Equity Residential (EQR) 10-Q 8 May 14 2014 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Mar. 31, 2014	2-May-14
Entity Registrant Name	'EQUITY RESIDENTIAL	'
Entity Central Index Key	'0000906107	'
Document Type	'10-Q	'
Document Period End Date	31-Mar-14	'
Amendment Flag	'false	'
Document Fiscal Year Focus	'2014	'
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	'	361,203,075
OPERATING PARTNERSHIP	'	'
Entity Registrant Name	'ERP OPERATING LIMITED PARTNERSHIP	'
Entity Central Index Key	'0000931182	'
Document Type	'10-Q	'
Document Period End Date	31-Mar-14	'
Amendment Flag	'false	'
Document Fiscal Year Focus	'2014	'
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 $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Investment in real estate	'	'
Land	$6,281,124	$6,192,512
Depreciable property	19,623,472	19,226,047
Projects under development	865,177	988,867
Land held for development	295,357	393,522
Real Estate Investment Property, at Cost	27,065,130	26,800,948
Real Estate Investment Property, Accumulated Depreciation	-4,992,877	-4,807,709
Investment in real estate, net	22,072,253	21,993,239
Cash and cash equivalents	37,209	53,534
Investments in unconsolidated entities	205,068	178,526
Deposits - restricted	91,081	103,567
Escrow deposits - mortgage	43,995	42,636
Deferred financing costs, net	55,754	58,486
Other assets	384,271	404,557
Total assets	22,889,631	22,834,545
Liabilities:	'	'
Mortgage notes payable	5,167,626	5,174,166
Notes, net	5,477,656	5,477,088
Lines of credit	298,000	115,000
Accounts payable and accrued expenses	161,838	118,791
Accrued interest payable	78,140	78,309
Other liabilities	321,043	347,748
Security deposits	72,735	71,592
Distributions payable	187,759	243,511
Total liabilities	11,764,797	11,626,205
Commitments and contingencies	'	'
Redeemable Noncontrolling Interests - Operating Partnership	405,276	363,144
Shareholders' equity:	'	'
100,000,000 shares authorized; 1,000,000 shares issued and outstanding as of March 31, 2014 and December 31, 2013	50,000	50,000
1,000,000,000 shares authorized; 361,148,189 shares issued and outstanding as of March 31, 2014 and 360,479,260 shares issued and outstanding as of December 31, 2013	3,611	3,605
Paid in capital	8,541,046	8,561,500
Retained earnings	1,944,798	2,047,258
Accumulated other comprehensive (loss)	-162,894	-155,162
Total shareholders' equity	10,376,561	10,507,201
Noncontrolling Interests:	'	'
Operating Partnership	215,339	211,412
Noncontrolling Interests - Partially Owned Properties	127,658	126,583
Total Noncontrolling Interests	342,997	337,995
Total equity	10,719,558	10,845,196
Total liabilities and equity	$22,889,631	$22,834,545

CONSOLIDATED_BALANCE_SHEETS_Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) (Unaudited) (USD $)	Mar. 31, 2014	Dec. 31, 2013
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	1,000,000	1,000,000
Preferred Shares of beneficial interest, shares outstanding	1,000,000	1,000,000
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	361,148,189	360,479,260
Common Shares of beneficial interest, shares outstanding	361,148,189	360,479,260

CONSOLIDATED_BALANCE_SHEETS_OF

CONSOLIDATED BALANCE SHEETS OF ERP OPERATING LIMITED PARTNERSHIP (Unaudited) (USD $)	Mar. 31, 2014	Dec. 31, 2013
Investment in real estate	'	'
Land	$6,281,124,000	$6,192,512,000
Depreciable property	19,623,472,000	19,226,047,000
Projects under development	865,177,000	988,867,000
Land held for development	295,357,000	393,522,000
Real Estate Investment Property, at Cost	27,065,130,000	26,800,948,000
Real Estate Investment Property, Accumulated Depreciation	-4,992,877,000	-4,807,709,000
Investment in real estate, net	22,072,253,000	21,993,239,000
Cash and cash equivalents	37,209,000	53,534,000
Investments in unconsolidated entities	205,068,000	178,526,000
Deposits - restricted	91,081,000	103,567,000
Escrow deposits - mortgage	43,995,000	42,636,000
Deferred financing costs, net	55,754,000	58,486,000
Other assets	384,271,000	404,557,000
Total assets	22,889,631,000	22,834,545,000
Liabilities:	'	'
Mortgage notes payable	5,167,626,000	5,174,166,000
Notes, net	5,477,656,000	5,477,088,000
Lines of credit	298,000,000	115,000,000
Accounts payable and accrued expenses	161,838,000	118,791,000
Accrued interest payable	78,140,000	78,309,000
Other liabilities	321,043,000	347,748,000
Security deposits	72,735,000	71,592,000
Distributions payable	187,759,000	243,511,000
Total liabilities	11,764,797,000	11,626,205,000
Commitments and contingencies	'	'
Partnersb Capital:	'	'
Accumulated other comprehensive (loss)	-162,894,000	-155,162,000
Noncontrolling Interests - Partially Owned Properties	127,658,000	126,583,000
Total liabilities and equity	22,889,631,000	22,834,545,000
OPERATING PARTNERSHIP	'	'
Investment in real estate	'	'
Land	6,281,124,000	6,192,512,000
Depreciable property	19,623,472,000	19,226,047,000
Projects under development	865,177,000	988,867,000
Land held for development	295,357,000	393,522,000
Real Estate Investment Property, at Cost	27,065,130,000	26,800,948,000
Real Estate Investment Property, Accumulated Depreciation	-4,992,877,000	-4,807,709,000
Investment in real estate, net	22,072,253,000	21,993,239,000
Cash and cash equivalents	37,209,000	53,534,000
Investments in unconsolidated entities	205,068,000	178,526,000
Deposits - restricted	91,081,000	103,567,000
Escrow deposits - mortgage	43,995,000	42,636,000
Deferred financing costs, net	55,754,000	58,486,000
Other assets	384,271,000	404,557,000
Total assets	22,889,631,000	22,834,545,000
Liabilities:	'	'
Mortgage notes payable	5,167,626,000	5,174,166,000
Notes, net	5,477,656,000	5,477,088,000
Lines of credit	298,000,000	115,000,000
Accounts payable and accrued expenses	161,838,000	118,791,000
Accrued interest payable	78,140,000	78,309,000
Other liabilities	321,043,000	347,748,000
Security deposits	72,735,000	71,592,000
Distributions payable	187,759,000	243,511,000
Total liabilities	11,764,797,000	11,626,205,000
Commitments and contingencies	'	'
Redeemable Limited Partners	405,276,000	363,144,000
Partnersb Capital:	'	'
Preference Units	50,000,000	50,000,000
General Partner	10,489,455,000	10,612,363,000
Limited Partners	215,339,000	211,412,000
Accumulated other comprehensive (loss)	-162,894,000	-155,162,000
Total partnersb capital	10,591,900,000	10,718,613,000
Noncontrolling Interests - Partially Owned Properties	127,658,000	126,583,000
Total capital	10,719,558,000	10,845,196,000
Total liabilities and equity	$22,889,631,000	$22,834,545,000

