536
Line of credit and commercial paper	30,000	414,830
Accounts payable and accrued expenses	166,522	107,366
Accrued interest payable	56,777	65,896
Lease liabilities	313,361	329,130
Other liabilities	350,201	345,064
Security deposits	64,617	60,480
Distributions payable	233,306	232,262
Total liabilities	9,329,432	9,184,454
Commitments and contingencies
Redeemable Limited Partners	459,933	338,951
Partners’ Capital:
Preference Units	37,280	37,280
General Partner	10,661,943	10,532,037
Limited Partners	208,955	233,162
Accumulated other comprehensive income (loss)	(36,666)	(43,666)
Total partners’ capital	10,871,512	10,758,813
Noncontrolling Interests – Partially Owned Properties	2,138	4,673
Total capital	10,873,650	10,763,486
Total liabilities and equity/capital	$ 20,663,015	$ 20,286,891

CONSOLIDATED STATEMENTS OF OP_2

CONSOLIDATED STATEMENTS OF OPERATIONS OF ERP OPERATING LIMITED PARTNERSHIP (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
REVENUES
Rental income	$ 623,206	$ 622,433	$ 1,818,867	$ 1,958,270
EXPENSES
Property and maintenance	116,461	113,065	341,261	333,333
Real estate taxes and insurance	96,909	95,273	297,780	288,043
Property management	23,772	20,196	74,357	71,513
General and administrative	13,041	10,859	43,102	37,212
Depreciation	215,397	200,605	616,032	619,003
Total expenses	465,580	439,998	1,372,532	1,349,104
Net gain (loss) on sales of real estate properties	363,928	(25)	587,623	352,218
Operating income	521,554	182,410	1,033,958	961,384
Interest and other income	973	535	25,293	4,006
Other expenses	(3,456)	(4,097)	(10,908)	(8,324)
Interest:
Expense incurred, net	(68,251)	(80,874)	(202,733)	(248,349)
Amortization of deferred financing costs	(2,048)	(2,101)	(6,172)	(6,253)
Income before income and other taxes, income (loss) from investments in unconsolidated entities and net gain (loss) on sales of land parcels	448,772	95,873	839,438	702,464
Income and other tax (expense) benefit	(284)	(262)	(679)	(502)
Income (loss) from investments in unconsolidated entities	(1,156)	(246)	(3,028)	(2,445)
Net gain (loss) on sales of land parcels			5
Net income	447,332	95,365	835,736	699,517
Partially Owned Properties	(534)	(703)	(1,957)	(14,113)
Net income attributable to controlling interests	$ 431,951	$ 91,286	$ 805,876	$ 660,780
Earnings per Unit – basic:
Net income available to Units	$ 1.15	$ 0.24	$ 2.15	$ 1.77
Earnings per Unit – diluted:
Net income available to Units	$ 1.15	$ 0.24	$ 2.14	$ 1.77
Weighted average Units outstanding	388,374	385,652	387,642	385,973
ERPOP [Member]
REVENUES
Rental income	$ 623,206	$ 622,433	$ 1,818,867	$ 1,958,270
EXPENSES
Property and maintenance	116,461	113,065	341,261	333,333
Real estate taxes and insurance	96,909	95,273	297,780	288,043
Property management	23,772	20,196	74,357	71,513
General and administrative	13,041	10,859	43,102	37,212
Depreciation	215,397	200,605	616,032	619,003
Total expenses	465,580	439,998	1,372,532	1,349,104
Net gain (loss) on sales of real estate properties	363,928	(25)	587,623	352,218
Operating income	521,554	182,410	1,033,958	961,384
Interest and other income	973	535	25,293	4,006
Other expenses	(3,456)	(4,097)	(10,908)	(8,324)
Interest:
Expense incurred, net	(68,251)	(80,874)	(202,733)	(248,349)
Amortization of deferred financing costs	(2,048)	(2,101)	(6,172)	(6,253)
Income before income and other taxes, income (loss) from investments in unconsolidated entities and net gain (loss) on sales of land parcels	448,772	95,873	839,438	702,464
Income and other tax (expense) benefit	(284)	(262)	(679)	(502)
Income (loss) from investments in unconsolidated entities	(1,156)	(246)	(3,028)	(2,445)
Net gain (loss) on sales of land parcels			5
Net income	447,332	95,365	835,736	699,517
Partially Owned Properties	(534)	(703)	(1,957)	(14,113)
Net income attributable to controlling interests	446,798	94,662	833,779	685,404
ALLOCATION OF NET INCOME:
Preference Units	773	773	2,318	2,318
General Partner	431,178	90,513	803,558	658,462
Limited Partners	14,847	3,376	27,903	24,624
Net income available to Units	$ 446,025	$ 93,889	$ 831,461	$ 683,086
Earnings per Unit – basic:
Net income available to Units	$ 1.15	$ 0.24	$ 2.15	$ 1.77
Weighted average Units outstanding	386,327	384,871	385,841	384,759
Earnings per Unit – diluted:
Net income available to Units	$ 1.15	$ 0.24	$ 2.14	$ 1.77
Weighted average Units outstanding	388,374	385,652	387,642	385,973

CONSOLIDATED STATEMENTS OF CO_2

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME OF ERP OPERATING LIMITED PARTNERSHIP (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Comprehensive income:
Net income	$ 447,332	$ 95,365	$ 835,736	$ 699,517
Other comprehensive income (loss) – derivative instruments:
Unrealized holding gains (losses) arising during the period				(1,190)
Losses reclassified into earnings from other comprehensive income	2,363	5,877	7,000	17,275
Other comprehensive income (loss)	2,363	5,877	7,000	16,085
Comprehensive income	449,695	101,242	842,736	715,602
Comprehensive (income) attributable to Noncontrolling Interests – Partially Owned Properties	(15,459)	(4,290)	(30,100)	(39,316)
Comprehensive income attributable to controlling interests	434,236	96,952	812,636	676,286
ERPOP [Member]
Comprehensive income:
Net income	447,332	95,365	835,736	699,517
Other comprehensive income (loss) – derivative instruments:
Unrealized holding gains (losses) arising during the period				(1,190)
Losses reclassified into earnings from other comprehensive income	2,363	5,877	7,000	17,275
Other comprehensive income (loss)	2,363	5,877	7,000	16,085
Comprehensive income	449,695	101,242	842,736	715,602
Comprehensive (income) attributable to Noncontrolling Interests – Partially Owned Properties	(534)	(703)	(1,957)	(14,113)
Comprehensive income attributable to controlling interests	$ 449,161	$ 100,539	$ 840,779	$ 701,489

CONSOLIDATED STATEMENTS OF CA_2

CONSOLIDATED STATEMENTS OF CASH FLOWS OF ERP OPERATING LIMITED PARTNERSHIP (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 835,736	$ 699,517
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	616,032	619,003
Amortization of deferred financing costs	6,172	6,253
Amortization of above/below market lease intangibles	(154)	(53)
Amortization of discounts and premiums on debt	3,934	3,834
Amortization of deferred settlements on derivative instruments	6,991	17,266
Amortization of right-of-use assets	10,286	8,785
Write-off of pursuit costs	3,557	4,864
(Income) loss from investments in unconsolidated entities	3,028	2,445
Distributions from unconsolidated entities – return on capital		100
Net (gain) loss on sales of real estate properties	(587,623)	(352,218)
Net (gain) loss on sales of land parcels	(5)
Realized/unrealized (gain) loss on derivative instruments		50
Realized (gain) loss on sale of investment securities	(23,432)
Compensation paid with Company Common Shares	21,919	18,275
Other operating activities, net		1,805
Changes in assets and liabilities:
(Increase) decrease in other assets	16,269	(30,197)
Increase (decrease) in accounts payable and accrued expenses	69,170	54,418
Increase (decrease) in accrued interest payable	(9,119)	(1,183)
Increase (decrease) in lease liabilities	(4,112)	(1,650)
Increase (decrease) in other liabilities	5,427	(8,381)
Increase (decrease) in security deposits	4,137	(8,609)
Net cash provided by operating activities	978,213	1,034,324
CASH FLOWS FROM INVESTING ACTIVITIES:
Investment in real estate – acquisitions	(1,022,275)	(48,898)
Investment in real estate – development/other	(172,850)	(157,778)
Capital expenditures to real estate	(107,706)	(92,123)
Non-real estate capital additions	(1,251)	(19,290)
Proceeds from disposition of real estate, net	1,014,328	747,600
Investments in unconsolidated entities	(31,081)	(6,664)
Distributions from unconsolidated entities – return of capital	4	1,000
Purchase of investment securities and other investments	(167,791)	(509)
Proceeds from sale of investment securities	191,398
Net cash provided by (used for) investing activities	(309,589)	416,458
CASH FLOWS FROM FINANCING ACTIVITIES:
Debt financing costs	(6,447)	(2,923)
Mortgage notes payable, net:
Proceeds	51,298	505,375
Lump sum payoffs	(59,880)	(127,767)
Scheduled principal repayments	(5,570)	(5,821)
Notes, net:
Proceeds	497,470
Line of credit and commercial paper:
Line of credit proceeds		1,870,000
Line of credit repayments		(1,890,000)
Commercial paper proceeds	4,305,170	6,726,167
Commercial paper repayments	(4,690,000)	(7,724,000)
Proceeds from (payments on) settlement of derivative instruments		(1,240)
Finance ground lease principal payments	(349)
Proceeds from Employee Share Purchase Plan (ESPP)	3,455	3,556
Proceeds from exercise of EQR options	68,807	11,426
Payment of offering costs	(267)
Other financing activities, net	(31)	(31)
Contributions – Noncontrolling Interests – Partially Owned Properties		417
Contributions – Limited Partners		12
Distributions:
OP Units – General Partner	(674,531)	(659,668)
Preference Units	(2,318)	(2,318)
OP Units – Limited Partners	(23,949)	(24,440)
Noncontrolling Interests – Partially Owned Properties	(4,461)	(11,312)
Net cash provided by (used for) financing activities	(541,603)	(1,332,567)
Net increase (decrease) in cash and cash equivalents and restricted deposits	127,021	118,215
Cash and cash equivalents and restricted deposits, beginning of period	99,728	116,999
Cash and cash equivalents and restricted deposits, end of period	226,749	235,214
Cash and cash equivalents	39,707	178,333
Restricted deposits	187,042	56,881
SUPPLEMENTAL INFORMATION:
Cash paid for interest, net of amounts capitalized	199,799	223,703
Net cash paid (received) for income and other taxes	1,040	(1,092)
Amortization of deferred financing costs:
Investment in real estate, net	(227)	(180)
Other assets	1,754	1,755
Mortgage notes payable, net	1,702	1,337
Notes, net	2,943	3,341
Amortization of discounts and premiums on debt:
Mortgage notes payable, net	2,069	1,791
Notes, net	1,865	2,043
Amortization of deferred settlements on derivative instruments:
Other liabilities	(9)	(9)
Accumulated other comprehensive income	7,000	17,275
Write-off of pursuit costs:
Investment in real estate, net	3,000	4,621
Other assets	533	219
Accounts payable and accrued expenses	24	24
(Income) loss from investments in unconsolidated entities:
Investments in unconsolidated entities	2,062	1,474
Other liabilities	966	971
Realized/unrealized (gain) loss on derivative instruments:
Other liabilities		1,240
Accumulated other comprehensive income		(1,190)
Interest capitalized for real estate and unconsolidated entities under development:
Investment in real estate, net	(12,260)	(6,880)
Investments in unconsolidated entities	(105)
Investments in unconsolidated entities:
Investment in real estate, net	967
Investments in unconsolidated entities	(30,038)	(5,164)
Other liabilities	(2,010)	(1,500)
Debt financing costs:
Other assets	228	(231)
Mortgage notes payable, net	(2,344)	(2,692)
Notes, net	(4,331)
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	1,430
Other assets	(1,430)
ERPOP [Member]
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	835,736	699,517
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	616,032	619,003
Amortization of deferred financing costs	6,172	6,253
Amortization of above/below market lease intangibles	(154)	(53)
Amortization of discounts and premiums on debt	3,934	3,834
Amortization of deferred settlements on derivative instruments	6,991	17,266
Amortization of right-of-use assets	10,286	8,785
Write-off of pursuit costs	3,557	4,864
(Income) loss from investments in unconsolidated entities	3,028	2,445
Distributions from unconsolidated entities – return on capital		100
Net (gain) loss on sales of real estate properties	(587,623)	(352,218)
Net (gain) loss on sales of land parcels	(5)
Realized/unrealized (gain) loss on derivative instruments		50
Realized (gain) loss on sale of investment securities	(23,432)
Compensation paid with Company Common Shares	21,919	18,275
Other operating activities, net		1,805
Changes in assets and liabilities:
(Increase) decrease in other assets	16,269	(30,197)
Increase (decrease) in accounts payable and accrued expenses	69,170	54,418
Increase (decrease) in accrued interest payable	(9,119)	(1,183)
Increase (decrease) in lease liabilities	(4,112)	(1,650)
Increase (decrease) in other liabilities	5,427	(8,381)
Increase (decrease) in security deposits	4,137	(8,609)
Net cash provided by operating activities	978,213	1,034,324
CASH FLOWS FROM INVESTING ACTIVITIES:
Investment in real estate – acquisitions	(1,022,275)	(48,898)
Investment in real estate – development/other	(172,850)	(157,778)
Capital expenditures to real estate	(107,706)	(92,123)
Non-real estate capital additions	(1,251)	(19,290)
Interest capitalized for real estate and unconsolidated entities under development	(12,365)	(6,880)
Proceeds from disposition of real estate, net	1,014,328	747,600
Investments in unconsolidated entities	(31,081)	(6,664)
Distributions from unconsolidated entities – return of capital	4	1,000
Purchase of investment securities and other investments	(167,791)	(509)
Proceeds from sale of investment securities	191,398
Net cash provided by (used for) investing activities	(309,589)	416,458
CASH FLOWS FROM FINANCING ACTIVITIES:
Debt financing costs	(6,447)	(2,923)
Mortgage notes payable, net:
Proceeds	51,298	505,375
Lump sum payoffs	(59,880)	(127,767)
Scheduled principal repayments	(5,570)	(5,821)
Notes, net:
Proceeds	497,470
Line of credit and commercial paper:
Line of credit proceeds		1,870,000
Line of credit repayments		(1,890,000)
Commercial paper proceeds	4,305,170	6,726,167
Commercial paper repayments	(4,690,000)	(7,724,000)
Proceeds from (payments on) settlement of derivative instruments		(1,240)
Finance ground lease principal payments	(349)
Proceeds from Employee Share Purchase Plan (ESPP)	3,455	3,556
Proceeds from exercise of EQR options	68,807	11,426
Payment of offering costs	(267)
Other financing activities, net	(31)	(31)
Contributions – Noncontrolling Interests – Partially Owned Properties		417
Contributions – Limited Partners		12
Distributions:
OP Units – General Partner	(674,531)	(659,668)
Preference Units	(2,318)	(2,318)
OP Units – Limited Partners	(23,949)	(24,440)
Noncontrolling Interests – Partially Owned Properties	(4,461)	(11,312)
Net cash provided by (used for) financing activities	(541,603)	(1,332,567)
Net increase (decrease) in cash and cash equivalents and restricted deposits	127,021	118,215
Cash and cash equivalents and restricted deposits, beginning of period	99,728	116,999
Cash and cash equivalents and restricted deposits, end of period	226,749	235,214
Cash and cash equivalents	39,707	178,333
Restricted deposits	187,042	56,881
SUPPLEMENTAL INFORMATION:
Cash paid for interest, net of amounts capitalized	199,799	223,703
Net cash paid (received) for income and other taxes	1,040	(1,092)
Amortization of deferred financing costs:
Investment in real estate, net	(227)	(180)
Other assets	1,754	1,755
Mortgage notes payable, net	1,702	1,337
Notes, net	2,943	3,341
Amortization of discounts and premiums on debt:
Mortgage notes payable, net	2,069	1,791
Notes, net	1,865	2,043
Amortization of deferred settlements on derivative instruments:
Other liabilities	(9)	(9)
Accumulated other comprehensive income	7,000	17,275
Write-off of pursuit costs:
Investment in real estate, net	3,000	4,621
Other assets	533	219
Accounts payable and accrued expenses	24	24
(Income) loss from investments in unconsolidated entities:
Investments in unconsolidated entities	2,062	1,474
Other liabilities	966	971
Realized/unrealized (gain) loss on derivative instruments:
Other liabilities		1,240
Accumulated other comprehensive income		(1,190)
Interest capitalized for real estate and unconsolidated entities under development:
Investment in real estate, net	(12,260)	(6,880)
Investments in unconsolidated entities	(105)
Investments in unconsolidated entities:
Investment in real estate, net	967
Investments in unconsolidated entities	(30,038)	(5,164)
Other liabilities	(2,010)	(1,500)
Debt financing costs:
Other assets	228	(231)
Mortgage notes payable, net	(2,344)	$ (2,692)
Notes, net	(4,331)
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	1,430
Other assets	$ (1,430)

