Erp Operating LTD Partnership 10-Q 5 May 16 2016 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2016	Apr. 29, 2016
Entity Registrant Name	EQUITY RESIDENTIAL
Entity Central Index Key	906,107
Document Type	10-Q
Document Period End Date	Mar. 31, 2016
Amendment Flag	false
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q1
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		365,502,137
OPERATING PARTNERSHIP
Entity Registrant Name	ERP OPERATING LIMITED PARTNERSHIP
Entity Central Index Key	931,182
Document Type	10-Q
Document Period End Date	Mar. 31, 2016
Amendment Flag	false
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q1
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer

CONSOLIDATED BALANCE SHEETS (Un

CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Investment in real estate
Land	$ 5,777,206	$ 5,864,046
Depreciable property	18,115,815	18,037,087
Projects under development	1,073,822	1,122,376
Land held for development	154,023	158,843
Investment in real estate	25,120,866	25,182,352
Accumulated depreciation	(4,977,274)	(4,905,406)
Investment in real estate, net	20,143,592	20,276,946
Real estate held for sale	0	2,181,135
Cash and cash equivalents	368,049	42,276
Investments in unconsolidated entities	66,476	68,101
Deposits – restricted	241,741	55,893
Escrow deposits – mortgage	59,355	56,946
Other assets	422,079	428,899
Total assets	21,301,292	23,110,196
Liabilities:
Mortgage notes payable, net	4,223,681	4,685,134
Notes, net	4,360,137	5,848,956
Line of credit and commercial paper	0	387,276
Accounts payable and accrued expenses	215,817	187,124
Accrued interest payable	69,404	85,221
Other liabilities	347,553	366,387
Security deposits	63,592	77,582
Distributions payable	191,313	209,378
Total liabilities	$ 9,471,497	$ 11,847,058
Commitments and contingencies
Redeemable Noncontrolling Interests – Operating Partnership	$ 521,080	$ 566,783
Shareholders’ equity:
Preferred Shares of beneficial interest, $0.01 par value; 100,000,000 shares authorized; 745,600 shares issued and outstanding as of March 31, 2016 and December 31, 2015	37,280	37,280
Common Shares of beneficial interest, $0.01 par value; 1,000,000,000 shares authorized; 365,496,019 shares issued and outstanding as of March 31, 2016 and 364,755,444 shares issued and outstanding as of December 31, 2015	3,655	3,648
Paid in capital	8,658,169	8,572,365
Retained earnings	2,490,861	2,009,091
Accumulated other comprehensive (loss)	(126,193)	(152,016)
Total shareholders’ equity	11,063,772	10,470,368
Noncontrolling Interests:
Operating Partnership	240,544	221,379
Noncontrolling Interests – Partially Owned Properties	4,399	4,608
Total Noncontrolling Interests	244,943	225,987
Total equity	11,308,715	10,696,355
Total liabilities and equity	$ 21,301,292	$ 23,110,196

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) (Unaudited) - $ / shares	Mar. 31, 2016	Dec. 31, 2015
Shareholders’ equity:
Preferred Shares of beneficial interest, par value	$ 0.01	$ 0.01
Preferred Shares of beneficial interest, shares authorized	100,000,000	100,000,000
Preferred Shares of beneficial interest, shares issued	745,600	745,600
Preferred Shares of beneficial interest, shares outstanding	745,600	745,600
Common Shares of beneficial interest, par value	$ 0.01	$ 0.01
Common Shares of beneficial interest, shares authorized	1,000,000,000	1,000,000,000
Common Shares of beneficial interest, shares issued	365,496,019	364,755,444
Common Shares of beneficial interest, shares outstanding	365,496,019	364,755,444

CONSOLIDATED BALANCE SHEETS OF

CONSOLIDATED BALANCE SHEETS OF ERP OPERATING LIMITED PARTNERSHIP (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Investment in real estate
Land	$ 5,777,206	$ 5,864,046
Depreciable property	18,115,815	18,037,087
Projects under development	1,073,822	1,122,376
Land held for development	154,023	158,843
Investment in real estate	25,120,866	25,182,352
Accumulated depreciation	(4,977,274)	(4,905,406)
Investment in real estate, net	20,143,592	20,276,946
Real estate held for sale	0	2,181,135
Cash and cash equivalents	368,049	42,276
Investments in unconsolidated entities	66,476	68,101
Deposits – restricted	241,741	55,893
Escrow deposits – mortgage	59,355	56,946
Other assets	422,079	428,899
Total assets	21,301,292	23,110,196
Liabilities:
Mortgage notes payable, net	4,223,681	4,685,134
Notes, net	4,360,137	5,848,956
Line of credit and commercial paper	0	387,276
Accounts payable and accrued expenses	215,817	187,124
Accrued interest payable	69,404	85,221
Other liabilities	347,553	366,387
Security deposits	63,592	77,582
Distributions payable	191,313	209,378
Total liabilities	$ 9,471,497	$ 11,847,058
Commitments and contingencies
Partners' Capital:
Accumulated other comprehensive (loss)	$ (126,193)	$ (152,016)
Noncontrolling Interests – Partially Owned Properties	4,399	4,608
Total liabilities and equity	21,301,292	23,110,196
ERPOP [Member]
Investment in real estate
Land	5,777,206	5,864,046
Depreciable property	18,115,815	18,037,087
Projects under development	1,073,822	1,122,376
Land held for development	154,023	158,843
Investment in real estate	25,120,866	25,182,352
Accumulated depreciation	(4,977,274)	(4,905,406)
Investment in real estate, net	20,143,592	20,276,946
Real estate held for sale	0	2,181,135
Cash and cash equivalents	368,049	42,276
Investments in unconsolidated entities	66,476	68,101
Deposits – restricted	241,741	55,893
Escrow deposits – mortgage	59,355	56,946
Other assets	422,079	428,899
Total assets	21,301,292	23,110,196
Liabilities:
Mortgage notes payable, net	4,223,681	4,685,134
Notes, net	4,360,137	5,848,956
Line of credit and commercial paper	0	387,276
Accounts payable and accrued expenses	215,817	187,124
Accrued interest payable	69,404	85,221
Other liabilities	347,553	366,387
Security deposits	63,592	77,582
Distributions payable	191,313	209,378
Total liabilities	$ 9,471,497	$ 11,847,058
Commitments and contingencies
Redeemable Limited Partners	$ 521,080	$ 566,783
Partners' Capital:
Preference Units	37,280	37,280
General Partner	11,152,685	10,585,104
Limited Partners	240,544	221,379
Accumulated other comprehensive (loss)	(126,193)	(152,016)
Total partners' capital	11,304,316	10,691,747
Noncontrolling Interests – Partially Owned Properties	4,399	4,608
Total capital	11,308,715	10,696,355
Total liabilities and equity	$ 21,301,292	$ 23,110,196

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
REVENUES
Rental income	$ 616,165	$ 664,606
Fee and asset management	2,918	1,765
Total revenues	619,083	666,371
EXPENSES
Property and maintenance	109,165	124,560
Real estate taxes and insurance	80,196	86,432
Property management	23,495	22,765
General and administrative	16,717	19,762
Depreciation	172,885	194,521
Total expenses	402,458	448,040
Operating income	216,625	218,331
Interest and other income	3,058	169
Other expenses	(2,556)	70
Interest:
Expense incurred, net	(213,492)	(108,782)
Amortization of deferred financing costs	(5,394)	(2,589)
(Loss) income before income and other taxes, (loss) income from investments in unconsolidated entities, net gain (loss) on sales of real estate properties and land parcels and discontinued operations	(1,759)	107,199
Income and other tax (expense) benefit	(350)	(43)
(Loss) income from investments in unconsolidated entities	(1,104)	2,963
Net gain on sales of real estate properties	3,723,479	79,951
Net gain (loss) on sales of land parcels	11,722	(1)
Income from continuing operations	3,731,988	190,069
Discontinued operations, net	(157)	155
Net income	3,731,831	190,224
Net (income) attributable to Noncontrolling Interests:
Net (income) attributable to Noncontrolling Interests	(143,309)	(7,059)
Net (income) attributable to Noncontrolling Interests – Partially Owned Properties	(764)	(643)
Net income attributable to controlling interests	3,587,758	182,522
Preferred distributions	(773)	(891)
Premium on redemption of Preferred Shares	0	(2,789)
Net income available to Common Shares	$ 3,586,985	$ 178,842
Earnings per share – basic:
Income from continuing operations available to Common Shares	$ 9.84	$ 0.49
Net income available to Common Shares	$ 9.84	$ 0.49
Weighted average Common Shares outstanding	364,592	363,098
Earnings per share – diluted:
Income from continuing operations available to Common Shares	$ 9.76	$ 0.49
Net income available to Common Shares	$ 9.76	$ 0.49
Weighted Average Number of Shares/Units Outstanding, Diluted	382,243	380,327
Distributions declared per Common Share outstanding	$ 8.50375	$ 0.5525

CONSOLIDATED STATEMENTS OF OPE6

CONSOLIDATED STATEMENTS OF OPERATIONS OF ERP OPERATING LIMITED PARTNERSHIP (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
REVENUES
Rental income	$ 616,165	$ 664,606
Fee and asset management	2,918	1,765
Total revenues	619,083	666,371
EXPENSES
Property and maintenance	109,165	124,560
Real estate taxes and insurance	80,196	86,432
Property management	23,495	22,765
General and administrative	16,717	19,762
Depreciation	172,885	194,521
Total expenses	402,458	448,040
Operating income	216,625	218,331
Interest and other income	3,058	169
Other expenses	(2,556)	70
Interest:
Expense incurred, net	(213,492)	(108,782)
Amortization of deferred financing costs	(5,394)	(2,589)
(Loss) income before income and other taxes, (loss) income from investments in unconsolidated entities, net gain (loss) on sales of real estate properties and land parcels and discontinued operations	(1,759)	107,199
Income and other tax (expense) benefit	(350)	(43)
(Loss) income from investments in unconsolidated entities	(1,104)	2,963
Net gain on sales of real estate properties	3,723,479	79,951
Net gain (loss) on sales of land parcels	11,722	(1)
Income from continuing operations	3,731,988	190,069
Discontinued operations, net	(157)	155
Net income	3,731,831	190,224
Net (income) attributable to Noncontrolling Interests – Partially Owned Properties	(764)	(643)
Net income attributable to controlling interests	3,587,758	182,522
ALLOCATION OF NET INCOME:
Premium on redemption of Preference Units	$ 0	$ (2,789)
Earnings per Unit – basic:
Income from continuing operations available to Units	$ 9.84	$ 0.49
Net income available to Units	9.84	0.49
Earnings per Unit – diluted:
Income from continuing operations available to Units	9.76	0.49
Net income available to Units	$ 9.76	$ 0.49
Weighted Average Number of Shares/Units Outstanding, Diluted	382,243	380,327
ERPOP [Member]
REVENUES
Rental income	$ 616,165	$ 664,606
Fee and asset management	2,918	1,765
Total revenues	619,083	666,371
EXPENSES
Property and maintenance	109,165	124,560
Real estate taxes and insurance	80,196	86,432
Property management	23,495	22,765
General and administrative	16,717	19,762
Depreciation	172,885	194,521
Total expenses	402,458	448,040
Operating income	216,625	218,331
Interest and other income	3,058	169
Other expenses	(2,556)	70
Interest:
Expense incurred, net	(213,492)	(108,782)
Amortization of deferred financing costs	(5,394)	(2,589)
(Loss) income before income and other taxes, (loss) income from investments in unconsolidated entities, net gain (loss) on sales of real estate properties and land parcels and discontinued operations	(1,759)	107,199
Income and other tax (expense) benefit	(350)	(43)
(Loss) income from investments in unconsolidated entities	(1,104)	2,963
Net gain on sales of real estate properties	3,723,479	79,951
Net gain (loss) on sales of land parcels	11,722	(1)
Income from continuing operations	3,731,988	190,069
Discontinued operations, net	(157)	155
Net income	3,731,831	190,224
Net (income) attributable to Noncontrolling Interests – Partially Owned Properties	(764)	(643)
Net income attributable to controlling interests	3,731,067	189,581
ALLOCATION OF NET INCOME:
Preference Units	773	891
Premium on redemption of Preference Units	0	2,789
General Partner	3,586,985	178,842
Limited Partners	143,309	7,059
Net income available to Units	$ 3,730,294	$ 185,901
Earnings per Unit – basic:
Income from continuing operations available to Units	$ 9.84	$ 0.49
Net income available to Units	$ 9.84	$ 0.49
Weighted average Units outstanding	378,289	376,696
Earnings per Unit – diluted:
Income from continuing operations available to Units	$ 9.76	$ 0.49
Net income available to Units	$ 9.76	$ 0.49
Weighted Average Number of Shares/Units Outstanding, Diluted	382,243	380,327
Distributions declared per Unit outstanding	$ 8.50375	$ 0.5525

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Comprehensive income:
Net income	$ 3,731,831	$ 190,224
Other comprehensive income (loss) – derivative instruments:
Unrealized holding (losses) arising during the period	(2,906)	(11,788)
Losses reclassified into earnings from other comprehensive income	28,654	4,338
Other comprehensive income (loss) – foreign currency:
Currency translation adjustments arising during the period	75	(420)
Other comprehensive income (loss)	25,823	(7,870)
Comprehensive income	3,757,654	182,354
Comprehensive (income) attributable to Noncontrolling Interests	(145,070)	(7,402)
Comprehensive income attributable to controlling interests	$ 3,612,584	$ 174,952

CONSOLIDATED STATEMENTS OF COM8

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME OF ERP OPERATING LIMITED PARTNERSHIP (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Comprehensive income:
Net income	$ 3,731,831	$ 190,224
Other comprehensive income (loss) – derivative instruments:
Unrealized holding (losses) arising during the period	(2,906)	(11,788)
Losses reclassified into earnings from other comprehensive income	28,654	4,338
Other comprehensive income (loss) – foreign currency:
Currency translation adjustments arising during the period	75	(420)
Other comprehensive income (loss)	25,823	(7,870)
Comprehensive income	3,757,654	182,354
Comprehensive (income) attributable to Noncontrolling Interests – Partially Owned Properties	(145,070)	(7,402)
Comprehensive income attributable to controlling interests	3,612,584	174,952
ERPOP [Member]
Comprehensive income:
Net income	3,731,831	190,224
Other comprehensive income (loss) – derivative instruments:
Unrealized holding (losses) arising during the period	(2,906)	(11,788)
Losses reclassified into earnings from other comprehensive income	28,654	4,338
Other comprehensive income (loss) – foreign currency:
Currency translation adjustments arising during the period	75	(420)
Other comprehensive income (loss)	25,823	(7,870)
Comprehensive income	3,757,654	182,354
Comprehensive (income) attributable to Noncontrolling Interests – Partially Owned Properties	(764)	(643)
Comprehensive income attributable to controlling interests	$ 3,756,890	$ 181,711

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 3,731,831	$ 190,224
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	172,885	194,521
Amortization of deferred financing costs	5,394	2,589
Amortization of above/below market leases	851	846
Amortization of discounts and premiums on debt	(19,563)	(3,751)
Amortization of deferred settlements on derivative instruments	28,585	4,205
Write-off of pursuit costs	1,448	493
Loss (income) from investments in unconsolidated entities	1,104	(2,963)
Distributions from unconsolidated entities – return on capital	655	516
Net (gain) on sales of investment securities and other investments	(556)	0
Net (gain) on sales of real estate properties	(3,723,479)	(79,951)
Net (gain) loss on sales of land parcels	(11,722)	1
Net (gain) on sales of discontinued operations	(15)	0
Realized/unrealized loss on derivative instruments	0	24
Compensation paid with Company Common Shares	9,967	13,610
Changes in assets and liabilities:
Decrease in deposits – restricted	7,823	290
(Increase) in mortgage deposits	(455)	(456)
Decrease (increase) in other assets	17,175	(4,237)
Increase in accounts payable and accrued expenses	32,964	45,450
(Decrease) in accrued interest payable	(15,817)	(4,870)
(Decrease) in other liabilities	(23,703)	(8,307)
(Decrease) in security deposits	(13,990)	(339)
Net cash provided by operating activities	201,382	347,895
CASH FLOWS FROM INVESTING ACTIVITIES:
Investment in real estate – acquisitions	(160,680)	(6,720)
Investment in real estate – development/other	(150,164)	(146,194)
Capital expenditures to real estate	(33,902)	(38,170)
Non-real estate capital additions	(1,205)	(469)
Interest capitalized for real estate under development	(14,246)	(15,313)
Proceeds from disposition of real estate, net	6,303,904	142,931
Investments in unconsolidated entities	(900)	(2,410)
Distributions from unconsolidated entities – return of capital	336	18,969
Proceeds from sale of investment securities and other investments	1,430	0
(Increase) in deposits on real estate acquisitions and investments, net	(193,533)	(131,787)
Decrease (increase) in mortgage deposits	196	(59)
Net cash provided by (used for) investing activities	5,751,236	(179,222)
CASH FLOWS FROM FINANCING ACTIVITIES:
Debt financing costs	(397)	0
Mortgage deposits	(2,150)	(2,059)
Mortgage notes payable, net:
Lump sum payoffs	(482,601)	(121,326)
Scheduled principal repayments	(2,208)	(2,746)
Notes, net:
Lump sum payoffs	(1,500,000)	0
Line of credit and commercial paper:
Line of credit proceeds	246,000	1,997,000
Line of credit repayments	(246,000)	(2,200,000)
Commercial paper proceeds	1,324,784	1,155,228
Commercial paper repayments	(1,712,472)	(814,600)
(Payments on) settlement of derivative instruments	0	(25)
Proceeds from Employee Share Purchase Plan (ESPP)	982	1,927
Proceeds from exercise of options	20,687	32,213
Redemption of Preferred Shares	0	(9,820)
Premium on redemption of Preferred Shares	0	(2,789)
Other financing activities, net	(138)	0
Contributions – Noncontrolling Interests – Operating Partnership	1	1
Distributions:
Common Shares	(3,122,652)	(181,408)
Preferred Shares	(773)	(891)
Noncontrolling Interests – Operating Partnership	(123,127)	(7,149)
Noncontrolling Interests – Partially Owned Properties	(26,781)	(2,891)
Net cash (used for) financing activities	(5,626,845)	(159,335)
Net increase in cash and cash equivalents	325,773	9,338
Cash and cash equivalents, beginning of period	42,276	40,080
Cash and cash equivalents, end of period	368,049	49,418
SUPPLEMENTAL INFORMATION:
Cash paid for interest, net of amounts capitalized	220,385	113,113
Net cash paid for income and other taxes	524	718
Real estate acquisitions/dispositions/other:
Mortgage loans assumed	43,400	0
Amortization of deferred financing costs:
Other assets	763	764
Mortgage notes payable, net	1,868	843
Notes, net	2,763	982
Amortization of discounts and premiums on debt:
Mortgage notes payable, net	(21,515)	(4,567)
Notes, net	1,540	618
Line of credit and commercial paper	412	198
Amortization of deferred settlements on derivative instruments:
Other liabilities	(69)	(133)
Accumulated other comprehensive income	28,654	4,338
Write-off of pursuit costs:
Investment in real estate, net	982	434
Other assets	389	59
Accounts payable and accrued expenses	77	0
Loss (income) from investments in unconsolidated entities:
Investments in unconsolidated entities	709	(3,625)
Other liabilities	395	662
Realized/unrealized loss on derivative instruments:
Other assets	(6,878)	(4,963)
Notes, net	6,878	4,842
Other liabilities	2,906	11,933
Unrealized holding (losses) arising during the period	(2,906)	(11,788)
Investments in unconsolidated entities:
Investments in unconsolidated entities	0	(130)
Other liabilities	(900)	(2,280)
Debt financing costs [Abstract]
Payments of Financing Costs	(397)	0
Other:
Foreign currency translation adjustments	$ (75)	$ 420