CONSOLIDATED_STATEMENTS_OF_OPE

CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
REVENUES	'	'
Rental income	$630,725	$502,562
Fee and asset management	2,717	2,160
Total revenues	633,442	504,722
EXPENSES	'	'
Property and maintenance	125,573	98,529
Real estate taxes and insurance	82,094	65,095
Property management	22,118	22,489
Fee and asset management	1,662	1,646
Depreciation	185,167	196,222
General and administrative	17,576	16,495
Total expenses	434,190	400,476
Operating Income	199,252	104,246
Interest and other income	605	320
Other expenses	-657	-21,719
Interest:	'	'
Expense incurred, net	-113,049	-194,467
Amortization of deferred financing costs	-2,792	-6,948
Income (loss) before income and other taxes, (loss) from investments in unconsolidated entities, net (loss) on sales of land parcels and discontinued operations	83,359	-118,568
Income and other tax (expense) benefit	-222	-405
(Loss) from investments in unconsolidated entities	-1,409	-46,366
Net (loss) on sales of land parcels	-30	0
Income (loss) from continuing operations	81,698	-165,339
Discontinued operations, net	1,034	1,226,373
Net income	82,732	1,061,034
Net (income) attributable to Noncontrolling Interests:	'	'
Net (Income) Attributable to Noncontrolling Interest	-3,093	-43,323
Net (income) attributable to Noncontrolling Interests b Partially Owned Properties	-504	-25
Net income attributable to controlling interests	79,135	1,017,686
Preferred distributions	-1,036	-1,036
Net income available to Common Shares	$78,099	$1,016,650
Earnings per share - basic:	'	'
Income (loss) from continuing operations available to Common Shares	$0.21	($0.47)
Net income available to Common Shares	$0.22	$3.01
Weighted average Common Shares outstanding	360,470	337,532
Earnings per share - diluted:	'	'
Income (loss) from continuing operations available to Common Shares	$0.21	($0.47)
Net income available to Common Shares	$0.22	$3.01
Weighted average Common Shares outstanding	376,384	337,532
Distributions declared per Common Share outstanding	$0.50	$0.40

CONSOLIDATED_STATEMENTS_OF_OPE1

CONSOLIDATED STATEMENTS OF OPERATIONS OF ERP OPERATING LIMITED PARTNERSHIP (Unaudited) (USD $)	3 Months Ended
Share data in Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
REVENUES	'	'
Rental income	$630,725,000	$502,562,000
Fee and asset management	2,717,000	2,160,000
Total revenues	633,442,000	504,722,000
EXPENSES	'	'
Property and maintenance	125,573,000	98,529,000
Real estate taxes and insurance	82,094,000	65,095,000
Property management	22,118,000	22,489,000
Fee and asset management	1,662,000	1,646,000
Depreciation	185,167,000	196,222,000
General and administrative	17,576,000	16,495,000
Total expenses	434,190,000	400,476,000
Operating Income	199,252,000	104,246,000
Interest and other income	605,000	320,000
Other expenses	-657,000	-21,719,000
Interest:	'	'
Expense incurred, net	-113,049,000	-194,467,000
Amortization of deferred financing costs	-2,792,000	-6,948,000
Income (loss) before income and other taxes, (loss) from investments in unconsolidated entities, net (loss) on sales of land parcels and discontinued operations	83,359,000	-118,568,000
Income and other tax (expense) benefit	-222,000	-405,000
(Loss) from investments in unconsolidated entities	-1,409,000	-46,366,000
Net (loss) on sales of land parcels	-30,000	0
Income (loss) from continuing operations	81,698,000	-165,339,000
Discontinued operations, net	1,034,000	1,226,373,000
Net income	82,732,000	1,061,034,000
Net (income) attributable to Noncontrolling Interests b Partially Owned Properties	-504,000	-25,000
Net income attributable to controlling interests	79,135,000	1,017,686,000
Earnings per Unit - basic:	'	'
Income (loss) from continuing operations available to Units	$0.21	($0.47)
Net income available to Units	$0.22	$3.01
Earnings per Unit - diluted:	'	'
Income (loss) from continuing operations available to Units	$0.21	($0.47)
Net income available to Units	$0.22	$3.01
OPERATING PARTNERSHIP	'	'
REVENUES	'	'
Rental income	630,725,000	502,562,000
Fee and asset management	2,717,000	2,160,000
Total revenues	633,442,000	504,722,000
EXPENSES	'	'
Property and maintenance	125,573,000	98,529,000
Real estate taxes and insurance	82,094,000	65,095,000
Property management	22,118,000	22,489,000
Fee and asset management	1,662,000	1,646,000
Depreciation	185,167,000	196,222,000
General and administrative	17,576,000	16,495,000
Total expenses	434,190,000	400,476,000
Operating Income	199,252,000	104,246,000
Interest and other income	605,000	320,000
Other expenses	-657,000	-21,719,000
Interest:	'	'
Expense incurred, net	-113,049,000	-194,467,000
Amortization of deferred financing costs	-2,792,000	-6,948,000
Income (loss) before income and other taxes, (loss) from investments in unconsolidated entities, net (loss) on sales of land parcels and discontinued operations	83,359,000	-118,568,000
Income and other tax (expense) benefit	-222,000	-405,000
(Loss) from investments in unconsolidated entities	-1,409,000	-46,366,000
Net (loss) on sales of land parcels	-30,000	0
Income (loss) from continuing operations	81,698,000	-165,339,000
Discontinued operations, net	1,034,000	1,226,373,000
Net income	82,732,000	1,061,034,000
Net (income) attributable to Noncontrolling Interests b Partially Owned Properties	-504,000	-25,000
Net income attributable to controlling interests	82,228,000	1,061,009,000
ALLOCATION OF NET INCOME:	'	'
Preference Units	1,036,000	1,036,000
General Partner	78,099,000	1,016,650,000
Limited Partners	3,093,000	43,323,000
Net income available to Units	$81,192,000	$1,059,973,000
Earnings per Unit - basic:	'	'
Income (loss) from continuing operations available to Units	$0.21	($0.47)
Net income available to Units	$0.22	$3.01
Weighted average Units outstanding	374,201	351,255
Earnings per Unit - diluted:	'	'
Income (loss) from continuing operations available to Units	$0.21	($0.47)
Net income available to Units	$0.22	$3.01
Weighted average Units outstanding	376,384	351,255
Distributions declared per Unit outstanding	$0.50	$0.40