CONSOLIDATED STATEMENTS OF CH_3

CONSOLIDATED STATEMENTS OF CHANGES IN CAPITAL OF ERP OPERATING LIMITED PARTNERSHIP (Unaudited) - USD ($) $ in Thousands	Total	ERPOP [Member]	PREFERRED SHARESERPOP [Member]	General Partner [Member]ERPOP [Member]	Limited PartnerERPOP [Member]	ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)ERPOP [Member]	DISTRIBUTIONS [Member]ERPOP [Member]	PARTIALLY OWNED PROPERTIES [Member]ERPOP [Member]
Balance, beginning of year at Dec. 31, 2019			$ 37,280	$ 10,355,789	$ 227,837	$ (77,563)
Balance, beginning of year at Dec. 31, 2019								$ 1,183
Conversion of OP Units held by Limited Partners into OP Units held by General Partner				3,913	(3,913)
Exercise of EQR share options				11,426
EQR's Employee Share Purchase Plan (ESPP)				3,556
EQR restricted shares				9,238	12
EQR share options				1,819
EQR ESPP discount				626
Net income available to Units - General Partner		$ 658,462		658,462
OP Units General Partner distributions				(673,019)
Supplemental Executive Retirement Plan (SERP)				(395)
Change in market value of Redeemable Limited Partners				169,825
Adjustment for Limited Partners ownership in Operating Partnership				438	(438)
Equity compensation associated with Units - Limited Partners					9,525
Net income available to Units - Limited Partners		24,624			24,624
Units - Limited Partners distributions					(25,000)
Change in carrying value of Redeemable Limited Partners					(131)
Unrealized holding (losses) arising during the period	$ 14,113	14,113				(1,190)
Losses reclassified into earnings from other comprehensive income	(17,275)	(17,275)				17,275
Distributions declared per Unit outstanding							$ 1.8075
Net income attributable to Noncontrolling Interests	699,517	699,517						14,113
Contributions by Noncontrolling Interests								417
Distributions to Noncontrolling Interests								(11,343)
Balance, end of period at Sep. 30, 2020			37,280	10,541,678	232,516	(61,478)
Balance, end of period at Sep. 30, 2020								4,370
Balance, beginning of year at Jun. 30, 2020			37,280	10,627,748	235,169	(67,355)
Balance, beginning of year at Jun. 30, 2020								4,634
Conversion of OP Units held by Limited Partners into OP Units held by General Partner				57	(57)
Exercise of EQR share options				104
EQR's Employee Share Purchase Plan (ESPP)				1,197
EQR restricted shares				1,984
EQR share options				526
EQR ESPP discount				210
Net income available to Units - General Partner		90,513		90,513
OP Units General Partner distributions				(224,269)
Supplemental Executive Retirement Plan (SERP)				111
Change in market value of Redeemable Limited Partners				41,072
Adjustment for Limited Partners ownership in Operating Partnership				2,425	(2,425)
Equity compensation associated with Units - Limited Partners					2,499
Net income available to Units - Limited Partners		3,376			3,376
Units - Limited Partners distributions					(7,963)
Change in carrying value of Redeemable Limited Partners					1,917
Unrealized holding (losses) arising during the period	703	703
Losses reclassified into earnings from other comprehensive income	(5,877)	(5,877)				5,877
Distributions declared per Unit outstanding							0.6025
Net income attributable to Noncontrolling Interests	95,365	95,365						703
Contributions by Noncontrolling Interests								76
Distributions to Noncontrolling Interests								(1,043)
Balance, end of period at Sep. 30, 2020			37,280	10,541,678	232,516	(61,478)
Balance, end of period at Sep. 30, 2020								4,370
Balance, beginning of year at Dec. 31, 2020			37,280	10,532,037	233,162	(43,666)
Balance, beginning of year at Dec. 31, 2020								4,673
Conversion of OP Units held by Limited Partners into OP Units held by General Partner				68,257	(68,257)
Exercise of EQR share options				68,807
EQR's Employee Share Purchase Plan (ESPP)				3,455
EQR restricted shares				6,572
EQR share options				2,541
EQR ESPP discount				798
Net income available to Units - General Partner		803,558		803,558
OP Units General Partner distributions				(676,158)
Offering costs				(267)
Supplemental Executive Retirement Plan (SERP)				(1,335)
Change in market value of Redeemable Limited Partners				(119,237)
Adjustment for Limited Partners ownership in Operating Partnership				(27,085)	27,085
Equity compensation associated with Units - Limited Partners					14,173
Net income available to Units - Limited Partners		27,903			27,903
Units - Limited Partners distributions					(23,366)
Change in carrying value of Redeemable Limited Partners					(1,745)
Unrealized holding (losses) arising during the period	1,957	1,957
Losses reclassified into earnings from other comprehensive income	(7,000)	(7,000)				7,000
Distributions declared per Unit outstanding							1.8075
Net income attributable to Noncontrolling Interests	835,736	835,736						1,957
Distributions to Noncontrolling Interests								(4,492)
Balance, end of period at Sep. 30, 2021			37,280	10,661,943	208,955	(36,666)
Balance, end of period at Sep. 30, 2021								2,138
Balance, beginning of year at Jun. 30, 2021			37,280	10,435,740	205,691	(39,029)
Balance, beginning of year at Jun. 30, 2021								2,365
Conversion of OP Units held by Limited Partners into OP Units held by General Partner				1,597	(1,597)
Exercise of EQR share options				29,184
EQR's Employee Share Purchase Plan (ESPP)				788
EQR restricted shares				1,758
EQR share options				565
EQR ESPP discount				165
Net income available to Units - General Partner		431,178		431,178
OP Units General Partner distributions				(225,938)
Offering costs				(267)
Supplemental Executive Retirement Plan (SERP)				722
Change in market value of Redeemable Limited Partners				(17,271)
Adjustment for Limited Partners ownership in Operating Partnership				3,722	(3,722)
Equity compensation associated with Units - Limited Partners					3,642
Net income available to Units - Limited Partners		14,847			14,847
Units - Limited Partners distributions					(7,367)
Change in carrying value of Redeemable Limited Partners					(2,539)
Unrealized holding (losses) arising during the period	534	534
Losses reclassified into earnings from other comprehensive income	(2,363)	(2,363)				2,363
Distributions declared per Unit outstanding							$ 0.6025
Net income attributable to Noncontrolling Interests	$ 447,332	$ 447,332						534
Distributions to Noncontrolling Interests								(761)
Balance, end of period at Sep. 30, 2021			$ 37,280	$ 10,661,943	$ 208,955	$ (36,666)
Balance, end of period at Sep. 30, 2021								$ 2,138

Business

Business	9 Months Ended
	Sep. 30, 2021
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Business	1. Business Equity Residential (“EQR”) is an S&P 500 company focused on the acquisition, development and management of residential properties located in and around dynamic cities that attract high quality long-term renters, a business that is conducted on its behalf by ERP Operating Limited Partnership (“ERPOP”). EQR is a Maryland real estate investment trust (“REIT”) formed in March 1993 and ERPOP is an Illinois limited partnership formed in May 1993. ERPOP. ERPOP. EQR is the general partner of, and as of September 30, 2021 owned an approximate 96.7% ownership interest in, ERPOP. All of the Company’s property ownership, development and related business operations are conducted through the Operating Partnership ERPOP. ERPOP, As of September 30, 2021, the Company, directly or indirectly through investments in title holding entities, owned all or a portion of 307 properties located in 10 states and the District of Columbia consisting of 79,322 apartment units. The ownership breakdown includes (table does not include various uncompleted development properties): Properties Apartment Units Wholly Owned Properties 290 75,548 Partially Owned Properties – Consolidated 17 3,774 307 79,322 Note: Effective July 31, 2021, the Company took over management of its last remaining third-party master-leased property containing 162 apartment units located in the Washington D.C. market COVID-19 Pandemic The Company continues to monitor the effects of and take various actions in response to the novel coronavirus (“COVID-19”) pandemic and its accompanying variants. Its duration, severity and the extent of the adverse health impact on the general population, our residents and employees, the rate of vaccine distribution and effectiveness of vaccinations, the overall reopening progress in the cities in which we operate and the potential long-term changes in customer preferences for living in our communities, are among the many unknowns that have had or could continue to have a significant future impact on the Company. These, among other items, have impacted the economy, the unemployment rate and our operations and could materially affect our future consolidated results of operations, financial condition, liquidity, investments and overall performance. There have been no material changes to the overall COVID-19 disclosures that were discussed in the notes to the consolidated financial statements of the Company’s and the Operating Partnership’s Annual Report on Form 10-K for the year ended December 31, 2020.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2021
Summary Of Significant Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by accounting principles generally accepted in the United States for complete financial statements. In the opinion of management, all adjustments (consisting of normal recurring accruals) and certain reclassifications considered necessary for a fair presentation have been included. Operating results for the nine months ended September 30, 2021 are not necessarily indicative of the results that may be expected for the year ending December 31, 2021. In preparation of the Company’s financial statements in conformity with accounting principles generally accepted in the United States, management makes estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements as well as the reported amounts of revenues and expenses during the reporting period. Actual results could differ from these estimates. In response to the COVID-19 pandemic, management evaluated whether its estimates , such as lease collectibility (discuss ed below in Recently Adopted Accounting Pronouncements ) and impairment, require d revised approaches and generally concluded that no revisions were necessary at this time . The balance sheets at December 31, 2020 have been derived from the audited financial statements at that date but do not include all of the information and footnotes required by accounting principles generally accepted in the United States for complete financial statements. For further information, including definitions of capitalized terms not defined herein, refer to the consolidated financial statements and footnotes thereto included in the Company’s and the Operating Partnership’s Annual Report on Form 10-K for the year ended December 31, 2020. Income and Other Taxes EQR has elected to be taxed as a REIT. This, along with the nature of the operations of its operating properties, resulted in no provision for federal income taxes at the EQR level. In addition, ERPOP generally is not liable for federal income taxes as the partners recognize their allocable share of income or loss in their tax returns; therefore no provision for federal income taxes has been made at the ERPOP level. Historically, the Company has generally only incurred certain state and local income, excise and franchise taxes. The Company has elected taxable REIT subsidiary (“TRS”) status for certain of its corporate subsidiaries and, as a result, these entities will incur both federal and state income taxes on any taxable income of such entities after consideration of any net operating losses. On March 27, 2020, the President signed into law the Coronavirus Aid, Relief, and Economic Security Act (the “CARES Act”). Included in the CARES Act were tax provisions which increased allowable interest expense deductions for 2019 and 2020 and increased the ability for taxpayers to use net operating losses. These provisions did not result in a material impact to the Company’s taxable income or tax liabilities. Recently Issued Accounting Pronouncements In August 2020, the Financial Accounting Standards Board (“FASB”) issued an amendment to the debt and equity financial instruments standards which simplifies the accounting for convertible instruments and accounting for contracts in an entity’s own equity. Instead of being required to assess whether an equity contract permits settlement in unregistered shares, which may require a legal analysis under the securities laws, entities will only analyze whether cash settlements are explicitly required when registered shares are unavailable. As a result, such contracts may be classified in permanent rather than mezzanine equity, which may affect the way the Company’s OP Units are presented on its financial statements. The update is effective for the Company beginning on January 1, 2022 as the Company did not early adopt the standard as allowed on January 1, 2021. The Company is currently evaluating the impact of adopting the new standard on its consolidated results of operations and financial position. Recently Adopted Accounting Pronouncements In August 2021, the FASB issued an amendment to the presentation of financial statements standard which aligns the financial statements and disclosure requirements with those of the final rules released by the SEC in May 2020. The amendment changes the significance tests that determine what disclosures about significant business acquisitions are required, the periods the financial statements must cover and the pro forma financial information that must be included in certain reports. The amendment was effective for the Company upon issuance on August 9, 2021. The Company has not yet acquired businesses that exceed the threshold as defined by the standard, therefore, the amendment did not have a material effect on its consolidated results of operations and financial position. In March 2020, the FASB issued an amendment to the reference rate reform standard which provides the option for a limited period of time to ease the potential burden in accounting for, or recognizing the effects of, reference rate reform on contract modifications and hedge accounting. An example of such reform is the expected market transition from the London Interbank Offered Rate (“LIBOR”) and other interbank offered rates to alternative reference rates. Entities that make this optional expedient election would not have to remeasure the contracts at the modification date or reassess the accounting treatment if certain criteria are met and would continue applying hedge accounting for relationships affected by reference rate reform. The new standard was effective for the Company upon issuance and elections can be made through December 31, 2022. The Company elected to apply the hedge accounting expedients related to probability and the assessments of effectiveness for future LIBOR-indexed cash flows to assume that the index upon which future hedged transactions will be based matches the index on the corresponding derivatives. Application of these expedients preserves the presentation of derivatives consistent with past presentation. The Company continues to evaluate the impact of the guidance and may apply other elections as applicable as additional changes in the market occur. In April 2020, a FASB staff question and answer document was issued which intended to reduce the challenges of evaluating the enforceable rights and obligations of leases for concessions granted to lessees in response to the COVID-19 pandemic. We elected not to evaluate whether qualifying concessions provided by the Company in response to the COVID-19 pandemic are a lease modification, subject to the criteria that the total payments under the amended lease cannot result in a substantial increase in the rights of the lessor or obligations of the lessee . We also elected to treat the concessions as though they were contemplated as part of the existing contracts and therefore will not apply lease modification rules to the qualifying lease concession amendments. As such, deferrals deemed collectible are recorded as rental receivables with no change to timing of rental revenues and deferrals deemed non-collectible and abatements reduce rental revenues in the deferral/abatement period and cause rental revenues to effectively follow a cash basis related to the changes. The accounting elections provided by the FASB mainly apply to the Company’s non-residential leases and the majority of the amendments will not require a straight-line adjustment. See Note 8 for additional discussion. In June 2016, the FASB issued a standard which requires companies to adopt a new approach for estimating credit losses on certain types of financial instruments, such as trade and other receivables and loans. The standard requires entities to estimate a lifetime expected credit loss for most financial instruments, including trade receivables. In November 2018, the FASB issued an amendment excluding operating lease receivables accounted for under the lease standard from the scope of the credit losses standard. The Company adopted this standard as required effective January 1, 2020 and it did not have a material effect on its consolidated results of operations and financial position.

Equity, Capital and Other Inter

Equity, Capital and Other Interests	9 Months Ended
	Sep. 30, 2021
Equity Capital And Other Interests [Abstract]
Equity, Capital and Other Interests	3. Equity, Capital and Other Interests The Company refers to “Common Shares” and “Units” (which refer to both OP Units and restricted units) as equity securities for EQR and “General Partner Units” and “Limited Partner Units” as equity securities for ERPOP. To provide a streamlined and more readable presentation of the disclosures for the Company and the Operating Partnership, several sections below refer to the respective terminology for each with the same financial information and separate sections are provided, where needed, to further distinguish any differences in financial information and terminology. The following table presents the changes in the Company’s issued and outstanding Common Shares and Units for the nine months ended September 30, 2021 and 2020: 2021 2020 Common Shares Common Shares outstanding at January 1, 372,302,000 371,670,884 Common Shares Issued: Conversion of OP Units 1,153,963 99,737 Exercise of share options 1,401,755 219,922 Employee Share Purchase Plan (ESPP) 59,297 69,986 Restricted share grants, net 85,573 178,720 Common Shares outstanding at September 30, 375,002,588 372,239,249 Units Units outstanding at January 1, 13,858,073 13,731,315 Restricted unit grants, net 155,638 247,822 Conversion of OP Units to Common Shares (1,153,963 ) (99,737 ) Units outstanding at September 30, 12,859,748 13,879,400 Total Common Shares and Units outstanding at September 30, 387,862,336 386,118,649 Units Ownership Interest in Operating Partnership 3.3 % 3.6 % The following table presents the changes in the Operating Partnership’s issued and outstanding General Partner Units and Limited Partner Units for the nine months ended September 30, 2021 and 2020: 2021 2020 General and Limited Partner Units General and Limited Partner Units outstanding at January 1, 386,160,073 385,402,199 Issued to General Partner: Exercise of EQR share options 1,401,755 219,922 EQR’s Employee Share Purchase Plan (ESPP) 59,297 69,986 EQR’s restricted share grants, net 85,573 178,720 Issued to Limited Partners: Restricted unit grants, net 155,638 247,822 General and Limited Partner Units outstanding at September 30, 387,862,336 386,118,649 Limited Partner Units Limited Partner Units outstanding at January 1, 13,858,073 13,731,315 Limited Partner restricted unit grants, net 155,638 247,822 Conversion of Limited Partner OP Units to EQR Common Shares (1,153,963 ) (99,737 ) Limited Partner Units outstanding at September 30, 12,859,748 13,879,400 Limited Partner Units Ownership Interest in Operating Partnership 3.3 % 3.6 % The equity positions of various individuals and entities that contributed their properties to the Operating Partnership in exchange for OP Units, as well as the equity positions of the holders of restricted units, are collectively referred to as the “Noncontrolling Interests – Operating Partnership” and “Limited Partners Capital,” respectively, for the Company and the Operating Partnership. Subject to certain exceptions (including the “book-up” requirements of restricted units), the Noncontrolling Interests – Operating Partnership/Limited Partners Capital may exchange their Units with EQR for Common Shares on a one-for-one basis. The carrying value of the Noncontrolling Interests – Operating Partnership/Limited Partners Capital (including redeemable interests) is allocated based on the number of Noncontrolling Interests – Operating Partnership/Limited Partners Capital in total in proportion to the number of Noncontrolling Interests – Operating Partnership/Limited Partners Capital in total plus the total number of Common Shares/General Partner Units. Net income is allocated to the Noncontrolling Interests – Operating Partnership/Limited Partners Capital based on the weighted average ownership percentage during the period. The Operating Partnership has the right but not the obligation to make a cash payment instead of issuing Common Shares to any and all holders of Noncontrolling Interests – Operating Partnership/Limited Partners Capital requesting an exchange of their Noncontrolling Interests – Operating Partnership/Limited Partners Capital with EQR. Once the Operating Partnership elects not to redeem the Noncontrolling Interests – Operating Partnership/Limited Partners Capital for cash, EQR is obligated to deliver Common Shares to the exchanging holder of the Noncontrolling Interests – Operating Partnership/Limited Partners Capital. The Noncontrolling Interests – Operating Partnership/Limited Partners Capital are classified as either mezzanine equity or permanent equity. If EQR is required, either by contract or securities law, to deliver registered Common Shares, such Noncontrolling Interests – Operating Partnership/Limited Partners Capital are differentiated and referred to as “Redeemable Noncontrolling Interests – Operating Partnership” and “Redeemable Limited Partners,” respectively. Instruments that require settlement in registered shares cannot be classified in permanent equity as it is not always completely within an issuer’s control to deliver registered shares. Therefore, settlement in cash is assumed and that responsibility for settlement in cash is deemed to fall to the Operating Partnership as the primary source of cash for EQR, resulting in presentation in the mezzanine section of the balance sheet. The Redeemable Noncontrolling Interests – Operating Partnership/Redeemable Limited Partners are adjusted to the greater of carrying value or fair market value based on the Common Share price of EQR at the end of each respective reporting period. EQR has the ability to deliver unregistered Common Shares for the remaining portion of the Noncontrolling Interests – Operating Partnership/Limited Partners Capital that are classified in permanent equity at September 30, 2021 and December 31, 2020. The carrying value of the Redeemable Noncontrolling Interests – Operating Partnership/Redeemable Limited Partners is allocated based on the number of Redeemable Noncontrolling Interests – Operating Partnership/Redeemable Limited Partners in proportion to the number of Noncontrolling Interests – Operating Partnership/Limited Partners Capital in total. Such percentage of the total carrying value of Units/Limited Partner Units which is ascribed to the Redeemable Noncontrolling Interests – Operating Partnership/Redeemable Limited Partners is then adjusted to the greater of carrying value or fair market value as described above. As of September 30, 2021 and 2020, the Redeemable Noncontrolling Interests – Operating Partnership/Redeemable Limited Partners have a redemption value of approximately The following table presents the changes in the redemption value of the Redeemable Noncontrolling Interests – Operating Partnership/Redeemable Limited Partners for the nine months ended September 30, 2021 and 2020, respectively (amounts in 2021 2020 Balance at January 1, $ 338,951 $ 463,400 Change in market value 119,237 (169,825 ) Change in carrying value 1,745 131 Balance at September 30, $ 459,933 $ 293,706 Net proceeds from EQR Common Share and Preferred Share (see definition below) offerings and proceeds from exercise of options for Common Shares are contributed by EQR to ERPOP. In return for those contributions, EQR receives a number of OP Units in ERPOP equal to the number of Common Shares it has issued in the equity offering (or in the case of a preferred equity offering, a number of preference units in ERPOP equal in number and having the same terms as the Preferred Shares issued in the equity offering). As a result, the net proceeds from Common Shares and Preferred Shares are allocated for the Company between shareholders’ equity and Noncontrolling Interests – Operating Partnership and for the Operating Partnership between General Partner’s Capital and Limited Partners Capital to account for the change in their respective percentage ownership of the underlying equity. The 100,000,000 The following table presents the Company’s issued and outstanding Preferred Shares/Preference Units as September 30, 2021 and December 31, 2020 Amounts in thousands Annual Call Dividend Per September 30, December 31, Date (1) Share/Unit (2) 2021 2020 Preferred Shares/Preference Units of beneficial interest, $0.01 par value; 100,000,000 shares authorized: 8.29% Series K Cumulative Redeemable Preferred Shares/Preference Units; liquidation value $50 per share/unit; 745,600 shares/units issued and outstanding as of September 30, 2021 and December 31, 2020 12/10/26 $ 4.145 $ 37,280 $ 37,280 $ 37,280 $ 37,280 (1) On or after the call date, redeemable Preferred Shares/Preference Units may be redeemed for cash at the option of the Company or the Operating Partnership, respectively, in whole or in part, at a redemption price equal to the liquidation price per share/unit, plus accrued and unpaid distributions, if any. (2) Dividends on Preferred Shares/Preference Units are payable quarterly. Other EQR and ERPOP currently have an active universal shelf registration statement for the issuance of equity and debt securities that automatically became effective upon filing with the SEC in June 2019 and expires in June 2022. Per the terms of ERPOP’s partnership agreement, EQR contributes the net proceeds of all equity offerings to the capital of ERPOP in exchange for additional OP Units (on a one-for-one Common Share per OP Unit basis) or preference units (on a one-for-one preferred share per preference unit basis). The Company has an At-The-Market (“ATM”) share offering program which allows EQR to issue Common Shares from time to time into the existing trading market at current market prices or through negotiated transactions, including under forward sale arrangements. The current program matures in June 2022 and gives EQR the authority to issue up to 13.0 million shares, all of which remain outstanding as of September 30, 2021, pending the settlement of any outstanding forward sale agreements. As of September 30, 2021, the Company had entered into such forward sale agreements under this program for a total of approximately 1.7 million Common Shares at a weighted average initial forward price per share of $83.25. These forward sale agreements allow the Company, at its election, to settle the agreements by issuing Common Shares in exchange for net proceeds at the then-applicable forward sale price specified by the agreement or, alternatively, to settle the agreements in whole or in part through the delivery or receipt of Common Shares or cash. Issuances of shares under these forward sale agreements are classified as equity transactions. Accordingly, no amounts relating to the forward sale agreements are recorded in the consolidated financial statements until settlement occurs. Prior to any settlements, the only impact to the consolidated financial statements is the potential inclusion of incremental shares, if any, within the calculation of diluted net income per share using the treasury stock method. The actual forward price per share to be received by the Company upon settlement will be determined on the applicable settlement date based on adjustments made to the initial forward price to reflect the then-current overnight federal funds rate and the amount of dividends paid to holders of the Company’s Common Shares over the term of the forward sale agreement. As of September 30, 2021, no shares under the forward sale agreements have been settled. These forward sale agreements must be settled by March 2023 . The Company may repurchase up to 13.0 million Common Shares under its share repurchase program. No open market repurchases have occurred since 2008, and no repurchases of any kind have occurred since February 2014. As of September 30, 2021, EQR has remaining authorization to repurchase up to 13.0 million of its shares.