CONSOLIDATED STATEMENTS OF CA10

CONSOLIDATED STATEMENTS OF CASH FLOWS OF ERP OPERATING LIMITED PARTNERSHIP (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 3,731,831	$ 190,224
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	172,885	194,521
Amortization of deferred financing costs	5,394	2,589
Amortization of above/below market leases	851	846
Amortization of discounts and premiums on debt	(19,563)	(3,751)
Amortization of deferred settlements on derivative instruments	28,585	4,205
Write-off of pursuit costs	1,448	493
Loss (income) from investments in unconsolidated entities	1,104	(2,963)
Distributions from unconsolidated entities – return on capital	655	516
Net (gain) on sales of investment securities and other investments	(556)	0
Net (gain) on sales of real estate properties	(3,723,479)	(79,951)
Net (gain) loss on sales of land parcels	(11,722)	1
Net (gain) on sales of discontinued operations	(15)	0
Realized/unrealized loss on derivative instruments	0	24
Compensation paid with Company Common Shares	9,967	13,610
Changes in assets and liabilities:
Decrease in deposits – restricted	7,823	290
(Increase) in mortgage deposits	(455)	(456)
Decrease (increase) in other assets	17,175	(4,237)
Increase in accounts payable and accrued expenses	32,964	45,450
(Decrease) in accrued interest payable	(15,817)	(4,870)
(Decrease) in other liabilities	(23,703)	(8,307)
(Decrease) in security deposits	(13,990)	(339)
Net cash provided by operating activities	201,382	347,895
CASH FLOWS FROM INVESTING ACTIVITIES:
Investment in real estate – acquisitions	(160,680)	(6,720)
Investment in real estate – development/other	(150,164)	(146,194)
Capital expenditures to real estate	(33,902)	(38,170)
Non-real estate capital additions	(1,205)	(469)
Interest capitalized for real estate under development	(14,246)	(15,313)
Proceeds from disposition of real estate, net	6,303,904	142,931
Investments in unconsolidated entities	(900)	(2,410)
Distributions from unconsolidated entities – return of capital	336	18,969
Proceeds from sale of investment securities and other investments	1,430	0
(Increase) in deposits on real estate acquisitions and investments, net	(193,533)	(131,787)
Decrease (increase) in mortgage deposits	196	(59)
Net cash provided by (used for) investing activities	5,751,236	(179,222)
CASH FLOWS FROM FINANCING ACTIVITIES:
Debt financing costs	(397)	0
Mortgage deposits	(2,150)	(2,059)
Mortgage notes payable, net:
Lump sum payoffs	(482,601)	(121,326)
Scheduled principal repayments	(2,208)	(2,746)
Notes, net:
Lump sum payoffs	(1,500,000)	0
Line of credit and commercial paper:
Line of credit proceeds	246,000	1,997,000
Line of credit repayments	(246,000)	(2,200,000)
Commercial paper proceeds	1,324,784	1,155,228
Commercial paper repayments	(1,712,472)	(814,600)
(Payments on) settlement of derivative instruments	0	(25)
Proceeds from EQR's Employee Share Purchase Plan (ESPP)	982	1,927
Proceeds from exercise of options	20,687	32,213
Redemption of Preference Units	0	(9,820)
Premium on redemption of Preference Units	0	(2,789)
Other financing activities, net	(138)	0
Contributions – Limited Partners	1	1
Distributions:
Noncontrolling Interests – Partially Owned Properties	(26,781)	(2,891)
Net cash (used for) financing activities	(5,626,845)	(159,335)
Net increase in cash and cash equivalents	325,773	9,338
Cash and cash equivalents, beginning of period	42,276	40,080
Cash and cash equivalents, end of period	368,049	49,418
SUPPLEMENTAL INFORMATION:
Cash paid for interest, net of amounts capitalized	220,385	113,113
Net cash paid for income and other taxes	524	718
Real estate acquisitions/dispositions/other:
Mortgage loans assumed	43,400	0
Amortization of deferred financing costs:
Other assets	763	764
Mortgage notes payable, net	1,868	843
Notes, net	2,763	982
Amortization of discounts and premiums on debt:
Mortgage notes payable, net	(21,515)	(4,567)
Notes, net	1,540	618
Line of credit and commercial paper	412	198
Amortization of deferred settlements on derivative instruments:
Other liabilities	(69)	(133)
Accumulated other comprehensive income	28,654	4,338
Write-off of pursuit costs:
Investment in real estate, net	982	434
Other assets	389	59
Accounts payable and accrued expenses	77	0
Loss (income) from investments in unconsolidated entities:
Investments in unconsolidated entities	709	(3,625)
Other liabilities	395	662
Realized/unrealized loss on derivative instruments:
Other assets	(6,878)	(4,963)
Notes, net	6,878	4,842
Other liabilities	2,906	11,933
Unrealized holding (losses) arising during the period	(2,906)	(11,788)
Investments in unconsolidated entities:
Investments in unconsolidated entities	0	(130)
Other liabilities	(900)	(2,280)
Debt financing costs [Abstract]
Payments of Financing Costs	(397)	0
Other:
Foreign currency translation adjustments	(75)	420
ERPOP [Member]
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	3,731,831	190,224
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	172,885	194,521
Amortization of deferred financing costs	5,394	2,589
Amortization of above/below market leases	851	846
Amortization of discounts and premiums on debt	(19,563)	(3,751)
Amortization of deferred settlements on derivative instruments	28,585	4,205
Write-off of pursuit costs	1,448	493
Loss (income) from investments in unconsolidated entities	1,104	(2,963)
Distributions from unconsolidated entities – return on capital	655	516
Net (gain) on sales of investment securities and other investments	(556)	0
Net (gain) on sales of real estate properties	(3,723,479)	(79,951)
Net (gain) loss on sales of land parcels	(11,722)	1
Net (gain) on sales of discontinued operations	(15)	0
Realized/unrealized loss on derivative instruments	0	24
Compensation paid with Company Common Shares	9,967	13,610
Changes in assets and liabilities:
Decrease in deposits – restricted	7,823	290
(Increase) in mortgage deposits	(455)	(456)
Decrease (increase) in other assets	17,175	(4,237)
Increase in accounts payable and accrued expenses	32,964	45,450
(Decrease) in accrued interest payable	(15,817)	(4,870)
(Decrease) in other liabilities	(23,703)	(8,307)
(Decrease) in security deposits	(13,990)	(339)
Net cash provided by operating activities	201,382	347,895
CASH FLOWS FROM INVESTING ACTIVITIES:
Investment in real estate – acquisitions	(160,680)	(6,720)
Investment in real estate – development/other	(150,164)	(146,194)
Capital expenditures to real estate	(33,902)	(38,170)
Non-real estate capital additions	(1,205)	(469)
Interest capitalized for real estate under development	(14,246)	(15,313)
Proceeds from disposition of real estate, net	6,303,904	142,931
Investments in unconsolidated entities	(900)	(2,410)
Distributions from unconsolidated entities – return of capital	336	18,969
Proceeds from sale of investment securities and other investments	1,430	0
(Increase) in deposits on real estate acquisitions and investments, net	(193,533)	(131,787)
Decrease (increase) in mortgage deposits	196	(59)
Net cash provided by (used for) investing activities	5,751,236	(179,222)
CASH FLOWS FROM FINANCING ACTIVITIES:
Debt financing costs	(397)	0
Mortgage deposits	(2,150)	(2,059)
Mortgage notes payable, net:
Lump sum payoffs	(482,601)	(121,326)
Scheduled principal repayments	(2,208)	(2,746)
Notes, net:
Lump sum payoffs	(1,500,000)	0
Line of credit and commercial paper:
Line of credit proceeds	246,000	1,997,000
Line of credit repayments	(246,000)	(2,200,000)
Commercial paper proceeds	1,324,784	1,155,228
Commercial paper repayments	(1,712,472)	(814,600)
(Payments on) settlement of derivative instruments	0	(25)
Proceeds from EQR's Employee Share Purchase Plan (ESPP)	982	1,927
Proceeds from exercise of options	20,687	32,213
Redemption of Preference Units	0	(9,820)
Premium on redemption of Preference Units	0	(2,789)
Other financing activities, net	(138)	0
Contributions – Limited Partners	1	1
Distributions:
OP Units – General Partner	(3,122,652)	(181,408)
Preference Units	(773)	(891)
OP Units – Limited Partners	(123,127)	(7,149)
Noncontrolling Interests – Partially Owned Properties	(26,781)	(2,891)
Net cash (used for) financing activities	(5,626,845)	(159,335)
Net increase in cash and cash equivalents	325,773	9,338
Cash and cash equivalents, beginning of period	42,276	40,080
Cash and cash equivalents, end of period	368,049	49,418
SUPPLEMENTAL INFORMATION:
Cash paid for interest, net of amounts capitalized	220,385	113,113
Net cash paid for income and other taxes	524	718
Real estate acquisitions/dispositions/other:
Mortgage loans assumed	43,400	0
Amortization of deferred financing costs:
Other assets	763	764
Mortgage notes payable, net	1,868	843
Notes, net	2,763	982
Amortization of discounts and premiums on debt:
Mortgage notes payable, net	(21,515)	(4,567)
Notes, net	1,540	618
Line of credit and commercial paper	412	198
Amortization of deferred settlements on derivative instruments:
Other liabilities	(69)	(133)
Accumulated other comprehensive income	28,654	4,338
Write-off of pursuit costs:
Investment in real estate, net	982	434
Other assets	389	59
Loss (income) from investments in unconsolidated entities:
Investments in unconsolidated entities	709	(3,625)
Other liabilities	395	662
Realized/unrealized loss on derivative instruments:
Other assets	(6,878)	(4,963)
Notes, net	6,878	4,842
Other liabilities	2,906	11,933
Unrealized holding (losses) arising during the period	(2,906)	(11,788)
Investments in unconsolidated entities:
Investments in unconsolidated entities	0	(130)
Other liabilities	(900)	(2,280)
Debt financing costs [Abstract]
Payments of Financing Costs	(397)	0
Other:
Foreign currency translation adjustments	(75)	420
Land [Member] | ERPOP [Member]
Write-off of pursuit costs:
Accounts payable and accrued expenses	$ 77	$ 0

CONSOLIDATED STATEMENT OF CHANG

CONSOLIDATED STATEMENT OF CHANGES IN EQUITY (Unaudited) - 3 months ended Mar. 31, 2016 - USD ($) $ in Thousands	Total	PREFERRED SHARES	COMMON SHARES, $0.01 PAR VALUE	Additional Paid-in Capital [Member]	RETAINED EARNINGS	Accumulated Other Comprehensive (Loss)	Noncontrolling Interest [Member]	Partially Owned [Domain]
Balance, beginning of year at Dec. 31, 2015	$ 10,470,368	$ 37,280	$ 3,648	$ 8,572,365	$ 2,009,091	$ (152,016)
Balance, beginning of year at Dec. 31, 2015	225,987						$ 221,379	$ 4,608
Common Share Issuance:
Exercise of share options			6	20,681
Restricted shares			1	5,133
PAID IN CAPITAL
Conversion of OP Units into Common Shares				144			(144)
EQR's Employee Share Purchase Plan (ESPP)				982
Share-based employee compensation expense:
Share options				810
ESPP discount				173
Supplemental Executive Retirement Plan (SERP)				1,341
Change in market value of Redeemable Noncontrolling Interests – Operating Partnership	(55,478)			55,478
Adjustment for Noncontrolling Interests ownership in Operating Partnership				1,062			(1,062)
Net income attributable to controlling interests	3,587,758				3,587,758
Common Share distributions					(3,105,215)
Preferred Share distributions					(773)
Other comprehensive income (loss) – derivative instruments:
Unrealized holding (losses) arising during the period	(2,906)					(2,906)
Losses reclassified into earnings from other comprehensive income	(28,654)					28,654
Currency translation adjustments arising during the period	75					75
OPERATING PARTNERSHIP
Issuance of restricted units to Noncontrolling Interests							1
Equity compensation associated with Noncontrolling Interests							9,335
Net income attributable to Noncontrolling Interests	(143,309)						143,309
Distributions to Noncontrolling Interests							(122,499)	(26,781)
Change in carrying value of Redeemable Noncontrolling Interests – Operating Partnership	9,775						(9,775)
PARTIALLY OWNED PROPERTIES
Net income attributable to Noncontrolling Interests	764							764
Other								25,808
Balance, end of period at Mar. 31, 2016	244,943						$ 240,544	$ 4,399
Balance, end of period at Mar. 31, 2016	$ 11,063,772	$ 37,280	$ 3,655	$ 8,658,169	$ 2,490,861	$ (126,193)

CONSOLIDATED STATEMENT OF CHA12

CONSOLIDATED STATEMENT OF CHANGES IN CAPITAL OF ERP OPERATING LIMITED PARTNERSHIP (Unaudited) - 3 months ended Mar. 31, 2016 - USD ($) $ in Thousands	Total	ERPOP [Member]	ERPOP [Member]Accumulated Other Comprehensive (Loss)	ERPOP [Member]Preferred Partner [Member]	ERPOP [Member]General Partner [Member]	ERPOP [Member]Limited Partner [Member]	ERPOP [Member]Noncontrolling Interest [Member]
Balance, beginning of year at Dec. 31, 2015			$ (152,016)	$ 37,280	$ 10,585,104	$ 221,379
Balance, beginning of year at Dec. 31, 2015							$ 4,608
OP Unit Issuance:
Conversion of OP Units held by Limited Partners into OP Units held by General Partner					144	(144)
Exercise of EQR share options					20,687
EQR's Employee Share Purchase Plan (ESPP)					982
Share-based employee compensation expense:
EQR restricted shares					5,134
EQR share options					810
EQR ESPP discount					173
Net income available to Units – General Partner		$ 3,586,985			3,586,985
OP Units – General Partner distributions					(3,105,215)
Supplemental Executive Retirement Plan (SERP)					1,341
Change in market value of Redeemable Limited Partners		55,478			55,478
Adjustment for Noncontrolling Interests ownership in Operating Partnership					1,062	(1,062)
Limited Partners' Capital Account [Abstract]
Issuance of restricted units to Noncontrolling Interests						1
Equity compensation associated with Units – Limited Partners						9,335
Net income available to Units – Limited Partners		143,309				143,309
Units – Limited Partners distributions						(122,499)
Change in carrying value of Redeemable Limited Partners		(9,775)				(9,775)
Other comprehensive income (loss) – derivative instruments:
Unrealized holding (losses) arising during the period	$ (2,906)	(2,906)	(2,906)
Losses reclassified into earnings from other comprehensive income	(28,654)	(28,654)	28,654
Accumulated other comprehensive income – foreign currency:
Currency translation adjustments arising during the period	75	75	75
PARTIALLY OWNED PROPERTIES
Net income attributable to Noncontrolling Interests	$ 764	$ 764					764
Distributions to Noncontrolling Interests							(26,781)
Other							25,808
Balance, end of period at Mar. 31, 2016			$ (126,193)	$ 37,280	$ 11,152,685	$ 240,544
Balance, end of period at Mar. 31, 2016							$ 4,399

Business

Business	3 Months Ended
	Mar. 31, 2016
Business [Abstract]
Business	1. Business Equity Residential (“EQR”), a Maryland real estate investment trust (“REIT”) formed in March 1993, is an S&P 500 company focused on the acquisition, development and management of high quality apartment properties in top United States growth markets. ERP Operating Limited Partnership ("ERPOP"), an Illinois limited partnership, was formed in May 1993 to conduct the multifamily residential property business of Equity Residential. EQR has elected to be taxed as a REIT. References to the "Company," "we," "us" or "our" mean collectively EQR, ERPOP and those entities/subsidiaries owned or controlled by EQR and/or ERPOP. References to the "Operating Partnership" mean collectively ERPOP and those entities/subsidiaries owned or controlled by ERPOP. Unless otherwise indicated, the notes to consolidated financial statements apply to both the Company and the Operating Partnership. EQR is the general partner of, and as of March 31, 2016 owned an approximate 96.1% ownership interest in, ERPOP. All of the Company's property ownership, development and related business operations are conducted through the Operating Partnership and EQR has no material assets or liabilities other than its investment in ERPOP. EQR issues public equity from time to time but does not have any indebtedness as all debt is incurred by the Operating Partnership. The Operating Partnership holds substantially all of the assets of the Company, including the Company's ownership interests in its joint ventures. The Operating Partnership conducts the operations of the business and is structured as a partnership with no publicly traded equity. As of March 31, 2016 , the Company, directly or indirectly through investments in title holding entities, owned all or a portion of 317 properties located in 11 states and the District of Columbia consisting of 83,992 apartment units. The ownership breakdown includes (table does not include various uncompleted development properties): Properties Apartment Units Wholly Owned Properties 291 73,226 Master-Leased Properties – Consolidated 3 853 Partially Owned Properties – Consolidated 18 3,471 Partially Owned Properties – Unconsolidated 3 1,281 Military Housing (A) 2 5,161 317 83,992 (A) The Company sold its interest in the management contracts and related rights associated with the military housing ventures at Joint Base Lewis McChord effective April 1, 2016.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2016
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. Certain reclassifications have been made to the prior period financial statements in order to conform to the current year presentation. These reclassifications did not have an impact on net income previously reported. Operating results for the quarter ended March 31, 2016 are not necessarily indicative of the results that may be expected for the year ending December 31, 2016 . 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. The balance sheets at December 31, 2015 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, 2015 . Income and Other Taxes Due to the structure of EQR as a REIT and the nature of the operations of its operating properties, no provision for federal income taxes has been made at the EQR level. In addition, ERPOP generally is not liable for federal income taxes as the partners recognize their proportionate 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. Deferred tax assets and liabilities applicable to the TRS are recognized for future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. These assets and liabilities are measured using enacted tax rates for which the temporary differences are expected to be recovered or settled. The effects of changes in tax rates on deferred tax assets and liabilities are recognized in earnings in the period enacted. The Company’s deferred tax assets are generally the result of tax affected suspended interest deductions, net operating losses, differing depreciable lives on capitalized assets and the timing of expense recognition for certain accrued liabilities. As of March 31, 2016 , the Company has recorded a deferred tax asset, which is fully offset by a valuation allowance due to the uncertainty of realization. Recent Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (the "FASB") issued a comprehensive new revenue recognition standard entitled Revenue from Contracts with Customers that will supersede nearly all existing revenue recognition guidance. The new standard specifically excludes lease revenue. The new standard’s core principle is that a company will recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. Companies will likely need to use more judgment and make more estimates than under current revenue recognition guidance. These may include identifying performance obligations in the contract, estimating the amount of variable consideration, if any, to include in the transaction price and allocating the transaction price to each separate performance obligation. The new standard will be effective for the Company beginning on January 1, 2018 and early adoption will be permitted beginning on January 1, 2017. The new standard may be applied retrospectively to each prior period presented or prospectively with the cumulative effect recognized as of the date of adoption. The Company has not yet selected a transition method and is currently evaluating the impact of adopting the new standard on its consolidated results of operations and financial position. In August 2014, the FASB issued a new standard that will explicitly require management to assess an entity's ability to continue as a going concern and to provide related footnote disclosures in certain circumstances. In connection with each annual and interim period, management will assess whether there is substantial doubt about an entity's ability to continue as a going concern within one year after the issuance date. Disclosures will be required if conditions give rise to substantial doubt. However, to determine the specific disclosures, management will need to assess whether its plans will alleviate substantial doubt. The new standard is effective for the annual period ending after December 15, 2016 and for interim periods thereafter. The Company does not expect that this will have a material effect on its consolidated results of operations or financial position. In February 2015, the FASB issued new consolidation guidance which makes changes to both the variable interest model and the voting model. Among other changes, the new standard specifically eliminates the presumption in the current voting model that a general partner controls a limited partnership or similar entity unless that presumption can be overcome. Generally, only a single limited partner that is able to exercise substantive kick-out rights will consolidate. The Company adopted this standard as required effective January 1, 2016. While adoption of this standard did not result in any changes to conclusions about whether a joint venture was consolidated or unconsolidated, the Company has determined that certain of its joint ventures and the Operating Partnership now qualify as variable interest entities ("VIEs") and therefore require additional disclosures. See Note 6 for further discussion. In April 2015, the FASB issued a new standard which requires companies to present debt financing costs as a direct deduction from the carrying amount of the associated debt liability rather than as an asset, consistent with the presentation of debt discounts on the consolidated balance sheets. Companies will be permitted to present debt issuance costs related to line of credit arrangements as an asset and amortize these costs over the term of the arrangement, regardless of whether there are any outstanding borrowings on the arrangement. The new standard must be applied retrospectively to all prior periods presented in the consolidated financial statements. The Company adopted this standard as required effective January 1, 2016 and other than presentation on the consolidated balance sheets, it did not have a material effect on its consolidated results of operations or financial position. As of March 31, 2016, $6.1 million , $18.3 million and $24.6 million of deferred financing costs were included within other assets, mortgage notes payable, net and notes, net, respectively, on the consolidated balance sheets. As of December 31, 2015, the following amounts of deferred financing costs were reclassified (amounts in thousands): December 31, 2015 As Originally Reclassification As Presented Deferred financing costs, net $ 54,004 $ (54,004 ) $ — Other assets $ 422,027 $ 6,872 $ 428,899 Mortgage notes payable, net $ 4,704,870 $ (19,736 ) $ 4,685,134 Notes, net $ 5,876,352 $ (27,396 ) $ 5,848,956 In January 2016, the FASB issued a new standard which requires companies to measure all equity securities with readily determinable fair values at fair value on the balance sheet, with changes in fair value recognized in net income. The new standard will be effective for the Company beginning on January 1, 2018. The Company does not expect that this will have a material effect on its consolidated results of operations or financial position. In February 2016, the FASB issued a new leases standard which sets out the principles for the recognition, measurement, presentation and disclosure of leases for both parties to a contract (i.e. lessees and lessors). The new standard requires lessees to apply a dual approach, classifying leases as either finance or operating leases based on the principle of whether or not the lease is effectively a financed purchase of the leased asset by the lessee. This classification will determine whether the lease expense is recognized based on an effective interest method or on a straight-line basis over the term of the lease. A lessee is also required to record a right-of-use asset and a lease liability for all leases with a term of greater than 12 months regardless of their classification. Leases with a term of 12 months or less will be accounted for similar to existing guidance for operating leases today. The new standard requires lessors to account for leases using an approach that is substantially equivalent to existing guidance for sales-type leases, direct financing leases and operating leases. The new standard is expected to impact the Company’s consolidated financial statements as the Company has certain operating ground lease arrangements for which it is the lessee. The new standard will be effective for the Company beginning on January 1, 2019, with early adoption permitted. The Company is currently evaluating the impact of adopting the new standard on its consolidated results of operations and financial position. Other The Company is the controlling partner in various consolidated partnerships owning 18 properties and 3,471 apartment units having a noncontrolling interest book value of $4.4 million at March 31, 2016 . The Company is required to make certain disclosures regarding noncontrolling interests in consolidated limited-life subsidiaries. Of the consolidated entities described above, the Company is the controlling partner in limited-life partnerships owning five properties having a noncontrolling interest deficit balance of $9.4 million . These five partnership agreements contain provisions that require the partnerships to be liquidated through the sale of their assets upon reaching a date specified in each respective partnership agreement. The Company, as controlling partner, has an obligation to cause the property owning partnerships to distribute the proceeds of liquidation to the Noncontrolling Interests in these Partially Owned Properties only to the extent that the net proceeds received by the partnerships from the sale of their assets warrant a distribution based on the partnership agreements. As of March 31, 2016 , the Company estimates the value of Noncontrolling Interest distributions for these five properties would have been approximately $54.0 million (“Settlement Value”) had the partnerships been liquidated. This Settlement Value is based on estimated third party consideration realized by the partnerships upon disposition of the five Partially Owned Properties and is net of all other assets and liabilities, including yield maintenance on the mortgages encumbering the properties, that would have been due on March 31, 2016 had those mortgages been prepaid. Due to, among other things, the inherent uncertainty in the sale of real estate assets, the amount of any potential distribution to the Noncontrolling Interests in the Company's Partially Owned Properties is subject to change. To the extent that the partnerships' underlying assets are worth less than the underlying liabilities, the Company has no obligation to remit any consideration to the Noncontrolling Interests in these Partially Owned Properties.