CONSOLIDATED_STATEMENTS_OF_COM

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Net income	$82,732	$1,061,034
Other comprehensive (loss) income b derivative instruments:	'	'
Unrealized holding (losses) gains arising during the period	-11,952	2,814
Losses reclassified into earnings from other comprehensive income	4,129	8,272
Other comprehensive income b other instruments:	'	'
Unrealized holding gains arising during the period	0	427
Other comprehensive income (loss) b foreign currency:	'	'
Currency translation adjustments arising during the period	91	-873
Other comprehensive (loss) income	-7,732	10,640
Comprehensive income	75,000	1,071,674
Comprehensive (income) attributable to Noncontrolling Interests	-3,302	-43,774
Comprehensive income attributable to controlling interests	$71,698	$1,027,900

CONSOLIDATED_STATEMENTS_OF_COM1

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME OF ERP OPERATING LIMITED PARTNERSHIP (Unaudited) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Comprehensive income:	'	'
Net income	$82,732	$1,061,034
Other comprehensive (loss) income b derivative instruments:	'	'
Unrealized holding (losses) gains arising during the period	-11,952	2,814
Losses reclassified into earnings from other comprehensive income	-4,129	-8,272
Other comprehensive income b other instruments:	'	'
Unrealized holding gains arising during the period	0	427
Other comprehensive income (loss) b foreign currency:	'	'
Currency translation adjustments arising during the period	91	-873
Other comprehensive (loss) income	-7,732	10,640
Comprehensive income	75,000	1,071,674
Comprehensive (income) attributable to Noncontrolling Interests b Partially Owned Properties	-3,302	-43,774
Comprehensive income attributable to controlling interests	71,698	1,027,900
OPERATING PARTNERSHIP	'	'
Comprehensive income:	'	'
Net income	82,732	1,061,034
Other comprehensive (loss) income b derivative instruments:	'	'
Unrealized holding (losses) gains arising during the period	-11,952	2,814
Losses reclassified into earnings from other comprehensive income	4,129	8,272
Other comprehensive income b other instruments:	'	'
Unrealized holding gains arising during the period	0	427
Other comprehensive income (loss) b foreign currency:	'	'
Currency translation adjustments arising during the period	91	-873
Other comprehensive (loss) income	-7,732	10,640
Comprehensive income	75,000	1,071,674
Comprehensive (income) attributable to Noncontrolling Interests b Partially Owned Properties	-504	-25
Comprehensive income attributable to controlling interests	$74,496	$1,071,649