Real Estate

Real Estate	9 Months Ended
	Sep. 30, 2021
Real Estate [Abstract]
Real Estate	4. Real Estate The following table summarizes the carrying amounts for the Company’s investment in real estate (at cost) as of September 30, 2021 and December 31, 2020 (amounts in thousands): September 30, 2021 December 31, 2020 Land $ 5,779,686 $ 5,785,367 Depreciable property: Buildings and improvements 19,211,662 18,464,484 Furniture, fixtures and equipment 2,125,441 1,970,033 In-Place lease intangibles 503,241 486,137 Projects under development: Land 4,121 23,531 Construction-in-progress 159,538 387,603 Land held for development: Land 46,160 46,160 Construction-in-progress 35,866 40,010 Investment in real estate 27,865,715 27,203,325 Accumulated depreciation (8,260,846 ) (7,859,657 ) Investment in real estate, net $ 19,604,869 $ 19,343,668 During the nine months ended September 30, 2021, the Company acquired the following from unaffiliated parties (purchase price in thousands): Properties Apartment Units Purchase Price Rental Properties – Consolidated (1) 11 2,921 $ 1,020,425 Total 11 2,921 $ 1,020,425 (1) Purchase price includes an allocation of approximately $134.2 million to land and $888.1 million to depreciable property (inclusive of capitalized closing costs). During the nine months ended September 30, 2021, the Company disposed of the following to unaffiliated parties (sales price in thousands): Properties Apartment Units Sales Price Rental Properties – Consolidated 10 1,842 $ 1,021,800 Total 10 1,842 $ 1,021,800 The Company recognized a net gain on sales of real estate properties of approximately $587.6 million on the above sales.

Commitments to Acquire_Dispose

Commitments to Acquire/Dispose of Real Estate	9 Months Ended
	Sep. 30, 2021
Commitments To Acquire Dispose Of Real Estate [Abstract]
Commitments to Acquire/Dispose of Real Estate	5. Commitments to Acquire/Dispose of Real The Company has not entered into any agreements to acquire rental properties or land parcels as of the date of filing. The Company has entered into separate agreements to dispose of the following (sales price and net book value in thousands): Properties Apartment Units Sales Price Net Book Value at September 30, 2021 Rental Properties - Consolidated 2 744 $ 410,000 $ 130,762 Total 2 744 $ 410,000 $ 130,762 The closing of pending transactions is subject to certain conditions and restrictions; therefore, there can be no assurance that the transactions will be consummated or that the final terms will not differ in material respects from any agreements summarized above. See Note 14 for discussion of the properties acquired or disposed of, if any, subsequent to September 30, 2021.

Investments in Partially Owned

Investments in Partially Owned Entities	9 Months Ended
	Sep. 30, 2021
Investments In Partially Owned Entities [Abstract]
Investments in Partially Owned Entities	6. Investments in Partially Owned The entities Consolidated Variable Interest Entities (“VIEs”) In accordance with accounting standards for consolidation of VIEs , the As the sole general partner of ERPOP, EQR has exclusive control of ERPOP’s day-to-day management. The limited partners are not able to exercise substantive kick-out or participating rights. As a result, ERPOP qualifies as a VIE. EQR has a controlling financial interest in ERPOP and, thus, is ERPOP’s primary beneficiary. EQR has the power to direct the activities of ERPOP that most significantly impact ERPOP’s economic performance as well as the obligation to absorb losses or the right to receive benefits from ERPOP that could potentially be significant to ERPOP. The Company has various equity interests in certain joint ventures owning 17 properties containing 3,774 apartment units. The Company has determined that these joint ventures are VIEs and the Company is the VIEs’ primary beneficiary. As a result, the joint ventures are required to be consolidated on the Company’s financial statements. The Company also has a separate consolidated joint venture which leases a land parcel that is currently being developed into a multifamily rental property. This joint venture has been deemed to be a VIE and is consolidated due to the Company being the primary beneficiary. The consolidated assets and liabilities related to the VIEs discussed above were approximately $839.3 million and $247.9 million, respectively, at September 30, 2021 and approximately $784.1 million and $224.0 million, respectively, at December 31, 2020. Investments in Unconsolidated Entities During the nine months ended September 30, 2021, the Company acquired two land parcels through separate unconsolidated joint ventures for the purpose of developing multifamily rental properties for an aggregate gross purchase price of approximately $55.4 million, with the Company’s share approximating $21.8 million. The Company, as a limited partner in both joint ventures, does not have substantive kick-out or voting rights in the entities. As a result, the entities qualify as VIEs. The Company has the obligation to absorb losses and the right to receive benefits from the VIE that could potentially be significant to the VIE, but does not have the power to direct the activities of the VIE that most significantly impact the VIE’s economic performance. As a result, the Company is not the primary beneficiary and these entities are unconsolidated and recorded using the equity method of accounting. The following table and information summarizes the Company’s investments in unconsolidated entities, which are accounted for under the equity method of accounting as the requirements for consolidation are not met, as of September 30, 2021 December 31, 2020 September 30, 2021 December 31, 2020 Ownership Percentage Investments in Unconsolidated Entities: Operating Property (VIE) (1) $ 36,652 $ 38,288 33.3% Projects Under Development (VIE) (2) 24,927 — Varies Real Estate Technology (3) 18,127 14,866 Varies Other (277 ) (372 ) Varies Investments in Unconsolidated Entities $ 79,429 $ 52,782 (1) Represents an unconsolidated interest in an entity that owns the land underlying one of the consolidated joint venture properties noted above and owns and operates a related parking facility. The joint venture, as a limited partner, does not have substantive kick-out or participating rights in the entity. As a result, the entity qualifies as a VIE. The joint venture does not have a controlling financial interest in the VIE and is not the VIE’s primary beneficiary. The joint venture does not have the power to direct the activities of the VIE that most significantly impact the VIE’s economic performance or the obligation to absorb losses or the right to receive benefits from the VIE that could potentially be significant to the VIE. As a result, the entity that owns the land and owns and operates the parking facility is unconsolidated and recorded using the equity method of accounting. (2) Represents unconsolidated interests in the two unconsolidated joint ventures noted above. (3) Represents unconsolidated investments in six separate real estate technology funds/companies.

Restricted Deposits

Restricted Deposits	9 Months Ended
	Sep. 30, 2021
Deposits Restricted [Abstract]
Restricted Deposits	7. Restricted Deposits The following table presents the Company’s restricted deposits as of September 30, 2021 and December 31, 2020 (amounts in thousands): September 30, 2021 December 31, 2020 Mortgage escrow deposits: Replacement reserves $ 10,830 $ 9,877 Mortgage principal reserves/sinking funds 17,828 14,168 Mortgage escrow deposits 28,658 24,045 Restricted cash: Tax-deferred (1031) exchange proceeds 121,799 — Restricted deposits on real estate investments 292 307 Resident security and utility deposits 34,459 31,412 Other 1,834 1,373 Restricted cash 158,384 33,092 Restricted deposits $ 187,042 $ 57,137

Leases

Leases	9 Months Ended
	Sep. 30, 2021
Leases [Abstract]
Leases	8 . Leases Lessor Accounting The Company is the lessor for its residential and non-residential leases and these leases will continue to be accounted for as operating leases under the lease standard. For the nine months ended September 30, 2021, approximately 97% of the Company’s total lease revenue is generated from residential apartment leases that are generally twelve months or less in length. The residential apartment leases may include lease income related to such items as utility recoveries, parking, storage and pet rent that the Company treats as a single lease component because the amenities cannot be leased on their own and the timing and pattern of revenue recognition are the same. The collection of lease payments at lease commencement is probable and therefore the Company subsequently recognizes lease income over the lease term on a straight-line basis. Residential leases are renewable upon consent of both parties on an annual or monthly basis. For the nine months ended September 30, 2021, approximately 3% of the Company’s total lease revenue is generated by non-residential leases that are generally for terms ranging between five to ten years. The non-residential leases generally consist of ground floor retail spaces and master-leased parking garages that serve as additional amenities for our residents. The non-residential leases may include lease income related to such items as utility recoveries, parking rent and storage rent that the Company treats as a single lease component because the amenities cannot be leased on their own and the timing and pattern of revenue recognition are the same. The collection of lease payments at lease commencement is probable and therefore the Company subsequently recognizes lease income over the lease term on a straight-line basis. Non-residential leases are renewable with market-based renewal options. The following table presents the lease income types relating to lease payments for residential and non-residential leases along with the total other rental income for the nine months ended September 30, 2021 and 2020 (amounts in thousands): Nine Months Ended September 30, 2021 Nine Months Ended September 30, 2020 Income Type Residential Leases Non-Residential Leases Total Residential Leases Non-Residential Leases Total Residential and non-residential rent $ 1,629,778 $ 45,680 $ 1,675,458 $ 1,783,298 $ 36,263 $ 1,819,561 Utility recoveries (RUBS income) (1) 55,331 519 55,850 52,538 509 53,047 Parking rent 30,403 465 30,868 29,052 324 29,376 Other lease revenue (2) (19,442 ) 2,914 (16,528 ) (19,000 ) (5,530 ) (24,530 ) Total lease revenue $ 1,696,070 $ 49,578 1,745,648 $ 1,845,888 $ 31,566 1,877,454 Parking revenue 18,455 16,648 Other revenue 54,764 64,168 Total other rental income (3) 73,219 80,816 Rental income $ 1,818,867 $ 1,958,270 (1) RUBS income primarily consists of variable payments representing the recovery of utility costs from residents. (2) Other lease revenue consists of the revenue adjustment related to bad debt and other miscellaneous lease revenue. (3) Other rental income is accounted for under the revenue recognition standard. The following table presents the lease income types relating to lease payments for residential and non-residential leases along with the total other rental income for the quarters ended September 30, 2021 and 2020 (amounts in thousands): Quarter Ended September 30, 2021 Quarter Ended September 30, 2020 Income Type Residential Leases Non-Residential Leases Total Residential Leases Non-Residential Leases Total Residential and non-residential rent $ 551,474 $ 14,443 $ 565,917 $ 576,192 $ 6,042 $ 582,234 Utility recoveries (RUBS income) (1) 18,798 189 18,987 17,306 134 17,440 Parking rent 10,513 103 10,616 9,592 101 9,693 Other lease revenue (2) (472 ) 1,776 1,304 (12,727 ) (4,299 ) (17,026 ) Total lease revenue $ 580,313 $ 16,511 596,824 $ 590,363 $ 1,978 592,341 Parking revenue 6,883 5,336 Other revenue 19,499 24,756 Total other rental income (3) 26,382 30,092 Rental income $ 623,206 $ 622,433 (1) RUBS income primarily consists of variable payments representing the recovery of utility costs from residents. (2) Other lease revenue consists of the revenue adjustment related to bad debt and other miscellaneous lease revenue. (3) Other rental income is accounted for under the revenue recognition standard. The economic impact of the pandemic on a subset of our residents and tenants has led to elevated levels of bad debt, which was reduced, in part, by governmental rental assistance payments paid on their behalf. We continue to work with our residents and tenants on payment plans and collections and our bad debt allowance policies remain consistent from those existing prior to the pandemic. The following table presents residential and non-residential accounts receivable and straight-line receivable balances for the Company’s properties as of September 30, 2021 and December 31, 2020 (amounts in thousands): Residential Non-Residential Balance Sheet (Other assets): September 30, 2021 December 31, 2020 September 30, 2021 December 31, 2020 Resident/tenant accounts receivable balances $ 42,126 $ 30,856 $ 4,001 $ 7,598 Allowance for doubtful accounts (37,669 ) (24,021 ) (3,442 ) (6,527 ) Net receivable balances $ 4,457 (1) $ 6,835 $ 559 $ 1,071 Straight-line receivable balances $ 12,650 $ 19,992 $ 12,759 $ 13,413 (1) The Company held residential security deposits approximating 58.4% of the net receivable balance at September 30, 2021 The following table presents residential bad debt for the Company’s properties for the nine months and quarters ended September 30, 2021 and 2020 (amounts in thousands): Nine Months Ended September 30, Quarter Ended September 30, Income Statement (Rental income): 2021 2020 2021 2020 Bad debt, net (1) $ 29,751 $ 29,419 $ 3,979 $ 16,071 % of rental income 1.7 % 1.5 % 0.7 % 2.6 % (1) The nine months and quarter ended September 30, 2021 benefited from additional resident payments due to governmental rental assistance programs. Due to the impact of COVID-19 and the resulting economic impact on our non-residential tenants, we recognized a non-cash write-off of non-residential straight-line lease receivables of approximately $0.1 million and $12.9 million during the nine months ended September 30, 2021 and 2020, respectively.