Equity, Capital and Other Inter

Equity, Capital and Other Interests	3 Months Ended
	Mar. 31, 2016
Equity, Capital and other Interests [Abstract]
Equity Capital And Other Interests [Text Block]	3. Equity, Capital and Other Interests Equity and Redeemable Noncontrolling Interests of Equity Residential The following tables present the changes in the Company’s issued and outstanding Common Shares and “Units” (which includes OP Units and restricted units) for the quarter ended March 31, 2016 : 2016 Common Shares Common Shares outstanding at January 1, 364,755,444 Common Shares Issued: Conversion of OP Units 5,577 Exercise of share options 582,435 Employee Share Purchase Plan (ESPP) 15,506 Restricted share grants, net 137,057 Common Shares outstanding at March 31, 365,496,019 Units Units outstanding at January 1, 14,427,164 Restricted unit grants, net 282,030 Conversion of OP Units to Common Shares (5,577 ) Units outstanding at March 31, 14,703,617 Total Common Shares and Units outstanding at March 31, 380,199,636 Units Ownership Interest in Operating Partnership 3.9 % 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”. Subject to certain exceptions (including the “book-up” requirements of restricted units), the Noncontrolling Interests – Operating Partnership may exchange their Units with EQR for Common Shares on a one-for-one basis. The carrying value of the Noncontrolling Interests – Operating Partnership (including redeemable interests) is allocated based on the number of Noncontrolling Interests – Operating Partnership Units in total in proportion to the number of Noncontrolling Interests – Operating Partnership Units in total plus the number of Common Shares. Net income is allocated to the Noncontrolling Interests – Operating Partnership 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 Units requesting an exchange of their OP Units with EQR. Once the Operating Partnership elects not to redeem the Noncontrolling Interests – Operating Partnership Units for cash, EQR is obligated to deliver Common Shares to the exchanging holder of the Noncontrolling Interests – Operating Partnership Units. The Noncontrolling Interests – Operating Partnership Units 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 are differentiated and referred to as “Redeemable Noncontrolling Interests – Operating Partnership”. 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 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 Units that are classified in permanent equity at March 31, 2016 and December 31, 2015 . The carrying value of the Redeemable Noncontrolling Interests – Operating Partnership is allocated based on the number of Redeemable Noncontrolling Interests – Operating Partnership Units in proportion to the number of Noncontrolling Interests – Operating Partnership Units in total. Such percentage of the total carrying value of Units which is ascribed to the Redeemable Noncontrolling Interests – Operating Partnership is then adjusted to the greater of carrying value or fair market value as described above. As of March 31, 2016 , the Redeemable Noncontrolling Interests – Operating Partnership have a redemption value of approximately $521.1 million , which represents the value of Common Shares that would be issued in exchange for the Redeemable Noncontrolling Interests – Operating Partnership Units. The following table presents the changes in the redemption value of the Redeemable Noncontrolling Interests – Operating Partnership for the quarter ended March 31, 2016 (amounts in thousands): 2016 Balance at January 1, $ 566,783 Change in market value (55,478 ) Change in carrying value 9,775 Balance at March 31, $ 521,080 Net proceeds from EQR Common Share and Preferred Share (see definition below) offerings 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 offering proceeds from Common Shares and Preferred Shares are allocated between shareholders’ equity and Noncontrolling Interests – Operating Partnership to account for the change in their respective percentage ownership of the underlying equity of ERPOP. The Company’s declaration of trust authorizes it to issue up to 100,000,000 preferred shares of beneficial interest, $0.01 par value per share (the “Preferred Shares”), with specific rights, preferences and other attributes as the Board of Trustees may determine, which may include preferences, powers and rights that are senior to the rights of holders of the Company’s Common Shares. The following table presents the Company’s issued and outstanding Preferred Shares as of March 31, 2016 and December 31, 2015 : Amounts in thousands Redemption Annual March 31, December 31, Preferred Shares of beneficial interest, $0.01 par value; 8.29% Series K Cumulative Redeemable Preferred; liquidation 12/10/26 $4.145 $ 37,280 $ 37,280 $ 37,280 $ 37,280 (1) On or after the redemption date, redeemable preferred shares may be redeemed for cash at the option of the Company, in whole or in part, at a redemption price equal to the liquidation price per share, plus accrued and unpaid distributions, if any. (2) Dividends on Preferred Shares are payable quarterly. Capital and Redeemable Limited Partners of ERP Operating Limited Partnership The following tables present the changes in the Operating Partnership’s issued and outstanding Units and in the limited partners’ Units for the quarter ended March 31, 2016 : 2016 General and Limited Partner Units General and Limited Partner Units outstanding at January 1, 379,182,608 Issued to General Partner: Exercise of EQR share options 582,435 EQR’s Employee Share Purchase Plan (ESPP) 15,506 EQR's restricted share grants, net 137,057 Issued to Limited Partners: Restricted unit grants, net 282,030 General and Limited Partner Units outstanding at March 31, 380,199,636 Limited Partner Units Limited Partner Units outstanding at January 1, 14,427,164 Limited Partner restricted unit grants, net 282,030 Conversion of Limited Partner OP Units to EQR Common Shares (5,577 ) Limited Partner Units outstanding at March 31, 14,703,617 Limited Partner Units Ownership Interest in Operating Partnership 3.9 % The Limited Partners of the Operating Partnership as of March 31, 2016 include 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. Subject to certain exceptions (including the “book-up” requirements of restricted units), Limited Partners may exchange their Units with EQR for Common Shares on a one-for-one basis. The carrying value of the Limited Partner Units (including redeemable interests) is allocated based on the number of Limited Partner Units in total in proportion to the number of Limited Partner Units in total plus the number of General Partner Units. Net income is allocated to the Limited Partner Units 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 Limited Partner Units requesting an exchange of their OP Units with EQR. Once the Operating Partnership elects not to redeem the Limited Partner Units for cash, EQR is obligated to deliver Common Shares to the exchanging limited partner. The Limited Partner Units 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 Limited Partner Units are differentiated and referred to as “Redeemable Limited Partner Units”. 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 Limited Partner Units 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 Limited Partner Units that are classified in permanent equity at March 31, 2016 and December 31, 2015 . The carrying value of the Redeemable Limited Partner Units is allocated based on the number of Redeemable Limited Partner Units in proportion to the number of Limited Partner Units in total. Such percentage of the total carrying value of Limited Partner Units which is ascribed to the Redeemable Limited Partner Units is then adjusted to the greater of carrying value or fair market value as described above. As of March 31, 2016 , the Redeemable Limited Partner Units have a redemption value of approximately $521.1 million , which represents the value of Common Shares that would be issued in exchange for the Redeemable Limited Partner Units. The following table presents the changes in the redemption value of the Redeemable Limited Partners for the quarter ended March 31, 2016 (amounts in thousands): 2016 Balance at January 1, $ 566,783 Change in market value (55,478 ) Change in carrying value 9,775 Balance at March 31, $ 521,080 EQR contributes all net proceeds from its various equity offerings (including proceeds from exercise of options for Common Shares) 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). The following table presents the Operating Partnership's issued and outstanding “Preference Units” as of March 31, 2016 and December 31, 2015 : Amounts in thousands Redemption Date (1) Annual March 31, December 31, Preference Units: 8.29% Series K Cumulative Redeemable Preference Units; 12/10/26 $4.145 $ 37,280 $ 37,280 $ 37,280 $ 37,280 (1) On or after the redemption date, redeemable preference units may be redeemed for cash at the option of the Operating Partnership, in whole or in part, at a redemption price equal to the liquidation price per unit, plus accrued and unpaid distributions, if any, in conjunction with the concurrent redemption of the corresponding Company Preferred Shares. (2) Dividends on Preference Units are payable quarterly. Other In September 2009, the Company announced the establishment of an At-The-Market (“ATM”) share offering program which would allow EQR to sell Common Shares from time to time into the existing trading market at current market prices as well as through negotiated transactions. Per the terms of ERPOP's partnership agreement, EQR contributes the net proceeds from 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). On July 30, 2013, the Board of Trustees approved an increase to the amount of shares which may be offered under the ATM program to 13.0 million Common Shares and extended the program maturity to July 2016. EQR has not issued any shares under this program since September 14, 2012. Effective July 30, 2013, the Board of Trustees approved an increase and modification to the Company's share repurchase program to allow for the potential repurchase of up to 13.0 million Common Shares. No shares were repurchased during the quarter ended March 31, 2016 . As of March 31, 2016 , EQR has remaining authorization to repurchase an additional 12,968,760 of its shares.

Real Estate

Real Estate	3 Months Ended
	Mar. 31, 2016
Real Estate [Abstract]
Real Estate Disclosure [Text Block]	4. Real Estate, Real Estate Held for Sale and Lease Intangibles The following table summarizes the carrying amounts for the Company’s investment in real estate (at cost) as of March 31, 2016 and December 31, 2015 (amounts in thousands): March 31, 2016 December 31, 2015 Land $ 5,777,206 $ 5,864,046 Depreciable property: Buildings and improvements 16,430,979 16,346,829 Furniture, fixtures and equipment 1,219,444 1,207,098 In-Place lease intangibles 465,392 483,160 Projects under development: Land 247,568 284,995 Construction-in-progress 826,254 837,381 Land held for development: Land 114,149 120,007 Construction-in-progress 39,874 38,836 Investment in real estate 25,120,866 25,182,352 Accumulated depreciation (4,977,274 ) (4,905,406 ) Investment in real estate, net $ 20,143,592 $ 20,276,946 The following table summarizes the carrying amounts for the Company's above and below market ground and retail lease intangibles as of March 31, 2016 and December 31, 2015 (amounts in thousands): Description Balance Sheet Location March 31, 2016 December 31, 2015 Assets Ground lease intangibles – below market Other Assets $ 178,251 $ 178,251 Retail lease intangibles – above market Other Assets 1,260 1,260 Lease intangible assets 179,511 179,511 Accumulated amortization (14,582 ) (13,451 ) Lease intangible assets, net $ 164,929 $ 166,060 Liabilities Ground lease intangibles – above market Other Liabilities $ 2,400 $ 2,400 Retail lease intangibles – below market Other Liabilities 5,270 5,270 Lease intangible liabilities 7,670 7,670 Accumulated amortization (3,694 ) (3,414 ) Lease intangible liabilities, net $ 3,976 $ 4,256 During the quarters ended March 31, 2016 and 2015 , the Company amortized approximately $1.1 million and $1.1 million , respectively, of above and below market ground lease intangibles which is included (net increase) in property and maintenance expense in the accompanying consolidated statements of operations and comprehensive income and approximately $0.2 million and $0.2 million , respectively, of above and below market retail lease intangibles which is included (net increase) in rental income in the accompanying consolidated statements of operations and comprehensive income. The following table provides a summary of the aggregate amortization expense for above and below market ground lease intangibles and retail lease intangibles for each of the next five years (amounts in thousands): Remaining 2016 2017 2018 2019 2020 2021 Ground lease intangibles $ 3,241 $ 4,321 $ 4,321 $ 4,321 $ 4,321 $ 4,321 Retail lease intangibles (667 ) (540 ) (71 ) (71 ) (71 ) (67 ) Total $ 2,574 $ 3,781 $ 4,250 $ 4,250 $ 4,250 $ 4,254 Acquisitions and Dispositions During the quarter ended March 31, 2016 , the Company acquired the entire equity interest in the following from unaffiliated parties (purchase price in thousands): Properties Apartment Units Purchase Price Rental Properties – Consolidated (1) 3 479 $ 204,134 Total 3 479 $ 204,134 (1) Purchase price includes an allocation of approximately $80.9 million to land and $123.2 million to depreciable property. During the quarter ended March 31, 2016 , the Company disposed of the following to unaffiliated parties (sales price in thousands): Properties Apartment Units Sales Price Rental Properties – Consolidated (1) 80 26,162 $ 6,314,953 Land Parcels — — 27,455 Total 80 26,162 $ 6,342,408 (1) Includes the Starwood portfolio sale (see further discussion below) representing 72 operating properties consisting of 23,262 apartment units for $5.365 billion . The Company recognized a net gain on sales of real estate properties of approximately $3.7 billion (inclusive of $3.2 billion on the Starwood portfolio sale) and a net gain on sales of land parcels of approximately $11.7 million on the above sales. Starwood Disposition Following the approval by the Company's Board of Trustees, the Company executed an agreement with controlled affiliates of Starwood Capital Group ("Starwood") on October 23, 2015 to sell a portfolio of 72 operating properties consisting of 23,262 apartment units located in five markets across the United States for $5.365 billion (the "Starwood Transaction"). As of December 31, 2015, Starwood had deposited $250.0 million in cash into escrow as earnest money, which was non-refundable unless the Company defaulted on the sales agreement. On January 26 and 27, 2016, the Company closed on the sale of the entire portfolio described above. As a result, the Starwood Transaction met the held for sale criteria at December 31, 2015. In accordance with this classification, the Company ceased depreciation on all assets in the Starwood portfolio as of November 1, 2015 and the following assets were classified as held for sale in the accompanying consolidated balance sheets at December 31, 2015 (amounts in thousands): December 31, 2015 Land $ 602,737 Depreciable property: Buildings and improvements 2,386,489 Furniture, fixtures and equipment 335,565 In-Place lease intangibles 35,554 Real estate held for sale before accumulated depreciation 3,360,345 Accumulated depreciation (1,179,210 ) Real estate held for sale $ 2,181,135 The following table provides the operating segments/locations of the properties and apartment units sold in the Starwood Transaction, which represents substantially all of the assets in the Company's South Florida and Denver markets and certain assets in the Washington D.C., Seattle and Inland Empire, California (part of Los Angeles) markets. The sale of these properties represents the continuation of the Company's long-term strategy of investing in high barrier to entry urban markets. See Note 11 for further discussion. Markets/Metro Areas Properties Apartment Units South Florida 33 10,742 Denver 18 6,635 Washington D.C. 10 3,020 Seattle 8 1,721 Inland Empire, CA (part of Los Angeles) 3 1,144 Total 72 23,262 The Company used proceeds from the Starwood Transaction and other sales discussed above to pay a special dividend of $8.00 per share/unit (approximately $3.0 billion ) on March 10, 2016 to shareholders and holders of OP Units of record as of March 3, 2016. The Company used the majority of the remaining proceeds to reduce aggregate indebtedness in order to make the transaction leverage neutral. See Note 8 for further discussion.

Commitments to Acquire_Dispose

Commitments to Acquire/Dispose of Real Estate	3 Months Ended
	Mar. 31, 2016
Commitments to Acquire Dispose of Real Estate [Abstract]
Commitments To Acquire Dispose Of Real Estate Text Block	5. Commitments to Acquire/Dispose of Real Estate The Company has not entered into any separate agreements to acquire rental properties or land parcels as of May 5, 2016. The Company has entered into separate agreements to dispose of the following (sales price in thousands): Properties Apartment Units Sales Price Rental Properties 4 772 $ 134,450 Land Parcels (three) — — 66,550 Total 4 772 $ 201,000 The closings of these pending transactions are subject to certain conditions and restrictions, therefore, there can be no assurance that these transactions will be consummated or that the final terms will not differ in material respects from those summarized in the preceding paragraphs.

Investments in Partially Owned

Investments in Partially Owned Entities	3 Months Ended
	Mar. 31, 2016
Investments in Partially Owned Entities [Abstract]
Investments in Partially Owned Entities	6. Investments in Partially Owned Entities The Company has co-invested in various properties with unrelated third parties which are either consolidated or accounted for under the equity method of accounting (unconsolidated). The following tables and information summarize the Company’s investments in partially owned entities as of March 31, 2016 (amounts in thousands except for property and apartment unit amounts): Consolidated Unconsolidated (VIE) (Non-VIE) (VIE) Total Total properties 18 2 1 3 Total apartment units 3,471 945 336 1,281 Balance sheet information at 3/31/16 (at 100%): ASSETS Investment in real estate $ 665,996 $ 234,383 $ 229,599 $ 463,982 Accumulated depreciation (209,424 ) (24,991 ) (49,194 ) (74,185 ) Investment in real estate, net 456,572 209,392 180,405 389,797 Cash and cash equivalents 15,051 7,836 1,201 9,037 Investments in unconsolidated entities 48,797 — — — Deposits – restricted 351 242 47 289 Other assets 25,948 103 786 889 Total assets $ 546,719 $ 217,573 $ 182,439 $ 400,012 LIABILITIES AND EQUITY/CAPITAL Mortgage notes payable, net (1) $ 317,801 $ 145,423 $ 29,269 $ 174,692 Accounts payable & accrued expenses 2,786 1,729 351 2,080 Accrued interest payable 1,099 691 — 691 Other liabilities 521 258 216 474 Security deposits 1,939 510 159 669 Total liabilities 324,146 148,611 29,995 178,606 Noncontrolling Interests – Partially Owned Properties/Partners' equity 4,399 63,809 108,968 172,777 Company equity/General and Limited Partners' Capital 218,174 5,153 43,476 48,629 Total equity/capital 222,573 68,962 152,444 221,406 Total liabilities and equity/capital $ 546,719 $ 217,573 $ 182,439 $ 400,012 Consolidated Unconsolidated (VIE) (Non-VIE) (VIE) Total Operating information for the quarter ended 3/31/16 (at 100%): Operating revenue $ 22,997 $ 6,528 $ 2,913 $ 9,441 Operating expenses 5,598 2,196 1,153 3,349 Net operating income 17,399 4,332 1,760 6,092 Property management 811 190 19 209 General and administrative/other 15 — 86 86 Depreciation 5,369 2,621 1,858 4,479 Operating income (loss) 11,204 1,521 (203 ) 1,318 Interest and other income 20 — — — Interest: Expense incurred, net (4,038 ) (2,072 ) (272 ) (2,344 ) Amortization of deferred financing costs (147 ) — — — Income (loss) before income and other taxes and (loss) from 7,039 (551 ) (475 ) (1,026 ) Income and other tax (expense) benefit (12 ) — — — (Loss) from investments in unconsolidated entities (369 ) — — — Net income (loss) $ 6,658 $ (551 ) $ (475 ) $ (1,026 ) (1) All debt is non-recourse to the Company. Note: The above tables exclude EQR's ownership interest in ERPOP and the Company's interests in unconsolidated joint ventures entered into with AvalonBay Communities, Inc. (“AVB”) in connection with the acquisition of certain real estate related assets from Archstone Enterprise LP (such assets are referred to herein as "Archstone"). These ventures owned certain Archstone assets and succeeded to certain residual Archstone liabilities/litigation, as well as responsibility for tax protection arrangements and third-party preferred interests in former Archstone subsidiaries. The preferred interests had an aggregate liquidation value of $42.2 million at March 31, 2016 . The ventures are owned 60% by the Company and 40% by AVB. See below for further discussion. Operating Properties The Company has various equity interests in certain limited partnerships owning 17 properties containing 3,039 apartment units. Each partnership owns a multifamily property. The Company is the general partner of these limited partnerships and is responsible for managing the operations and affairs of the partnerships as well as making all decisions regarding the businesses of the partnerships. The limited partners are not able to exercise substantive kick-out or participating rights. As a result, the partnerships qualify as VIEs. The Company has a controlling financial interest in the VIEs and, thus, is the VIEs' primary beneficiary. The Company has both the power to direct the activities of the VIEs that most significantly impact the VIEs' economic performance as well as the obligation to absorb losses or the right to receive benefits from the VIEs that could potentially be significant to the VIEs. As a result, the partnerships are required to be consolidated on the Company's balance sheet. The Company has a 75% equity interest in the Wisconsin Place joint venture. The project contains a mixed-use site located in Chevy Chase, Maryland consisting of residential, retail, office and accessory uses, including underground parking facilities. The joint venture owns the 432 unit residential component, but has no ownership interest in the retail and office components. At March 31, 2016 , the residential component had a net book value of $174.5 million . The Company is the managing member and is responsible for conducting all administrative day-to-day matters and affairs of the joint venture as well as implementing all decisions with respect to the joint venture. The limited partner is not able to exercise substantive kick-out or participating rights. As a result, the joint venture qualifies as a VIE. The Company has a controlling financial interest in the VIE and, thus, is the VIE's primary beneficiary. The Company has both the power to direct the activities of the VIE that most significantly impact the VIE's economic performance as well as 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 residential component is required to be consolidated on the Company's balance sheet. The Wisconsin Place joint venture also retains an unconsolidated interest in an entity that owns the land underlying the entire project and owns and operates the parking facility. At March 31, 2016 , the basis of this investment was $48.8 million . 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. The Company has a 20% equity interest in the Waterton Tenside joint venture which owns a 336 unit apartment property located in Atlanta, Georgia and had a basis of $3.9 million at March 31, 2016 . The partner is the managing member and its predecessor by merger developed the project. The project is encumbered by a non-recourse mortgage loan that has a current outstanding balance of $29.3 million , bears interest at 3.66% and matures December 1, 2018 . The Company, as the limited partner, does not have substantive kick-out or participating rights. As a result, the entity qualifies as a VIE. The Company does not have a controlling financial interest in the VIE and is not the VIE's primary beneficiary. The Company 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 is unconsolidated and recorded using the equity method of accounting. The Company has a 20% equity interest in each of the Nexus Sawgrass and Domain joint ventures. The Nexus Sawgrass joint venture owns a 501 unit apartment property located in Sunrise, Florida and the Company's interest had a basis of $4.9 million at March 31, 2016 . The Domain joint venture owns a 444 unit apartment property located in San Jose, California and the Company's interest had a basis of $9.8 million at March 31, 2016 . Nexus Sawgrass and Domain were completed and stabilized during the quarters ended September 30, 2014 and March 31, 2015 , respectively. Construction on both properties was predominantly funded with long-term, non-recourse secured loans from the partner. The mortgage loan on Nexus Sawgrass has a current unconsolidated outstanding balance of $48.6 million , bears interest at 5.60% and matures January 1, 2021 . The mortgage loan on Domain has a current unconsolidated outstanding balance of $96.8 million , bears interest at 5.75% and matures January 1, 2022 . While the Company is the managing member of both of the joint ventures, was responsible for constructing both of the properties and gave certain construction cost overrun guarantees, the joint venture partner has significant participating rights and has active involvement in and oversight of the operations. As a result, the entities do not qualify as VIEs. The Company alone does not have the power to direct the activities of the entities that most significantly impact the entities' economic performance and as a result, the entities are unconsolidated and recorded using the equity method of accounting. The Company currently has no further funding obligations related to these properties. Other 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. As a result, ERPOP is required to be consolidated on EQR's balance sheet. On February 27, 2013, in connection with the acquisition of Archstone, subsidiaries of the Company and AVB entered into three limited liability company agreements (collectively, the “Residual JV”). The Residual JV owned certain Archstone assets and succeeded to certain residual Archstone liabilities/litigation. The Residual JV is owned 60% by the Company and 40% by AVB. The Company's initial investment was $147.6 million and the Company's basis at March 31, 2016 was a net obligation of $0.9 million . The Residual JV is managed by a Management Committee consisting of two members from each of the Company and AVB. Both partners have equal participation in the Management Committee and all significant participating rights are shared by both partners. As a result, the Residual JV does not qualify as a VIE. The Company alone does not have the power to direct the activities of the Residual JV that most significantly impact the Residual JV's economic performance and as a result, the Residual JV is unconsolidated and recorded using the equity method of accounting. The Residual JV has sold all of the real estate assets that were acquired as part of the acquisition of Archstone, including all of the German assets, and is in the process of winding down all remaining activities. On February 27, 2013, in connection with the acquisition of Archstone, a subsidiary of the Company and AVB entered into a limited liability company agreement (the “Legacy JV”), through which they assumed obligations of Archstone in the form of preferred interests, some of which are governed by tax protection arrangements. At March 31, 2016 , the remaining preferred interests had an aggregate liquidation value of $42.2 million , our share of which is included in other liabilities in the accompanying consolidated balance sheets. Obligations of the Legacy JV are borne 60% by the Company and 40% by AVB. The Legacy JV is managed by a Management Committee consisting of two members from each of the Company and AVB. Both partners have equal participation in the Management Committee and all significant participating rights are shared by both partners. As a result, the Legacy JV does not qualify as a VIE. The Company alone does not have the power to direct the activities of the Legacy JV that most significantly impact the Legacy JV's economic performance and as a result, the Legacy JV is unconsolidated and recorded using the equity method of accounting.