CONSOLIDATED_STATEMENTS_OF_CAS

CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
CASH FLOWS FROM OPERATING ACTIVITIES:	'	'
Net income	$82,732	$1,061,034
Adjustments to reconcile net income to net cash provided by operating activities:	'	'
Depreciation	185,167	220,038
Amortization of deferred financing costs	2,792	7,176
Amortization of Intangible Assets	829	292
Amortization of discounts and premiums on debt	-2,938	-7,071
Amortization of deferred settlements on derivative instruments	3,996	8,139
Write-off of pursuit costs	452	2,533
Loss from investments in unconsolidated entities	1,409	46,366
Distributions from unconsolidated entities - return on capital	914	257
Net loss on sales of land parcels	30	0
Net (gain) on sales of discontinued operations	-71	-1,198,922
Unrealized (gain) on derivative instruments	-3	0
Compensation paid with Company Common Shares	12,981	10,236
Changes in assets and liabilities:	'	'
(Increase) decrease in deposits b restricted	-418	1,733
Decrease in mortgage deposits	375	1,651
Decrease in other assets	18,613	15,220
Increase in accounts payable and accrued expenses	55,263	47,498
(Decrease) increase in accrued interest payable	-169	1,039
(Decrease) in other liabilities	-26,194	-18,437
Increase (decrease) in security deposits	1,143	-5,268
Net cash provided by operating activities	336,903	193,514
CASH FLOWS FROM INVESTING ACTIVITIES:	'	'
Payments to Acquire Businesses, Net of Cash Acquired	0	-4,000,643
Investment in real estate b acquisitions	-148,535	0
Investment in real estate - development/other	-122,340	-65,232
Improvements to real estate	-32,191	-26,599
Additions to non-real estate property	-159	-1,942
Interest capitalized for real estate and unconsolidated entities under development	-12,792	-8,413
Proceeds from disposition of real estate, net	0	2,955,398
Investments in unconsolidated entities	-6,254	-283
Proceeds From Distributions Received From Unconsolidated Subsidiaries	7,680	0
Decrease in deposits on real estate acquisitions and investments, net	12,904	101,668
(Increase) decrease in mortgage deposits	-91	4,473
Acquisition of Noncontrolling Interests b Partially Owned Properties	-2,501	0
Net cash (used for) investing activities	-304,279	-1,041,573
CASH FLOWS FROM FINANCING ACTIVITIES:	'	'
Loan and bond acquisition costs	-60	-13,869
Mortgage Deposits	-1,643	-632
Mortgage notes payable:	'	'
Lump sum payoffs	0	-584,020
Scheduled principal repayments	-3,034	-3,244
Notes, net:	'	'
Proceeds from Notes Payable	0	750,000
Line of Credit Facility:	'	'
Proceeds	1,751,000	5,850,000
Repayments	-1,568,000	-5,455,000
Proceeds from Employee Stock Purchase Plan	1,741	1,763
Proceeds from exercise of options	15,785	7,174
Payments for Repurchase of Common Stock	-1,777	0
Payment of offering costs	0	-406
Contributions - Noncontrolling Interests - Partially Owned Properties	5,684	3,299
Contributions - Noncontrolling Interests - Operating Partnership	3	3
Distributions:	'	'
Common Shares	-234,282	-249,330
Preferred Shares	-1,036	0
Noncontrolling Interests b Operating Partnership	-9,217	-10,837
Noncontrolling Interests b Partially Owned Properties	-4,113	-3,345
Net cash (used for) provided by financing activities	-48,949	291,556
Net (decrease) in cash and cash equivalents	-16,325	-556,503
Cash and cash equivalents, beginning of period	53,534	612,590
Cash and cash equivalents, end of period	37,209	56,087
SUPPLEMENTAL INFORMATION:	'	'
Cash paid for interest, net of amounts capitalized	112,152	182,356
Net cash paid for income and other taxes	596	483
AmortizationOfDeferredFinancingCosts [Abstract]	'	'
Amortization Of Deferred Financing Costs Investment In Real Estate Net	0	-1
Amortization Of Deferred Financing Costs Deferred Financing Costs Net	2,792	7,177
Amortization of discounts and premiums on debt:	'	'
Mortgage notes payable	-3,506	-7,557
Notes, net	568	486
Amortization of deferred settlements on derivative instruments:	'	'
Other liabilities	-133	-133
Losses reclassified into earnings from other comprehensive income	4,129	8,272
Loss From Investments In Unconsolidated Entities [Abstract]	'	'
Income Loss From Equity Method Investments Merger	472	42,213
Other Liabilities Loss From Investments in unconsolidated entities	937	4,153
Distributions from unconsolidated entities return on capital [Abstract]	'	'
Distributions from unconsolidated entities investments in unconsolidated entities	862	257
Distributions from unconsolidated entities other liabilities	52	0
Unrealized (gain) on derivative instruments:	'	'
Other assets	7,279	1,471
Notes, net	0	-1,471
Other liabilities	4,670	-2,814
Unrealized holding (losses) gains arising during the period	-11,952	2,814
Acquisition of Archstone, net of cash acquired [Abstract]	'	'
Acquisition of Archstone Investment in Real Estate Net	39,929	-8,707,967
Acquisition of Archstone Investments in Unconsolidated Entities	-33,993	-218,197
Acquisition of Archstone Deposits Restricted	0	-474
Acquisition of Archstone Escrow Deposits Mortgage	0	-35,898
Acquisition of Archstone Deferred Financing Costs	0	-25,780
Acquisition of Archstone Other Assets	-2,586	-204,523
Acquisition of Archstone Mortgage Notes Payable	0	3,076,876
Acquisition of Archstone Accounts Payable And Accrued Liabilities	-146	17,593
Acqusition of Archstone Interest Payable	0	11,256
Acquisition of Archstone Other Liabilities	-3,204	117,391
Acquisition of Archstone Security Deposits	0	10,949
Acquisition of Archstone Common Shares Issued	0	1,929,868
Acquisition of Archstone Noncontrolling Interests Partially Owned Properties	0	28,263
Interest capitalized for real estate and unconsolidated entities under development:	'	'
Investment in real estate, net	-12,774	-8,089
Investments in unconsolidated entities	-18	-324
Investments in unconsolidated entities [Abstract]	'	'
Investments in unconsolidated entities	-1,454	-283
Investments in unconsolidated entities other liabilities	-4,800	0
Other:	'	'
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax	($91)	$873