Debt

Debt	9 Months Ended
	Sep. 30, 2021
Debt Disclosure [Abstract]
Debt	9 . Debt EQR Mortgage Notes Payable The following table summarizes the Company’s mortgage notes payable activity for the nine months ended September 30, 2021 (amounts in thousands): Mortgage notes payable, net as of December 31, 2020 Proceeds Lump sum payoffs Scheduled principal repayments Amortization of premiums/ discounts Amortization of deferred financing costs, net (1) Mortgage notes payable, net as of September 30, 2021 Fixed Rate Debt: Secured – Conventional $ 1,901,091 $ 28,500 (2) $ (28,200 ) $ (5,570 ) $ 1,140 $ 689 $ 1,897,650 Floating Rate Debt: Secured – Conventional 31,494 22,798 — — — (1,719 ) 52,573 Secured – Tax Exempt 361,305 — (31,680 ) — 929 388 330,942 Floating Rate Debt 392,799 22,798 (31,680 ) — 929 (1,331 ) 383,515 Total $ 2,293,890 $ 51,298 $ (59,880 ) $ (5,570 ) $ 2,069 $ (642 ) $ 2,281,165 (1) Represents amortization of deferred financing costs, net of debt financing costs. (2) Obtained 3.58% fixed rate mortgage debt maturing on March 1, 2031. The following table summarizes certain interest rate and maturity date information as of and for the nine months ended September 30, 2021: September 30, 2021 Interest Rate Ranges 0.06% - 4.21% Weighted Average Interest Rate 3.16% Maturity Date Ranges 2022-2061 As of September 30, 2021, the Company had $250.0 million of secured debt (primarily tax-exempt bonds) subject to third-party credit enhancement. Notes The following table summarizes the Company’s notes activity for the nine months ended September 30, 2021 (amounts in thousands): Notes, net as of December 31, 2020 Proceeds Lump sum payoffs Realized/unrealized (gain) loss on derivative instruments Amortization of premiums/ discounts Amortization of deferred financing costs, net (1) Notes, net as of September 30, 2021 Fixed Rate Debt: Unsecured – Public $ 5,335,536 $ 497,470 (2) $ — $ — $ 1,865 $ (1,388 ) $ 5,833,483 (1) Represents amortization of deferred financing costs, net of debt financing costs. (2) Issued $500.0 million of ten-year 1.85% unsecured notes, receiving net proceeds before underwriting fees and other expenses. The following table summarizes certain interest rate and maturity date information as of and for the nine months ended September 30, 2021: September 30, 2021 Interest Rate Ranges 1.85% - 7.57% Weighted Average Interest Rate 3.69% Maturity Date Ranges 2023-2047 The Company’s unsecured public notes contain certain financial and operating covenants including, among other things, maintenance of certain financial ratios. The Company was in compliance with its unsecured public debt covenants for the nine months ended September 30, 2021. Line of Credit and Commercial Paper The Company has a $2.5 billion unsecured revolving credit facility maturing November 1, 2024. The Company has the ability to increase available borrowings by an additional $750.0 million by adding lenders to the facility, obtaining the agreement of existing lenders to increase their commitments or incurring one or more term loans. The interest rate on advances under the facility will generally be LIBOR plus a spread (currently 0.775%), or based on bids received from the lending group, and the Company pays an annual facility fee (currently 0.125%). Both the spread and the facility fee are dependent on the Company’s senior unsecured credit rating. The Company did not borrow any amounts under its revolving credit facility during the nine months ended September 30, 2021. The Company has an unsecured commercial paper note program in which it may borrow up to a maximum of $1.0 billion subject to market conditions. The notes will be sold under customary terms in the United States commercial paper note market and will rank pari passu with all of the Company’s other unsecured senior indebtedness. The notes bear interest at various floating rates with a weighted average interest rate of 0.28% for the nine months ended September 30, 2021 and a weighted average maturity of 1 day as of September 30, 2021. The weighted average amount outstanding for the nine months ended September 30, 2021 was approximately $556.7 million. The Company limits its utilization of the revolving credit facility in order to maintain liquidity to support its $1.0 billion commercial paper program along with certain other obligations. The following table presents the availability on the Company’s unsecured revolving credit facility as of September 30, 2021 (amounts in thousands): September 30, 2021 Unsecured revolving credit facility commitment $ 2,500,000 Commercial paper balance outstanding (30,000 ) Unsecured revolving credit facility balance outstanding — Other restricted amounts (100,442 ) Unsecured revolving credit facility availability $ 2,369,558 Other The following table summarizes the Company’s total debt extinguishment costs recorded as additional interest expense during the nine months ended September 30, 2021 September 30, 2021 Write-offs of unamortized deferred financing costs $ 264

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Fair Value Measurements	10 . Fair Value Measurements The valuation of financial instruments requires the Company to make estimates and judgments that affect the fair value of the instruments. The Company, where possible, bases the fair values of its financial instruments on listed market prices and third-party quotes. Where these are not available, the Company bases its estimates on current instruments with similar terms and maturities or on other factors relevant to the financial instruments. In the normal course of business, the Company is exposed to the effect of interest rate changes. The Company may seek to manage these risks by following established risk management policies and procedures including the use of derivatives to hedge interest rate risk on debt instruments. The Company may also use derivatives to manage commodity prices in the daily operations of the business. During the nine months ended September 30, 2021 w A • Level 1 – Inputs to the valuation methodology are quoted prices (unadjusted) for identical assets or liabilities in active markets. • Level 2 – Inputs to the valuation methodology include quoted prices for similar assets and liabilities in active markets, and inputs that are observable for the asset or liability, either directly or indirectly, for substantially the full term of the financial instrument. • Level 3 – Inputs to the valuation methodology are unobservable and significant to the fair value The following table summarizes the inputs to the valuations for each type of fair value measurement: Fair Value Measurement Type Valuation Inputs Employee holdings (other than Common Shares) within the supplemental executive retirement plan (the “SERP”) Quoted market prices for identical assets. These holdings are included in other assets and other liabilities on the consolidated balance sheets. Redeemable Noncontrolling Interests – Operating Partnership/Redeemable Limited Partners Quoted market price of Common Shares. Mortgage notes payable and private unsecured debt (including its commercial paper and line of credit, if applicable) Indicative rates provided by lenders of similar loans. Public unsecured notes Quoted market prices for each underlying issuance. The fair values of the Company’s financial instruments (other than mortgage notes payable, unsecured notes, commercial paper, line of credit and derivative instruments), including cash and cash equivalents and other financial instruments, approximate their carrying or contract value. The following table provides a summary of the carrying and fair values for the Company’s mortgage notes payable and unsecured debt (including its commercial paper and line of credit, if applicable) at September 30, 2021 and December 31, 2020 , respectively (amounts in thousands): September 30, 2021 December 31, 2020 Carrying Value Estimated Fair Value (Level 2) Carrying Value Estimated Fair Value (Level 2) Mortgage notes payable, net $ 2,281,165 $ 2,303,890 $ 2,293,890 $ 2,313,263 Unsecured debt, net 5,863,483 6,534,974 5,750,366 6,686,612 Total debt, net $ 8,144,648 $ 8,838,864 $ 8,044,256 $ 8,999,875 The Fair Value Measurements at Reporting Date Using Description Balance Sheet Location 9/30/2021 Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets Supplemental Executive Retirement Plan Other Assets $ 160,914 $ 160,914 $ — $ — Liabilities Supplemental Executive Retirement Plan Other Liabilities $ 160,914 $ 160,914 $ — $ — Redeemable Noncontrolling Interests – Operating Partnership/Redeemable Limited Partners Mezzanine $ 459,933 $ — $ 459,933 $ — Fair Value Measurements at Reporting Date Using Description Balance Sheet Location 12/31/2020 Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets Supplemental Executive Retirement Plan Other Assets $ 160,293 $ 160,293 $ — $ — Liabilities Supplemental Executive Retirement Plan Other Liabilities $ 160,293 $ 160,293 $ — $ — Redeemable Noncontrolling Interests – Operating Partnership/Redeemable Limited Partners Mezzanine $ 338,951 $ — $ 338,951 $ — The September 30, 2021 Type of Cash Flow Hedge Amount of Gain/(Loss) Recognized in OCI on Derivative Location of Gain/(Loss) Reclassified from Accumulated OCI into Income Amount of Gain/(Loss) Reclassified from Accumulated OCI into Income Derivatives designated as hedging instruments: Interest Rate Contracts: Forward Starting Swaps $ — Interest expense $ (7,000 ) Total $ — $ (7,000 ) September 30, 2020 Type of Cash Flow Hedge Amount of Gain/(Loss) Recognized in OCI on Derivative Location of Gain/(Loss) Reclassified from Accumulated OCI into Income Amount of Gain/(Loss) Reclassified from Accumulated OCI into Income Derivatives designated as hedging instruments: Interest Rate Contracts: Forward Starting Swaps $ (1,190 ) Interest expense $ (17,275 ) Total $ (1,190 ) $ (17,275 ) As

Earnings Per Share and Earnings

Earnings Per Share and Earnings Per Unit	9 Months Ended
	Sep. 30, 2021
Earnings Per Share [Abstract]
Earnings Per Share And Earnings Per Unit	1 1 . Earnings Per Share and Earnings Per Equity Residential The Nine Months Ended September 30, Quarter Ended September 30, 2021 2020 2021 2020 Numerator for net income per share – basic: Net income $ 835,736 $ 699,517 $ 447,332 $ 95,365 Allocation to Noncontrolling Interests – Operating Partnership (27,903 ) (24,624 ) (14,847 ) (3,376 ) Net (income) loss attributable to Noncontrolling Interests – Partially Owned Properties (1,957 ) (14,113 ) (534 ) (703 ) Preferred distributions (2,318 ) (2,318 ) (773 ) (773 ) Numerator for net income per share – basic $ 803,558 $ 658,462 $ 431,178 $ 90,513 Numerator for net income per share – diluted: Net income $ 835,736 $ 699,517 $ 447,332 $ 95,365 Net (income) loss attributable to Noncontrolling Interests – Partially Owned Properties (1,957 ) (14,113 ) (534 ) (703 ) Preferred distributions (2,318 ) (2,318 ) (773 ) (773 ) Numerator for net income per share – diluted $ 831,461 $ 683,086 $ 446,025 $ 93,889 Denominator for net income per share – basic and diluted: Denominator for net income per share – basic 373,474 371,749 374,308 371,869 Effect of dilutive securities: OP Units 12,367 13,010 12,019 13,002 Long-term compensation shares/units 1,801 1,214 2,047 781 Denominator for net income per share – diluted 387,642 385,973 388,374 385,652 Net income per share – basic $ 2.15 $ 1.77 $ 1.15 $ 0.24 Net income per share – diluted $ 2.14 $ 1.77 $ 1.15 $ 0.24 ERP Operating Limited Partnership The following tables set forth the computation of net income per Unit – basic and net income per Unit – diluted for the Operating Partnership (amounts in thousands except per Unit amounts): Nine Months Ended September 30, Quarter Ended September 30, 2021 2020 2021 2020 Numerator for net income per Unit – basic and diluted: Net income $ 835,736 $ 699,517 $ 447,332 $ 95,365 Net (income) loss attributable to Noncontrolling Interests – Partially Owned Properties (1,957 ) (14,113 ) (534 ) (703 ) Allocation to Preference Units (2,318 ) (2,318 ) (773 ) (773 ) Numerator for net income per Unit – basic and diluted $ 831,461 $ 683,086 $ 446,025 $ 93,889 Denominator for net income per Unit – basic and diluted: Denominator for net income per Unit – basic 385,841 384,759 386,327 384,871 Effect of dilutive securities: Dilution for Units issuable upon assumed exercise/vesting of the Company’s long-term compensation shares/units 1,801 1,214 2,047 781 Denominator for net income per Unit – diluted 387,642 385,973 388,374 385,652 Net income per Unit – basic $ 2.15 $ 1.77 $ 1.15 $ 0.24 Net income per Unit – diluted $ 2.14 $ 1.77 $ 1.15 $ 0.24

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2021
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	1 2 . The Company, as an owner of real estate, is subject to various Federal, state and local laws, including, but not limited to, rent regulations and environmental laws. Compliance by the Company with existing laws has not had a material adverse effect on the Company. However, the Company cannot predict the impact of new or changed laws or regulations, whether related to COVID-19 or otherwise, on its current properties or on properties that it may acquire in the future. The Company does not believe there is any litigation pending or threatened against it that, individually or in the aggregate, may reasonably be expected to have a material adverse effect on the Company. As of September 30, 2021, the Company has two consolidated projects (one wholly owned and one partially owned) and two unconsolidated projects totaling 1,441 apartment units in various stages of development with remaining commitments to fund of approximately $328.8 million (inclusive of applicable construction loans and joint venture partner obligations) and estimated completion dates ranging through June 30, 2024, as well as two consolidated completed development projects (one wholly owned and one partially owned) that are in lease-up. As of September 30, 2021, the Company has two consolidated joint venture agreements with third-party partners for the development of multifamily rental properties, one of which is currently under construction as noted above and one of which was substantially completed during the quarter ended June 30, 2021. The Company also has two unconsolidated joint venture agreements with third-party partners for the development of multifamily rental properties, both of which are currently under construction as noted above. The joint venture agreements with each partner include a buy-sell provision that provides the right, but not the obligation, for the Company to acquire each respective partner’s interests or sell its interests at any time following the occurrence of certain pre-defined events described in the joint venture agreements. See Note 6 for additional discussion. As of September 30, 2021, the Company entered into a commitment agreement (the “Commitment Agreement”) with Toll Brothers, Inc. (“Toll”) to pursue the joint development of multifamily rental properties. Over the next three years, the Company intends to invest 75% of the equity for each selected project and Toll intends to invest 25%. It is expected that each project will also be financed with approximately 60% non-recourse construction debt. The parties have targeted an initial minimum co-investment of approximately $750.0 million in combined equity. As of September 30, 2021, the Company and Toll had not yet entered into any joint venture agreements under the Commitment Agreement.

Reportable Segments

Reportable Segments	9 Months Ended
	Sep. 30, 2021
Segment Reporting [Abstract]
Reportable Segments	1 3 . Reportable Operating segments are defined as components of an enterprise that engage in business activities from which they may earn revenues and incur expenses and about which discrete financial information is available that is evaluated regularly by the chief The Company’s primary business is the acquisition, development and management of multifamily residential properties, which includes the generation of rental and other related income through the leasing of apartment units to residents. The chief operating decision maker evaluates the Company’s operating performance geographically by market and both on a same store and non-same store basis. While the Company does maintain a non-residential presence, it accounts for approximately 3.8% of total revenues for the nine months ended September 30, 2021 and is designed as an amenity for our residential residents. The chief operating decision maker evaluates the performance of each property on a consolidated residential and non-residential basis. The Company’s geographic consolidated same store operating segments represent its reportable segments. The Company’s development activities are other business activities that do not constitute an operating segment and as such, have been aggregated in the “Other” category in the tables presented below. All The primary financial measure for the Company’s rental real estate segment is net operating income (“NOI”), which represents The Nine Months Ended September 30, Quarter Ended September 30, 2021 2020 2021 2020 Rental income $ 1,818,867 $ 1,958,270 $ 623,206 $ 622,433 Property and maintenance expense (341,261 ) (333,333 ) (116,461 ) (113,065 ) Real estate taxes and insurance expense (297,780 ) (288,043 ) (96,909 ) (95,273 ) Total operating expenses (639,041 ) (621,376 ) (213,370 ) (208,338 ) Net operating income $ 1,179,826 $ 1,336,894 $ 409,836 $ 414,095 The following tables present NOI for each segment from our rental real estate for the nine months and quarters ended September 30, 2021 and 2020, respectively, as well as total assets and capital expenditures at September 30, 2021 (amounts in thousands): Nine Months Ended September 30, 2021 Nine Months Ended September 30, 2020 Rental Income Operating Expenses NOI Rental Income Operating Expenses NOI Same store (1) Los Angeles $ 337,153 $ 109,997 $ 227,156 $ 346,599 $ 108,594 $ 238,005 Orange County 80,773 18,937 61,836 79,241 18,539 60,702 San Diego 58,211 13,920 44,291 56,001 13,684 42,317 Subtotal - Southern California 476,137 142,854 333,283 481,841 140,817 341,024 San Francisco 302,043 93,983 208,060 346,089 90,849 255,240 Washington D.C. 298,165 99,369 198,796 311,119 95,799 215,320 New York 299,320 152,228 147,092 324,866 148,145 176,721 Seattle 181,908 58,616 123,292 195,198 55,845 139,353 Boston 171,871 57,041 114,830 182,502 53,727 128,775 Denver 28,732 8,614 20,118 28,584 8,320 20,264 Total same store 1,758,176 612,705 1,145,471 1,870,199 593,502 1,276,697 Non-same store/other (2) (3) Non-same store 28,581 10,916 17,665 11,440 2,534 8,906 Other (3) 32,110 15,420 16,690 76,631 25,340 51,291 Total non-same store/other 60,691 26,336 34,355 88,071 27,874 60,197 Totals $ 1,818,867 $ 639,041 $ 1,179,826 $ 1,958,270 $ 621,376 $ 1,336,894 (1) For the nine months ended September 30, 2021 and 2020, same store primarily includes all properties acquired or completed that were stabilized prior to January 1, 2020, less properties subsequently sold, which represented 75,288 apartment (2) For the nine months ended September 30, 2021 and 2020, non-same store primarily includes properties acquired after January 1, 2020, plus any properties in lease-up and not stabilized as of January 1, (3) Other includes development, other corporate operations and operations prior to disposition for properties sold. Quarter Ended September 30, 2021 Quarter Ended September 30, 2020 Rental Income Operating Expenses NOI Rental Income Operating Expenses NOI Same store (1) Los Angeles $ 117,542 $ 36,929 $ 80,613 $ 112,201 $ 36,783 $ 75,418 Orange County 28,264 6,480 21,784 26,229 6,457 19,772 San Diego 20,282 4,735 15,547 18,637 4,652 13,985 Subtotal - Southern California 166,088 48,144 117,944 157,067 47,892 109,175 San Francisco 102,166 31,542 70,624 109,908 30,913 78,995 Washington D.C. 100,019 34,397 65,622 103,160 32,979 70,181 New York 103,015 49,939 53,076 98,333 49,915 48,418 Seattle 61,888 20,117 41,771 62,748 18,972 43,776 Boston 58,864 19,504 39,360 59,527 18,601 40,926 Denver 9,812 2,940 6,872 9,509 2,892 6,617 Total same store 601,852 206,583 395,269 600,252 202,164 398,088 Non-same store/other (2) (3) Non-same store 16,563 6,777 9,786 2,481 539 1,942 Other (3) 4,791 10 4,781 19,700 5,635 14,065 Total non-same store/other 21,354 6,787 14,567 22,181 6,174 16,007 Totals $ 623,206 $ 213,370 $ 409,836 $ 622,433 $ 208,338 $ 414,095 (1) For the quarters ended September 30, 2021 and 2020, same store primarily includes all properties acquired or completed that were stabilized prior to July 1, 2020, less properties subsequently sold, which represented 75,509 apartment (2) For the quarters ended September 30, 2021 and 2020 , non-same store primarily includes properties acquired a fter July 1, 20 20 , plus any properties in lease-u p and not stabilized as of July 1, 20 20 . (3) Other includes development, other corporate operations and operations prior to disposition for properties sold. Nine Months Ended September 30, 2021 Total Assets Capital Expenditures Same store (1) Los Angeles $ 2,926,617 $ 13,959 Orange County 375,365 4,124 San Diego 234,733 2,060 Subtotal - Southern California 3,536,715 20,143 San Francisco 3,264,017 15,853 Washington D.C. 3,270,172 20,392 New York 3,902,715 22,641 Seattle 1,975,574 10,234 Boston 1,710,489 15,766 Denver 496,969 1,101 Total same store 18,156,651 106,130 Non-same store/other (2) (3) Non-same store 1,484,091 659 Other (3) 1,022,273 917 Total non-same store/other 2,506,364 1,576 Totals $ 20,663,015 $ 107,706 (1) Same store primarily includes all properties acquired or completed that were stabilized prior to January 1, 2020, less properties subsequently sold, which represented 75,288 apartment (2) Non-same store primarily includes properties acquired after January 1, 2020, plus any properties in lease-up and not stabilized as of January 1, (3) Other includes development, other corporate operations and capital expenditures for properties