Deposits - Restricted

Deposits - Restricted	3 Months Ended
	Mar. 31, 2016
Deposits - Restricted [Abstract]
Restricted Cash And Cash Equivalents Disclosure [Text Block]	7. Deposits – Restricted and Escrow Deposits – Mortgage The following table presents the Company’s restricted deposits as of March 31, 2016 and December 31, 2015 (amounts in thousands): March 31, December 31, Tax-deferred (1031) exchange proceeds $ 195,636 $ — Earnest money on pending acquisitions — 1,000 Restricted deposits on real estate investments 4,974 6,077 Resident security and utility deposits 38,635 48,458 Other 2,496 358 Totals $ 241,741 $ 55,893 The following table presents the Company’s escrow deposits as of March 31, 2016 and December 31, 2015 (amounts in thousands): March 31, December 31, Real estate taxes and insurance $ 2,432 $ 1,977 Replacement reserves 3,766 3,962 Mortgage principal reserves/sinking funds 52,305 50,155 Other 852 852 Totals $ 59,355 $ 56,946

Debt

Debt	3 Months Ended
	Mar. 31, 2016
Debt Disclosure [Abstract]
Debt Disclosure [Text Block]	8. Debt EQR does not have any indebtedness as all debt is incurred by the Operating Partnership. EQR guarantees the Operating Partnership’s revolving credit facility up to the maximum amount and for the full term of the facility. See Note 2 for a discussion regarding adoption of the new accounting standard impacting deferred financing costs. Mortgage Notes Payable As of March 31, 2016 , the Company had outstanding mortgage debt of approximately $4.2 billion . During the quarter ended March 31, 2016 , the Company: ▪ Repaid $440.8 million of 6.256% mortgage debt held in a Fannie Mae loan pool maturing in 2017 and incurred a prepayment penalty of approximately $29.3 million ; ▪ Repaid $41.8 million of various tax-exempt mortgage bonds maturing in 2026 through 2034 and incurred a prepayment penalty of approximately $0.2 million ; ▪ Repaid $2.2 million of scheduled principal repayments on various mortgage debt; and ▪ Assumed $43.4 million of mortgage debt on one acquired property. The Company recorded $1.2 million of write-offs of unamortized deferred financing costs during the quarter ended March 31, 2016 as additional interest expense related to debt extinguishment of mortgages. The Company also recorded $20.6 million of write-offs of net unamortized premiums during the quarter ended March 31, 2016 as a reduction of interest expense related to debt extinguishment of mortgages. As of March 31, 2016 , the Company had $627.0 million of secured debt subject to third party credit enhancement. As of March 31, 2016 , scheduled maturities for the Company’s outstanding mortgage indebtedness were at various dates through May 1, 2061 . At March 31, 2016 , the interest rate range on the Company’s mortgage debt was 0.10% to 7.25% . During the quarter ended March 31, 2016 , the weighted average interest rate on the Company’s mortgage debt was 4.33% . Notes As of March 31, 2016 , the Company had outstanding unsecured notes of approximately $4.4 billion . During the quarter ended March 31, 2016 , the Company: • Repaid $228.9 million of 5.125% unsecured notes maturing in 2016 and incurred a prepayment penalty of approximately $1.4 million and repaid the remaining $271.1 million of 5.125% unsecured notes at maturity; • Repaid $400.0 million of 5.375% unsecured notes maturing in 2016 and incurred a prepayment penalty of approximately $9.5 million ; • Repaid $255.9 million of 5.750% unsecured notes maturing in 2017 and incurred a prepayment penalty of approximately $16.5 million ; • Repaid $46.1 million of 7.125% unsecured notes maturing in 2017 and incurred a prepayment penalty of approximately $4.6 million ; • Repaid $250.0 million of 4.625% unsecured notes maturing in 2021 and incurred a prepayment penalty of approximately $31.6 million ; and • Repaid $48.0 million of 7.570% unsecured notes maturing in 2026 and incurred a prepayment penalty of approximately $19.3 million . The Company recorded $1.9 million of write-offs of unamortized deferred financing costs during the quarter ended March 31, 2016 as additional interest expense related to debt extinguishment of unsecured notes. The Company also recorded $25.2 million of write-offs of net unamortized premiums/discounts/OCI/treasury locks during the quarter ended March 31, 2016 as additional interest expense related to debt extinguishment of unsecured notes. As of March 31, 2016 , scheduled maturities for the Company’s outstanding notes were at various dates through June 1, 2045 . At March 31, 2016 , the interest rate range on the Company’s notes was 2.375% to 7.57% . During the quarter ended March 31, 2016 , the weighted average interest rate on the Company’s notes was 4.62% . Line of Credit and Commercial Paper On January 11, 2013, the Company replaced its existing $1.75 billion facility with a $2.5 billion unsecured revolving credit facility maturing April 1, 2018 . The Company has the ability to increase available borrowings by an additional $500.0 million by adding additional banks to the facility or obtaining the agreement of existing banks to increase their commitments. The interest rate on advances under the facility will generally be LIBOR plus a spread (currently 0.95% ) and the Company pays an annual facility fee (currently 15 basis points ). Both the spread and the facility fee are dependent on the credit rating of the Company's long-term debt. On February 2, 2015, the Company entered into an unsecured commercial paper note program in the United States. The Company may borrow up to a maximum of $500.0 million under this program 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. As of March 31, 2016 , there was no commercial paper outstanding. The notes bear interest at various floating rates with a weighted average of 0.96% for the quarter ended March 31, 2016 . As of March 31, 2016 , the amount available on the revolving credit facility was $2.44 billion (net of $64.5 million which was restricted/dedicated to support letters of credit). During the quarter ended March 31, 2016 , the weighted average interest rate on the revolving credit facility was 1.36% .

Derivative and Other Fair Value

Derivative and Other Fair Value Instruments	3 Months Ended
	Mar. 31, 2016
Fair Value Disclosures [Abstract]
Derivatives and Fair Value [Text Block]	9. Derivative and Other Fair Value Instruments 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, including its derivative 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 seeks 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 its exposure to foreign exchange rates or manage commodity prices in the daily operations of the business. A three-level valuation hierarchy exists for disclosure of fair value measurements. The valuation hierarchy is based upon the transparency of inputs to the valuation of an asset or liability as of the measurement date. A financial instrument’s categorization within the valuation hierarchy is based upon the lowest level of input that is significant to the fair value measurement. The three levels are defined as follows: • 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 measurement. The Company’s derivative positions are valued using models developed by the respective counterparty as well as models developed internally by the Company that use as their basis readily observable market parameters (such as forward yield curves and credit default swap data). Employee holdings other than Common Shares within the supplemental executive retirement plan (the “SERP”) are valued using quoted market prices for identical assets and are included in other assets and other liabilities on the consolidated balance sheets. Redeemable Noncontrolling Interests – Operating Partnership/Redeemable Limited Partners are valued using the quoted market price of Common Shares. The fair values disclosed for mortgage notes payable and unsecured debt (including its commercial paper) were calculated using indicative rates provided by lenders of similar loans in the case of mortgage notes payable and the private unsecured debt (including its commercial paper) and quoted market prices for each underlying issuance in the case of the public unsecured notes. The carrying values of the Company’s mortgage notes payable and unsecured notes were approximately $4.2 billion and $4.4 billion , respectively, at March 31, 2016 . The fair values of the Company’s mortgage notes payable and unsecured notes were approximately $4.4 billion (Level 2) and $4.7 billion (Level 2), respectively, at March 31, 2016 . The carrying values of the Company's mortgage notes payable and unsecured debt (including its commercial paper) were approximately $4.7 billion and $6.2 billion , respectively, at December 31, 2015 . The fair values of the Company’s mortgage notes payable and unsecured debt (including its commercial paper) were approximately $4.6 billion (Level 2) and $6.5 billion (Level 2), respectively, at December 31, 2015 . The fair values of the Company’s financial instruments (other than mortgage notes payable, unsecured notes, commercial paper and derivative instruments), including cash and cash equivalents and other financial instruments, approximate their carrying or contract values. The following table summarizes the Company’s consolidated derivative instruments at March 31, 2016 (dollar amounts are in thousands): Fair Value Forward Current Notional Balance $ 450,000 $ 50,000 Lowest Possible Notional $ 450,000 $ 50,000 Highest Possible Notional $ 450,000 $ 50,000 Lowest Interest Rate 2.375 % 2.500 % Highest Interest Rate 2.375 % 2.500 % Earliest Maturity Date 2019 2026 Latest Maturity Date 2019 2026 (1) Fair Value Hedges – Converts outstanding fixed rate unsecured notes ( $450.0 million 2.375% notes due July 1, 2019 ) to a floating interest rate of 90-Day LIBOR plus 0.61% . (2) Forward Starting Swaps – Designed to partially fix interest rates in advance of a planned future debt issuance. This swap has a mandatory counterparty termination in 2017, and is targeted to a 2016 issuance. The following tables provide a summary of the fair value measurements for each major category of assets and liabilities measured at fair value on a recurring basis and the location within the accompanying consolidated balance sheets at March 31, 2016 and December 31, 2015 , respectively (amounts in thousands): Fair Value Measurements at Reporting Date Using Description Balance Sheet Location 3/31/2016 Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets Derivatives designated as hedging instruments: Interest Rate Contracts: Fair Value Hedges Other Assets $ 10,533 $ — $ 10,533 $ — Supplemental Executive Retirement Plan Other Assets 114,123 114,123 — — Total $ 124,656 $ 114,123 $ 10,533 $ — Liabilities Derivatives designated as hedging instruments: Interest Rate Contracts: Forward Starting Swaps Other Liabilities $ 3,579 $ — $ 3,579 $ — Supplemental Executive Retirement Plan Other Liabilities 114,123 114,123 — — Total $ 117,702 $ 114,123 $ 3,579 $ — Redeemable Noncontrolling Interests – Operating Partnership/Redeemable Limited Partners Mezzanine $ 521,080 $ — $ 521,080 $ — Fair Value Measurements at Reporting Date Using Description Balance Sheet Location 12/31/2015 Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets Derivatives designated as hedging instruments: Interest Rate Contracts: Fair Value Hedges Other Assets $ 3,655 $ — $ 3,655 $ — Supplemental Executive Retirement Plan Other Assets 105,942 105,942 — — Total $ 109,597 $ 105,942 $ 3,655 $ — Liabilities Derivatives designated as hedging instruments: Interest Rate Contracts: Forward Starting Swaps Other Liabilities $ 673 $ — $ 673 $ — Supplemental Executive Retirement Plan Other Liabilities 105,942 105,942 — — Total $ 106,615 $ 105,942 $ 673 $ — Redeemable Noncontrolling Interests – Operating Partnership/Redeemable Limited Partners Mezzanine $ 566,783 $ — $ 566,783 $ — The following tables provide a summary of the effect of fair value hedges on the Company’s accompanying consolidated statements of operations and comprehensive income for the quarters ended March 31, 2016 and 2015 , respectively (amounts in thousands): March 31, 2016 Type of Fair Value Hedge Location of Gain/(Loss) Recognized in Income on Derivative Amount of Gain/(Loss) Recognized in Income on Derivative Hedged Item Income Statement Location of Hedged Item Gain/(Loss) Amount of Gain/(Loss) Recognized in Income on Hedged Item Derivatives designated as hedging instruments: Interest Rate Contracts: Interest Rate Swaps Interest expense $ 6,878 Fixed rate debt Interest expense $ (6,878 ) Total $ 6,878 $ (6,878 ) March 31, 2015 Type of Fair Value Hedge Location of Derivative Amount of Derivative Hedged Item Income Statement Amount of Gain/(Loss) Recognized in Income on Hedged Item Derivatives designated as hedging instruments: Interest Rate Contracts: Interest Rate Swaps Interest expense $ 4,842 Fixed rate debt Interest expense $ (4,842 ) Total $ 4,842 $ (4,842 ) The following tables provide a summary of the effect of cash flow hedges on the Company’s accompanying consolidated statements of operations and comprehensive income for the quarters ended March 31, 2016 and 2015 , respectively (amounts in thousands): Effective Portion Ineffective Portion March 31, 2016 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/ Location of Gain/(Loss) Recognized in Income on Derivative Amount of Gain/ Derivatives designated as hedging instruments: Interest Rate Contracts: Forward Starting Swaps $ (2,906 ) Interest expense $ (28,654 ) N/A $ — Total $ (2,906 ) $ (28,654 ) $ — Effective Portion Ineffective Portion March 31, 2015 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/ Location of Gain/(Loss) Recognized in Income on Derivative Amount of Gain/ Derivatives designated as hedging instruments: Interest Rate Contracts: Forward Starting Swaps $ (11,788 ) Interest expense $ (4,338 ) N/A $ — Total $ (11,788 ) $ (4,338 ) $ — As of March 31, 2016 and December 31, 2015 , there were approximately $126.0 million and $151.8 million in deferred losses, net, included in accumulated other comprehensive (loss), respectively, related to derivative instruments. Based on the estimated fair values of the net derivative instruments at March 31, 2016 , the Company may recognize an estimated $20.8 million of accumulated other comprehensive (loss) as additional interest expense during the twelve months ending March 31, 2017 .

Earnings Per Share

Earnings Per Share	3 Months Ended
	Mar. 31, 2016
Earnings Per Share [Abstract]
Earnings Per Share And Earnings Per Unit [Text Block]	10. Earning Per Share and Earnings Per Unit Equity Residential The following tables set forth the computation of net income per share – basic and net income per share – diluted for the Company (amounts in thousands except per share amounts): Quarter Ended March 31, 2016 2015 Numerator for net income per share – basic: Income from continuing operations $ 3,731,988 $ 190,069 Allocation to Noncontrolling Interests – Operating Partnership, net (143,315 ) (7,053 ) Net (income) attributable to Noncontrolling Interests – Partially Owned Properties (764 ) (643 ) Preferred distributions (773 ) (891 ) Premium on redemption of Preferred Shares — (2,789 ) Income from continuing operations available to Common Shares, net of Noncontrolling Interests 3,587,136 178,693 Discontinued operations, net of Noncontrolling Interests (151 ) 149 Numerator for net income per share – basic $ 3,586,985 $ 178,842 Numerator for net income per share – diluted: Income from continuing operations $ 3,731,988 $ 190,069 Net (income) attributable to Noncontrolling Interests – Partially Owned Properties (764 ) (643 ) Preferred distributions (773 ) (891 ) Premium on redemption of Preferred Shares — (2,789 ) Income from continuing operations available to Common Shares 3,730,451 185,746 Discontinued operations, net (157 ) 155 Numerator for net income per share – diluted $ 3,730,294 $ 185,901 Denominator for net income per share – basic and diluted: Denominator for net income per share – basic 364,592 363,098 Effect of dilutive securities: OP Units 13,697 13,598 Long-term compensation shares/units 3,954 3,631 Denominator for net income per share – diluted 382,243 380,327 Net income per share – basic $ 9.84 $ 0.49 Net income per share – diluted $ 9.76 $ 0.49 Net income per share – basic: Income from continuing operations available to Common Shares, net of Noncontrolling Interests $ 9.84 $ 0.49 Discontinued operations, net of Noncontrolling Interests — — Net income per share – basic $ 9.84 $ 0.49 Net income per share – diluted: Income from continuing operations available to Common Shares $ 9.76 $ 0.49 Discontinued operations, net — — Net income per share – diluted $ 9.76 $ 0.49 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): Quarter Ended March 31, 2016 2015 Numerator for net income per Unit – basic and diluted: Income from continuing operations $ 3,731,988 $ 190,069 Net (income) attributable to Noncontrolling Interests – Partially Owned Properties (764 ) (643 ) Allocation to Preference Units (773 ) (891 ) Allocation to premium on redemption of Preference Units — (2,789 ) Income from continuing operations available to Units 3,730,451 185,746 Discontinued operations, net (157 ) 155 Numerator for net income per Unit – basic and diluted $ 3,730,294 $ 185,901 Denominator for net income per Unit – basic and diluted: Denominator for net income per Unit – basic 378,289 376,696 Effect of dilutive securities: Dilution for Units issuable upon assumed exercise/vesting of the Company’s long-term 3,954 3,631 Denominator for net income per Unit – diluted 382,243 380,327 Net income per Unit – basic $ 9.84 $ 0.49 Net income per Unit – diluted $ 9.76 $ 0.49 Net income per Unit – basic: Income from continuing operations available to Units $ 9.84 $ 0.49 Discontinued operations, net — — Net income per Unit – basic $ 9.84 $ 0.49 Net income per Unit – diluted: Income from continuing operations available to Units $ 9.76 $ 0.49 Discontinued operations, net — — Net income per Unit – diluted $ 9.76 $ 0.49

Discontinued Operations

Discontinued Operations	3 Months Ended
	Mar. 31, 2016
Discontinued Operations and Disposal Groups [Abstract]
Discontinued Operations	11. Individually Significant Dispositions and Discontinued Operations In April 2014, the FASB issued new guidance for reporting discontinued operations. Only disposals representing a strategic shift in operations that has a major effect on a company’s operations and financial results will be presented as discontinued operations. Companies are required to expand their disclosures about discontinued operations to provide more information on the assets, liabilities, income and expenses of the discontinued operations. Companies are also required to disclose the pre-tax income attributable to a disposal of a significant part of a company that does not qualify for discontinued operations reporting. Application of this guidance is prospective from the date of adoption and early adoption was permitted, but only for disposals (or classifications as held for sale) that had not been reported in financial statements previously issued. The new standard was effective January 1, 2015, but the Company early adopted it as allowed effective January 1, 2014. Adoption of this standard resulted in and will likely continue to result in substantially fewer of the Company's dispositions meeting the discontinued operations qualifications. Individually Significant Dispositions The Company concluded that the Starwood Transaction does not qualify for discontinued operations reporting as it does not represent a strategic shift that will have a major effect on the Company’s operations and financial results. The Company has been investing only in its six coastal, high barrier to entry markets (Boston, New York, Washington D.C., Southern California, San Francisco and Seattle) and has not been acquiring or developing any new assets in its other markets. Over the past several years, the Company has been repositioning its portfolio by selling assets located in low barrier to entry markets and reducing its exposure to these markets. However, the Company concluded that the Starwood Transaction does qualify as an individually significant component of the Company as the amount received upon disposal exceeded 10% of total assets and NOI (see definition in Note 13) of the Starwood portfolio represents approximately 4.5% (for the approximate one-month period owned in 2016) and 16.0% , respectively, of consolidated NOI for the Company for the quarters ended March 31, 2016 and 2015. In addition, the Starwood Transaction met the held for sale criteria at December 31, 2015 and was classified as held for sale in the accompanying consolidated balance sheets at December 31, 2015 (see Note 4 for further discussion). In accordance with this classification, the Company ceased depreciation on all assets in the Starwood portfolio as of November 1, 2015. As a result, the following table summarizes the results of operations attributable to the Starwood Transaction for the quarters ended March 31, 2016 and 2015 (amounts in thousands): Quarter Ended March 31, 2016 2015 REVENUES Rental income $ 30,117 $ 103,709 Total revenues 30,117 103,709 EXPENSES (1) Property and maintenance 7,890 19,086 Real estate taxes and insurance 2,872 12,147 Property management 2 3 General and administrative 1 1 Depreciation — 26,194 Total expenses 10,765 57,431 Operating income 19,352 46,278 Interest and other income 2 — Interest (2): Expense incurred, net (328 ) (164 ) Amortization of deferred financing costs (707 ) (24 ) Net gain on sales of real estate properties 3,161,221 — Income from operations attributable to controlling interests – Operating Partnership 3,179,540 46,090 Income from operations attributable to Noncontrolling Interests – Operating Partnership (122,132 ) (1,754 ) Income from operations attributable to controlling interests – Company $ 3,057,408 $ 44,336 (1) Includes expenses paid in the current period for properties held for sale. (2) Includes only interest expense specific to secured mortgage notes payable for properties held for sale which was repaid at or before closing. Discontinued Operations The Company has presented separately as discontinued operations in all periods the results of operations for all consolidated assets disposed of and all properties held for sale, if any, for properties sold in 2013 and prior years. The amounts included in discontinued operations for the quarters ended March 31, 2016 and 2015 represent trailing activity for properties sold in 2013 and prior years. None of the properties sold during the quarters ended March 31, 2016 and 2015 met the new criteria for reporting discontinued operations. The components of discontinued operations are outlined below and include the results of operations for the respective periods that the Company owned such assets for properties sold in 2013 and prior years during the quarters ended March 31, 2016 and 2015 (amounts in thousands). Quarter Ended March 31, 2016 2015 REVENUES Rental income $ 118 $ 161 Total revenues 118 161 EXPENSES (1) Property and maintenance (3 ) (67 ) Real estate taxes and insurance 1 52 General and administrative 4 6 Total expenses 2 (9 ) Discontinued operating income 116 170 Other expenses (280 ) — Income and other tax (expense) benefit (8 ) (15 ) Discontinued operations (172 ) 155 Net gain on sales of discontinued operations 15 — Discontinued operations, net $ (157 ) $ 155 (1) Includes expenses paid in the current period for properties sold in prior periods related to the Company’s period of ownership.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2016
Commitments and Contingencies [Abstract]
Commitments and Contingencies	12. Commitments and Contingencies The Company, as an owner of real estate, is subject to various Federal, state and local 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 on its current properties or on properties that it may acquire in the future. The Company is party to a housing discrimination lawsuit brought by a non-profit civil rights organization in April 2006 in the U.S. District Court for the District of Maryland. The suit as presently configured alleges that the Company designed and built many of its properties in violation of the accessibility requirements of the Fair Housing Act (“FHA”) and Americans With Disabilities Act (“ADA”). The suit seeks actual and punitive damages, injunctive relief (including modification of non-compliant properties), costs and attorneys’ fees. In the 10 years the case has been pending, the Court has made several important rulings, including that the plaintiff lacks standing under the ADA and thus cannot pursue claims under that statute. On March 31, 2016, the Court found that certain features at seven of the Company’s properties do not satisfy the accessibility requirements of the FHA. The Court also found that six of the Company's properties do not belong in the case based on date of design/construction or the fact that the Company did not participate in design/construction. It is unclear at this time what effect the Court’s recent rulings will have on as yet unresolved liability issues as well as potential remedies for violations found. The Company will continue to defend the suit vigorously, and due to the uncertainty of the many critical factual and legal issues, it is not possible to determine or predict the outcome of the suit or a possible loss or a range of loss, and no amounts have been accrued at March 31, 2016 . While no assurances can be given, the Company does not believe that the suit, if adversely determined, would have a material adverse effect on the Company. The Company has established a reserve related to various litigation matters associated with its Massachusetts properties and periodically assesses the adequacy of the reserve and makes adjustments as necessary. During the quarter ended March 31, 2016 , the Company recorded a reduction to the reserve of approximately $0.5 million , resulting in a total reserve of approximately $2.5 million at March 31, 2016 . While no assurances can be given, the Company does not believe that the ultimate resolution of any of these remaining litigation matters, if adversely determined, would have a material adverse effect on the Company. The Company does not believe there is any other 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 March 31, 2016 , the Company has 10 wholly owned projects totaling 3,983 apartment units in various stages of development with commitments to fund of approximately $626.2 million and estimated completion dates ranging through September 30, 2017 , as well as other completed development projects that are in various stages of lease up or are stabilized. As of March 31, 2016 , the Company has two completed unconsolidated development properties that are stabilized. Both properties were co-developed with the same third party development partner in different ventures. The development venture agreements with this partner are primarily deal-specific regarding profit-sharing, equity contributions, returns on investment, buy-sell agreements and other customary provisions. The Company currently has no further funding obligations related to these properties. While the Company is the managing member of both of the joint ventures, was responsible for constructing both of the properties and gave certain construction cost overrun guarantees, the joint venture partner has significant participating rights and has active involvement in and oversight of the ongoing operations. The buy-sell arrangements contain provisions that provide the right, but not the obligation, for the Company to acquire the partner’s interests or sell its interests at any time following the occurrence of certain pre-defined events (including at stabilization) described in the development venture agreements. See Note 6 for further discussion.