CONSOLIDATED_STATEMENTS_OF_CAS1

CONSOLIDATED STATEMENTS OF CASH FLOWS OF ERP OPERATING LIMITED PARTNERSHIP (Unaudited) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
CASH FLOWS FROM OPERATING ACTIVITIES:	'	'
Net income	$82,732	$1,061,034
Adjustments to reconcile net income to net cash provided by operating activities:	'	'
Depreciation	185,167	220,038
Amortization of deferred financing costs	2,792	7,176
Amortization of Intangible Assets	829	292
Amortization of discounts and premiums on debt	-2,938	-7,071
Amortization of deferred settlements on derivative instruments	3,996	8,139
Write-off of pursuit costs	452	2,533
Loss from investments in unconsolidated entities	1,409	46,366
Distributions from unconsolidated entities - return on capital	914	257
Net (gain) on sales of discontinued operations	-71	-1,198,922
Unrealized (gain) on derivative instruments	-3	0
Compensation paid with Company Common Shares	12,981	10,236
Changes in assets and liabilities:	'	'
(Increase) decrease in deposits b restricted	-418	1,733
Decrease in mortgage deposits	375	1,651
Decrease in other assets	18,613	15,220
Increase in accounts payable and accrued expenses	55,263	47,498
(Decrease) increase in accrued interest payable	-169	1,039
(Decrease) in other liabilities	-26,194	-18,437
Increase (decrease) in security deposits	1,143	-5,268
Net cash provided by operating activities	336,903	193,514
CASH FLOWS FROM INVESTING ACTIVITIES:	'	'
Payments to Acquire Businesses, Net of Cash Acquired	0	-4,000,643
Investment in real estate - acquisitions	-148,535	0
Investment in real estate - development/other	-122,340	-65,232
Improvements to real estate	-32,191	-26,599
Additions to non-real estate property	-159	-1,942
Interest capitalized for real estate and unconsolidated entities under development	-12,792	-8,413
Proceeds from disposition of real estate, net	0	2,955,398
Investments in unconsolidated entities	-6,254	-283
Proceeds From Distributions Received From Unconsolidated Subsidiaries	7,680	0
Decrease in deposits on real estate acquisitions and investments, net	12,904	101,668
(Increase) decrease in mortgage deposits	-91	4,473
Acquisition of Noncontrolling Interests b Partially Owned Properties	-2,501	0
Net cash (used for) investing activities	-304,279	-1,041,573
CASH FLOWS FROM FINANCING ACTIVITIES:	'	'
Loan and bond acquisition costs	-60	-13,869
Mortgage Deposits	-1,643	-632
Mortgage notes payable:	'	'
Scheduled principal repayments	-3,034	-3,244
Notes, net:	'	'
Proceeds from Notes Payable	0	750,000
Line of Credit Facility:	'	'
Proceeds	1,751,000	5,850,000
Repayments	-1,568,000	-5,455,000
Proceeds from exercise of options	15,785	7,174
Payment of offering costs	0	-406
Contributions - Noncontrolling Interests - Partially Owned Properties	5,684	3,299
Contributions - Noncontrolling Interests - Operating Partnership	3	3
Distributions:	'	'
Noncontrolling Interests b Partially Owned Properties	-4,113	-3,345
Net cash (used for) provided by financing activities	-48,949	291,556
Net (decrease) in cash and cash equivalents	-16,325	-556,503
Cash and cash equivalents, beginning of period	53,534	612,590
Cash and cash equivalents, end of period	37,209	56,087
SUPPLEMENTAL INFORMATION:	'	'
Cash paid for interest, net of amounts capitalized	112,152	182,356
Net cash paid for income and other taxes	596	483
AmortizationOfDeferredFinancingCosts [Abstract]	'	'
Amortization Of Deferred Financing Costs Investment In Real Estate Net	0	-1
Amortization Of Deferred Financing Costs Deferred Financing Costs Net	2,792	7,177
Amortization of discounts and premiums on debt:	'	'
Mortgage notes payable	-3,506	-7,557
Notes, net	568	486
Amortization of deferred settlements on derivative instruments:	'	'
Other liabilities	-133	-133
Losses reclassified into earnings from other comprehensive income	-4,129	-8,272
Loss From Investments In Unconsolidated Entities [Abstract]	'	'
Income Loss From Equity Method Investments Merger	472	42,213
Other Liabilities Loss From Investments in unconsolidated entities	937	4,153
Distributions from unconsolidated entities return on capital [Abstract]	'	'
Distributions from unconsolidated entities investments in unconsolidated entities	862	257
Distributions from unconsolidated entities other liabilities	52	0
Unrealized (gain) on derivative instruments:	'	'
Other assets	7,279	1,471
Notes, net	0	-1,471
Other liabilities	4,670	-2,814
Unrealized holding (losses) gains arising during the period	-11,952	2,814
Acquisition of Archstone, net of cash acquired [Abstract]	'	'
Acquisition of Archstone Investment in Real Estate Net	39,929	-8,707,967
Acquisition of Archstone Investments in Unconsolidated Entities	-33,993	-218,197
Acquisition of Archstone Deposits Restricted	0	-474
Acquisition of Archstone Escrow Deposits Mortgage	0	-35,898
Acquisition of Archstone Deferred Financing Costs	0	-25,780
Acquisition of Archstone Other Assets	-2,586	-204,523
Acquisition of Archstone Mortgage Notes Payable	0	3,076,876
Acquisition of Archstone Accounts Payable And Accrued Liabilities	-146	17,593
Acqusition of Archstone Interest Payable	0	11,256
Acquisition of Archstone Other Liabilities	-3,204	117,391
Acquisition of Archstone Security Deposits	0	10,949
Acquisition of Archstone Common Shares Issued	0	1,929,868
Acquisition of Archstone Noncontrolling Interests Partially Owned Properties	0	28,263
Interest capitalized for real estate and unconsolidated entities under development:	'	'
Investment in real estate, net	-12,774	-8,089
Investments in unconsolidated entities	-18	-324
Investments in unconsolidated entities [Abstract]	'	'
Investments in unconsolidated entities	-1,454	-283
Investments in unconsolidated entities other liabilities	-4,800	0
Other:	'	'
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax	-91	873
OPERATING PARTNERSHIP	'	'
CASH FLOWS FROM OPERATING ACTIVITIES:	'	'
Net income	82,732	1,061,034
Adjustments to reconcile net income to net cash provided by operating activities:	'	'
Depreciation	185,167	220,038
Amortization of deferred financing costs	2,792	7,176
Amortization of Intangible Assets	829	292
Amortization of discounts and premiums on debt	-2,938	-7,071
Amortization of deferred settlements on derivative instruments	3,996	8,139
Write-off of pursuit costs	452	2,533
Loss from investments in unconsolidated entities	1,409	46,366
Distributions from unconsolidated entities - return on capital	914	257
Net loss on sales of land parcels	30	0
Net (gain) on sales of discontinued operations	-71	-1,198,922
Unrealized (gain) on derivative instruments	-3	0
Compensation paid with Company Common Shares	12,981	10,236
Changes in assets and liabilities:	'	'
(Increase) decrease in deposits b restricted	-418	1,733
Decrease in mortgage deposits	375	1,651
Decrease in other assets	18,613	15,220
Increase in accounts payable and accrued expenses	55,263	47,498
(Decrease) increase in accrued interest payable	-169	1,039
(Decrease) in other liabilities	-26,194	-18,437
Increase (decrease) in security deposits	1,143	-5,268
Net cash provided by operating activities	336,903	193,514
CASH FLOWS FROM INVESTING ACTIVITIES:	'	'
Payments to Acquire Businesses, Net of Cash Acquired	0	-4,000,643
Investment in real estate - acquisitions	-148,535	0
Investment in real estate - development/other	-122,340	-65,232
Improvements to real estate	-32,191	-26,599
Additions to non-real estate property	-159	-1,942
Interest capitalized for real estate and unconsolidated entities under development	-12,792	-8,413
Proceeds from disposition of real estate, net	0	2,955,398
Investments in unconsolidated entities	-6,254	-283
Proceeds From Distributions Received From Unconsolidated Subsidiaries	7,680	0
Decrease in deposits on real estate acquisitions and investments, net	12,904	101,668
(Increase) decrease in mortgage deposits	-91	4,473
Acquisition of Noncontrolling Interests b Partially Owned Properties	-2,501	0
Net cash (used for) investing activities	-304,279	-1,041,573
CASH FLOWS FROM FINANCING ACTIVITIES:	'	'
Loan and bond acquisition costs	-60	-13,869
Mortgage Deposits	-1,643	-632
Mortgage notes payable:	'	'
Lump sum payoffs	0	-584,020
Scheduled principal repayments	-3,034	-3,244
Notes, net:	'	'
Proceeds from Notes Payable	0	750,000
Line of Credit Facility:	'	'
Proceeds	1,751,000	5,850,000
Repayments	-1,568,000	-5,455,000
Stock Issued During Period, Value, Employee Stock Purchase Plan	1,741	1,763
Proceeds from exercise of options	15,785	7,174
Payments For Repurchase Of Op Units	-1,777	0
Payment of offering costs	0	-406
Contributions - Noncontrolling Interests - Partially Owned Properties	5,684	3,299
Contributions - Noncontrolling Interests - Operating Partnership	3	3
Distributions:	'	'
OP Units - General Partner	-234,282	-249,330
Preference Units	-1,036	0
OP Units - Limited Partners	-9,217	-10,837
Noncontrolling Interests b Partially Owned Properties	-4,113	-3,345
Net cash (used for) provided by financing activities	-48,949	291,556
Net (decrease) in cash and cash equivalents	-16,325	-556,503
Cash and cash equivalents, beginning of period	53,534	612,590
Cash and cash equivalents, end of period	37,209	56,087
SUPPLEMENTAL INFORMATION:	'	'
Cash paid for interest, net of amounts capitalized	112,152	182,356
Net cash paid for income and other taxes	596	483
AmortizationOfDeferredFinancingCosts [Abstract]	'	'
Amortization Of Deferred Financing Costs Investment In Real Estate Net	0	-1
Amortization Of Deferred Financing Costs Deferred Financing Costs Net	2,792	7,177
Amortization of discounts and premiums on debt:	'	'
Mortgage notes payable	-3,506	-7,557
Notes, net	568	486
Amortization of deferred settlements on derivative instruments:	'	'
Other liabilities	-133	-133
Losses reclassified into earnings from other comprehensive income	4,129	8,272
Loss From Investments In Unconsolidated Entities [Abstract]	'	'
Income Loss From Equity Method Investments Merger	472	42,213
Other Liabilities Loss From Investments in unconsolidated entities	937	4,153
Distributions from unconsolidated entities return on capital [Abstract]	'	'
Distributions from unconsolidated entities investments in unconsolidated entities	862	257
Distributions from unconsolidated entities other liabilities	52	0
Unrealized (gain) on derivative instruments:	'	'
Other assets	7,279	1,471
Notes, net	0	-1,471
Other liabilities	4,670	-2,814
Unrealized holding (losses) gains arising during the period	-11,952	2,814
Acquisition of Archstone, net of cash acquired [Abstract]	'	'
Acquisition of Archstone Investment in Real Estate Net	39,929	-8,707,967
Acquisition of Archstone Investments in Unconsolidated Entities	-33,993	-218,197
Acquisition of Archstone Deposits Restricted	0	-474
Acquisition of Archstone Escrow Deposits Mortgage	0	-35,898
Acquisition of Archstone Deferred Financing Costs	0	-25,780
Acquisition of Archstone Other Assets	-2,586	-204,523
Acquisition of Archstone Mortgage Notes Payable	0	3,076,876
Acquisition of Archstone Accounts Payable And Accrued Liabilities	-146	17,593
Acqusition of Archstone Interest Payable	0	11,256
Acquisition of Archstone Other Liabilities	-3,204	117,391
Acquisition of Archstone Security Deposits	0	10,949
Acquisition of Archstone Common Shares Issued	0	1,929,868
Acquisition of Archstone Noncontrolling Interests Partially Owned Properties	0	28,263
Interest capitalized for real estate and unconsolidated entities under development:	'	'
Investment in real estate, net	-12,774	-8,089
Investments in unconsolidated entities	-18	-324
Investments in unconsolidated entities [Abstract]	'	'
Investments in unconsolidated entities	-1,454	-283
Investments in unconsolidated entities other liabilities	-4,800	0
Other:	'	'
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax	($91)	$873