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2021
Subsequent Events [Abstract]
Subsequent Events	1 4 . Subsequent Subsequent to September 30, 2021, the Company: • Contributed $5.8 million for an unconsolidated land parcel subject to a long-term ground lease and $11.6 million for two unconsolidated land parcel acquisitions in connection with the formation of separate joint ventures with Toll under the Commitment Agreement; and • Contributed $1.1 million for an unconsolidated land parcel acquisition as part of the formation of a joint venture with a third-party.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2021
Summary Of Significant Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by accounting principles generally accepted in the United States for complete financial statements. In the opinion of management, all adjustments (consisting of normal recurring accruals) and certain reclassifications considered necessary for a fair presentation have been included. Operating results for the nine months ended September 30, 2021 are not necessarily indicative of the results that may be expected for the year ending December 31, 2021. In preparation of the Company’s financial statements in conformity with accounting principles generally accepted in the United States, management makes estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements as well as the reported amounts of revenues and expenses during the reporting period. Actual results could differ from these estimates. In response to the COVID-19 pandemic, management evaluated whether its estimates , such as lease collectibility (discuss ed below in Recently Adopted Accounting Pronouncements ) and impairment, require d revised approaches and generally concluded that no revisions were necessary at this time . The balance sheets at December 31, 2020 have been derived from the audited financial statements at that date but do not include all of the information and footnotes required by accounting principles generally accepted in the United States for complete financial statements. For further information, including definitions of capitalized terms not defined herein, refer to the consolidated financial statements and footnotes thereto included in the Company’s and the Operating Partnership’s Annual Report on Form 10-K for the year ended December 31, 2020.
Income and Other Taxes	Income and Other Taxes EQR has elected to be taxed as a REIT. This, along with the nature of the operations of its operating properties, resulted in no provision for federal income taxes at the EQR level. In addition, ERPOP generally is not liable for federal income taxes as the partners recognize their allocable share of income or loss in their tax returns; therefore no provision for federal income taxes has been made at the ERPOP level. Historically, the Company has generally only incurred certain state and local income, excise and franchise taxes. The Company has elected taxable REIT subsidiary (“TRS”) status for certain of its corporate subsidiaries and, as a result, these entities will incur both federal and state income taxes on any taxable income of such entities after consideration of any net operating losses. On March 27, 2020, the President signed into law the Coronavirus Aid, Relief, and Economic Security Act (the “CARES Act”). Included in the CARES Act were tax provisions which increased allowable interest expense deductions for 2019 and 2020 and increased the ability for taxpayers to use net operating losses. These provisions did not result in a material impact to the Company’s taxable income or tax liabilities.
Recently Issued and Adopted Accounting Pronouncements	Recently Issued Accounting Pronouncements In August 2020, the Financial Accounting Standards Board (“FASB”) issued an amendment to the debt and equity financial instruments standards which simplifies the accounting for convertible instruments and accounting for contracts in an entity’s own equity. Instead of being required to assess whether an equity contract permits settlement in unregistered shares, which may require a legal analysis under the securities laws, entities will only analyze whether cash settlements are explicitly required when registered shares are unavailable. As a result, such contracts may be classified in permanent rather than mezzanine equity, which may affect the way the Company’s OP Units are presented on its financial statements. The update is effective for the Company beginning on January 1, 2022 as the Company did not early adopt the standard as allowed on January 1, 2021. The Company is currently evaluating the impact of adopting the new standard on its consolidated results of operations and financial position. Recently Adopted Accounting Pronouncements In August 2021, the FASB issued an amendment to the presentation of financial statements standard which aligns the financial statements and disclosure requirements with those of the final rules released by the SEC in May 2020. The amendment changes the significance tests that determine what disclosures about significant business acquisitions are required, the periods the financial statements must cover and the pro forma financial information that must be included in certain reports. The amendment was effective for the Company upon issuance on August 9, 2021. The Company has not yet acquired businesses that exceed the threshold as defined by the standard, therefore, the amendment did not have a material effect on its consolidated results of operations and financial position. In March 2020, the FASB issued an amendment to the reference rate reform standard which provides the option for a limited period of time to ease the potential burden in accounting for, or recognizing the effects of, reference rate reform on contract modifications and hedge accounting. An example of such reform is the expected market transition from the London Interbank Offered Rate (“LIBOR”) and other interbank offered rates to alternative reference rates. Entities that make this optional expedient election would not have to remeasure the contracts at the modification date or reassess the accounting treatment if certain criteria are met and would continue applying hedge accounting for relationships affected by reference rate reform. The new standard was effective for the Company upon issuance and elections can be made through December 31, 2022. The Company elected to apply the hedge accounting expedients related to probability and the assessments of effectiveness for future LIBOR-indexed cash flows to assume that the index upon which future hedged transactions will be based matches the index on the corresponding derivatives. Application of these expedients preserves the presentation of derivatives consistent with past presentation. The Company continues to evaluate the impact of the guidance and may apply other elections as applicable as additional changes in the market occur. In April 2020, a FASB staff question and answer document was issued which intended to reduce the challenges of evaluating the enforceable rights and obligations of leases for concessions granted to lessees in response to the COVID-19 pandemic. We elected not to evaluate whether qualifying concessions provided by the Company in response to the COVID-19 pandemic are a lease modification, subject to the criteria that the total payments under the amended lease cannot result in a substantial increase in the rights of the lessor or obligations of the lessee . We also elected to treat the concessions as though they were contemplated as part of the existing contracts and therefore will not apply lease modification rules to the qualifying lease concession amendments. As such, deferrals deemed collectible are recorded as rental receivables with no change to timing of rental revenues and deferrals deemed non-collectible and abatements reduce rental revenues in the deferral/abatement period and cause rental revenues to effectively follow a cash basis related to the changes. The accounting elections provided by the FASB mainly apply to the Company’s non-residential leases and the majority of the amendments will not require a straight-line adjustment. See Note 8 for additional discussion. In June 2016, the FASB issued a standard which requires companies to adopt a new approach for estimating credit losses on certain types of financial instruments, such as trade and other receivables and loans. The standard requires entities to estimate a lifetime expected credit loss for most financial instruments, including trade receivables. In November 2018, the FASB issued an amendment excluding operating lease receivables accounted for under the lease standard from the scope of the credit losses standard. The Company adopted this standard as required effective January 1, 2020 and it did not have a material effect on its consolidated results of operations and financial position.

Business (Tables)

Business (Tables)	9 Months Ended
	Sep. 30, 2021
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Ownership Breakdown	The ownership breakdown includes (table does not include various uncompleted development properties): Properties Apartment Units Wholly Owned Properties 290 75,548 Partially Owned Properties – Consolidated 17 3,774 307 79,322 Note: Effective July 31, 2021, the Company took over management of its last remaining third-party master-leased property containing 162 apartment units located in the Washington D.C. market

Equity, Capital and Other Int_2

Equity, Capital and Other Interests (Tables)	9 Months Ended
	Sep. 30, 2021
Class Of Stock [Line Items]
Changes in Issued and Outstanding Common Shares and Units	The following table presents the changes in the Company’s issued and outstanding Common Shares and Units for the nine months ended September 30, 2021 and 2020: 2021 2020 Common Shares Common Shares outstanding at January 1, 372,302,000 371,670,884 Common Shares Issued: Conversion of OP Units 1,153,963 99,737 Exercise of share options 1,401,755 219,922 Employee Share Purchase Plan (ESPP) 59,297 69,986 Restricted share grants, net 85,573 178,720 Common Shares outstanding at September 30, 375,002,588 372,239,249 Units Units outstanding at January 1, 13,858,073 13,731,315 Restricted unit grants, net 155,638 247,822 Conversion of OP Units to Common Shares (1,153,963 ) (99,737 ) Units outstanding at September 30, 12,859,748 13,879,400 Total Common Shares and Units outstanding at September 30, 387,862,336 386,118,649 Units Ownership Interest in Operating Partnership 3.3 % 3.6 %
Changes in Redemption Value of Redeemable Noncontrolling Interests - Operating Partnership/Redeemable Limited Partners	The following table presents the changes in the redemption value of the Redeemable Noncontrolling Interests – Operating Partnership/Redeemable Limited Partners for the nine months ended September 30, 2021 and 2020, respectively (amounts in 2021 2020 Balance at January 1, $ 338,951 $ 463,400 Change in market value 119,237 (169,825 ) Change in carrying value 1,745 131 Balance at September 30, $ 459,933 $ 293,706
Issued and Outstanding Preferred Shares and Preference Units	The following table presents the Company’s issued and outstanding Preferred Shares/Preference Units as September 30, 2021 and December 31, 2020 Amounts in thousands Annual Call Dividend Per September 30, December 31, Date (1) Share/Unit (2) 2021 2020 Preferred Shares/Preference Units of beneficial interest, $0.01 par value; 100,000,000 shares authorized: 8.29% Series K Cumulative Redeemable Preferred Shares/Preference Units; liquidation value $50 per share/unit; 745,600 shares/units issued and outstanding as of September 30, 2021 and December 31, 2020 12/10/26 $ 4.145 $ 37,280 $ 37,280 $ 37,280 $ 37,280 (1) On or after the call date, redeemable Preferred Shares/Preference Units may be redeemed for cash at the option of the Company or the Operating Partnership, respectively, in whole or in part, at a redemption price equal to the liquidation price per share/unit, plus accrued and unpaid distributions, if any. (2) Dividends on Preferred Shares/Preference Units are payable quarterly.
ERPOP [Member]
Class Of Stock [Line Items]
Changes in Issued and Outstanding Common Shares and Units	The following table presents the changes in the Operating Partnership’s issued and outstanding General Partner Units and Limited Partner Units for the nine months ended September 30, 2021 and 2020: 2021 2020 General and Limited Partner Units General and Limited Partner Units outstanding at January 1, 386,160,073 385,402,199 Issued to General Partner: Exercise of EQR share options 1,401,755 219,922 EQR’s Employee Share Purchase Plan (ESPP) 59,297 69,986 EQR’s restricted share grants, net 85,573 178,720 Issued to Limited Partners: Restricted unit grants, net 155,638 247,822 General and Limited Partner Units outstanding at September 30, 387,862,336 386,118,649 Limited Partner Units Limited Partner Units outstanding at January 1, 13,858,073 13,731,315 Limited Partner restricted unit grants, net 155,638 247,822 Conversion of Limited Partner OP Units to EQR Common Shares (1,153,963 ) (99,737 ) Limited Partner Units outstanding at September 30, 12,859,748 13,879,400 Limited Partner Units Ownership Interest in Operating Partnership 3.3 % 3.6 %

Real Estate (Tables)

Real Estate (Tables)	9 Months Ended
	Sep. 30, 2021
Real Estate [Abstract]
Summary of Carrying Amounts of Investment in Real Estate	The following table summarizes the carrying amounts for the Company’s investment in real estate (at cost) as of September 30, 2021 and December 31, 2020 (amounts in thousands): September 30, 2021 December 31, 2020 Land $ 5,779,686 $ 5,785,367 Depreciable property: Buildings and improvements 19,211,662 18,464,484 Furniture, fixtures and equipment 2,125,441 1,970,033 In-Place lease intangibles 503,241 486,137 Projects under development: Land 4,121 23,531 Construction-in-progress 159,538 387,603 Land held for development: Land 46,160 46,160 Construction-in-progress 35,866 40,010 Investment in real estate 27,865,715 27,203,325 Accumulated depreciation (8,260,846 ) (7,859,657 ) Investment in real estate, net $ 19,604,869 $ 19,343,668
Acquired Properties From Unaffiliated Parties	During the nine months ended September 30, 2021, the Company acquired the following from unaffiliated parties (purchase price in thousands): Properties Apartment Units Purchase Price Rental Properties – Consolidated (1) 11 2,921 $ 1,020,425 Total 11 2,921 $ 1,020,425 (1) Purchase price includes an allocation of approximately $134.2 million to land and $888.1 million to depreciable property (inclusive of capitalized closing costs).
Disposed Properties to Unaffiliated Parties	During the nine months ended September 30, 2021, the Company disposed of the following to unaffiliated parties (sales price in thousands): Properties Apartment Units Sales Price Rental Properties – Consolidated 10 1,842 $ 1,021,800 Total 10 1,842 $ 1,021,800

Commitments to Acquire_Dispos_2

Commitments to Acquire/Dispose of Real Estate (Tables)	9 Months Ended
	Sep. 30, 2021
Commitments To Acquire Dispose Of Real Estate [Abstract]
Agreements to Dispose	The Company has entered into separate agreements to dispose of the following (sales price and net book value in thousands): Properties Apartment Units Sales Price Net Book Value at September 30, 2021 Rental Properties - Consolidated 2 744 $ 410,000 $ 130,762 Total 2 744 $ 410,000 $ 130,762

Investments in Partially Owne_2

Investments in Partially Owned Entities (Tables)	9 Months Ended
	Sep. 30, 2021
Investments In Partially Owned Entities [Abstract]
Summary of Company's Investment in Unconsolidated Entities	The following table and information summarizes the Company’s investments in unconsolidated entities, which are accounted for under the equity method of accounting as the requirements for consolidation are not met, as of September 30, 2021 December 31, 2020 September 30, 2021 December 31, 2020 Ownership Percentage Investments in Unconsolidated Entities: Operating Property (VIE) (1) $ 36,652 $ 38,288 33.3% Projects Under Development (VIE) (2) 24,927 — Varies Real Estate Technology (3) 18,127 14,866 Varies Other (277 ) (372 ) Varies Investments in Unconsolidated Entities $ 79,429 $ 52,782 (1) Represents an unconsolidated interest in an entity that owns the land underlying one of the consolidated joint venture properties noted above and owns and operates a related parking facility. The joint venture, as a limited partner, does not have substantive kick-out or participating rights in the entity. As a result, the entity qualifies as a VIE. The joint venture does not have a controlling financial interest in the VIE and is not the VIE’s primary beneficiary. The joint venture does not have the power to direct the activities of the VIE that most significantly impact the VIE’s economic performance or the obligation to absorb losses or the right to receive benefits from the VIE that could potentially be significant to the VIE. As a result, the entity that owns the land and owns and operates the parking facility is unconsolidated and recorded using the equity method of accounting. (2) Represents unconsolidated interests in the two unconsolidated joint ventures noted above. (3) Represents unconsolidated investments in six separate real estate technology funds/companies.

Restricted Deposits (Tables)

Restricted Deposits (Tables)	9 Months Ended
	Sep. 30, 2021
Deposits Restricted [Abstract]
Restricted Deposits	The following table presents the Company’s restricted deposits as of September 30, 2021 and December 31, 2020 (amounts in thousands): September 30, 2021 December 31, 2020 Mortgage escrow deposits: Replacement reserves $ 10,830 $ 9,877 Mortgage principal reserves/sinking funds 17,828 14,168 Mortgage escrow deposits 28,658 24,045 Restricted cash: Tax-deferred (1031) exchange proceeds 121,799 — Restricted deposits on real estate investments 292 307 Resident security and utility deposits 34,459 31,412 Other 1,834 1,373 Restricted cash 158,384 33,092 Restricted deposits $ 187,042 $ 57,137

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2021
Leases [Abstract]
Summary of Lease Income Types Relating to Lease Payments Along With the Total Other Rental Income	The following table presents the lease income types relating to lease payments for residential and non-residential leases along with the total other rental income for the nine months ended September 30, 2021 and 2020 (amounts in thousands): Nine Months Ended September 30, 2021 Nine Months Ended September 30, 2020 Income Type Residential Leases Non-Residential Leases Total Residential Leases Non-Residential Leases Total Residential and non-residential rent $ 1,629,778 $ 45,680 $ 1,675,458 $ 1,783,298 $ 36,263 $ 1,819,561 Utility recoveries (RUBS income) (1) 55,331 519 55,850 52,538 509 53,047 Parking rent 30,403 465 30,868 29,052 324 29,376 Other lease revenue (2) (19,442 ) 2,914 (16,528 ) (19,000 ) (5,530 ) (24,530 ) Total lease revenue $ 1,696,070 $ 49,578 1,745,648 $ 1,845,888 $ 31,566 1,877,454 Parking revenue 18,455 16,648 Other revenue 54,764 64,168 Total other rental income (3) 73,219 80,816 Rental income $ 1,818,867 $ 1,958,270 (1) RUBS income primarily consists of variable payments representing the recovery of utility costs from residents. (2) Other lease revenue consists of the revenue adjustment related to bad debt and other miscellaneous lease revenue. (3) Other rental income is accounted for under the revenue recognition standard. The following table presents the lease income types relating to lease payments for residential and non-residential leases along with the total other rental income for the quarters ended September 30, 2021 and 2020 (amounts in thousands): Quarter Ended September 30, 2021 Quarter Ended September 30, 2020 Income Type Residential Leases Non-Residential Leases Total Residential Leases Non-Residential Leases Total Residential and non-residential rent $ 551,474 $ 14,443 $ 565,917 $ 576,192 $ 6,042 $ 582,234 Utility recoveries (RUBS income) (1) 18,798 189 18,987 17,306 134 17,440 Parking rent 10,513 103 10,616 9,592 101 9,693 Other lease revenue (2) (472 ) 1,776 1,304 (12,727 ) (4,299 ) (17,026 ) Total lease revenue $ 580,313 $ 16,511 596,824 $ 590,363 $ 1,978 592,341 Parking revenue 6,883 5,336 Other revenue 19,499 24,756 Total other rental income (3) 26,382 30,092 Rental income $ 623,206 $ 622,433 (1) RUBS income primarily consists of variable payments representing the recovery of utility costs from residents. (2) Other lease revenue consists of the revenue adjustment related to bad debt and other miscellaneous lease revenue. (3) Other rental income is accounted for under the revenue recognition standard.
Summary of Residential and Non-Residential Accounts Receivable and Straight-Line Receivable Balances	The following table presents residential and non-residential accounts receivable and straight-line receivable balances for the Company’s properties as of September 30, 2021 and December 31, 2020 (amounts in thousands): Residential Non-Residential Balance Sheet (Other assets): September 30, 2021 December 31, 2020 September 30, 2021 December 31, 2020 Resident/tenant accounts receivable balances $ 42,126 $ 30,856 $ 4,001 $ 7,598 Allowance for doubtful accounts (37,669 ) (24,021 ) (3,442 ) (6,527 ) Net receivable balances $ 4,457 (1) $ 6,835 $ 559 $ 1,071 Straight-line receivable balances $ 12,650 $ 19,992 $ 12,759 $ 13,413 (1) The Company held residential security deposits approximating 58.4% of the net receivable balance at September 30, 2021
Summary of Residential Bad Debt for Company's Properties	The following table presents residential bad debt for the Company’s properties for the nine months and quarters ended September 30, 2021 and 2020 (amounts in thousands): Nine Months Ended September 30, Quarter Ended September 30, Income Statement (Rental income): 2021 2020 2021 2020 Bad debt, net (1) $ 29,751 $ 29,419 $ 3,979 $ 16,071 % of rental income 1.7 % 1.5 % 0.7 % 2.6 % (1) The nine months and quarter ended September 30, 2021 benefited from additional resident payments due to governmental rental assistance programs.