Reportable Segments

Reportable Segments	3 Months Ended
	Mar. 31, 2016
Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]
Segment Reporting Disclosure [Text Block]	13. Reportable Segments 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 operating decision maker. The chief operating decision maker decides how resources are allocated and assesses performance on a recurring basis at least quarterly. 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. The Company’s operating segments located in its coastal markets represent its reportable segments. As of March 31, 2016 , the Company has revised the presentation of Southern California to show separate results for Los Angeles, San Diego and Orange County, along with a subtotal of the three markets combined, for both the current and comparable periods. The Company's operating segments located in its other markets that are not material have been included in the tables presented below. See also Note 4 for further discussion of the Starwood Transaction and the operating segments/locations in which properties were sold. The Company’s fee and asset management and development activities are other business activities that do not constitute an operating segment and as such, have been included in the "Other" category in the tables presented below. All revenues are from external customers and there is no customer who contributed 10% or more of the Company’s total revenues during the quarters ended March 31, 2016 and 2015 , respectively. The primary financial measure for the Company’s rental real estate segment is net operating income (“NOI”), which represents rental income less: 1) property and maintenance expense and 2) real estate taxes and insurance expense (all as reflected in the accompanying consolidated statements of operations and comprehensive income). As of March 31, 2016, NOI no longer includes an allocation of property management expenses either in the current or comparable periods. The Company believes that NOI is helpful to investors as a supplemental measure of its operating performance because it is a direct measure of the actual operating results of the Company’s apartment properties. Current year NOI is compared to prior year NOI and current year budgeted NOI as a measure of financial performance. The following table presents a reconciliation of NOI from our rental real estate specific to continuing operations for the quarters ended March 31, 2016 and 2015 , respectively (amounts in thousands): Quarter Ended March 31, 2016 2015 Rental income $ 616,165 $ 664,606 Property and maintenance expense (109,165 ) (124,560 ) Real estate taxes and insurance expense (80,196 ) (86,432 ) Total operating expenses (189,361 ) (210,992 ) Net operating income $ 426,804 $ 453,614 The following tables present NOI for each segment from our rental real estate specific to continuing operations for the quarters ended March 31, 2016 and 2015 , respectively, as well as total assets and capital expenditures at March 31, 2016 (amounts in thousands): Quarter Ended March 31, 2016 Quarter Ended March 31, 2015 Rental Income Operating Expenses NOI Rental Income Operating Expenses NOI Same store (1) Los Angeles $ 90,150 $ 26,359 $ 63,791 $ 84,654 $ 26,189 $ 58,465 San Diego 21,428 5,835 15,593 20,231 5,661 14,570 Orange County 19,314 4,733 14,581 18,321 4,688 13,633 Subtotal – Southern California 130,892 36,927 93,965 123,206 36,538 86,668 New York 113,204 40,141 73,063 110,123 39,507 70,616 Washington D.C. 104,268 31,425 72,843 103,340 32,037 71,303 San Francisco 90,674 22,198 68,476 82,784 21,519 61,265 Boston 62,325 17,648 44,677 60,512 19,124 41,388 Seattle 37,243 10,572 26,671 35,131 9,807 25,324 All Other Markets 9,070 3,765 5,305 8,643 4,131 4,512 Total same store 547,676 162,676 385,000 523,739 162,663 361,076 Non-same store/other (2) (3) Los Angeles 7,264 2,573 4,691 7,339 2,384 4,955 Orange County 1,158 334 824 — — — Subtotal – Southern California 8,422 2,907 5,515 7,339 2,384 4,955 New York 7,086 3,625 3,461 292 432 (140 ) Washington D.C. 959 170 789 1,047 197 850 San Francisco 4,298 1,550 2,748 83 221 (138 ) Boston 2,634 710 1,924 946 202 744 Seattle 5,679 1,259 4,420 1,941 496 1,445 Other (3) 39,411 16,464 22,947 129,219 44,397 84,822 Total non-same store/other 68,489 26,685 41,804 140,867 48,329 92,538 Total $ 616,165 $ 189,361 $ 426,804 $ 664,606 $ 210,992 $ 453,614 (1) Same store primarily includes all properties acquired or completed that are stabilized prior to January 1, 2015, less properties subsequently sold, which represented 73,222 apartment units. (2) Non-same store primarily includes properties acquired after January 1, 2015, plus any properties in lease-up and not stabilized as of January 1, 2015. (3) Other includes development, other corporate operations and operations prior to sale for properties sold from 2014 through 2016 that do not meet the new discontinued operations criteria. Quarter Ended March 31, 2016 Total Assets Capital Expenditures Same store (1) Los Angeles $ 2,567,837 $ 5,031 San Diego 483,643 673 Orange County 266,770 1,738 Subtotal – Southern California 3,318,250 7,442 New York 4,348,318 3,994 Washington D.C. 3,993,480 5,556 San Francisco 2,518,610 4,891 Boston 1,811,047 3,626 Seattle 1,053,316 2,345 All Other Markets 126,515 254 Total same store 17,169,536 28,108 Non-same store/other (2) (3) Los Angeles 459,013 3,164 Orange County 77,324 12 Subtotal – Southern California 536,337 3,176 New York 440,315 19 Washington D.C. 45,975 — San Francisco 262,882 — Boston 170,841 294 Seattle 334,233 258 Other (3) 2,341,173 2,047 Total non-same store/other 4,131,756 5,794 Total $ 21,301,292 $ 33,902 (1) Same store primarily includes all properties acquired or completed that are stabilized prior to January 1, 2015, less properties subsequently sold, which represented 73,222 apartment units. (2) Non-same store primarily includes properties acquired after January 1, 2015, plus any properties in lease-up and not stabilized as of January 1, 2015. (3) Other includes development, other corporate operations and capital expenditures for properties sold. Note: Markets/Metro Areas included in the above All Other Markets segment are as follows: (a) New England (excluding Boston) and Phoenix.

Subsequent Events_Other

Subsequent Events/Other	3 Months Ended
	Mar. 31, 2016
Subsequent Events Other [Abstract]
Subsequent Events/Other	14. Subsequent Events/Other Subsequent Events Subsequent to March 31, 2016 , the Company: • Sold its interest in the management contracts and related rights associated with the military housing ventures at Joint Base Lewis McChord located in Tacoma, Washington for approximately $63.3 million (consisted of 5,161 apartment units); and • Partially paid down $2.9 million on one tax-exempt mortgage bond. Other During the quarters ended March 31, 2016 and 2015 , the Company incurred charges of $1.3 million and $0.1 million , respectively, related to property acquisition costs, such as survey, title and legal fees, on the acquisition of operating properties and $1.5 million and $0.5 million , respectively, related to the write-off of various pursuit and out-of-pocket costs for terminated acquisition, disposition and development transactions. These costs, totaling $2.8 million and $0.6 million , respectively, are included in other expenses in the accompanying consolidated statements of operations and comprehensive income.

Summary of Significant Accoun27

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2016
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. Certain reclassifications have been made to the prior period financial statements in order to conform to the current year presentation. These reclassifications did not have an impact on net income previously reported. Operating results for the quarter ended March 31, 2016 are not necessarily indicative of the results that may be expected for the year ending December 31, 2016 . 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. The balance sheets at December 31, 2015 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, 2015 .
Income and Other Taxes	Income and Other Taxes Due to the structure of EQR as a REIT and the nature of the operations of its operating properties, no provision for federal income taxes has been made at the EQR level. In addition, ERPOP generally is not liable for federal income taxes as the partners recognize their proportionate 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. Deferred tax assets and liabilities applicable to the TRS are recognized for future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. These assets and liabilities are measured using enacted tax rates for which the temporary differences are expected to be recovered or settled. The effects of changes in tax rates on deferred tax assets and liabilities are recognized in earnings in the period enacted. The Company’s deferred tax assets are generally the result of tax affected suspended interest deductions, net operating losses, differing depreciable lives on capitalized assets and the timing of expense recognition for certain accrued liabilities. As of March 31, 2016 , the Company has recorded a deferred tax asset, which is fully offset by a valuation allowance due to the uncertainty of realization.
New Accounting Pronouncements	Recent Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (the "FASB") issued a comprehensive new revenue recognition standard entitled Revenue from Contracts with Customers that will supersede nearly all existing revenue recognition guidance. The new standard specifically excludes lease revenue. The new standard’s core principle is that a company will recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. Companies will likely need to use more judgment and make more estimates than under current revenue recognition guidance. These may include identifying performance obligations in the contract, estimating the amount of variable consideration, if any, to include in the transaction price and allocating the transaction price to each separate performance obligation. The new standard will be effective for the Company beginning on January 1, 2018 and early adoption will be permitted beginning on January 1, 2017. The new standard may be applied retrospectively to each prior period presented or prospectively with the cumulative effect recognized as of the date of adoption. The Company has not yet selected a transition method and is currently evaluating the impact of adopting the new standard on its consolidated results of operations and financial position. In August 2014, the FASB issued a new standard that will explicitly require management to assess an entity's ability to continue as a going concern and to provide related footnote disclosures in certain circumstances. In connection with each annual and interim period, management will assess whether there is substantial doubt about an entity's ability to continue as a going concern within one year after the issuance date. Disclosures will be required if conditions give rise to substantial doubt. However, to determine the specific disclosures, management will need to assess whether its plans will alleviate substantial doubt. The new standard is effective for the annual period ending after December 15, 2016 and for interim periods thereafter. The Company does not expect that this will have a material effect on its consolidated results of operations or financial position. In February 2015, the FASB issued new consolidation guidance which makes changes to both the variable interest model and the voting model. Among other changes, the new standard specifically eliminates the presumption in the current voting model that a general partner controls a limited partnership or similar entity unless that presumption can be overcome. Generally, only a single limited partner that is able to exercise substantive kick-out rights will consolidate. The Company adopted this standard as required effective January 1, 2016. While adoption of this standard did not result in any changes to conclusions about whether a joint venture was consolidated or unconsolidated, the Company has determined that certain of its joint ventures and the Operating Partnership now qualify as variable interest entities ("VIEs") and therefore require additional disclosures. See Note 6 for further discussion. In April 2015, the FASB issued a new standard which requires companies to present debt financing costs as a direct deduction from the carrying amount of the associated debt liability rather than as an asset, consistent with the presentation of debt discounts on the consolidated balance sheets. Companies will be permitted to present debt issuance costs related to line of credit arrangements as an asset and amortize these costs over the term of the arrangement, regardless of whether there are any outstanding borrowings on the arrangement. The new standard must be applied retrospectively to all prior periods presented in the consolidated financial statements. The Company adopted this standard as required effective January 1, 2016 and other than presentation on the consolidated balance sheets, it did not have a material effect on its consolidated results of operations or financial position. As of March 31, 2016, $6.1 million , $18.3 million and $24.6 million of deferred financing costs were included within other assets, mortgage notes payable, net and notes, net, respectively, on the consolidated balance sheets. As of December 31, 2015, the following amounts of deferred financing costs were reclassified (amounts in thousands): December 31, 2015 As Originally Reclassification As Presented Deferred financing costs, net $ 54,004 $ (54,004 ) $ — Other assets $ 422,027 $ 6,872 $ 428,899 Mortgage notes payable, net $ 4,704,870 $ (19,736 ) $ 4,685,134 Notes, net $ 5,876,352 $ (27,396 ) $ 5,848,956 In January 2016, the FASB issued a new standard which requires companies to measure all equity securities with readily determinable fair values at fair value on the balance sheet, with changes in fair value recognized in net income. The new standard will be effective for the Company beginning on January 1, 2018. The Company does not expect that this will have a material effect on its consolidated results of operations or financial position. In February 2016, the FASB issued a new leases standard which sets out the principles for the recognition, measurement, presentation and disclosure of leases for both parties to a contract (i.e. lessees and lessors). The new standard requires lessees to apply a dual approach, classifying leases as either finance or operating leases based on the principle of whether or not the lease is effectively a financed purchase of the leased asset by the lessee. This classification will determine whether the lease expense is recognized based on an effective interest method or on a straight-line basis over the term of the lease. A lessee is also required to record a right-of-use asset and a lease liability for all leases with a term of greater than 12 months regardless of their classification. Leases with a term of 12 months or less will be accounted for similar to existing guidance for operating leases today. The new standard requires lessors to account for leases using an approach that is substantially equivalent to existing guidance for sales-type leases, direct financing leases and operating leases. The new standard is expected to impact the Company’s consolidated financial statements as the Company has certain operating ground lease arrangements for which it is the lessee. The new standard will be effective for the Company beginning on January 1, 2019, with early adoption permitted. The Company is currently evaluating the impact of adopting the new standard on its consolidated results of operations and financial position.
Other	Other The Company is the controlling partner in various consolidated partnerships owning 18 properties and 3,471 apartment units having a noncontrolling interest book value of $4.4 million at March 31, 2016 . The Company is required to make certain disclosures regarding noncontrolling interests in consolidated limited-life subsidiaries. Of the consolidated entities described above, the Company is the controlling partner in limited-life partnerships owning five properties having a noncontrolling interest deficit balance of $9.4 million . These five partnership agreements contain provisions that require the partnerships to be liquidated through the sale of their assets upon reaching a date specified in each respective partnership agreement. The Company, as controlling partner, has an obligation to cause the property owning partnerships to distribute the proceeds of liquidation to the Noncontrolling Interests in these Partially Owned Properties only to the extent that the net proceeds received by the partnerships from the sale of their assets warrant a distribution based on the partnership agreements. As of March 31, 2016 , the Company estimates the value of Noncontrolling Interest distributions for these five properties would have been approximately $54.0 million (“Settlement Value”) had the partnerships been liquidated. This Settlement Value is based on estimated third party consideration realized by the partnerships upon disposition of the five Partially Owned Properties and is net of all other assets and liabilities, including yield maintenance on the mortgages encumbering the properties, that would have been due on March 31, 2016 had those mortgages been prepaid. Due to, among other things, the inherent uncertainty in the sale of real estate assets, the amount of any potential distribution to the Noncontrolling Interests in the Company's Partially Owned Properties is subject to change. To the extent that the partnerships' underlying assets are worth less than the underlying liabilities, the Company has no obligation to remit any consideration to the Noncontrolling Interests in these Partially Owned Properties.

Business (Tables)

Business (Tables)	3 Months Ended
	Mar. 31, 2016
Business [Abstract]
Schedule of Real Estate Properties	The ownership breakdown includes (table does not include various uncompleted development properties): Properties Apartment Units Wholly Owned Properties 291 73,226 Master-Leased Properties – Consolidated 3 853 Partially Owned Properties – Consolidated 18 3,471 Partially Owned Properties – Unconsolidated 3 1,281 Military Housing (A) 2 5,161 317 83,992 (A) The Company sold its interest in the management contracts and related rights associated with the military housing ventures at Joint Base Lewis McChord effective April 1, 2016.

Summary of Significant Accoun29

Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2016
Summary of Significant Accounting Policies [Abstract]
Schedule of New Accounting Pronouncements and Changes in Accounting Principles [Table Text Block]	As of December 31, 2015, the following amounts of deferred financing costs were reclassified (amounts in thousands): December 31, 2015 As Originally Reclassification As Presented Deferred financing costs, net $ 54,004 $ (54,004 ) $ — Other assets $ 422,027 $ 6,872 $ 428,899 Mortgage notes payable, net $ 4,704,870 $ (19,736 ) $ 4,685,134 Notes, net $ 5,876,352 $ (27,396 ) $ 5,848,956

Equity, Capital and Other Int30

Equity, Capital and Other Interests (Tables)	3 Months Ended
	Mar. 31, 2016
Common shares and units rollforward	The following tables present the changes in the Company’s issued and outstanding Common Shares and “Units” (which includes OP Units and restricted units) for the quarter ended March 31, 2016 : 2016 Common Shares Common Shares outstanding at January 1, 364,755,444 Common Shares Issued: Conversion of OP Units 5,577 Exercise of share options 582,435 Employee Share Purchase Plan (ESPP) 15,506 Restricted share grants, net 137,057 Common Shares outstanding at March 31, 365,496,019 Units Units outstanding at January 1, 14,427,164 Restricted unit grants, net 282,030 Conversion of OP Units to Common Shares (5,577 ) Units outstanding at March 31, 14,703,617 Total Common Shares and Units outstanding at March 31, 380,199,636 Units Ownership Interest in Operating Partnership 3.9 %
Redeemable Noncontrolling Interest [Table Text Block]	The following table presents the changes in the redemption value of the Redeemable Noncontrolling Interests – Operating Partnership for the quarter ended March 31, 2016 (amounts in thousands): 2016 Balance at January 1, $ 566,783 Change in market value (55,478 ) Change in carrying value 9,775 Balance at March 31, $ 521,080
Schedule Of Preferred Stock [Table Text Block]	The following table presents the Company’s issued and outstanding Preferred Shares as of March 31, 2016 and December 31, 2015 : Amounts in thousands Redemption Annual March 31, December 31, Preferred Shares of beneficial interest, $0.01 par value; 8.29% Series K Cumulative Redeemable Preferred; liquidation 12/10/26 $4.145 $ 37,280 $ 37,280 $ 37,280 $ 37,280 (1) On or after the redemption date, redeemable preferred shares may be redeemed for cash at the option of the Company, in whole or in part, at a redemption price equal to the liquidation price per share, plus accrued and unpaid distributions, if any. (2) Dividends on Preferred Shares are payable quarterly.
ERPOP [Member]
Common shares and units rollforward	The following tables present the changes in the Operating Partnership’s issued and outstanding Units and in the limited partners’ Units for the quarter ended March 31, 2016 : 2016 General and Limited Partner Units General and Limited Partner Units outstanding at January 1, 379,182,608 Issued to General Partner: Exercise of EQR share options 582,435 EQR’s Employee Share Purchase Plan (ESPP) 15,506 EQR's restricted share grants, net 137,057 Issued to Limited Partners: Restricted unit grants, net 282,030 General and Limited Partner Units outstanding at March 31, 380,199,636 Limited Partner Units Limited Partner Units outstanding at January 1, 14,427,164 Limited Partner restricted unit grants, net 282,030 Conversion of Limited Partner OP Units to EQR Common Shares (5,577 ) Limited Partner Units outstanding at March 31, 14,703,617 Limited Partner Units Ownership Interest in Operating Partnership 3.9 %
Redeemable Noncontrolling Interest [Table Text Block]	The following table presents the changes in the redemption value of the Redeemable Limited Partners for the quarter ended March 31, 2016 (amounts in thousands): 2016 Balance at January 1, $ 566,783 Change in market value (55,478 ) Change in carrying value 9,775 Balance at March 31, $ 521,080
Schedule Of Preferred Stock [Table Text Block]	The following table presents the Operating Partnership's issued and outstanding “Preference Units” as of March 31, 2016 and December 31, 2015 : Amounts in thousands Redemption Date (1) Annual March 31, December 31, Preference Units: 8.29% Series K Cumulative Redeemable Preference Units; 12/10/26 $4.145 $ 37,280 $ 37,280 $ 37,280 $ 37,280 (1) On or after the redemption date, redeemable preference units may be redeemed for cash at the option of the Operating Partnership, in whole or in part, at a redemption price equal to the liquidation price per unit, plus accrued and unpaid distributions, if any, in conjunction with the concurrent redemption of the corresponding Company Preferred Shares. (2) Dividends on Preference Units are payable quarterly.

Real Estate (Tables)

Real Estate (Tables)	3 Months Ended
	Mar. 31, 2016
Schedule of Real Estate Investments And Accumlated Depreciation [Table Text Block}	The following table summarizes the carrying amounts for the Company’s investment in real estate (at cost) as of March 31, 2016 and December 31, 2015 (amounts in thousands): March 31, 2016 December 31, 2015 Land $ 5,777,206 $ 5,864,046 Depreciable property: Buildings and improvements 16,430,979 16,346,829 Furniture, fixtures and equipment 1,219,444 1,207,098 In-Place lease intangibles 465,392 483,160 Projects under development: Land 247,568 284,995 Construction-in-progress 826,254 837,381 Land held for development: Land 114,149 120,007 Construction-in-progress 39,874 38,836 Investment in real estate 25,120,866 25,182,352 Accumulated depreciation (4,977,274 ) (4,905,406 ) Investment in real estate, net $ 20,143,592 $ 20,276,946
Schedule of Finite-Lived Intangible Assets [Table Text Block]	The following table summarizes the carrying amounts for the Company's above and below market ground and retail lease intangibles as of March 31, 2016 and December 31, 2015 (amounts in thousands): Description Balance Sheet Location March 31, 2016 December 31, 2015 Assets Ground lease intangibles – below market Other Assets $ 178,251 $ 178,251 Retail lease intangibles – above market Other Assets 1,260 1,260 Lease intangible assets 179,511 179,511 Accumulated amortization (14,582 ) (13,451 ) Lease intangible assets, net $ 164,929 $ 166,060 Liabilities Ground lease intangibles – above market Other Liabilities $ 2,400 $ 2,400 Retail lease intangibles – below market Other Liabilities 5,270 5,270 Lease intangible liabilities 7,670 7,670 Accumulated amortization (3,694 ) (3,414 ) Lease intangible liabilities, net $ 3,976 $ 4,256
Schedule of Expected Amortization Expense [Table Text Block]	The following table provides a summary of the aggregate amortization expense for above and below market ground lease intangibles and retail lease intangibles for each of the next five years (amounts in thousands): Remaining 2016 2017 2018 2019 2020 2021 Ground lease intangibles $ 3,241 $ 4,321 $ 4,321 $ 4,321 $ 4,321 $ 4,321 Retail lease intangibles (667 ) (540 ) (71 ) (71 ) (71 ) (67 ) Total $ 2,574 $ 3,781 $ 4,250 $ 4,250 $ 4,250 $ 4,254
Acquired and Disposed Properties [Table Text Block]	Acquisitions and Dispositions During the quarter ended March 31, 2016 , the Company acquired the entire equity interest in the following from unaffiliated parties (purchase price in thousands): Properties Apartment Units Purchase Price Rental Properties – Consolidated (1) 3 479 $ 204,134 Total 3 479 $ 204,134 (1) Purchase price includes an allocation of approximately $80.9 million to land and $123.2 million to depreciable property. During the quarter ended March 31, 2016 , the Company disposed of the following to unaffiliated parties (sales price in thousands): Properties Apartment Units Sales Price Rental Properties – Consolidated (1) 80 26,162 $ 6,314,953 Land Parcels — — 27,455 Total 80 26,162 $ 6,342,408
Starwood Portfolio [Member]
Schedule of Real Estate Investments And Accumlated Depreciation [Table Text Block}	In accordance with this classification, the Company ceased depreciation on all assets in the Starwood portfolio as of November 1, 2015 and the following assets were classified as held for sale in the accompanying consolidated balance sheets at December 31, 2015 (amounts in thousands): December 31, 2015 Land $ 602,737 Depreciable property: Buildings and improvements 2,386,489 Furniture, fixtures and equipment 335,565 In-Place lease intangibles 35,554 Real estate held for sale before accumulated depreciation 3,360,345 Accumulated depreciation (1,179,210 ) Real estate held for sale $ 2,181,135
Disposed Properties [Table Text Block]	The following table provides the operating segments/locations of the properties and apartment units sold in the Starwood Transaction, which represents substantially all of the assets in the Company's South Florida and Denver markets and certain assets in the Washington D.C., Seattle and Inland Empire, California (part of Los Angeles) markets. The sale of these properties represents the continuation of the Company's long-term strategy of investing in high barrier to entry urban markets. See Note 11 for further discussion. Markets/Metro Areas Properties Apartment Units South Florida 33 10,742 Denver 18 6,635 Washington D.C. 10 3,020 Seattle 8 1,721 Inland Empire, CA (part of Los Angeles) 3 1,144 Total 72 23,262

Commitments to Acquire_Dispos32

Commitments to Acquire/Dispose of Real Estate (Tables)	3 Months Ended
	Mar. 31, 2016
Commitments to Acquire Dispose of Real Estate [Abstract]
Real Estate To Be Disposed Of Text Block	The Company has entered into separate agreements to dispose of the following (sales price in thousands): Properties Apartment Units Sales Price Rental Properties 4 772 $ 134,450 Land Parcels (three) — — 66,550 Total 4 772 $ 201,000