CONSOLIDATED_STATEMENT_OF_CHAN

CONSOLIDATED STATEMENT OF CHANGES IN EQUITY (Unaudited) (USD $)	Total	PREFERRED SHARES	COMMON SHARES, $0.01 PAR VALUE	Additional Paid-in Capital [Member]	RETAINED EARNINGS	Accumulated Other Comprehensive (Loss)	OPERATING PARTNERSHIP	Partially Owned Properties [Member]
In Thousands, unless otherwise specified
Beginning Balance, Noncontrolling Interest at Dec. 31, 2013	$337,995	'	'	'	'	'	$211,412	$126,583
Beginning Balance, Parent at Dec. 31, 2013	10,507,201	50,000	3,605	8,561,500	2,047,258	-155,162	'	'
Common Share Issuance:	'	'	'	'	'	'	'	'
Conversion of OP Units held by Noncontrolling Interests into OP Units held by General Partner	'	'	'	480	'	'	-480	'
Exercise of share options	'	'	5	15,780	'	'	'	'
Stock Issued During Period, Value, Employee Stock Purchase Plan	'	'	'	1,741	'	'	'	'
Conversion of restricted shares to Ltip Units	'	'	'	-278	'	'	278	'
Share-based employee compensation expense:	'	'	'	'	'	'	'	'
Adjustments to Additional Paid in Capital, Share-based Compensation, Restricted Stock Unit or Restricted Stock Award, Requisite Service Period Recognition	'	'	1	4,869	'	'	'	'
Share options	'	'	'	3,122	'	'	'	'
ESPP discount	'	'	'	477	'	'	'	'
Payments for Repurchase of Common Stock	-1,777	'	'	-1,777	'	'	'	'
Supplemental Executive Retirement Plan (SERP)	'	'	'	848	'	'	'	'
Acquisition Noncontrolling Interests Partially Owned Properties	'	'	'	-553	'	'	'	-1,000
Change in market value	-44,530	'	'	-44,530	'	'	'	'
Adjustment for Noncontrolling Interests ownership in Operating Partnership	'	'	'	-633	'	'	633	'
Net income attributable to controlling interests	79,135	'	'	'	79,135	'	'	'
Common Share distributions	'	'	'	'	-180,559	'	'	'
Dividends, Preferred Stock, Cash	'	'	'	'	-1,036	'	'	'
Other comprehensive (loss) income b derivative instruments:	'	'	'	'	'	'	'	'
Unrealized holding (losses) gains arising during the period	-11,952	'	'	'	'	-11,952	'	'
Losses reclassified into earnings from other comprehensive income	-4,129	'	'	'	'	4,129	'	'
Currency translation adjustments arising during the period	91	'	'	'	'	91	'	'
Issuance of LTIP Units to Noncontrolling Interests	'	'	'	'	'	'	3	'
Equity Compensation associated with Noncontrolling Interests	'	'	'	'	'	'	5,190	'
Net (Income) Attributable to Noncontrolling Interest	3,093	'	'	'	'	'	3,093	504
Contributions by Noncontrolling Interests	5,684	'	'	'	'	'	'	5,684
Distributions to Noncontrolling Interests	'	'	'	'	'	'	-7,188	-4,113
Change in carrying value	-2,398	'	'	'	'	'	2,398	'
Ending Balance, Noncontrolling Interest at Mar. 31, 2014	342,997	'	'	'	'	'	215,339	127,658
Ending Balance, Parent at Mar. 31, 2014	$10,376,561	$50,000	$3,611	$8,541,046	$1,944,798	($162,894)	'	'