Debt (Tables)

Debt (Tables)	9 Months Ended
	Sep. 30, 2021
Debt Instrument [Line Items]
Summary of Mortgage Notes Payable Activity	The following table summarizes the Company’s mortgage notes payable activity for the nine months ended September 30, 2021 (amounts in thousands): Mortgage notes payable, net as of December 31, 2020 Proceeds Lump sum payoffs Scheduled principal repayments Amortization of premiums/ discounts Amortization of deferred financing costs, net (1) Mortgage notes payable, net as of September 30, 2021 Fixed Rate Debt: Secured – Conventional $ 1,901,091 $ 28,500 (2) $ (28,200 ) $ (5,570 ) $ 1,140 $ 689 $ 1,897,650 Floating Rate Debt: Secured – Conventional 31,494 22,798 — — — (1,719 ) 52,573 Secured – Tax Exempt 361,305 — (31,680 ) — 929 388 330,942 Floating Rate Debt 392,799 22,798 (31,680 ) — 929 (1,331 ) 383,515 Total $ 2,293,890 $ 51,298 $ (59,880 ) $ (5,570 ) $ 2,069 $ (642 ) $ 2,281,165 (1) Represents amortization of deferred financing costs, net of debt financing costs. (2) Obtained 3.58% fixed rate mortgage debt maturing on March 1, 2031.
Summary of Notes Activity	The following table summarizes the Company’s notes activity for the nine months ended September 30, 2021 (amounts in thousands): Notes, net as of December 31, 2020 Proceeds Lump sum payoffs Realized/unrealized (gain) loss on derivative instruments Amortization of premiums/ discounts Amortization of deferred financing costs, net (1) Notes, net as of September 30, 2021 Fixed Rate Debt: Unsecured – Public $ 5,335,536 $ 497,470 (2) $ — $ — $ 1,865 $ (1,388 ) $ 5,833,483 (1) Represents amortization of deferred financing costs, net of debt financing costs. (2) Issued $500.0 million of ten-year 1.85% unsecured notes, receiving net proceeds before underwriting fees and other expenses.
Schedule of Unsecured Revolving Credit Facility	The following table presents the availability on the Company’s unsecured revolving credit facility as of September 30, 2021 (amounts in thousands): September 30, 2021 Unsecured revolving credit facility commitment $ 2,500,000 Commercial paper balance outstanding (30,000 ) Unsecured revolving credit facility balance outstanding — Other restricted amounts (100,442 ) Unsecured revolving credit facility availability $ 2,369,558
Schedule of Debt Extinguishment Costs Recorded as Additional Interest Expense	The following table summarizes the Company’s total debt extinguishment costs recorded as additional interest expense during the nine months ended September 30, 2021 September 30, 2021 Write-offs of unamortized deferred financing costs $ 264
Mortgages [Member]
Debt Instrument [Line Items]
Summary of Certain Interest Rate and Maturity Date Information	The following table summarizes certain interest rate and maturity date information as of and for the nine months ended September 30, 2021: September 30, 2021 Interest Rate Ranges 0.06% - 4.21% Weighted Average Interest Rate 3.16% Maturity Date Ranges 2022-2061
Notes [Member]
Debt Instrument [Line Items]
Summary of Certain Interest Rate and Maturity Date Information	The following table summarizes certain interest rate and maturity date information as of and for the nine months ended September 30, 2021: September 30, 2021 Interest Rate Ranges 1.85% - 7.57% Weighted Average Interest Rate 3.69% Maturity Date Ranges 2023-2047

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Summary of Valuations for Each Type of Fair Value Measurement	The following table summarizes the inputs to the valuations for each type of fair value measurement: Fair Value Measurement Type Valuation Inputs Employee holdings (other than Common Shares) within the supplemental executive retirement plan (the “SERP”) Quoted market prices for identical assets. These holdings are included in other assets and other liabilities on the consolidated balance sheets. Redeemable Noncontrolling Interests – Operating Partnership/Redeemable Limited Partners Quoted market price of Common Shares. Mortgage notes payable and private unsecured debt (including its commercial paper and line of credit, if applicable) Indicative rates provided by lenders of similar loans. Public unsecured notes Quoted market prices for each underlying issuance.
Summary of Carrying and Fair Values of Financial Instruments	The following table provides a summary of the carrying and fair values for the Company’s mortgage notes payable and unsecured debt (including its commercial paper and line of credit, if applicable) at September 30, 2021 and December 31, 2020 , respectively (amounts in thousands): September 30, 2021 December 31, 2020 Carrying Value Estimated Fair Value (Level 2) Carrying Value Estimated Fair Value (Level 2) Mortgage notes payable, net $ 2,281,165 $ 2,303,890 $ 2,293,890 $ 2,313,263 Unsecured debt, net 5,863,483 6,534,974 5,750,366 6,686,612 Total debt, net $ 8,144,648 $ 8,838,864 $ 8,044,256 $ 8,999,875
Summary of Fair Value Measurements for Each Major Category of Assets and Liabilities Measured at Fair Value on Recurring Basis	The Fair Value Measurements at Reporting Date Using Description Balance Sheet Location 9/30/2021 Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets Supplemental Executive Retirement Plan Other Assets $ 160,914 $ 160,914 $ — $ — Liabilities Supplemental Executive Retirement Plan Other Liabilities $ 160,914 $ 160,914 $ — $ — Redeemable Noncontrolling Interests – Operating Partnership/Redeemable Limited Partners Mezzanine $ 459,933 $ — $ 459,933 $ — Fair Value Measurements at Reporting Date Using Description Balance Sheet Location 12/31/2020 Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets Supplemental Executive Retirement Plan Other Assets $ 160,293 $ 160,293 $ — $ — Liabilities Supplemental Executive Retirement Plan Other Liabilities $ 160,293 $ 160,293 $ — $ — Redeemable Noncontrolling Interests – Operating Partnership/Redeemable Limited Partners Mezzanine $ 338,951 $ — $ 338,951 $ —
Summary of Effect of Cash Flow Hedges on the Accompanying Consolidated Statements of Operations and Comprehensive Income	The September 30, 2021 Type of Cash Flow Hedge Amount of Gain/(Loss) Recognized in OCI on Derivative Location of Gain/(Loss) Reclassified from Accumulated OCI into Income Amount of Gain/(Loss) Reclassified from Accumulated OCI into Income Derivatives designated as hedging instruments: Interest Rate Contracts: Forward Starting Swaps $ — Interest expense $ (7,000 ) Total $ — $ (7,000 ) September 30, 2020 Type of Cash Flow Hedge Amount of Gain/(Loss) Recognized in OCI on Derivative Location of Gain/(Loss) Reclassified from Accumulated OCI into Income Amount of Gain/(Loss) Reclassified from Accumulated OCI into Income Derivatives designated as hedging instruments: Interest Rate Contracts: Forward Starting Swaps $ (1,190 ) Interest expense $ (17,275 ) Total $ (1,190 ) $ (17,275 )

Earnings Per Share and Earnin_2

Earnings Per Share and Earnings Per Unit (Tables)	9 Months Ended
	Sep. 30, 2021
Schedule of Calculation of Numerator and Denominator in Earnings Per Share and Earnings Per Unit	The Nine Months Ended September 30, Quarter Ended September 30, 2021 2020 2021 2020 Numerator for net income per share – basic: Net income $ 835,736 $ 699,517 $ 447,332 $ 95,365 Allocation to Noncontrolling Interests – Operating Partnership (27,903 ) (24,624 ) (14,847 ) (3,376 ) Net (income) loss attributable to Noncontrolling Interests – Partially Owned Properties (1,957 ) (14,113 ) (534 ) (703 ) Preferred distributions (2,318 ) (2,318 ) (773 ) (773 ) Numerator for net income per share – basic $ 803,558 $ 658,462 $ 431,178 $ 90,513 Numerator for net income per share – diluted: Net income $ 835,736 $ 699,517 $ 447,332 $ 95,365 Net (income) loss attributable to Noncontrolling Interests – Partially Owned Properties (1,957 ) (14,113 ) (534 ) (703 ) Preferred distributions (2,318 ) (2,318 ) (773 ) (773 ) Numerator for net income per share – diluted $ 831,461 $ 683,086 $ 446,025 $ 93,889 Denominator for net income per share – basic and diluted: Denominator for net income per share – basic 373,474 371,749 374,308 371,869 Effect of dilutive securities: OP Units 12,367 13,010 12,019 13,002 Long-term compensation shares/units 1,801 1,214 2,047 781 Denominator for net income per share – diluted 387,642 385,973 388,374 385,652 Net income per share – basic $ 2.15 $ 1.77 $ 1.15 $ 0.24 Net income per share – diluted $ 2.14 $ 1.77 $ 1.15 $ 0.24
ERPOP [Member]
Schedule of Calculation of Numerator and Denominator in Earnings Per Share and Earnings Per Unit	The following tables set forth the computation of net income per Unit – basic and net income per Unit – diluted for the Operating Partnership (amounts in thousands except per Unit amounts): Nine Months Ended September 30, Quarter Ended September 30, 2021 2020 2021 2020 Numerator for net income per Unit – basic and diluted: Net income $ 835,736 $ 699,517 $ 447,332 $ 95,365 Net (income) loss attributable to Noncontrolling Interests – Partially Owned Properties (1,957 ) (14,113 ) (534 ) (703 ) Allocation to Preference Units (2,318 ) (2,318 ) (773 ) (773 ) Numerator for net income per Unit – basic and diluted $ 831,461 $ 683,086 $ 446,025 $ 93,889 Denominator for net income per Unit – basic and diluted: Denominator for net income per Unit – basic 385,841 384,759 386,327 384,871 Effect of dilutive securities: Dilution for Units issuable upon assumed exercise/vesting of the Company’s long-term compensation shares/units 1,801 1,214 2,047 781 Denominator for net income per Unit – diluted 387,642 385,973 388,374 385,652 Net income per Unit – basic $ 2.15 $ 1.77 $ 1.15 $ 0.24 Net income per Unit – diluted $ 2.14 $ 1.77 $ 1.15 $ 0.24

Reportable Segments (Tables)

Reportable Segments (Tables)	9 Months Ended
	Sep. 30, 2021
Segment Reporting [Abstract]
Schedule of Reconciliation of NOI from Rental Real Estate Specific to Continuing Operations	The Nine Months Ended September 30, Quarter Ended September 30, 2021 2020 2021 2020 Rental income $ 1,818,867 $ 1,958,270 $ 623,206 $ 622,433 Property and maintenance expense (341,261 ) (333,333 ) (116,461 ) (113,065 ) Real estate taxes and insurance expense (297,780 ) (288,043 ) (96,909 ) (95,273 ) Total operating expenses (639,041 ) (621,376 ) (213,370 ) (208,338 ) Net operating income $ 1,179,826 $ 1,336,894 $ 409,836 $ 414,095
Schedule of NOI for Each Segment from Rental Real Estate Specific to Continuing Operations	The following tables present NOI for each segment from our rental real estate for the nine months and quarters ended September 30, 2021 and 2020, respectively, as well as total assets and capital expenditures at September 30, 2021 (amounts in thousands): Nine Months Ended September 30, 2021 Nine Months Ended September 30, 2020 Rental Income Operating Expenses NOI Rental Income Operating Expenses NOI Same store (1) Los Angeles $ 337,153 $ 109,997 $ 227,156 $ 346,599 $ 108,594 $ 238,005 Orange County 80,773 18,937 61,836 79,241 18,539 60,702 San Diego 58,211 13,920 44,291 56,001 13,684 42,317 Subtotal - Southern California 476,137 142,854 333,283 481,841 140,817 341,024 San Francisco 302,043 93,983 208,060 346,089 90,849 255,240 Washington D.C. 298,165 99,369 198,796 311,119 95,799 215,320 New York 299,320 152,228 147,092 324,866 148,145 176,721 Seattle 181,908 58,616 123,292 195,198 55,845 139,353 Boston 171,871 57,041 114,830 182,502 53,727 128,775 Denver 28,732 8,614 20,118 28,584 8,320 20,264 Total same store 1,758,176 612,705 1,145,471 1,870,199 593,502 1,276,697 Non-same store/other (2) (3) Non-same store 28,581 10,916 17,665 11,440 2,534 8,906 Other (3) 32,110 15,420 16,690 76,631 25,340 51,291 Total non-same store/other 60,691 26,336 34,355 88,071 27,874 60,197 Totals $ 1,818,867 $ 639,041 $ 1,179,826 $ 1,958,270 $ 621,376 $ 1,336,894 (1) For the nine months ended September 30, 2021 and 2020, same store primarily includes all properties acquired or completed that were stabilized prior to January 1, 2020, less properties subsequently sold, which represented 75,288 apartment (2) For the nine months ended September 30, 2021 and 2020, non-same store primarily includes properties acquired after January 1, 2020, plus any properties in lease-up and not stabilized as of January 1, (3) Other includes development, other corporate operations and operations prior to disposition for properties sold. Quarter Ended September 30, 2021 Quarter Ended September 30, 2020 Rental Income Operating Expenses NOI Rental Income Operating Expenses NOI Same store (1) Los Angeles $ 117,542 $ 36,929 $ 80,613 $ 112,201 $ 36,783 $ 75,418 Orange County 28,264 6,480 21,784 26,229 6,457 19,772 San Diego 20,282 4,735 15,547 18,637 4,652 13,985 Subtotal - Southern California 166,088 48,144 117,944 157,067 47,892 109,175 San Francisco 102,166 31,542 70,624 109,908 30,913 78,995 Washington D.C. 100,019 34,397 65,622 103,160 32,979 70,181 New York 103,015 49,939 53,076 98,333 49,915 48,418 Seattle 61,888 20,117 41,771 62,748 18,972 43,776 Boston 58,864 19,504 39,360 59,527 18,601 40,926 Denver 9,812 2,940 6,872 9,509 2,892 6,617 Total same store 601,852 206,583 395,269 600,252 202,164 398,088 Non-same store/other (2) (3) Non-same store 16,563 6,777 9,786 2,481 539 1,942 Other (3) 4,791 10 4,781 19,700 5,635 14,065 Total non-same store/other 21,354 6,787 14,567 22,181 6,174 16,007 Totals $ 623,206 $ 213,370 $ 409,836 $ 622,433 $ 208,338 $ 414,095 (1) For the quarters ended September 30, 2021 and 2020, same store primarily includes all properties acquired or completed that were stabilized prior to July 1, 2020, less properties subsequently sold, which represented 75,509 apartment (2) For the quarters ended September 30, 2021 and 2020 , non-same store primarily includes properties acquired a fter July 1, 20 20 , plus any properties in lease-u p and not stabilized as of July 1, 20 20 . (3) Other includes development, other corporate operations and operations prior to disposition for properties sold. Nine Months Ended September 30, 2021 Total Assets Capital Expenditures Same store (1) Los Angeles $ 2,926,617 $ 13,959 Orange County 375,365 4,124 San Diego 234,733 2,060 Subtotal - Southern California 3,536,715 20,143 San Francisco 3,264,017 15,853 Washington D.C. 3,270,172 20,392 New York 3,902,715 22,641 Seattle 1,975,574 10,234 Boston 1,710,489 15,766 Denver 496,969 1,101 Total same store 18,156,651 106,130 Non-same store/other (2) (3) Non-same store 1,484,091 659 Other (3) 1,022,273 917 Total non-same store/other 2,506,364 1,576 Totals $ 20,663,015 $ 107,706 (1) Same store primarily includes all properties acquired or completed that were stabilized prior to January 1, 2020, less properties subsequently sold, which represented 75,288 apartment (2) Non-same store primarily includes properties acquired after January 1, 2020, plus any properties in lease-up and not stabilized as of January 1, (3) Other includes development, other corporate operations and capital expenditures for properties

Business - Additional Informati

Business - Additional Information (Details)	Sep. 30, 2021StatePropertyApartmentUnit	Jul. 31, 2021ApartmentUnit
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Number of states in which entity operates | State	10
Properties | Property	307
Apartment units	79,322
Washington D.C.
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Apartment units		162
ERPOP [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Noncontrolling interest, ownership percentage by parent	96.70%

Business - Ownership Breakdown

Business - Ownership Breakdown (Details)	Sep. 30, 2021PropertyApartmentUnit
Property/Unit schedule
Properties | Property	307
Apartment Units | ApartmentUnit	79,322
Wholly Owned Properties
Property/Unit schedule
Properties | Property	290
Apartment Units | ApartmentUnit	75,548
Partially Owned Properties – Consolidated
Property/Unit schedule
Properties | Property	17
Apartment Units | ApartmentUnit	3,774

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Provision for income tax	$ 284,000	$ 262,000	$ 679,000	$ 502,000
Federal [Member]
Provision for income tax			$ 0

Equity, Capital and Other Int_3

Equity, Capital and Other Interests - Changes in Company's Issued and Outstanding Common Shares and Units (Details) - shares	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Equity Capital And Other Interests [Abstract]
Common Stock, Shares, Outstanding	372,302,000	371,670,884
Common Shares Issued:
Conversion of OP Units	1,153,963	99,737
Exercise of share options	1,401,755	219,922
Employee Share Purchase Plan (ESPP)	59,297	69,986
Restricted share grants, net	85,573	178,720
Common Stock, Shares, Outstanding	375,002,588	372,239,249
Units
Total Units Outstanding	13,858,073	13,731,315
Restricted unit grants, net	155,638	247,822
Conversion of OP Units to Common Shares	(1,153,963)	(99,737)
Total Units Outstanding	12,859,748	13,879,400
Common Shares And Units Outstanding	387,862,336	386,118,649
Units Ownership Interest in Operating Partnership	3.30%	3.60%