Investments in Partially Owne33

Investments in Partially Owned Entities (Tables)	3 Months Ended
	Mar. 31, 2016
Investments in Partially Owned Entities [Abstract]
Partially Owned Property Balance Sheet Schedule [Table Text Block]	The following tables and information summarize the Company’s investments in partially owned entities as of March 31, 2016 (amounts in thousands except for property and apartment unit amounts): Consolidated Unconsolidated (VIE) (Non-VIE) (VIE) Total Total properties 18 2 1 3 Total apartment units 3,471 945 336 1,281 Balance sheet information at 3/31/16 (at 100%): ASSETS Investment in real estate $ 665,996 $ 234,383 $ 229,599 $ 463,982 Accumulated depreciation (209,424 ) (24,991 ) (49,194 ) (74,185 ) Investment in real estate, net 456,572 209,392 180,405 389,797 Cash and cash equivalents 15,051 7,836 1,201 9,037 Investments in unconsolidated entities 48,797 — — — Deposits – restricted 351 242 47 289 Other assets 25,948 103 786 889 Total assets $ 546,719 $ 217,573 $ 182,439 $ 400,012 LIABILITIES AND EQUITY/CAPITAL Mortgage notes payable, net (1) $ 317,801 $ 145,423 $ 29,269 $ 174,692 Accounts payable & accrued expenses 2,786 1,729 351 2,080 Accrued interest payable 1,099 691 — 691 Other liabilities 521 258 216 474 Security deposits 1,939 510 159 669 Total liabilities 324,146 148,611 29,995 178,606 Noncontrolling Interests – Partially Owned Properties/Partners' equity 4,399 63,809 108,968 172,777 Company equity/General and Limited Partners' Capital 218,174 5,153 43,476 48,629 Total equity/capital 222,573 68,962 152,444 221,406 Total liabilities and equity/capital $ 546,719 $ 217,573 $ 182,439 $ 400,012
Partially Owned Property Income Statement Schedule [Table Text Block]	Consolidated Unconsolidated (VIE) (Non-VIE) (VIE) Total Operating information for the quarter ended 3/31/16 (at 100%): Operating revenue $ 22,997 $ 6,528 $ 2,913 $ 9,441 Operating expenses 5,598 2,196 1,153 3,349 Net operating income 17,399 4,332 1,760 6,092 Property management 811 190 19 209 General and administrative/other 15 — 86 86 Depreciation 5,369 2,621 1,858 4,479 Operating income (loss) 11,204 1,521 (203 ) 1,318 Interest and other income 20 — — — Interest: Expense incurred, net (4,038 ) (2,072 ) (272 ) (2,344 ) Amortization of deferred financing costs (147 ) — — — Income (loss) before income and other taxes and (loss) from 7,039 (551 ) (475 ) (1,026 ) Income and other tax (expense) benefit (12 ) — — — (Loss) from investments in unconsolidated entities (369 ) — — — Net income (loss) $ 6,658 $ (551 ) $ (475 ) $ (1,026 ) (1) All debt is non-recourse to the Company. Note: The above tables exclude EQR's ownership interest in ERPOP and the Company's interests in unconsolidated joint ventures entered into with AvalonBay Communities, Inc. (“AVB”) in connection with the acquisition of certain real estate related assets from Archstone Enterprise LP (such assets are referred to herein as "Archstone"). These ventures owned certain Archstone assets and succeeded to certain residual Archstone liabilities/litigation, as well as responsibility for tax protection arrangements and third-party preferred interests in former Archstone subsidiaries. The preferred interests had an aggregate liquidation value of $42.2 million at March 31, 2016 . The ventures are owned 60% by the Company and 40% by AVB.

Deposits - Restricted (Tables)

Deposits - Restricted (Tables)	3 Months Ended
	Mar. 31, 2016
Deposits - Restricted [Abstract]
Schedule of Restricted Cash and Cash Equivalents [Table Text Block]	The following table presents the Company’s restricted deposits as of March 31, 2016 and December 31, 2015 (amounts in thousands): March 31, December 31, Tax-deferred (1031) exchange proceeds $ 195,636 $ — Earnest money on pending acquisitions — 1,000 Restricted deposits on real estate investments 4,974 6,077 Resident security and utility deposits 38,635 48,458 Other 2,496 358 Totals $ 241,741 $ 55,893
Escrow Deposits [Text Block]	The following table presents the Company’s escrow deposits as of March 31, 2016 and December 31, 2015 (amounts in thousands): March 31, December 31, Real estate taxes and insurance $ 2,432 $ 1,977 Replacement reserves 3,766 3,962 Mortgage principal reserves/sinking funds 52,305 50,155 Other 852 852 Totals $ 59,355 $ 56,946

Derivative and Other Fair Val35

Derivative and Other Fair Value Instruments (Tables)	3 Months Ended
	Mar. 31, 2016
Fair Value Disclosures [Abstract]
Derivative Instrument Table	The following table summarizes the Company’s consolidated derivative instruments at March 31, 2016 (dollar amounts are in thousands): Fair Value Forward Current Notional Balance $ 450,000 $ 50,000 Lowest Possible Notional $ 450,000 $ 50,000 Highest Possible Notional $ 450,000 $ 50,000 Lowest Interest Rate 2.375 % 2.500 % Highest Interest Rate 2.375 % 2.500 % Earliest Maturity Date 2019 2026 Latest Maturity Date 2019 2026 (1) Fair Value Hedges – Converts outstanding fixed rate unsecured notes ( $450.0 million 2.375% notes due July 1, 2019 ) to a floating interest rate of 90-Day LIBOR plus 0.61% . (2) Forward Starting Swaps – Designed to partially fix interest rates in advance of a planned future debt issuance. This swap has a mandatory counterparty termination in 2017, and is targeted to a 2016 issuance.
Schedule of Location and Amount of Financial Instruments on Balanace Sheet	The following tables provide a summary of the fair value measurements for each major category of assets and liabilities measured at fair value on a recurring basis and the location within the accompanying consolidated balance sheets at March 31, 2016 and December 31, 2015 , respectively (amounts in thousands): Fair Value Measurements at Reporting Date Using Description Balance Sheet Location 3/31/2016 Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets Derivatives designated as hedging instruments: Interest Rate Contracts: Fair Value Hedges Other Assets $ 10,533 $ — $ 10,533 $ — Supplemental Executive Retirement Plan Other Assets 114,123 114,123 — — Total $ 124,656 $ 114,123 $ 10,533 $ — Liabilities Derivatives designated as hedging instruments: Interest Rate Contracts: Forward Starting Swaps Other Liabilities $ 3,579 $ — $ 3,579 $ — Supplemental Executive Retirement Plan Other Liabilities 114,123 114,123 — — Total $ 117,702 $ 114,123 $ 3,579 $ — Redeemable Noncontrolling Interests – Operating Partnership/Redeemable Limited Partners Mezzanine $ 521,080 $ — $ 521,080 $ — Fair Value Measurements at Reporting Date Using Description Balance Sheet Location 12/31/2015 Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets Derivatives designated as hedging instruments: Interest Rate Contracts: Fair Value Hedges Other Assets $ 3,655 $ — $ 3,655 $ — Supplemental Executive Retirement Plan Other Assets 105,942 105,942 — — Total $ 109,597 $ 105,942 $ 3,655 $ — Liabilities Derivatives designated as hedging instruments: Interest Rate Contracts: Forward Starting Swaps Other Liabilities $ 673 $ — $ 673 $ — Supplemental Executive Retirement Plan Other Liabilities 105,942 105,942 — — Total $ 106,615 $ 105,942 $ 673 $ — Redeemable Noncontrolling Interests – Operating Partnership/Redeemable Limited Partners Mezzanine $ 566,783 $ — $ 566,783 $ —
Schedule of Derivative Instruments, Gain (Loss) in Statement of Financial Performance [Table Text Block]	The following tables provide a summary of the effect of fair value hedges on the Company’s accompanying consolidated statements of operations and comprehensive income for the quarters ended March 31, 2016 and 2015 , respectively (amounts in thousands): March 31, 2016 Type of Fair Value Hedge Location of Gain/(Loss) Recognized in Income on Derivative Amount of Gain/(Loss) Recognized in Income on Derivative Hedged Item Income Statement Location of Hedged Item Gain/(Loss) Amount of Gain/(Loss) Recognized in Income on Hedged Item Derivatives designated as hedging instruments: Interest Rate Contracts: Interest Rate Swaps Interest expense $ 6,878 Fixed rate debt Interest expense $ (6,878 ) Total $ 6,878 $ (6,878 ) March 31, 2015 Type of Fair Value Hedge Location of Derivative Amount of Derivative Hedged Item Income Statement Amount of Gain/(Loss) Recognized in Income on Hedged Item Derivatives designated as hedging instruments: Interest Rate Contracts: Interest Rate Swaps Interest expense $ 4,842 Fixed rate debt Interest expense $ (4,842 ) Total $ 4,842 $ (4,842 )
Schedule of Cash Flow Hedging Instruments, Statements of Financial Performance and Financial Position, Location [Table Text Block]	The following tables provide a summary of the effect of cash flow hedges on the Company’s accompanying consolidated statements of operations and comprehensive income for the quarters ended March 31, 2016 and 2015 , respectively (amounts in thousands): Effective Portion Ineffective Portion March 31, 2016 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/ Location of Gain/(Loss) Recognized in Income on Derivative Amount of Gain/ Derivatives designated as hedging instruments: Interest Rate Contracts: Forward Starting Swaps $ (2,906 ) Interest expense $ (28,654 ) N/A $ — Total $ (2,906 ) $ (28,654 ) $ — Effective Portion Ineffective Portion March 31, 2015 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/ Location of Gain/(Loss) Recognized in Income on Derivative Amount of Gain/ Derivatives designated as hedging instruments: Interest Rate Contracts: Forward Starting Swaps $ (11,788 ) Interest expense $ (4,338 ) N/A $ — Total $ (11,788 ) $ (4,338 ) $ —

Earnings Per Share (Tables)

Earnings Per Share (Tables)	3 Months Ended
	Mar. 31, 2016
Schedule of Calculation of Numerator and Denominator in Earnings Per Share [Table Text Block]	The following tables set forth the computation of net income per share – basic and net income per share – diluted for the Company (amounts in thousands except per share amounts): Quarter Ended March 31, 2016 2015 Numerator for net income per share – basic: Income from continuing operations $ 3,731,988 $ 190,069 Allocation to Noncontrolling Interests – Operating Partnership, net (143,315 ) (7,053 ) Net (income) attributable to Noncontrolling Interests – Partially Owned Properties (764 ) (643 ) Preferred distributions (773 ) (891 ) Premium on redemption of Preferred Shares — (2,789 ) Income from continuing operations available to Common Shares, net of Noncontrolling Interests 3,587,136 178,693 Discontinued operations, net of Noncontrolling Interests (151 ) 149 Numerator for net income per share – basic $ 3,586,985 $ 178,842 Numerator for net income per share – diluted: Income from continuing operations $ 3,731,988 $ 190,069 Net (income) attributable to Noncontrolling Interests – Partially Owned Properties (764 ) (643 ) Preferred distributions (773 ) (891 ) Premium on redemption of Preferred Shares — (2,789 ) Income from continuing operations available to Common Shares 3,730,451 185,746 Discontinued operations, net (157 ) 155 Numerator for net income per share – diluted $ 3,730,294 $ 185,901 Denominator for net income per share – basic and diluted: Denominator for net income per share – basic 364,592 363,098 Effect of dilutive securities: OP Units 13,697 13,598 Long-term compensation shares/units 3,954 3,631 Denominator for net income per share – diluted 382,243 380,327 Net income per share – basic $ 9.84 $ 0.49 Net income per share – diluted $ 9.76 $ 0.49 Net income per share – basic: Income from continuing operations available to Common Shares, net of Noncontrolling Interests $ 9.84 $ 0.49 Discontinued operations, net of Noncontrolling Interests — — Net income per share – basic $ 9.84 $ 0.49 Net income per share – diluted: Income from continuing operations available to Common Shares $ 9.76 $ 0.49 Discontinued operations, net — — Net income per share – diluted $ 9.76 $ 0.49
ERPOP [Member]
Schedule of Calculation of Numerator and Denominator in Earnings Per Share [Table Text Block]	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): Quarter Ended March 31, 2016 2015 Numerator for net income per Unit – basic and diluted: Income from continuing operations $ 3,731,988 $ 190,069 Net (income) attributable to Noncontrolling Interests – Partially Owned Properties (764 ) (643 ) Allocation to Preference Units (773 ) (891 ) Allocation to premium on redemption of Preference Units — (2,789 ) Income from continuing operations available to Units 3,730,451 185,746 Discontinued operations, net (157 ) 155 Numerator for net income per Unit – basic and diluted $ 3,730,294 $ 185,901 Denominator for net income per Unit – basic and diluted: Denominator for net income per Unit – basic 378,289 376,696 Effect of dilutive securities: Dilution for Units issuable upon assumed exercise/vesting of the Company’s long-term 3,954 3,631 Denominator for net income per Unit – diluted 382,243 380,327 Net income per Unit – basic $ 9.84 $ 0.49 Net income per Unit – diluted $ 9.76 $ 0.49 Net income per Unit – basic: Income from continuing operations available to Units $ 9.84 $ 0.49 Discontinued operations, net — — Net income per Unit – basic $ 9.84 $ 0.49 Net income per Unit – diluted: Income from continuing operations available to Units $ 9.76 $ 0.49 Discontinued operations, net — — Net income per Unit – diluted $ 9.76 $ 0.49

Discontinued Operations (Tables

Discontinued Operations (Tables)	3 Months Ended
	Mar. 31, 2016
Discontinued Operations and Disposal Groups [Abstract]
Condensed Income Statement [Table Text Block]	As a result, the following table summarizes the results of operations attributable to the Starwood Transaction for the quarters ended March 31, 2016 and 2015 (amounts in thousands): Quarter Ended March 31, 2016 2015 REVENUES Rental income $ 30,117 $ 103,709 Total revenues 30,117 103,709 EXPENSES (1) Property and maintenance 7,890 19,086 Real estate taxes and insurance 2,872 12,147 Property management 2 3 General and administrative 1 1 Depreciation — 26,194 Total expenses 10,765 57,431 Operating income 19,352 46,278 Interest and other income 2 — Interest (2): Expense incurred, net (328 ) (164 ) Amortization of deferred financing costs (707 ) (24 ) Net gain on sales of real estate properties 3,161,221 — Income from operations attributable to controlling interests – Operating Partnership 3,179,540 46,090 Income from operations attributable to Noncontrolling Interests – Operating Partnership (122,132 ) (1,754 ) Income from operations attributable to controlling interests – Company $ 3,057,408 $ 44,336 (1) Includes expenses paid in the current period for properties held for sale. (2) Includes only interest expense specific to secured mortgage notes payable for properties held for sale which was repaid at or before closing.
Components of discontinued operations	The components of discontinued operations are outlined below and include the results of operations for the respective periods that the Company owned such assets for properties sold in 2013 and prior years during the quarters ended March 31, 2016 and 2015 (amounts in thousands). Quarter Ended March 31, 2016 2015 REVENUES Rental income $ 118 $ 161 Total revenues 118 161 EXPENSES (1) Property and maintenance (3 ) (67 ) Real estate taxes and insurance 1 52 General and administrative 4 6 Total expenses 2 (9 ) Discontinued operating income 116 170 Other expenses (280 ) — Income and other tax (expense) benefit (8 ) (15 ) Discontinued operations (172 ) 155 Net gain on sales of discontinued operations 15 — Discontinued operations, net $ (157 ) $ 155 (1) Includes expenses paid in the current period for properties sold in prior periods related to the Company’s period of ownership.

Reportable Segments (Tables)

Reportable Segments (Tables)	3 Months Ended
	Mar. 31, 2016
Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]
Reconciliation of NOI	The following table presents a reconciliation of NOI from our rental real estate specific to continuing operations for the quarters ended March 31, 2016 and 2015 , respectively (amounts in thousands): Quarter Ended March 31, 2016 2015 Rental income $ 616,165 $ 664,606 Property and maintenance expense (109,165 ) (124,560 ) Real estate taxes and insurance expense (80,196 ) (86,432 ) Total operating expenses (189,361 ) (210,992 ) Net operating income $ 426,804 $ 453,614
Schedule of Segment Reporting Information, by Segment [Table Text Block]	The following tables present NOI for each segment from our rental real estate specific to continuing operations for the quarters ended March 31, 2016 and 2015 , respectively, as well as total assets and capital expenditures at March 31, 2016 (amounts in thousands): Quarter Ended March 31, 2016 Quarter Ended March 31, 2015 Rental Income Operating Expenses NOI Rental Income Operating Expenses NOI Same store (1) Los Angeles $ 90,150 $ 26,359 $ 63,791 $ 84,654 $ 26,189 $ 58,465 San Diego 21,428 5,835 15,593 20,231 5,661 14,570 Orange County 19,314 4,733 14,581 18,321 4,688 13,633 Subtotal – Southern California 130,892 36,927 93,965 123,206 36,538 86,668 New York 113,204 40,141 73,063 110,123 39,507 70,616 Washington D.C. 104,268 31,425 72,843 103,340 32,037 71,303 San Francisco 90,674 22,198 68,476 82,784 21,519 61,265 Boston 62,325 17,648 44,677 60,512 19,124 41,388 Seattle 37,243 10,572 26,671 35,131 9,807 25,324 All Other Markets 9,070 3,765 5,305 8,643 4,131 4,512 Total same store 547,676 162,676 385,000 523,739 162,663 361,076 Non-same store/other (2) (3) Los Angeles 7,264 2,573 4,691 7,339 2,384 4,955 Orange County 1,158 334 824 — — — Subtotal – Southern California 8,422 2,907 5,515 7,339 2,384 4,955 New York 7,086 3,625 3,461 292 432 (140 ) Washington D.C. 959 170 789 1,047 197 850 San Francisco 4,298 1,550 2,748 83 221 (138 ) Boston 2,634 710 1,924 946 202 744 Seattle 5,679 1,259 4,420 1,941 496 1,445 Other (3) 39,411 16,464 22,947 129,219 44,397 84,822 Total non-same store/other 68,489 26,685 41,804 140,867 48,329 92,538 Total $ 616,165 $ 189,361 $ 426,804 $ 664,606 $ 210,992 $ 453,614 (1) Same store primarily includes all properties acquired or completed that are stabilized prior to January 1, 2015, less properties subsequently sold, which represented 73,222 apartment units. (2) Non-same store primarily includes properties acquired after January 1, 2015, plus any properties in lease-up and not stabilized as of January 1, 2015. (3) Other includes development, other corporate operations and operations prior to sale for properties sold from 2014 through 2016 that do not meet the new discontinued operations criteria. Quarter Ended March 31, 2016 Total Assets Capital Expenditures Same store (1) Los Angeles $ 2,567,837 $ 5,031 San Diego 483,643 673 Orange County 266,770 1,738 Subtotal – Southern California 3,318,250 7,442 New York 4,348,318 3,994 Washington D.C. 3,993,480 5,556 San Francisco 2,518,610 4,891 Boston 1,811,047 3,626 Seattle 1,053,316 2,345 All Other Markets 126,515 254 Total same store 17,169,536 28,108 Non-same store/other (2) (3) Los Angeles 459,013 3,164 Orange County 77,324 12 Subtotal – Southern California 536,337 3,176 New York 440,315 19 Washington D.C. 45,975 — San Francisco 262,882 — Boston 170,841 294 Seattle 334,233 258 Other (3) 2,341,173 2,047 Total non-same store/other 4,131,756 5,794 Total $ 21,301,292 $ 33,902 (1) Same store primarily includes all properties acquired or completed that are stabilized prior to January 1, 2015, less properties subsequently sold, which represented 73,222 apartment units. (2) Non-same store primarily includes properties acquired after January 1, 2015, plus any properties in lease-up and not stabilized as of January 1, 2015. (3) Other includes development, other corporate operations and capital expenditures for properties sold. Note: Markets/Metro Areas included in the above All Other Markets segment are as follows: (a) New England (excluding Boston) and Phoenix.