CONSOLIDATED_STATEMENT_OF_CHAN1

CONSOLIDATED STATEMENT OF CHANGES IN CAPITAL OF ERP OPERATING LIMITED PARTNERSHIP (Unaudited) (USD $)	Total	PREFERRED UNITS	General Partner [Member]	Limited Partner [Member]	Accumulated Other Comprehensive (Loss)	Partially Owned Properties [Member]
In Thousands, unless otherwise specified
Balance, beginning of year - Noncontrolling Interest at Dec. 31, 2013	'	'	'	'	'	$126,583
Balance, beginning of year at Dec. 31, 2013	'	50,000	10,612,363	211,412	-155,162	'
OP Unit Issuance:	'	'	'	'	'	'
Conversion of OP Units held by Limited Partners into OP Units held by General Partner	'	'	480	-480	'	'
Exercise of EQR share options	'	'	15,785	'	'	'
Stock Issued During Period, Value, Employee Stock Purchase Plan	'	'	1,741	'	'	'
Conversion of restricted shares to Ltip Units	'	'	-278	278	'	'
Share-based employee compensation expense:	'	'	'	'	'	'
EQR restricted shares	'	'	4,870	'	'	'
EQR share options	'	'	3,122	'	'	'
EQR ESPP discount	'	'	477	'	'	'
Payments For Repurchase Of Op Units	'	'	-1,777	'	'	'
Net income available to Units - General Partner	'	'	78,099	'	'	'
OP Units - General Partner distributions	'	'	-180,559	'	'	'
Supplemental Executive Retirement Plan (SERP)	'	'	848	'	'	'
Acquisition Noncontrolling Interests Partially Owned Properties	'	'	-553	'	'	-1,000
Change in market value of Redeemable Limited Partners	'	'	-44,530	'	'	'
Adjustment for Limited Partners ownership in Operating Partnership	'	'	-633	633	'	'
Issuance of LTIP Units to Noncontrolling Interests	'	'	'	3	'	'
Equity compensation associated with Units - Limited Partners	'	'	'	5,190	'	'
Net Income (Loss) Allocated to Limited Partners	'	'	'	3,093	'	'
Net (income) attributable to Noncontrolling Interests b Partially Owned Properties	504	'	'	'	'	504
Units - Limited Partners distributions	'	'	'	-7,188	'	-4,113
Change in carrying value of Redeemable Limited Partners	'	'	'	2,398	'	'
Other comprehensive (loss) income b derivative instruments:	'	'	'	'	'	'
Unrealized holding (losses) gains arising during the period	-11,952	'	'	'	-11,952	'
Losses reclassified into earnings from other comprehensive income	-4,129	'	'	'	4,129	'
Currency translation adjustments arising during the period	91	'	'	'	91	'
Contributions by Noncontrolling Interests	5,684	'	'	'	'	5,684
Balance, end of period - Noncontrolling Interest at Mar. 31, 2014	'	'	'	'	'	127,658
Balance, end of period at Mar. 31, 2014	'	$50,000	$10,489,455	$215,339	($162,894)	'

Business

Business	3 Months Ended
	Mar. 31, 2014
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, 2014 owned an approximate 96.2% 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, 2014, the Company, directly or indirectly through investments in title holding entities, owned all or a portion of 396 properties located in 12 states and the District of Columbia consisting of 111,537 apartment units. The ownership breakdown includes (table does not include various uncompleted development properties):
			Properties	Apartment
				Units
	Wholly Owned Properties		367	99,936
	Master-Leased Properties – Consolidated		3	853
	Partially Owned Properties – Consolidated		20	4,020
	Partially Owned Properties – Unconsolidated		4	1,669
	Military Housing		2	5,059
			396	111,537

Summary_of_Significant_Account

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2014
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. Operating results for the quarter ended March 31, 2014 are not necessarily indicative of the results that may be expected for the year ending December 31, 2014.
	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, 2013 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, 2013.
	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, 2014, the Company has recorded a deferred tax asset, which is fully offset by a valuation allowance due to the uncertainty in forecasting future TRS taxable income.
	Other
	The Company is the controlling partner in various consolidated partnerships owning 20 properties and 4,020 apartment units and various completed and uncompleted development properties having a noncontrolling interest book value of $127.7 million at March 31, 2014. 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 six properties having a noncontrolling interest deficit balance of $10.0 million. These six 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, 2014, the Company estimates the value of Noncontrolling Interest distributions for these six properties would have been approximately $52.5 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 six 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, 2014 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.
	Effective January 1, 2013, companies are required to report, in one place, information about reclassifications out of accumulated other comprehensive income ("AOCI"). Companies are also required to report changes in AOCI balances. For significant items reclassified out of AOCI to net income in their entirety in the same reporting period, reporting is required about the effect of the reclassifications on the respective line items in the statement where net income is presented. For items that are not reclassified to net income in their entirety in the same reporting period, a cross reference to other disclosures currently required under US GAAP is required in the notes. This does not have a material effect on the Company's consolidated results of operations or financial position. See Note 9 for further discussion.
	Effective January 1, 2014, companies are required to measure obligations resulting from joint and several liability arrangements for which the total amount of the obligation is fixed at the reporting date as the sum of the amount a company agreed to pay on the basis of its arrangement among its co-obligors and any additional amount a company expects to pay on behalf of its co-obligors. Companies are required to disclose the nature and amount of the obligation as well as other information about those obligations. This does not have a material effect on the Company's consolidated results of operations or financial position.
	Effective January 1, 2015, the criteria for reporting discontinued operations will change. 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 will be required to expand their disclosures about discontinued operations to provide more information on the assets, liabilities, income and expenses of the discontinued operations. Companies will also be 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 is permitted, but only for disposals (or classifications as held for sale) that have not been reported in financial statements previously issued. The Company adopted this standard effective January 1, 2014 but did not have any dispositions in the first quarter of 2014. Adoption of this standard did not have a material effect on the Company's overall consolidated results of operations or financial position. However, adoption will result in substantially fewer of the Company's dispositions meeting the discontinued operations qualifications.