Equity, Capital and Other Int_4

Equity, Capital and Other Interests - Changes in Operating Partnership's Issued and Outstanding General Partner Units and Limited Partner Units (Details) - shares	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
General and Limited Partner Units
Exercise of share options	1,401,755	219,922
Employee Share Purchase Plan (ESPP)	59,297	69,986
Restricted share grants, net	85,573	178,720
Restricted unit grants, net	155,638	247,822
Common Shares And Units Outstanding	387,862,336	386,118,649
Limited Partner Units
Total Units Outstanding	13,858,073	13,731,315
Restricted unit grants, net	155,638	247,822
Conversion of Limited Partner OP Units to EQR Common Shares	(1,153,963)	(99,737)
Total Units Outstanding	12,859,748	13,879,400
Units Ownership Interest in Operating Partnership	3.30%	3.60%
ERPOP [Member]
General and Limited Partner Units
Common Shares And Units Outstanding	386,160,073	385,402,199
Exercise of share options	1,401,755	219,922
Employee Share Purchase Plan (ESPP)	59,297	69,986
Restricted share grants, net	85,573	178,720
Restricted unit grants, net	155,638	247,822
Common Shares And Units Outstanding	387,862,336	386,118,649
Limited Partner Units
Total Units Outstanding	13,858,073	13,731,315
Restricted unit grants, net	155,638	247,822
Conversion of Limited Partner OP Units to EQR Common Shares	(1,153,963)	(99,737)
Total Units Outstanding	12,859,748	13,879,400
Units Ownership Interest in Operating Partnership	3.30%	3.60%

Equity, Capital and Other Int_5

Equity, Capital and Other Interests - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	Sep. 30, 2021	Dec. 31, 2020	Sep. 30, 2020	Dec. 31, 2019
Equity Capital And Other Interests [Abstract]
Redeemable noncontrolling interests - operating partnership	$ 459,933	$ 338,951	$ 293,706	$ 463,400
Preferred stock, shares authorized	100,000,000	100,000,000
Preferred stock, par or stated value per share	$ 0.01	$ 0.01

Equity, Capital and Other Int_6

Equity, Capital and Other Interests - Changes in Redemption Value of Redeemable Noncontrolling Interests - Operating Partnership (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Equity Capital And Other Interests [Abstract]
Redeemable Noncontrolling Interests - Operating Partnership Units	$ 338,951	$ 463,400
Change in market value of Redeemable Noncontrolling Interests - Operating Partnership	119,237	(169,825)
Change in carrying value of Redeemable Noncontrolling Interests - Operating Partnership	1,745	131
Redeemable Noncontrolling Interests - Operating Partnership Units	$ 459,933	$ 293,706

Equity, Capital and Other Int_7

Equity, Capital and Other Interests - Changes in Redemption Value of Redeemable Limited Partners Interest (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Equity Capital And Other Interests [Abstract]
Redeemable Limited Partners	$ 338,951	$ 463,400
Limited Partners Change In Redemption Value	119,237	(169,825)
Limited Partners Change In Carrying Value	1,745	131
Redeemable Limited Partners	$ 459,933	$ 293,706

Equity, Capital and Other Int_8

Equity, Capital and Other Interests - Issued and Outstanding Preferred Shares and Preference Units (Details) - ERPOP [Member] - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Class Of Stock [Line Items]
8.29% Series K Cumulative Redeemable Preferred Shares/Preference Units; liquidation value $50 per share/unit; 745,600 shares/units issued and outstanding as of September 30, 2021 and December 31, 2020	$ 37,280	$ 37,280
Preferred Stock
Class Of Stock [Line Items]
Preferred Stocks Preference Units Call Date	Dec. 10, 2026
Annual Dividend Per Preferred Share Preference Unit	$ 4.145
8.29% Series K Cumulative Redeemable Preferred Shares/Preference Units; liquidation value $50 per share/unit; 745,600 shares/units issued and outstanding as of September 30, 2021 and December 31, 2020	$ 37,280	$ 37,280

Equity, Capital and Other Int_9

Equity, Capital and Other Interests - Issued and Outstanding Preferred Shares and Preference Units (Parenthetical) (Details) - $ / shares	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Class Of Stock [Line Items]
Preferred Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Preferred Stock, Shares Authorized	100,000,000	100,000,000
Preferred Stock
Class Of Stock [Line Items]
Preferred Stock Preference Units Issued	745,600	745,600
Preferred Stock Preference Units Outstanding	745,600	745,600
Preferred Stock Preference Units Redemption Price Per Share	$ 50	$ 50
Preferred Stock Preference Units Dividend Rate Percentage	8.29%	8.29%

Equity, Capital and Other In_10

Equity, Capital and Other Interests - Other - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended	92 Months Ended	165 Months Ended
	Sep. 30, 2021	Sep. 30, 2021	Sep. 30, 2021	Dec. 31, 2020
Common Stock, Shares, Issued	375,002,588	375,002,588	375,002,588	372,302,000
Stock repurchase program, number of shares authorized to be repurchased	13,000,000	13,000,000	13,000,000
Stock open market repurchased and retired during period, shares		0	0
Stock repurchase program, remaining number of shares authorized to be repurchased	13,000,000	13,000,000	13,000,000
Forward Sales Agreements [Member]
Settlement of shares under forward sales agreement	0	0	0
Additional common shares authorized	13,000,000	13,000,000	13,000,000
Amount of share issuance	$ 0
Forward Sales Agreements [Member] | ATM Share Offering [Member]
Common Stock, Shares, Issued	1,700,000	1,700,000	1,700,000
Weighted average initial forward price per share	$ 83.25	$ 83.25	$ 83.25

Real Estate - Summary of Carryi

Real Estate - Summary of Carrying Amounts of Investment in Real Estate (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Land	$ 5,779,686	$ 5,785,367
Depreciable property:
Buildings and improvements	19,211,662	18,464,484
Furniture, fixtures and equipment	2,125,441	1,970,033
In-Place lease intangibles	503,241	486,137
Projects under development:
Projects under development	163,659	411,134
Land held for development:
Land held for development	82,026	86,170
Investment in real estate	27,865,715	27,203,325
Accumulated depreciation	(8,260,846)	(7,859,657)
Investment in real estate, net	19,604,869	19,343,668
Land [Member]
Projects under development:
Projects under development	4,121	23,531
Land held for development:
Land held for development	46,160	46,160
Construction-in-progress [Member]
Projects under development:
Projects under development	159,538	387,603
Land held for development:
Land held for development	$ 35,866	$ 40,010

Real Estate - Acquired Properti

Real Estate - Acquired Properties From Unaffiliated Parties (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2021USD ($)PropertyApartmentUnit
Properties acquired | Property	11
Property Units acquired | ApartmentUnit	2,921
Purchase Price | $	$ 1,020,425
Rental Properties – Consolidated [Member]
Properties acquired | Property	11
Property Units acquired | ApartmentUnit	2,921
Purchase Price | $	$ 1,020,425

Real Estate - Acquired Proper_2

Real Estate - Acquired Properties From Unaffiliated Parties (Parenthetical) (Details) $ in Thousands	Sep. 30, 2021USD ($)
Purchase price	$ 1,020,425
Land [Member]
Purchase price	134,200
Depreciable Property [Member]
Purchase price	$ 888,100

Real Estate - Disposed Properti

Real Estate - Disposed Properties to Unaffiliated Parties (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2021USD ($)PropertyApartmentUnit
Properties disposed | Property	10
Property Units disposed | ApartmentUnit	1,842
Sales Price | $	$ 1,021,800
Rental Properties – Consolidated [Member]
Properties disposed | Property	10
Property Units disposed | ApartmentUnit	1,842
Sales Price | $	$ 1,021,800

Real Estate - Additional Inform

Real Estate - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Real Estate [Abstract]
Net gain on sales of real estate properties	$ 363,928	$ (25)	$ 587,623	$ 352,218

Commitments to Acquire_Dispos_3

Commitments to Acquire/Dispose of Real Estate - Separate Agreements to Dispose (Details) $ in Thousands	Sep. 30, 2021USD ($)PropertyApartmentUnit
Property/Unit schedule
Properties | Property	2
Apartment Units | ApartmentUnit	744
Sales Price	$ 410,000
Net Book Value at September 30, 2021	$ 130,762
Rental Properties – Consolidated [Member] | Wholly Owned Properties [Member]
Property/Unit schedule
Properties | Property	2
Apartment Units | ApartmentUnit	744
Sales Price	$ 410,000
Net Book Value at September 30, 2021	$ 130,762

Investments in Partially Owne_3

Investments in Partially Owned Entities - Consolidated Variable Interest Entities ("VIEs") - Additional Information (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2021USD ($)PropertyApartmentUnit	Sep. 30, 2020USD ($)	Dec. 31, 2020USD ($)
Variable Interest Entity [Line Items]
Properties | Property	307
Apartment units | ApartmentUnit	79,322
Total assets	$ 20,663,015		$ 20,286,891
Total liabilities	$ 9,329,432		9,184,454
Number of unconsolidated land parcel acquired | Property	2
Aggregate gross purchase price to acquire land parcels	$ 1,022,275	$ 48,898
Unconsolidated Joint Venture [Member]
Variable Interest Entity [Line Items]
Aggregate gross purchase price to acquire land parcels	55,400
Equity Residential [Member]
Variable Interest Entity [Line Items]
Aggregate gross purchase price to acquire land parcels	$ 21,800
Consolidated VIE [Member]
Variable Interest Entity [Line Items]
Properties | Property	17
Apartment units | ApartmentUnit	3,774
Total assets	$ 839,300		784,100
Total liabilities	$ 247,900		$ 224,000

Investments in Partially Owne_4

Investments in Partially Owned Entities - Summary of Company's Investment in Unconsolidated Entities (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Variable Interest Entity [Line Items]
Investments in Unconsolidated Entities	$ 79,429	$ 52,782
Real Estate Technology [Member]
Variable Interest Entity [Line Items]
Investments in Unconsolidated Entities	18,127	14,866
Other [Member]
Variable Interest Entity [Line Items]
Investments in Unconsolidated Entities	(277)	(372)
Unconsolidated VIE [Member] | Operating Property [Member]
Variable Interest Entity [Line Items]
Investments in Unconsolidated Entities	$ 36,652	$ 38,288
Ownership Percentage	33.30%
Unconsolidated VIE [Member] | Projects Under Development [Member]
Variable Interest Entity [Line Items]
Investments in Unconsolidated Entities	$ 24,927

Investments in Partially Owne_5

Investments in Partially Owned Entities - Summary of Company's Investment in Unconsolidated Entities (Parenthetical) (Details)	Sep. 30, 2021Entity
Projects Under Development [Member]
Variable Interest Entity [Line Items]
Number of unconsolidated interest in entities	2
Real Estate Technology [Member]
Variable Interest Entity [Line Items]
Number of separate unconsolidated investment funds/Companies	6

Restricted Deposits - Restricte

Restricted Deposits - Restricted Deposits (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020	Sep. 30, 2020
Mortgage escrow deposits:
Replacement reserves	$ 10,830	$ 9,877
Mortgage principal reserves/sinking funds	17,828	14,168
Mortgage escrow deposits	28,658	24,045
Restricted cash:
Tax-deferred (1031) exchange proceeds	121,799
Restricted deposits on real estate investments	292	307
Resident security and utility deposits	34,459	31,412
Other	1,834	1,373
Restricted cash	158,384	33,092
Restricted deposits	$ 187,042	$ 57,137	$ 56,881

Leases - Additional Information

Leases - Additional Information (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
COVID-19 [Member]
Operating Leased Assets [Line Items]
Write-off of straight-line rent receivables	$ 0.1	$ 12.9
Decrease in rental revenues	$ 5.7	$ 5.6
Residential Apartment Leases [Member]
Operating Leased Assets [Line Items]
Percentage of rental income	97.00%
Residential Apartment Leases [Member] | Maximum [Member]
Operating Leased Assets [Line Items]
Retail leases term	12 months
Non-residential Leases [Member]
Operating Leased Assets [Line Items]
Percentage of rental income	3.00%
Non-residential Leases [Member] | Maximum [Member]
Operating Leased Assets [Line Items]
Retail leases term	10 years
Non-residential Leases [Member] | Minimum [Member]
Operating Leased Assets [Line Items]
Retail leases term	5 years

Leases - Summary of Lease Incom

Leases - Summary of Lease Income Types Relating to Lease Payments Along With the Total Other Rental Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Operating Leased Assets [Line Items]
Total lease revenue	$ 596,824	$ 592,341	$ 1,745,648	$ 1,877,454
Rental income	623,206	622,433	1,818,867	1,958,270
Residential Leases [Member]
Operating Leased Assets [Line Items]
Total lease revenue	580,313	590,363	1,696,070	1,845,888
Non-Residential Leases [Member]
Operating Leased Assets [Line Items]
Total lease revenue	16,511	1,978	49,578	31,566
Residential and Non-Residential Rent [Member]
Operating Leased Assets [Line Items]
Total lease revenue	565,917	582,234	1,675,458	1,819,561
Residential and Non-Residential Rent [Member] | Residential Leases [Member]
Operating Leased Assets [Line Items]
Total lease revenue	551,474	576,192	1,629,778	1,783,298
Residential and Non-Residential Rent [Member] | Non-Residential Leases [Member]
Operating Leased Assets [Line Items]
Total lease revenue	14,443	6,042	45,680	36,263
Utility Recoveries (RUBS Income) [Member]
Operating Leased Assets [Line Items]
Total lease revenue	18,987	17,440	55,850	53,047
Utility Recoveries (RUBS Income) [Member] | Residential Leases [Member]
Operating Leased Assets [Line Items]
Total lease revenue	18,798	17,306	55,331	52,538
Utility Recoveries (RUBS Income) [Member] | Non-Residential Leases [Member]
Operating Leased Assets [Line Items]
Total lease revenue	189	134	519	509
Parking Rent [Member]
Operating Leased Assets [Line Items]
Total lease revenue	10,616	9,693	30,868	29,376
Parking Rent [Member] | Residential Leases [Member]
Operating Leased Assets [Line Items]
Total lease revenue	10,513	9,592	30,403	29,052
Parking Rent [Member] | Non-Residential Leases [Member]
Operating Leased Assets [Line Items]
Total lease revenue	103	101	465	324
Other Lease Revenue [Member]
Operating Leased Assets [Line Items]
Total lease revenue	1,304	(17,026)	(16,528)	(24,530)
Other Lease Revenue [Member] | Residential Leases [Member]
Operating Leased Assets [Line Items]
Total lease revenue	(472)	(12,727)	(19,442)	(19,000)
Other Lease Revenue [Member] | Non-Residential Leases [Member]
Operating Leased Assets [Line Items]
Total lease revenue	1,776	(4,299)	2,914	(5,530)
Parking Revenue
Operating Leased Assets [Line Items]
Rental income	6,883	5,336	18,455	16,648
Other Revenue
Operating Leased Assets [Line Items]
Rental income	19,499	24,756	54,764	64,168
Other Rental Income [Member]
Operating Leased Assets [Line Items]
Rental income	$ 26,382	$ 30,092	$ 73,219	$ 80,816

Leases - Summary of Residential

Leases - Summary of Residential and Non-Residential Accounts Receivable and Straight-Line Receivable Balances (Details) - Other Assets [Member] - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Residential Leases [Member]
Operating Leased Assets [Line Items]
Resident/tenant accounts receivable balances	$ 42,126	$ 30,856
Allowance for doubtful accounts	(37,669)	(24,021)
Net receivable balances	4,457	6,835
Straight-line receivable balances	12,650	19,992
Non-Residential Leases [Member]
Operating Leased Assets [Line Items]
Resident/tenant accounts receivable balances	4,001	7,598
Allowance for doubtful accounts	(3,442)	(6,527)
Net receivable balances	559	1,071
Straight-line receivable balances	$ 12,759	$ 13,413

Leases - Summary of Residenti_2

Leases - Summary of Residential and Non-Residential Accounts Receivable and Straight-Line Receivable Balances (Parenthetical) (Details)	Sep. 30, 2021
Leases [Abstract]
Holding percentage of residential security deposits of net receivable	58.40%

Leases - Summary of Residenti_3

Leases - Summary of Residential Bad Debt for Company's Properties (Details) - Residential Leases [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Lessor Lease Description [Line Items]
Bad debt, net	$ 3,979	$ 16,071	$ 29,751	$ 29,419
% of rental income	0.70%	2.60%	1.70%	1.50%

Debt - Mortgage Notes Payable -

Debt - Mortgage Notes Payable - Summary of Mortgage Notes Payable Activity (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Debt Instrument [Line Items]
Mortgage notes payable, net beginning balance	$ 2,293,890
Proceeds	51,298	$ 505,375
Lump sum payoffs	(59,880)	(127,767)
Scheduled principal repayments	(5,570)
Amortization of premiums/ discounts	2,069	$ 1,791
Amortization of deferred financing costs, net	(642)
Mortgage notes payable, net ending balance	2,281,165
Fixed Rate Debt [Member] | Secured – Conventional [Member]
Debt Instrument [Line Items]
Mortgage notes payable, net beginning balance	1,901,091
Proceeds	28,500
Lump sum payoffs	(28,200)
Scheduled principal repayments	(5,570)
Amortization of premiums/ discounts	1,140
Amortization of deferred financing costs, net	689
Mortgage notes payable, net ending balance	1,897,650
Floating Rate Debt [Member]
Debt Instrument [Line Items]
Mortgage notes payable, net beginning balance	392,799
Proceeds	22,798
Lump sum payoffs	(31,680)
Amortization of premiums/ discounts	929
Amortization of deferred financing costs, net	(1,331)
Mortgage notes payable, net ending balance	383,515
Floating Rate Debt [Member] | Secured – Conventional [Member]
Debt Instrument [Line Items]
Mortgage notes payable, net beginning balance	31,494
Proceeds	22,798
Amortization of deferred financing costs, net	(1,719)
Mortgage notes payable, net ending balance	52,573
Floating Rate Debt [Member] | Secured – Tax Exempt [Member]
Debt Instrument [Line Items]
Mortgage notes payable, net beginning balance	361,305
Lump sum payoffs	(31,680)
Amortization of premiums/ discounts	929
Amortization of deferred financing costs, net	388
Mortgage notes payable, net ending balance	$ 330,942

Debt - Mortgage Notes Payable_2

Debt - Mortgage Notes Payable - Summary of Mortgage Notes Payable Activity (Parenthetical) (Details)	9 Months Ended
	Sep. 30, 2021
Debt Instrument [Line Items]
Debt instrument, maturity date	Nov. 1, 2024
Fannie Mae Loan Pool [Member] | Mortgages [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	3.58%
Debt instrument, maturity date	Mar. 1, 2031

Debt - Mortgage Notes Payable_3

Debt - Mortgage Notes Payable - Summary of Certain Interest Rate and Maturity Date Information (Details) - Mortgages [Member]	9 Months Ended
	Sep. 30, 2021
Debt Instrument [Line Items]
Weighted Average Interest Rate	3.16%
Maturity Date Ranges, Start	2022
Maturity Date Ranges, End	2061
Minimum [Member]
Debt Instrument [Line Items]
Interest Rate Ranges	0.06%
Maximum [Member]
Debt Instrument [Line Items]
Interest Rate Ranges	4.21%