Business (Details)

Business (Details)	Mar. 31, 2016
Property/Unit schedule
Wholly Owned Properties	291
Wholly Owned Units	73,226
Master Leased Properties Acquired	3
Master Leased Units	853
Partially Owned Consolidated Properties	18
Partially Owned Consolidated Units	3,471
Partially Owned Unconsolidated Properties	3
Partially Owned Unconsolidated Units	1,281
Military Housing Properties	2
Military Housing Units	5,161
Business (Textuals) [Abstract]
Noncontrolling Interest, Ownership Percentage by Parent	96.10%
Number of States in which Entity Operates	11
Number of Real Estate Properties	317
Number of Units in Real Estate Property	83,992

Summary of Significant Accoun40

Summary of Significant Accounting Policies (Details) $ in Thousands	Mar. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Deferred Finance Costs, Net		$ 0
Other assets	$ 422,079	428,899
Mortgage notes payable, net	4,223,681	4,685,134
Notes, net	$ 4,360,137	5,848,956
Partially Owned Consolidated Properties	18
Partially Owned Consolidated Units	3,471
Noncontrolling Interests – Partially Owned Properties/Partners' equity	$ 4,399	4,608
Scenario, Previously Reported [Member]
Deferred Finance Costs, Net		54,004
Other assets		422,027
Mortgage notes payable, net		4,704,870
Notes, net		5,876,352
Limited Life Partnership Properties [Member]
Partially Owned Consolidated Properties	5
Noncontrolling Interests – Partially Owned Properties/Partners' equity	$ 9,400
Noncontrolling Interests Settlement Value	54,000
Other assets
Deferred Finance Costs, Net	6,100
Mortgage notes payable, net
Deferred Finance Costs, Net	18,300
Notes, net
Deferred Finance Costs, Net	$ 24,600
Adjustments for New Accounting Pronouncement [Member]
Deferred Finance Costs, Net		(54,004)
Other assets		6,872
Mortgage notes payable, net		(19,736)
Notes, net		$ (27,396)

Equity and Redeemable Noncontro

Equity and Redeemable Noncontrolling Interests of Equity Residential (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
Common Shares of beneficial interest, shares outstanding	365,496,019	364,755,444
Common Shares Issued:
Conversion of OP Units	5,577
Exercise of share options	582,435
Employee Share Purchase Plan (ESPP)	15,506
Restricted share grants, net	137,057
Units
Common Shares And Units Outstanding	380,199,636
Units Ownership Interest in Operating Partnership	3.90%
Redeemable Noncontrolling Interests Operating Partnership	$ 521,080	$ 566,783
Change in market value of Redeemable Noncontrolling Interests – Operating Partnership	(55,478)
Change in carrying value of Redeemable Noncontrolling Interests – Operating Partnership	$ 9,775
ERPOP [Member]
Common Shares Issued:
Conversion of OP Units	(5,577)
Exercise of share options	582,435
Employee Share Purchase Plan (ESPP)	15,506
Restricted share grants, net	137,057
Units
Total Units Outstanding	14,703,617	14,427,164
Restricted unit grants, net	282,030
Shares Issued During Period Shares Conversion Of Units To Common Shares	(5,577)
Common Shares And Units Outstanding	380,199,636	379,182,608
Units Ownership Interest in Operating Partnership	3.90%

Capital and Redeemable Limited

Capital and Redeemable Limited Partners of ERP Operating Limited Partnership (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
Common Shares And Units Outstanding	380,199,636
Exercise of EQR share options	582,435
EQR’s Employee Share Purchase Plan (ESPP)	15,506
Restricted share grants, net	137,057
Conversion of Limited Partner OP Units to EQR Common Shares	5,577
Units Ownership Interest in Operating Partnership	3.90%
ERPOP [Member]
Common Shares And Units Outstanding	380,199,636	379,182,608
Exercise of EQR share options	582,435
EQR’s Employee Share Purchase Plan (ESPP)	15,506
Restricted share grants, net	137,057
Restricted unit grants, net	282,030
Total Units Outstanding	14,703,617	14,427,164
Conversion of Limited Partner OP Units to EQR Common Shares	(5,577)
Units Ownership Interest in Operating Partnership	3.90%
Redeemable Limited Partners	$ 521,080	$ 566,783
Limited Partners Change In Redemption Value	(55,478)
Limited Partners Change In Carrying Value	$ 9,775

Equity, Capital and Other Int43

Equity, Capital and Other Interests Preferred (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
Class of Stock [Line Items]
Preferred Stock, Shares Authorized	100,000,000	100,000,000
Preferred Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Preferred Shares of beneficial interest, $0.01 par value; 100,000,000 shares authorized; 745,600 shares issued and outstanding as of March 31, 2016 and December 31, 2015	$ 37,280	$ 37,280
ERPOP [Member]
Class of Stock [Line Items]
8.29% Series K Cumulative Redeemable Preference Units; liquidation value $50 per unit; 745,600 units issued and outstanding at March 31, 2016 and December 31, 2015	$ 37,280	$ 37,280
Series K Preferred Stock [Member]
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 Unit	$ 50	$ 50
Preferred Stock Preference Units Dividend Rate Percentage	8.29%	8.29%
Preferred Stocks Preference Units Redemption Date	Dec. 10, 2026
Annual Dividend Per Preferred Share Preference Unit	$ 4.145
Preferred Shares of beneficial interest, $0.01 par value; 100,000,000 shares authorized; 745,600 shares issued and outstanding as of March 31, 2016 and December 31, 2015	$ 37,280	$ 37,280
Series K Preferred Stock [Member] | ERPOP [Member]
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 Unit	$ 50	$ 50
Preferred Stock Preference Units Dividend Rate Percentage	8.29%	8.29%
Preferred Stocks Preference Units Redemption Date	Dec. 10, 2026
Annual Dividend Per Preferred Share Preference Unit	$ 4.145
8.29% Series K Cumulative Redeemable Preference Units; liquidation value $50 per unit; 745,600 units issued and outstanding at March 31, 2016 and December 31, 2015	$ 37,280	$ 37,280

Other (Details)

Other (Details)	Mar. 31, 2016shares
Additional Common Shares Authorized	13,000,000
Stock Repurchase Program, Number of Shares Authorized to be Repurchased	13,000,000
Stock Repurchase Program, Remaining Number of Shares Authorized to be Repurchased	12,968,760

Real Estate (Details)

Real Estate (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Land	$ 5,777,206		$ 5,864,046
Depreciable property:
Buildings and improvements	16,430,979		16,346,829
Furniture, fixtures and equipment	1,219,444		1,207,098
In-Place lease intangibles	465,392		483,160
Land Available for Development	154,023		158,843
Construction-in-progress	1,073,822		1,122,376
Investment in real estate	25,120,866		25,182,352
Accumulated depreciation	(4,977,274)		(4,905,406)
Investment in real estate, net	20,143,592		20,276,946
Lease intangible assets	179,511		179,511
Accumulated amortization	(14,582)		(13,451)
Lease intangible assets, net	164,929		166,060
Lease intangible liabilities	7,670		7,670
Accumulated amortization	(3,694)		(3,414)
Lease intangible liabilities, net	3,976		4,256
Amortization of above/below market leases	851	$ 846
Finite-Lived Intangible Assets, Amortization Expense, Remainder of Fiscal Year	2,574
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months	3,781
Finite-Lived Intangible Assets, Amortization Expense, Year Two	4,250
Finite-Lived Intangible Assets, Amortization Expense, Year Three	4,250
Finite-Lived Intangible Assets, Amortization Expense, Year Four	4,250
Finite-Lived Intangible Assets, Amortization Expense, Year Five	4,254
Assets [Member]
Depreciable property:
Lease intangibles – below market	178,251		178,251
Retail lease intangibles – above market	1,260		1,260
Ground Lease [Member]
Depreciable property:
Amortization of above/below market leases	1,100	1,100
Finite-Lived Intangible Assets, Amortization Expense, Remainder of Fiscal Year	3,241
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months	4,321
Finite-Lived Intangible Assets, Amortization Expense, Year Two	4,321
Finite-Lived Intangible Assets, Amortization Expense, Year Three	4,321
Finite-Lived Intangible Assets, Amortization Expense, Year Four	4,321
Finite-Lived Intangible Assets, Amortization Expense, Year Five	4,321
Retail Site [Member]
Depreciable property:
Amortization of above/below market leases	200	$ 200
Finite-Lived Intangible Assets, Amortization Expense, Remainder of Fiscal Year	(667)
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months	(540)
Finite-Lived Intangible Assets, Amortization Expense, Year Two	(71)
Finite-Lived Intangible Assets, Amortization Expense, Year Three	(71)
Finite-Lived Intangible Assets, Amortization Expense, Year Four	(71)
Finite-Lived Intangible Assets, Amortization Expense, Year Five	(67)
Liability [Member]
Depreciable property:
Lease intangibles – below market	5,270		5,270
Ground lease intangibles – above market	2,400		2,400
Projects under development [Member]
Depreciable property:
Land	247,568		284,995
Construction-in-progress	826,254		837,381
Land held for development [Member]
Depreciable property:
Land Available for Development	114,149		120,007
Construction-in-progress	$ 39,874		$ 38,836

Acquisitions and Dispositions (

Acquisitions and Dispositions (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2016USD ($)property	Mar. 31, 2015USD ($)
Properties acquired | property	3
Apartment Units	479
Purchase Price	$ 204,134
Disposed Properties | property	80
Apartment Units	26,162
Sales Price	$ 6,342,408
Net gain on sales of real estate properties	3,723,479	$ 79,951
Net gain (loss) on sales of land parcels	$ 11,722	(1)
Rental Properties – Consolidated (1)
Properties acquired | property	3
Apartment Units	479
Purchase Price	$ 204,134
Disposed Properties | property	80
Apartment Units	26,162
Sales Price	$ 6,314,953
Land [Member]
Disposed Land Parcels | property	2
Sales Price	$ 27,455
Depreciable Property [Member] | Rental Properties – Consolidated (1)
Purchase Price	123,200
Land [Member] | Rental Properties – Consolidated (1)
Purchase Price	$ 80,900
Starwood Portfolio [Member]
Disposed Properties | property	72
Apartment Units	23,262
Sales Price	$ 5,365,000
Net gain on sales of real estate properties	$ 3,161,221	$ 0
Starwood Portfolio [Member] | Rental Properties – Consolidated (1)
Disposed Properties | property	72
Apartment Units	23,262

Real Estate Starwood Dispositio

Real Estate Starwood Disposition (Details) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2016USD ($)property$ / shares	Mar. 31, 2015$ / shares	Dec. 31, 2015USD ($)
Disposed Properties | property	80
Apartment Units	26,162
Sales Price	$ 6,342,408
Earnest money on pending acquisitions	0		$ 1,000
Land	5,777,206		5,864,046
Depreciable property Abstract
Buildings and improvements	16,430,979		16,346,829
Furniture, fixtures and equipment	1,219,444		1,207,098
In-Place lease intangibles	179,511		179,511
Investment in real estate	25,120,866		25,182,352
Accumulated depreciation	(4,977,274)		(4,905,406)
Real estate held for sale	$ 0		$ 2,181,135
Common Stock, Dividends, Per Share, Declared | $ / shares	$ 8.50375	$ 0.5525
Starwood Portfolio [Member]
Disposed Properties | property	72
Apartment Units	23,262
Sales Price	$ 5,365,000
Earnest money on pending acquisitions	250,000
Land	602,737
Depreciable property Abstract
Buildings and improvements	2,386,489
Furniture, fixtures and equipment	335,565
In-Place lease intangibles	35,554
Investment in real estate	3,360,345
Accumulated depreciation	(1,179,210)
Real estate held for sale	$ 2,181,135
Common Stock, Dividends, Per Share, Declared | $ / shares	$ 8
Payments of Dividends	$ 3,000,000
Rental Properties – Consolidated (1)
Disposed Properties | property	80
Apartment Units	26,162
Sales Price	$ 6,314,953
Rental Properties – Consolidated (1) | Starwood Portfolio [Member]
Disposed Properties | property	72
Apartment Units	23,262
South Florida | Starwood Portfolio [Member]
Disposed Properties | property	33
Apartment Units	10,742
Denver | Starwood Portfolio [Member]
Disposed Properties | property	18
Apartment Units	6,635
Washington D.C. | Starwood Portfolio [Member]
Disposed Properties | property	10
Apartment Units	3,020
Seattle | Starwood Portfolio [Member]
Disposed Properties | property	8
Apartment Units	1,721
Inland Empire, CA (part of Los Angeles) | Starwood Portfolio [Member]
Disposed Properties | property	3
Apartment Units	1,144

Commitments to Acquire_Dispos48

Commitments to Acquire/Dispose of Real Estate (Details) - Commitments [Member] $ in Thousands	Apr. 29, 2016USD ($)property
Commitments to Dispose of Real Estate
Properties Contracted To Be Disposed | property	4
Units Contracted To Be Disposed	772
Sales Price For Commitments To Dispose	$ 201,000
Rental Properties Disposed of [Member]
Commitments to Dispose of Real Estate
Properties Contracted To Be Disposed | property	4
Units Contracted To Be Disposed	772
Sales Price For Commitments To Dispose	$ 134,450
Land [Member]
Commitments to Dispose of Real Estate
Land Parcels Contracted To Be Disposed	3
Sales Price For Commitments To Dispose	$ 66,550

Investments in Partially Owne49

Investments in Partially Owned Entities (Details) - USD ($)	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015	Dec. 31, 2014	Feb. 27, 2013
Partially Owned Property Balance Sheet Schedule
Number of Real Estate Properties	317
Number of Units in Real Estate Property	83,992
ASSETS
Investment in real estate	$ 25,120,866,000		$ 25,182,352,000
Accumulated depreciation	(4,977,274,000)		(4,905,406,000)
Investment in real estate, net	20,143,592,000		20,276,946,000
Cash and cash equivalents	368,049,000	$ 49,418,000	42,276,000	$ 40,080,000
Investments in unconsolidated entities	66,476,000		68,101,000
Deposits – restricted	241,741,000		55,893,000
Other assets	422,079,000		428,899,000
Total assets	21,301,292,000		23,110,196,000
LIABILITIES AND EQUITY
Secured Debt	4,223,681,000		4,685,134,000
Accounts payable & accrued expenses	215,817,000		187,124,000
Accrued interest payable	69,404,000		85,221,000
Other Liabilities	347,553,000		366,387,000
Security deposits	63,592,000		77,582,000
Total liabilities	9,471,497,000		11,847,058,000
Noncontrolling Interests – Partially Owned Properties/Partners' equity	4,399,000		4,608,000
Liabilities and Equity	21,301,292,000		$ 23,110,196,000
Partially Owned Property Income Statement Schedule
Operating revenue	619,083,000	666,371,000
Property management	23,495,000	22,765,000
General and administrative/other	172,885,000	194,521,000
Depreciation	16,717,000	19,762,000
Operating income	216,625,000	218,331,000
Interest and other income	3,058,000	169,000
Interest:
Expense incurred, net	(213,492,000)	(108,782,000)
Amortization of deferred financing costs	(5,394,000)	(2,589,000)
(Loss) income before income and other taxes, (loss) income from investments in unconsolidated entities, net gain (loss) on sales of real estate properties and land parcels and discontinued operations	(1,759,000)	107,199,000
Income and other tax (expense) benefit	(350,000)	(43,000)
(Loss) income from investments in unconsolidated entities	(1,104,000)	2,963,000
Net income	$ 3,731,831,000	$ 190,224,000
Consolidated VIE
Partially Owned Property Balance Sheet Schedule
Number of Real Estate Properties	18
Number of Units in Real Estate Property	3,471
ASSETS
Investment in real estate	$ 665,996,000
Accumulated depreciation	(209,424,000)
Investment in real estate, net	456,572,000
Cash and cash equivalents	15,051,000
Investments in unconsolidated entities	48,797,000
Deposits – restricted	351,000
Other assets	25,948,000
Total assets	546,719,000
LIABILITIES AND EQUITY
Secured Debt	317,801,000
Accounts payable & accrued expenses	2,786,000
Accrued interest payable	1,099,000
Other Liabilities	521,000
Security deposits	1,939,000
Total liabilities	324,146,000
Noncontrolling Interests – Partially Owned Properties/Partners' equity	4,399,000
Company equity/General and Limited Partners' Capital	218,174,000
Total equity/capital	222,573,000
Liabilities and Equity	546,719,000
Partially Owned Property Income Statement Schedule
Operating revenue	22,997,000
Operating Expenses	5,598,000
Net operating income	17,399,000
Property management	811,000
General and administrative/other	15,000
Depreciation	5,369,000
Operating income	11,204,000
Interest and other income	20,000
Interest:
Expense incurred, net	(4,038,000)
Amortization of deferred financing costs	(147,000)
(Loss) income before income and other taxes, (loss) income from investments in unconsolidated entities, net gain (loss) on sales of real estate properties and land parcels and discontinued operations	7,039,000
Income and other tax (expense) benefit	(12,000)
(Loss) income from investments in unconsolidated entities	(369,000)
Net income	$ 6,658,000
Unconsolidated Non-VIE
Partially Owned Property Balance Sheet Schedule
Number of Real Estate Properties	2
Number of Units in Real Estate Property	945
ASSETS
Investment in real estate	$ 234,383,000
Accumulated depreciation	(24,991,000)
Investment in real estate, net	209,392,000
Cash and cash equivalents	7,836,000
Investments in unconsolidated entities	0
Deposits – restricted	242,000
Other assets	103,000
Total assets	217,573,000
LIABILITIES AND EQUITY
Secured Debt	145,423,000
Accounts payable & accrued expenses	1,729,000
Accrued interest payable	691,000
Other Liabilities	258,000
Security deposits	510,000
Total liabilities	148,611,000
Noncontrolling Interests – Partially Owned Properties/Partners' equity	63,809,000
Company equity/General and Limited Partners' Capital	5,153,000
Total equity/capital	68,962,000
Liabilities and Equity	217,573,000
Partially Owned Property Income Statement Schedule
Operating revenue	6,528,000
Operating Expenses	2,196,000
Net operating income	4,332,000
Property management	190,000
General and administrative/other	0
Depreciation	2,621,000
Operating income	1,521,000
Interest and other income	0
Interest:
Expense incurred, net	(2,072,000)
Amortization of deferred financing costs	0
(Loss) income before income and other taxes, (loss) income from investments in unconsolidated entities, net gain (loss) on sales of real estate properties and land parcels and discontinued operations	(551,000)
Income and other tax (expense) benefit	0
(Loss) income from investments in unconsolidated entities	0
Net income	(551,000)
Unconsolidated Non-VIE | Residual JV [Domain]
ASSETS
Investments in unconsolidated entities	$ (900,000)				$ 147,600,000
Investments In Partially Owned Entities (Textuals) [Abstract]
Business Acquisition, Percentage of Voting Interests Acquired	60.00%
Joint Venture Partner Ownership Percentage	40.00%
Unconsolidated VIE
Partially Owned Property Balance Sheet Schedule
Number of Real Estate Properties	1
Number of Units in Real Estate Property	336
ASSETS
Investment in real estate	$ 229,599,000
Accumulated depreciation	(49,194,000)
Investment in real estate, net	180,405,000
Cash and cash equivalents	1,201,000
Investments in unconsolidated entities	0
Deposits – restricted	47,000
Other assets	786,000
Total assets	182,439,000
LIABILITIES AND EQUITY
Secured Debt	29,269,000
Accounts payable & accrued expenses	351,000
Accrued interest payable	0
Other Liabilities	216,000
Security deposits	159,000
Total liabilities	29,995,000
Noncontrolling Interests – Partially Owned Properties/Partners' equity	108,968,000
Company equity/General and Limited Partners' Capital	43,476,000
Total equity/capital	152,444,000
Liabilities and Equity	182,439,000
Partially Owned Property Income Statement Schedule
Operating revenue	2,913,000
Operating Expenses	1,153,000
Net operating income	1,760,000
Property management	19,000
General and administrative/other	86,000
Depreciation	1,858,000
Operating income	(203,000)
Interest and other income	0
Interest:
Expense incurred, net	(272,000)
Amortization of deferred financing costs	0
(Loss) income before income and other taxes, (loss) income from investments in unconsolidated entities, net gain (loss) on sales of real estate properties and land parcels and discontinued operations	(475,000)
Income and other tax (expense) benefit	0
(Loss) income from investments in unconsolidated entities	0
Net income	$ (475,000)
Unconsolidated Properties [Member]
Partially Owned Property Balance Sheet Schedule
Number of Real Estate Properties	3
Number of Units in Real Estate Property	1,281
ASSETS
Investment in real estate	$ 463,982,000
Accumulated depreciation	(74,185,000)
Investment in real estate, net	389,797,000
Cash and cash equivalents	9,037,000
Investments in unconsolidated entities	0
Deposits – restricted	289,000
Other assets	889,000
Total assets	400,012,000
LIABILITIES AND EQUITY
Secured Debt	174,692,000
Accounts payable & accrued expenses	2,080,000
Accrued interest payable	691,000
Other Liabilities	474,000
Security deposits	669,000
Total liabilities	178,606,000
Noncontrolling Interests – Partially Owned Properties/Partners' equity	172,777,000
Company equity/General and Limited Partners' Capital	48,629,000
Total equity/capital	221,406,000
Liabilities and Equity	400,012,000
Partially Owned Property Income Statement Schedule
Operating revenue	9,441,000
Operating Expenses	3,349,000
Net operating income	6,092,000
Property management	209,000
General and administrative/other	86,000
Depreciation	4,479,000
Operating income	1,318,000
Interest and other income	0
Interest:
Expense incurred, net	(2,344,000)
Amortization of deferred financing costs	0
(Loss) income before income and other taxes, (loss) income from investments in unconsolidated entities, net gain (loss) on sales of real estate properties and land parcels and discontinued operations	(1,026,000)
Income and other tax (expense) benefit	0
(Loss) income from investments in unconsolidated entities	0
Net income	$ (1,026,000)

Investments in Partially Owne50

Investments in Partially Owned Entities Operating Properties (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
Variable Interest Entity [Line Items]
Number of Real Estate Properties	317
Number of Units in Real Estate Property	83,992
Investments in unconsolidated entities	$ 66,476	$ 68,101
Mortgage notes payable, net	$ 4,223,681	$ 4,685,134
Consolidated VIE
Variable Interest Entity [Line Items]
Number of Real Estate Properties	18
Number of Units in Real Estate Property	3,471
Investments in unconsolidated entities	$ 48,797
Mortgage notes payable, net	$ 317,801
Unconsolidated VIE
Variable Interest Entity [Line Items]
Number of Real Estate Properties	1
Number of Units in Real Estate Property	336
Investments in unconsolidated entities	$ 0
Mortgage notes payable, net	$ 29,269
Operating Property [Member] | Consolidated VIE
Variable Interest Entity [Line Items]
Number of Real Estate Properties	17
Number of Units in Real Estate Property	3,039
Wisconsin Place [Domain] | Consolidated VIE
Variable Interest Entity [Line Items]
Number of Units in Real Estate Property	432
Business Acquisition, Percentage of Voting Interests Acquired	75.00%
Basis of joint venture	$ 174,500
Wisconsin Place [Domain] | Unconsolidated VIE
Variable Interest Entity [Line Items]
Investments in unconsolidated entities	$ 48,800
Waterton Tenside [Domain] | Unconsolidated VIE
Variable Interest Entity [Line Items]
Number of Units in Real Estate Property	336
Investments in unconsolidated entities	$ 3,900
Equity Method Investment, Ownership Percentage	20.00%
Mortgage notes payable, net	$ 29,300
Debt Instrument, Interest Rate, Stated Percentage	3.66%
Debt Instrument, Maturity Date	Dec. 1, 2018
Nexus Sawgrass [Member]
Variable Interest Entity [Line Items]
Number of Units in Real Estate Property	501
Investments in unconsolidated entities	$ 4,900
Equity Method Investment, Ownership Percentage	20.00%
Mortgage notes payable, net	$ 48,600
Debt Instrument, Interest Rate, Stated Percentage	5.60%
Debt Instrument, Maturity Date	Jan. 1, 2021
Domain [Member]
Variable Interest Entity [Line Items]
Number of Units in Real Estate Property	444
Investments in unconsolidated entities	$ 9,800
Equity Method Investment, Ownership Percentage	20.00%
Mortgage notes payable, net	$ 96,800
Debt Instrument, Interest Rate, Stated Percentage	5.75%
Debt Instrument, Maturity Date	Jan. 1, 2022

Investments in Partially Owne51

Investments in Partially Owned Entities Other (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015	Feb. 27, 2013
Variable Interest Entity [Line Items]
Investments in unconsolidated entities	$ 66,476	$ 68,101
Unconsolidated Non-VIE
Variable Interest Entity [Line Items]
Investments in unconsolidated entities	0
Residual JV [Domain] | Unconsolidated Non-VIE
Variable Interest Entity [Line Items]
Investments in unconsolidated entities	$ (900)		$ 147,600
Business Acquisition, Percentage of Voting Interests Acquired	60.00%
Joint Venture Partner Ownership Percentage	40.00%
Legacy JV [Domain] | Unconsolidated Non-VIE
Variable Interest Entity [Line Items]
Liquidation Value Preferred Interests	$ 42,200
Business Acquisition, Percentage of Voting Interests Acquired	60.00%
Joint Venture Partner Ownership Percentage	40.00%

Deposits - Restricted (Details)

Deposits - Restricted (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Restricted Cash and Cash Equivalents Items [Line Items]
Tax-deferred (1031) exchange proceeds	$ 195,636	$ 0
Earnest money on pending acquisitions	0	1,000
Restricted deposits on real estate investments	4,974	6,077
Resident security and utility deposits	38,635	48,458
Other	2,496	358
Totals	241,741	55,893
Real estate taxes and insurance	2,432	1,977
Replacement reserves	3,766	3,962
Mortgage principal reserves/sinking funds	52,305	50,155
Other	852	852
Totals	$ 59,355	$ 56,946