Debt - Mortgage Notes Payable_4

Debt - Mortgage Notes Payable - Additional Information (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Mortgage notes payable	$ 2,281,165	$ 2,293,890
Credit Enhanced Debt [Member]
Debt Instrument [Line Items]
Mortgage notes payable	$ 250,000

Debt - Notes - Summary of Notes

Debt - Notes - Summary of Notes Activity (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Debt Instrument [Line Items]
Notes, net beginning balance	$ 5,335,536
Proceeds	497,470
Amortization of premiums/ discounts	1,865	$ 2,043
Notes, net ending balance	5,833,483
Fixed Rate Debt [Member] | Unsecured – Public [Member]
Debt Instrument [Line Items]
Notes, net beginning balance	5,335,536
Proceeds	497,470
Amortization of premiums/ discounts	1,865
Amortization of deferred financing costs, net	(1,388)
Notes, net ending balance	$ 5,833,483

Debt - Notes - Summary of Not_2

Debt - Notes - Summary of Notes Activity (Parenthetical) (Details) - 1.85% Notes [Member]	9 Months Ended
	Sep. 30, 2021USD ($)
Debt Instrument [Line Items]
Proceeds from issuance of unsecured debt	$ 500,000
Debt instrument, interest rate, stated percentage	1.85%

Debt - Notes - Summary of Certa

Debt - Notes - Summary of Certain Interest Rate and Maturity Date Information (Details) - Notes [Member]	9 Months Ended
	Sep. 30, 2021
Debt Instrument [Line Items]
Weighted Average Interest Rate	3.69%
Maturity Date Ranges, Start	2023
Maturity Date Ranges, End	2047
Minimum [Member]
Debt Instrument [Line Items]
Interest Rate Ranges	1.85%
Maximum [Member]
Debt Instrument [Line Items]
Interest Rate Ranges	7.57%

Debt - Line of Credit and Comme

Debt - Line of Credit and Commercial Paper - Additional Information (Details)	9 Months Ended
	Sep. 30, 2021USD ($)
Line of Credit Facility [Line Items]
Debt instrument, maturity date	Nov. 1, 2024
Commercial paper balance outstanding	$ 1,000,000,000
Commercial Paper [Member]
Line of Credit Facility [Line Items]
Weighted average interest rates	0.28%
Commercial paper weighted average days outstanding	1 day
Weighted average amount outstanding	$ 556,700,000
Unsecured Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Unsecured revolving credit facility	2,500,000,000
Ability to increase LOC facility	$ 750,000,000
Debt instrument, basis spread on variable rate	0.775%
Percentage points of line of credit facility commitment fee	0.125%
Revolving credit facility	$ 0
Commercial paper balance outstanding	$ 30,000,000

Debt - Line of Credit and Com_2

Debt - Line of Credit and Commercial Paper - Schedule of Unsecured Revolving Credit Facility (Details)	9 Months Ended
	Sep. 30, 2021USD ($)
Line of Credit Facility [Line Items]
Commercial paper balance outstanding	$ (1,000,000,000)
Unsecured Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Unsecured revolving credit facility commitment	2,500,000,000
Commercial paper balance outstanding	(30,000,000)
Unsecured revolving credit facility balance outstanding	0
Other restricted amounts	(100,442,000)
Unsecured revolving credit facility availability	$ 2,369,558,000

Debt - Other - Schedule of Debt

Debt - Other - Schedule of Debt Extinguishment Costs Recorded as Additional Interest Expense (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2021USD ($)
Debt Disclosure [Abstract]
Write-offs of unamortized deferred financing costs	$ 264

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Derivative Instrument Detail [Abstract]
Net gain on sale of investments	$ 23,400,000
Investment securities outstanding	0
Unrealized gain (loss) on interest rate cash flow hedges, pretax, accumulated other comprehensive income (loss)	36,700,000	$ 43,700,000
Interest rate cash flow hedge gain (loss) to be reclassified during next 12 months, net	$ 10,500,000

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Valuations for Each Type of Fair Value Measurement (Details)	9 Months Ended
	Sep. 30, 2021
Employee Holdings Within The Supplemental Executive Retirement Plan
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value Measurement Type	Employee holdings (other than Common Shares) within the supplemental executive retirement plan (the “SERP”)
Valuation Inputs	Quoted market prices for identical assets. These holdings are included in other assets and other liabilities on the consolidated balance sheets.
Redeemable Noncontrolling Interests Operating Partnership Redeemable Limited Partners
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value Measurement Type	Redeemable Noncontrolling Interests – Operating Partnership/Redeemable Limited Partners
Valuation Inputs	Quoted market price of Common Shares.
Mortgage Notes Payable And Private Unsecured Debt
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value Measurement Type	Mortgage notes payable and private unsecured debt (including its commercial paper and line of credit, if applicable)
Valuation Inputs	Indicative rates provided by lenders of similar loans.
Public Unsecured Notes
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value Measurement Type	Public unsecured notes
Valuation Inputs	Quoted market prices for each underlying issuance.

Fair Value Measurements - Sum_2

Fair Value Measurements - Summary of Carrying and Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Carrying Value [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total debt, net	$ 8,144,648	$ 8,044,256
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total debt, net	8,838,864	8,999,875
Mortgage Notes Payable, Net [Member] | Carrying Value [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total debt, net	2,281,165	2,293,890
Mortgage Notes Payable, Net [Member] | Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total debt, net	2,303,890	2,313,263
Unsecured Debt [Member] | Carrying Value [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total debt, net	5,863,483	5,750,366
Unsecured Debt [Member] | Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total debt, net	$ 6,534,974	$ 6,686,612

Fair Value Measurements - Sum_3

Fair Value Measurements - Summary of Fair Value Measurements for Each Major Category of Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020	Sep. 30, 2020	Dec. 31, 2019
Derivatives, Fair Value [Line Items]
Fair Value Of SERP Investments	$ 160,914	$ 160,293
Other Liabilities, Fair Value Disclosure	160,914	160,293
Redeemable Noncontrolling Interests - Operating Partnership/Redeemable Limited Partners	459,933	338,951	$ 293,706	$ 463,400
Fair Value, Inputs, Level 1 [Member]
Derivatives, Fair Value [Line Items]
Fair Value Of SERP Investments	160,914	160,293
Other Liabilities, Fair Value Disclosure	160,914	160,293
Redeemable Noncontrolling Interests - Operating Partnership/Redeemable Limited Partners	0	0
Fair Value, Inputs, Level 2 [Member]
Derivatives, Fair Value [Line Items]
Fair Value Of SERP Investments	0	0
Other Liabilities, Fair Value Disclosure	0	0
Redeemable Noncontrolling Interests - Operating Partnership/Redeemable Limited Partners	459,933	338,951
Fair Value, Inputs, Level 3 [Member]
Derivatives, Fair Value [Line Items]
Fair Value Of SERP Investments	0	0
Other Liabilities, Fair Value Disclosure	0	0
Redeemable Noncontrolling Interests - Operating Partnership/Redeemable Limited Partners	$ 0	$ 0

Fair Value Measurements - Sum_4

Fair Value Measurements - Summary of Effect of Cash Flow Hedges on the Accompanying Consolidated Statements of Operations and Comprehensive Income (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain/(Loss) Recognized in OCI on Derivative	$ 0	$ (1,190)
Amount of Gain/(Loss) Reclassified from Accumulated OCI into Income	(7,000)	(17,275)
Forward Starting Swaps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain/(Loss) Recognized in OCI on Derivative	0	(1,190)
Amount of Gain/(Loss) Reclassified from Accumulated OCI into Income	$ (7,000)	$ (17,275)

Earnings Per Share and Earnin_3

Earnings Per Share and Earnings Per Unit - Computation of Net Income per Share Basic and Net Income per Share Diluted (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Earnings Per Share [Abstract]
Net income	$ 447,332	$ 95,365	$ 835,736	$ 699,517
Allocation to Noncontrolling Interests – Operating Partnership	(14,847)	(3,376)	(27,903)	(24,624)
Net (income) loss attributable to Noncontrolling Interests – Partially Owned Properties	(534)	(703)	(1,957)	(14,113)
Preferred distributions	(773)	(773)	(2,318)	(2,318)
Net income available to Common Shares	431,178	90,513	803,558	658,462
Numerator for net income per share – diluted	$ 446,025	$ 93,889	$ 831,461	$ 683,086
Weighted average Common Shares outstanding	374,308	371,869	373,474	371,749
OP Units	12,019	13,002	12,367	13,010
Dilutive Securities Options	2,047	781	1,801	1,214
Denominator for net income per share – diluted	388,374	385,652	387,642	385,973
Net income per share – basic	$ 1.15	$ 0.24	$ 2.15	$ 1.77
Net income per share – diluted	$ 1.15	$ 0.24	$ 2.14	$ 1.77

Earnings Per Share and Earnin_4

Earnings Per Share and Earnings Per Unit - Computation of Net Income per Unit Basic and Net Income per Unit Diluted for Operating Partnership (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Net income	$ 447,332	$ 95,365	$ 835,736	$ 699,517
Net (income) loss attributable to Noncontrolling Interests – Partially Owned Properties	$ (534)	$ (703)	$ (1,957)	$ (14,113)
Dilutive Securities Options	2,047	781	1,801	1,214
Denominator for net income per share – diluted	388,374	385,652	387,642	385,973
Net income per Unit – basic	$ 1.15	$ 0.24	$ 2.15	$ 1.77
Net income per Unit – diluted	$ 1.15	$ 0.24	$ 2.14	$ 1.77
ERPOP [Member]
Net income	$ 447,332	$ 95,365	$ 835,736	$ 699,517
Net (income) loss attributable to Noncontrolling Interests – Partially Owned Properties	(534)	(703)	(1,957)	(14,113)
Allocation to Preference Units	(773)	(773)	(2,318)	(2,318)
Numerator for net income per Unit – basic and diluted	$ 446,025	$ 93,889	$ 831,461	$ 683,086
Denominator for net income per Unit – basic	386,327	384,871	385,841	384,759
Dilutive Securities Options	2,047	781	1,801	1,214
Denominator for net income per share – diluted	388,374	385,652	387,642	385,973
Net income per Unit – basic	$ 1.15	$ 0.24	$ 2.15	$ 1.77
Net income per Unit – diluted	$ 1.15	$ 0.24	$ 2.14	$ 1.77

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) $ in Millions	3 Months Ended	9 Months Ended
	Jun. 30, 2021Agreement	Sep. 30, 2021USD ($)PropertyApartmentUnitAgreement
Commitments and Contingencies [Line Items]
Number of consolidated projects in various stages of development		2
Consolidated wholly owned projects in various stages of development		1
Consolidated partially owned projects in various stages of development		1
Number of unconsolidated projects in various stages of development		2
Number of consolidated projects in lease-up		2
Partially owned consolidated projects in lease-up		1
Wholly owned consolidated projects in lease-up		1
Units in various stages of development | ApartmentUnit		1,441
Consolidated project under development commitment fund | $		$ 328.8
Various stages of development with estimated completion dates ranging through Jun 30, 2024		Jun. 30, 2024
Number of joint venture agreement | Agreement		2
Number of joint venture agreement completed | Agreement	1
Number of joint venture agreement currently under construction | Agreement		1
Number of unconsolidated joint venture agreements | Agreement		2
Equity method investment period		3 years
Percentage of expected non-recourse construction debt		60.00%
Initial minimum co-investment of combined equity | $		$ 750
Equity Residential [Member]
Commitments and Contingencies [Line Items]
Ownership Percentage		75.00%
Toll Brothers Inc. [Member]
Commitments and Contingencies [Line Items]
Ownership Percentage		25.00%

Reportable Segments - Additiona

Reportable Segments - Additional Information (Details) - Customer	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Segment Reporting Information [Line Items]
Number of customer contributed 10% or more of total revenue	0	0
Non-residential Leases [Member] | Revenue [Member] | Revenue Concentration Risk [Member]
Segment Reporting Information [Line Items]
Concentration risk, percentage	3.80%

Reportable Segments - Reconcili

Reportable Segments - Reconciliation of NOI from Rental Real Estate Specific to Continuing Operations (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
Rental income	$ 623,206	$ 622,433	$ 1,818,867	$ 1,958,270
Property and maintenance expense	(116,461)	(113,065)	(341,261)	(333,333)
Real estate taxes and insurance expense	(96,909)	(95,273)	(297,780)	(288,043)
Operating income	521,554	182,410	1,033,958	961,384
Same Store, Non-same Store and Other
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
Rental income	623,206	622,433	1,818,867	1,958,270
Property and maintenance expense	(116,461)	(113,065)	(341,261)	(333,333)
Real estate taxes and insurance expense	(96,909)	(95,273)	(297,780)	(288,043)
Total operating expenses	(213,370)	(208,338)	(639,041)	(621,376)
Operating income	$ 409,836	$ 414,095	$ 1,179,826	$ 1,336,894

Reportable Segments - NOI for E

Reportable Segments - NOI for Each Segment from Our Rental Real Estate Specific to Continuing Operations (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Segment Reporting Information [Line Items]
Rental income	$ 623,206	$ 622,433	$ 1,818,867	$ 1,958,270
Operating income	521,554	182,410	1,033,958	961,384
Total Assets	20,663,015		20,663,015		$ 20,286,891
Capital Expenditures			107,706
Same Store
Segment Reporting Information [Line Items]
Rental income	601,852	600,252	1,758,176	1,870,199
Operating expenses	206,583	202,164	612,705	593,502
Operating income	395,269	398,088	1,145,471	1,276,697
Total Assets	18,156,651		18,156,651
Capital Expenditures			106,130
Non-same store/other
Segment Reporting Information [Line Items]
Rental income	21,354	22,181	60,691	88,071
Operating expenses	6,787	6,174	26,336	27,874
Operating income	14,567	16,007	34,355	60,197
Total Assets	2,506,364		2,506,364
Capital Expenditures			1,576
Same Store, Non-same Store and Other
Segment Reporting Information [Line Items]
Rental income	623,206	622,433	1,818,867	1,958,270
Operating expenses	213,370	208,338	639,041	621,376
Operating income	409,836	414,095	1,179,826	1,336,894
Los Angeles | Same Store
Segment Reporting Information [Line Items]
Rental income	117,542	112,201	337,153	346,599
Operating expenses	36,929	36,783	109,997	108,594
Operating income	80,613	75,418	227,156	238,005
Total Assets	2,926,617		2,926,617
Capital Expenditures			13,959
Orange County | Same Store
Segment Reporting Information [Line Items]
Rental income	28,264	26,229	80,773	79,241
Operating expenses	6,480	6,457	18,937	18,539
Operating income	21,784	19,772	61,836	60,702
Total Assets	375,365		375,365
Capital Expenditures			4,124
San Diego | Same Store
Segment Reporting Information [Line Items]
Rental income	20,282	18,637	58,211	56,001
Operating expenses	4,735	4,652	13,920	13,684
Operating income	15,547	13,985	44,291	42,317
Total Assets	234,733		234,733
Capital Expenditures			2,060
Subtotal - Southern California | Same Store
Segment Reporting Information [Line Items]
Rental income	166,088	157,067	476,137	481,841
Operating expenses	48,144	47,892	142,854	140,817
Operating income	117,944	109,175	333,283	341,024
Total Assets	3,536,715		3,536,715
Capital Expenditures			20,143
San Francisco | Same Store
Segment Reporting Information [Line Items]
Rental income	102,166	109,908	302,043	346,089
Operating expenses	31,542	30,913	93,983	90,849
Operating income	70,624	78,995	208,060	255,240
Total Assets	3,264,017		3,264,017
Capital Expenditures			15,853
Washington D.C. | Same Store
Segment Reporting Information [Line Items]
Rental income	100,019	103,160	298,165	311,119
Operating expenses	34,397	32,979	99,369	95,799
Operating income	65,622	70,181	198,796	215,320
Total Assets	3,270,172		3,270,172
Capital Expenditures			20,392
New York | Same Store
Segment Reporting Information [Line Items]
Rental income	103,015	98,333	299,320	324,866
Operating expenses	49,939	49,915	152,228	148,145
Operating income	53,076	48,418	147,092	176,721
Total Assets	3,902,715		3,902,715
Capital Expenditures			22,641
Boston | Same Store
Segment Reporting Information [Line Items]
Rental income	58,864	59,527	171,871	182,502
Operating expenses	19,504	18,601	57,041	53,727
Operating income	39,360	40,926	114,830	128,775
Total Assets	1,710,489		1,710,489
Capital Expenditures			15,766
Seattle | Same Store
Segment Reporting Information [Line Items]
Rental income	61,888	62,748	181,908	195,198
Operating expenses	20,117	18,972	58,616	55,845
Operating income	41,771	43,776	123,292	139,353
Total Assets	1,975,574		1,975,574
Capital Expenditures			10,234
Denver | Same Store
Segment Reporting Information [Line Items]
Rental income	9,812	9,509	28,732	28,584
Operating expenses	2,940	2,892	8,614	8,320
Operating income	6,872	6,617	20,118	20,264
Total Assets	496,969		496,969
Capital Expenditures			1,101
Non-same store | Non-same store/other
Segment Reporting Information [Line Items]
Rental income	16,563	2,481	28,581	11,440
Operating expenses	6,777	539	10,916	2,534
Operating income	9,786	1,942	17,665	8,906
Total Assets	1,484,091		1,484,091
Capital Expenditures			659
Other | Non-same store/other
Segment Reporting Information [Line Items]
Rental income	4,791	19,700	32,110	76,631
Operating expenses	10	5,635	15,420	25,340
Operating income	4,781	$ 14,065	16,690	$ 51,291
Total Assets	$ 1,022,273		1,022,273
Capital Expenditures			$ 917

Reportable Segments - NOI for_2

Reportable Segments - NOI for Each Segment from Our Rental Real Estate Specific to Continuing Operations (Parenthetical) (Details) - Property	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Segment Reporting Disclosure Of Entitys Reportable Segments [Abstract]
Units in same store properties	75,509	75,509	75,288	75,288

Subsequent Events - Additional

Subsequent Events - Additional Information (Details) $ in Millions	Oct. 01, 2021USD ($)Land	Sep. 30, 2021Property
Subsequent Event [Line Items]
Number of unconsolidated land parcel acquired | Property		2
Land Parcels | Subsequent Event
Subsequent Event [Line Items]
Payments to acquire unconsolidated land parcel	$ 1.1
Land Parcels | Subsequent Event | Long-term Ground Lease [Member]
Subsequent Event [Line Items]
Payments to acquire unconsolidated land parcel	5.8
Land Parcels | Subsequent Event | Commitment Agreement [Member]
Subsequent Event [Line Items]
Payments to acquire unconsolidated land parcel	$ 11.6
Number of unconsolidated land parcel acquired | Land	2