Debt Mortgage Notes Payable (De

Debt Mortgage Notes Payable (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2016USD ($)property	Dec. 31, 2015USD ($)
Debt Instrument [Line Items]
Mortgage notes payable	$ 4,223,681	$ 4,685,134
Noncash or Part Noncash Acquisition, Debt Assumed	$ 43,400
Properties acquired | property	3
Write Off Of Unamortized Deferred Financing Costs	$ 1,900
Write off unamortized premium discount	25,200
Mortgages [Member]
Debt Instrument [Line Items]
Repayments Of Long-term Debt	$ 2,200
Properties acquired | property	1
Write Off Of Unamortized Deferred Financing Costs	$ 1,200
Write off unamortized premium discount	$ 20,600
Debt Instrument, Maturity Date	May 1, 2061
Debt Instrument, Interest Rate, Stated Percentage Rate Range, Minimum	0.10%
Debt Instrument, Interest Rate, Stated Percentage Rate Range, Maximum	7.25%
Weighted Average Mortgage Debt Interest Rate	4.33%
Bonds [Member]
Debt Instrument [Line Items]
Repayments Of Long-term Debt	$ 41,800
Prepayment Penalty Charges	200
Credit enhanced debt [Member]
Debt Instrument [Line Items]
Mortgage notes payable	627,000
Fannie Mae Pool 3 [Member] | Mortgages [Member]
Debt Instrument [Line Items]
Repayments Of Long-term Debt	$ 440,800
Debt Instrument, Interest Rate, Stated Percentage	6.256%
Prepayment Penalty Charges	$ 29,300

Debt Notes (Details)

Debt Notes (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Debt Instrument [Line Items]
Notes, net	$ 4,360,137		$ 5,848,956
Repayments of Notes Payable	1,500,000	$ 0
Write Off Of Unamortized Deferred Financing Costs	1,900
Write off unamortized premium discount	25,200
5.125% Notes [Member]
Debt Instrument [Line Items]
Repayments of Notes Payable	$ 228,900
Debt Instrument, Interest Rate, Stated Percentage	5.125%
Prepayment Penalty Charges	$ 1,400
5.375% Notes [Member]
Debt Instrument [Line Items]
Repayments of Notes Payable	$ 400,000
Debt Instrument, Interest Rate, Stated Percentage	5.375%
Prepayment Penalty Charges	$ 9,500
5.750% Notes [Member]
Debt Instrument [Line Items]
Repayments of Notes Payable	$ 255,900
Debt Instrument, Interest Rate, Stated Percentage	5.75%
Prepayment Penalty Charges	$ 16,500
7.125% Notes [Member]
Debt Instrument [Line Items]
Repayments of Notes Payable	$ 46,100
Debt Instrument, Interest Rate, Stated Percentage	7.125%
Prepayment Penalty Charges	$ 4,600
4.625% Notes [Member]
Debt Instrument [Line Items]
Repayments of Notes Payable	$ 250,000
Debt Instrument, Interest Rate, Stated Percentage	4.625%
Prepayment Penalty Charges	$ 31,600
7.570% Notes [Member]
Debt Instrument [Line Items]
Repayments of Notes Payable	$ 48,000
Debt Instrument, Interest Rate, Stated Percentage	7.57%
Prepayment Penalty Charges	$ 19,300
Notes Payable, Other Payables [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date	Jun. 1, 2045
Debt Instrument, Interest Rate, Stated Percentage Rate Range, Minimum	2.375%
Debt Instrument, Interest Rate, Stated Percentage Rate Range, Maximum	7.57%
Weighted Average Interest Rate	4.62%
Paid at Maturity [Member] | 5.125% Notes [Member]
Debt Instrument [Line Items]
Repayments of Notes Payable	$ 271,100
Debt Instrument, Interest Rate, Stated Percentage	5.125%

Debt Line of Credit and Commerc

Debt Line of Credit and Commercial Paper (Details) $ in Millions	3 Months Ended
	Mar. 31, 2016USD ($)
A 175 billion LOC [Member]
Line of Credit Facility [Line Items]
Unsecured revolving credit facility	$ 1,750
A 250 billion LOC [Member]
Line of Credit Facility [Line Items]
Unsecured revolving credit facility	$ 2,500
Debt Instrument, Maturity Date	Apr. 1, 2018
500.0 million ability to increase	$ 500
Debt Instrument, Basis Spread on Variable Rate	0.95%
Line Of Credit Facility Commitment Fee	15 Basis Points
Remaining borrowing capacity	$ 2,440
Amount restricted/dedicated to support letters of credit	$ 64.5
Weighted Average Interest Rate Revolving Credit Facility	1.36%
Commercial Paper [Member]
Line of Credit Facility [Line Items]
Commercial paper, maximum borrowing capacity	$ 500
Weighted Average Interest Rate Commercial Paper	0.96%
Line of Credit [Member] | London Interbank Offered Rate (LIBOR) [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Description of Variable Rate Basis	LIBOR plus 0.95%

Derivative and Other Fair Val56

Derivative and Other Fair Value Instruments (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2016USD ($)
2.375% Notes [Member]
Derivative [Line Items]
Proceeds from Issuance of Unsecured Debt	$ 450,000
Debt Instrument, Interest Rate, Stated Percentage	2.375%
Debt Instrument, Maturity Date	Jul. 1, 2019
Debt Instrument, Basis Spread on Variable Rate	0.61%
Debt Instrument, Description of Variable Rate Basis	LIBOR plus 0.61%
Fair Value Hedges
Derivative [Line Items]
Current Notional Balance	$ 450,000
Lowest Possible Notional	450,000
Highest Possible Notional	$ 450,000
Lowest Interest Rate	2.375%
Highest Interest Rate	2.375%
Earliest Maturity Date	P2019Y0M0D
Latest Maturity Date	P2019Y0M0D
Forward Starting Swaps
Derivative [Line Items]
Current Notional Balance	$ 50,000
Lowest Possible Notional	50,000
Highest Possible Notional	$ 50,000
Lowest Interest Rate	2.50%
Highest Interest Rate	2.50%
Earliest Maturity Date	P2026Y0M0D
Latest Maturity Date	P2026Y0M0D

Derivative and Other Fair Val57

Derivative and Other Fair Value Instruments (Details 1) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Derivatives, Fair Value [Line Items]
Supplemental Executive Retirement Plan	$ 114,123	$ 105,942
Assets, Fair Value Disclosure	124,656	109,597
Supplemental Executive Retirement Plan	114,123	105,942
Financial and Nonfinancial Liabilities, Fair Value Disclosure	117,702	106,615
Redeemable Noncontrolling Interests Operating Partnership	521,080	566,783
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1)
Derivatives, Fair Value [Line Items]
Supplemental Executive Retirement Plan	114,123	105,942
Assets, Fair Value Disclosure	114,123	105,942
Supplemental Executive Retirement Plan	114,123	105,942
Financial and Nonfinancial Liabilities, Fair Value Disclosure	114,123	105,942
Redeemable Noncontrolling Interests Operating Partnership	0	0
Significant Other Observable Inputs (Level 2)
Derivatives, Fair Value [Line Items]
Supplemental Executive Retirement Plan	0	0
Assets, Fair Value Disclosure	10,533	3,655
Supplemental Executive Retirement Plan	0	0
Financial and Nonfinancial Liabilities, Fair Value Disclosure	3,579	673
Redeemable Noncontrolling Interests Operating Partnership	521,080	566,783
Significant Unobservable Inputs (Level 3)
Derivatives, Fair Value [Line Items]
Supplemental Executive Retirement Plan	0	0
Assets, Fair Value Disclosure	0	0
Supplemental Executive Retirement Plan	0	0
Financial and Nonfinancial Liabilities, Fair Value Disclosure	0	0
Redeemable Noncontrolling Interests Operating Partnership	0	0
Fair Value Hedges
Derivatives, Fair Value [Line Items]
Derivative Asset	10,533	3,655
Fair Value Hedges | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1)
Derivatives, Fair Value [Line Items]
Derivative Asset	0	0
Fair Value Hedges | Significant Other Observable Inputs (Level 2)
Derivatives, Fair Value [Line Items]
Derivative Asset	10,533	3,655
Fair Value Hedges | Significant Unobservable Inputs (Level 3)
Derivatives, Fair Value [Line Items]
Derivative Asset	0	0
Forward Starting Swaps
Derivatives, Fair Value [Line Items]
Derivative Liability	3,579	673
Forward Starting Swaps | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1)
Derivatives, Fair Value [Line Items]
Derivative Liability	0	0
Forward Starting Swaps | Significant Other Observable Inputs (Level 2)
Derivatives, Fair Value [Line Items]
Derivative Liability	3,579	673
Forward Starting Swaps | Significant Unobservable Inputs (Level 3)
Derivatives, Fair Value [Line Items]
Derivative Liability	$ 0	$ 0

Derivative and Other Fair Val58

Derivative and Other Fair Value Instruments (Details 3) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Derivatives designated as hedging instruments:
Amount of Gain/(Loss) Recognized in Income on Derivative	$ 6,878	$ 4,842
Amount of Gain/(Loss) Recognized in Income on Hedged Item	(6,878)	(4,842)
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	(2,906)	(11,788)
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	(28,654)	(4,338)
Ineffective Portion - Amount of Gain/ (Loss) Reclassifed from Accumulated OCI into Income	0	0
Interest Rate Swaps
Derivatives designated as hedging instruments:
Amount of Gain/(Loss) Recognized in Income on Derivative	$ 6,878	$ 4,842
Hedged Item	Fixed rate debt	Fixed rate debt
Amount of Gain/(Loss) Recognized in Income on Hedged Item	$ (6,878)	$ (4,842)
Forward Starting Swaps
Derivatives designated as hedging instruments:
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	(2,906)	(11,788)
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	(28,654)	(4,338)
Ineffective Portion - Amount of Gain/ (Loss) Reclassifed from Accumulated OCI into Income	$ 0	$ 0

Derivative and Other Fair Val59

Derivative and Other Fair Value Instruments (Details Textuals) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
Derivative [Line Items]
Mortgage notes payable	$ 4,223,681	$ 4,685,134
Unrealized Gain (Loss) on Interest Rate Cash Flow Hedges, Pretax, Accumulated Other Comprehensive Income (Loss)	(126,000)	(151,800)
Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net	20,800
Mortgage notes payable, net
Derivative [Line Items]
Mortgage notes payable	4,200,000	4,700,000
Debt Instrument, Fair Value Disclosure	4,400,000	4,600,000
Unsecured Debt [Member]
Derivative [Line Items]
Unsecured Debt	4,400,000	6,200,000
Debt Instrument, Fair Value Disclosure	$ 4,700,000	$ 6,500,000

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Income from continuing operations	$ 3,731,988	$ 190,069
Allocation to Noncontrolling Interests – Operating Partnership, net	(143,315)	(7,053)
Net (income) attributable to Noncontrolling Interests – Partially Owned Properties	(764)	(643)
Preferred distributions	(773)	(891)
Premium on redemption of Preferred Shares	0	(2,789)
Income from continuing operations available to Common Shares, net of Noncontrolling Interests	3,587,136	178,693
Discontinued operations, net of Noncontrolling Interests	(151)	149
Numerator for net income per share – basic	3,586,985	178,842
Income from continuing operations available to Common Shares	3,730,451	185,746
Discontinued operations, net	(157)	155
Numerator for net income per share – diluted	$ 3,730,294	$ 185,901
Denominator for net income per share – basic	364,592	363,098
Effect of dilutive securities - OP Units	13,697	13,598
Effect of dilutive securities - Long-term compensation shares/units	3,954	3,631
Denominator for net income per share – diluted	382,243	380,327
Net income available to Common Shares	$ 9.84	$ 0.49
Income from continuing operations available to Common Shares	9.84	0.49
Net income per share - basic - Discontinued operations, net of Noncontrolling Interests	0	0
Income from continuing operations available to Common Shares	9.76	0.49
Net income per share - diluted - discontinued operations, net	$ 0	$ 0
ERPOP [Member]
Income from continuing operations	$ 3,731,988	$ 190,069
Net (income) attributable to Noncontrolling Interests – Partially Owned Properties	(764)	(643)
Allocation to Preference Units	(773)	(891)
Premium on redemption of Preferred Shares	0	(2,789)
Discontinued operations, net	$ (157)	$ 155
Effect of dilutive securities - Long-term compensation shares/units	3,954	3,631
Denominator for net income per share – diluted	382,243	380,327
Net income available to Common Shares	$ 9.84	$ 0.49
Income from continuing operations available to Common Shares	9.84	0.49
Income from continuing operations available to Common Shares	$ 9.76	$ 0.49
Income from continuing operations available to Units	$ 3,730,451	$ 185,746
Numerator for net income per Unit – basic and diluted	$ 3,730,294	$ 185,901
Denominator for net income per Unit – basic	378,289	376,696
Net income per Unit - basic - Discontinued operations, net	$ 0	$ 0
Net income per Unit - diluted - Discontinued operations, net	$ 0	$ 0

Individually Significant Dispos

Individually Significant Dispositions (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
REVENUES
Rental income	$ 616,165	$ 664,606
Total revenues	619,083	666,371
EXPENSES (1)
Cost of Property Repairs and Maintenance	109,165	124,560
Real Estate Taxes and Insurance	80,196	86,432
Property management	23,495	22,765
General and administrative	16,717	19,762
Depreciation	172,885	194,521
Total expenses	402,458	448,040
Operating income	216,625	218,331
Interest and other income	3,058	169
INTEREST (2)
Expense incurred, net	(213,492)	(108,782)
Amortization of deferred financing costs	(5,394)	(2,589)
Net gain on sales of real estate properties	3,723,479	79,951
Net income attributable to Noncontrolling Interests	(143,309)	(7,059)
Net income attributable to controlling interests	$ 3,587,758	$ 182,522
Starwood Portfolio [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Percentage of consolidated NOI	4.50%	16.00%
REVENUES
Rental income	$ 30,117	$ 103,709
Total revenues	30,117	103,709
EXPENSES (1)
Cost of Property Repairs and Maintenance	7,890	19,086
Real Estate Taxes and Insurance	2,872	12,147
Property management	2	3
General and administrative	1	1
Depreciation	0	26,194
Total expenses	10,765	57,431
Operating income	19,352	46,278
Interest and other income	2	0
INTEREST (2)
Expense incurred, net	(328)	(164)
Amortization of deferred financing costs	(707)	(24)
Net gain on sales of real estate properties	3,161,221	0
Net Income (Loss) Allocated to General Partners	3,179,540	46,090
Net income attributable to Noncontrolling Interests	(122,132)	(1,754)
Net income attributable to controlling interests	$ 3,057,408	$ 44,336

Discontinued Operations (Detail

Discontinued Operations (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015
REVENUES
Discontinued Operations - Rental income		$ 118	$ 161
Discontinued Operations - Total revenue		118	161
EXPENSES (1)
Discontinued Operations - Property and maintenance	[1]	(3)	(67)
Discontinued Operations - Real estate taxes and insurance	[1]	1	52
Discontinued Operations - General and administrative	[1]	4	6
Discontinued Operations - Total expenses	[1]	2	(9)
Discontinued operating income		116	170
Disposal Group Including Discontinued Operation Other Expenses		(280)	0
Discontinued Operations - Income and other tax (expense) benefit		(8)	(15)
Income Loss From Discontinued Operations		(172)	155
Discontinued Operation - Net gain on sales of discontinued operations		15	0
Discontinued operations, net		$ (157)	$ 155
[1]	Includes expenses paid in the current period for properties sold in prior periods related to the Company’s period of ownership.

Commitments and Contingencies (

Commitments and Contingencies (Details) $ in Millions	3 Months Ended
	Mar. 31, 2016USD ($)
Loss Contingency Accrual, Period Increase (Decrease)	$ (0.5)
Loss Contingency Accrual	$ 2.5
Projects in various stages of development	10
Units in various stages of development	3,983
Consolidated Project Under Development Commitment Fund	$ 626.2
Various stages of development with estimated completion dates ranging through September 30, 2017	Sep. 30, 2017
Unconsolidated Properties [Member]
Number Of Unconsolidated Projects	2

Reportable Segments (Details)

Reportable Segments (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2016USD ($)	Mar. 31, 2015USD ($)	Dec. 31, 2015USD ($)
Reportable Segments - Reconciliation of NOI
Rental income	$ 616,165	$ 664,606
Property and maintenance expense	(109,165)	(124,560)
Real estate taxes and insurance expense	(80,196)	(86,432)
Total operating expenses	(189,361)	(210,992)
Net operating income	426,804	453,614
Rental income:
Rental Income - Same Store	547,676	523,739
Rental Income - Non-same store/other	68,489	140,867
Rental Income	616,165	664,606
Operating expenses:
Operating Expenses - Same Store	162,676	162,663
Operating Expenses - Non-same store/other	26,685	48,329
Operating expenses	189,361	210,992
NOI:
Net operating income - Same Store	385,000	361,076
Net operating income - Non-same store/other	41,804	92,538
Net operating income	426,804	453,614
Total Assets	21,301,292		$ 23,110,196
Capital Expenditures	$ 33,902
Units in same store properties	73,222
Los Angeles [Member] | Same Store [Member]
Rental income:
Rental Income - Same Store	$ 90,150	84,654
Operating expenses:
Operating Expenses - Same Store	26,359	26,189
NOI:
Net operating income - Same Store	63,791	58,465
Total Assets	2,567,837
Capital Expenditures	5,031
Los Angeles [Member] | Non-same store [Member]
Rental income:
Rental Income - Non-same store/other	7,264	7,339
Operating expenses:
Operating Expenses - Non-same store/other	2,573	2,384
NOI:
Net operating income - Non-same store/other	4,691	4,955
Total Assets	459,013
Capital Expenditures	3,164
San Diego [Member] | Same Store [Member]
Rental income:
Rental Income - Same Store	21,428	20,231
Operating expenses:
Operating Expenses - Same Store	5,835	5,661
NOI:
Net operating income - Same Store	15,593	14,570
Total Assets	483,643
Capital Expenditures	673
Orange County [Member] | Same Store [Member]
Rental income:
Rental Income - Same Store	19,314	18,321
Operating expenses:
Operating Expenses - Same Store	4,733	4,688
NOI:
Net operating income - Same Store	14,581	13,633
Total Assets	266,770
Capital Expenditures	1,738
Orange County [Member] | Non-same store [Member]
Rental income:
Rental Income - Non-same store/other	1,158	0
Operating expenses:
Operating Expenses - Non-same store/other	334	0
NOI:
Net operating income - Non-same store/other	824	0
Total Assets	77,324
Capital Expenditures	12
Southern California [Member] | Same Store [Member]
Rental income:
Rental Income - Same Store	130,892	123,206
Operating expenses:
Operating Expenses - Same Store	36,927	36,538
NOI:
Net operating income - Same Store	93,965	86,668
Total Assets	3,318,250
Capital Expenditures	7,442
Southern California [Member] | Non-same store [Member]
Rental income:
Rental Income - Non-same store/other	8,422	7,339
Operating expenses:
Operating Expenses - Non-same store/other	2,907	2,384
NOI:
Net operating income - Non-same store/other	5,515	4,955
Total Assets	536,337
Capital Expenditures	3,176
New York [Domain] | Same Store [Member]
Rental income:
Rental Income - Same Store	113,204	110,123
Operating expenses:
Operating Expenses - Same Store	40,141	39,507
NOI:
Net operating income - Same Store	73,063	70,616
Total Assets	4,348,318
Capital Expenditures	3,994
New York [Domain] | Non-same store [Member]
Rental income:
Rental Income - Non-same store/other	7,086	292
Operating expenses:
Operating Expenses - Non-same store/other	3,625	432
NOI:
Net operating income - Non-same store/other	3,461	(140)
Total Assets	440,315
Capital Expenditures	19
Washington DC [Member] | Same Store [Member]
Rental income:
Rental Income - Same Store	104,268	103,340
Operating expenses:
Operating Expenses - Same Store	31,425	32,037
NOI:
Net operating income - Same Store	72,843	71,303
Total Assets	3,993,480
Capital Expenditures	5,556
Washington DC [Member] | Non-same store [Member]
Rental income:
Rental Income - Non-same store/other	959	1,047
Operating expenses:
Operating Expenses - Non-same store/other	170	197
NOI:
Net operating income - Non-same store/other	789	850
Total Assets	45,975
Capital Expenditures	0
San Francisco [Member] | Same Store [Member]
Rental income:
Rental Income - Same Store	90,674	82,784
Operating expenses:
Operating Expenses - Same Store	22,198	21,519
NOI:
Net operating income - Same Store	68,476	61,265
Total Assets	2,518,610
Capital Expenditures	4,891
San Francisco [Member] | Non-same store [Member]
Rental income:
Rental Income - Non-same store/other	4,298	83
Operating expenses:
Operating Expenses - Non-same store/other	1,550	221
NOI:
Net operating income - Non-same store/other	2,748	(138)
Total Assets	262,882
Capital Expenditures	0
Boston [Member] | Same Store [Member]
Rental income:
Rental Income - Same Store	62,325	60,512
Operating expenses:
Operating Expenses - Same Store	17,648	19,124
NOI:
Net operating income - Same Store	44,677	41,388
Total Assets	1,811,047
Capital Expenditures	3,626
Boston [Member] | Non-same store [Member]
Rental income:
Rental Income - Non-same store/other	2,634	946
Operating expenses:
Operating Expenses - Non-same store/other	710	202
NOI:
Net operating income - Non-same store/other	1,924	744
Total Assets	170,841
Capital Expenditures	294
Seattle | Same Store [Member]
Rental income:
Rental Income - Same Store	37,243	35,131
Operating expenses:
Operating Expenses - Same Store	10,572	9,807
NOI:
Net operating income - Same Store	26,671	25,324
Total Assets	1,053,316
Capital Expenditures	2,345
Seattle | Non-same store [Member]
Rental income:
Rental Income - Non-same store/other	5,679	1,941
Operating expenses:
Operating Expenses - Non-same store/other	1,259	496
NOI:
Net operating income - Non-same store/other	4,420	1,445
Total Assets	334,233
Capital Expenditures	258
All Other Markets | Same Store [Member]
Rental income:
Rental Income - Same Store	9,070	8,643
Operating expenses:
Operating Expenses - Same Store	3,765	4,131
NOI:
Net operating income - Same Store	5,305	4,512
Total Assets	126,515
Capital Expenditures	254
Other [Member] | Non-same store [Member]
Rental income:
Rental Income - Non-same store/other	39,411	129,219
Operating expenses:
Operating Expenses - Non-same store/other	16,464	44,397
NOI:
Net operating income - Non-same store/other	22,947	$ 84,822
Total Assets	2,341,173
Capital Expenditures	2,047
Same Store [Member]
NOI:
Total Assets	17,169,536
Capital Expenditures	28,108
Non-same store [Member]
NOI:
Total Assets	4,131,756
Capital Expenditures	$ 5,794

Subsequent Events_Other (Detail

Subsequent Events/Other (Details) $ in Thousands	1 Months Ended	3 Months Ended
	Apr. 29, 2016USD ($)	Mar. 31, 2016USD ($)	Mar. 31, 2015USD ($)
Other [Line Items]
Sales Price		$ 6,342,408
Apartment Units		26,162
Business Combination, Acquisition Related Costs		$ 1,300	$ 100
Noncash Project Abandonment Costs		1,448	493
Other Expenses		2,800	600
Real Estate [Member]
Other [Line Items]
Noncash Project Abandonment Costs		1,500	$ 500
Bonds [Member]
Other [Line Items]
Repayments Of Long-term Debt		$ 41,800
Subsequent Event [Member] | Bonds [Member]
Other [Line Items]
Repayments Of Long-term Debt	$ 2,900
Military Housing [Member] | Subsequent Event [Member]
Other [Line Items]
Sales Price	$ 63,300
Apartment Units	5,161