Equity_Capital_and_Other_Inter

Equity, Capital and Other Interests	3 Months Ended
	Mar. 31, 2014
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 Long-Term Incentive Plan (“LTIP”) Units) for the quarter ended March 31, 2014:
			2014
	Common Shares
	Common Shares outstanding at January 1,		360,479,260
	Common Shares Issued:
	Conversion of OP Units		18,043
	Exercise of share options		493,995
	Employee Share Purchase Plan (ESPP)		37,928
	Restricted share grants, net		162,349
	Common Shares Other:
	Conversion of restricted shares to LTIP Units		(12,146	)
	Repurchased and retired		(31,240	)
	Common Shares outstanding at March 31,		361,148,189
	Units
	Units outstanding at January 1,		14,180,376
	LTIP Units, net		200,840
	Conversion of restricted shares to LTIP Units		12,146
	Conversion of OP Units to Common Shares		(18,043	)
	Units outstanding at March 31,		14,375,319
	Total Common Shares and Units outstanding at March 31,		375,523,508
	Units Ownership Interest in Operating Partnership		3.8	%
	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 LTIP Units, are collectively referred to as the “Noncontrolling Interests – Operating Partnership”. Subject to certain exceptions (including the “book-up” requirements of LTIP 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 can not 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, 2014 and December 31, 2013.
	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, 2014, the Redeemable Noncontrolling Interests – Operating Partnership have a redemption value of approximately $405.3 million, which represents the value of Common Shares that would be issued in exchange with 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, 2014 (amounts in thousands):
			2014
	Balance at January 1,		$	363,144
	Change in market value		44,530
	Change in carrying value		(2,398		)
	Balance at March 31,		$	405,276
	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, 2014 and December 31, 2013:
							Amounts in thousands
			Redemption		Annual		March 31,		December 31,
			Date (1)		Dividend per		2014		2013
					Share (2)
	Preferred Shares of beneficial interest, $0.01 par value;
	100,000,000 shares authorized:
	8.29% Series K Cumulative Redeemable Preferred; liquidation		12/10/26			$4.14	$	50,000	$	50,000
	value $50 per share; 1,000,000 shares issued and outstanding
	at March 31, 2014 and December 31, 2013
							$	50,000	$	50,000
	-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, 2014:
			2014
	General and Limited Partner Units
	General and Limited Partner Units outstanding at January 1,		374,659,636
	Issued to General Partner:
	Exercise of EQR share options		493,995
	EQR’s Employee Share Purchase Plan (ESPP)		37,928
	EQR's restricted share grants, net		162,349
	Issued to Limited Partners:
	LTIP Units, net		200,840
	OP Units Other:
	Repurchased and retired		(31,240	)
	General and Limited Partner Units outstanding at March 31,		375,523,508
Limited Partner Units
Limited Partner Units outstanding at January 1,		14,180,376
Limited Partner LTIP Units, net		200,840
Conversion of EQR restricted shares to LTIP Units		12,146
Conversion of Limited Partner OP Units to EQR Common Shares		(18,043	)
Limited Partner Units outstanding at March 31,		14,375,319
Limited Partner Units Ownership Interest in Operating Partnership		3.8	%
The Limited Partners of the Operating Partnership as of March 31, 2014 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 LTIP Units. Subject to certain exceptions (including the “book-up” requirements of LTIP 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 can not 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, 2014 and December 31, 2013.
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, 2014, the Redeemable Limited Partner Units have a redemption value of approximately $405.3 million, which represents the value of Common Shares that would be issued in exchange with 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, 2014 (amounts in thousands):
		2014
Balance at January 1,		$	363,144
Change in market value		44,530
Change in carrying value		(2,398		)
Balance at March 31,		$	405,276
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, 2014 and December 31, 2013:
						Amounts in thousands
		Redemption		Annual		March 31,		December 31,
		Date (1)		Dividend per		2014		2013
				Unit (2)
Preference Units:
8.29% Series K Cumulative Redeemable Preference Units;		12/10/26			$4.14	$	50,000	$	50,000
liquidation value $50 per unit; 1,000,000 units issued and
outstanding at March 31, 2014 and December 31, 2013
						$	50,000	$	50,000
-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
On February 27, 2013, the Company issued 34,468,085 Common Shares to an affiliate of Lehman Brothers Holdings Inc. as partial consideration for the portion of the Archstone Portfolio acquired by the Company (as discussed in Note 4 below). The shares had a total value of $1.9 billion based on the February 27, 2013 closing price of EQR Common Shares of $55.99 per share. Concurrent with this transaction, ERPOP issued 34,468,085 OP Units to EQR. On March 7, 2013, EQR filed a shelf registration statement relating to the resale of these shares by the selling shareholders.
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. Considering the repurchase activity for the quarter ended March 31, 2014 (see discussion below), EQR has remaining authorization to repurchase an additional 12,968,760 of its shares as of March 31, 2014.
During the quarter ended March 31, 2014, EQR repurchased 31,240 of its Common Shares at a price of $56.87 per share for total consideration of approximately $1.8 million. These shares were retired subsequent to the repurchases. Concurrent with these transactions, ERPOP repurchased and retired 31,240 OP Units previously issued to EQR. All of the shares repurchased during the quarter ended March 31, 2014 were repurchased from employees at the then current market price to cover the minimum statutory tax withholding obligations related to the vesting of employees’ restricted shares.
During the quarter ended March 31, 2014, the Company acquired all of its partner's interest in one consolidated partially owned land parcel for $2.5 million. In conjunction with this transaction, the Company reduced paid in capital (included in general partner's capital in the Operating Partnership's financial statements) by $0.5 million, Noncontrolling Interests – Partially Owned Properties by $1.0 million and other liabilities by $1.0 million.
See Note 6 for a discussion of the Noncontrolling Interests assumed in conjunction with the acquisition of Archstone.

Real_Estate

Real Estate	3 Months Ended
	Mar. 31, 2014
Real Estate [Abstract]	'
Real Estate Disclosure [Text Block]	'
	4	Real Estate and Lease Intangibles
	The following table summarizes the carrying amounts for the Company’s investment in real estate (at cost) as of March 31, 2014 and December 31, 2013 (amounts in thousands):
			March 31,				December 31,
			2014				2013
	Land		$	6,281,124			$	6,192,512
	Depreciable property:
	Buildings and improvements		17,843,201				17,509,609
	Furniture, fixtures and equipment		1,273,171				1,214,220
	In-Place lease intangibles		507,100				502,218
	Projects under development:
	Land		390,850				353,574
	Construction-in-progress		474,327				635,293
	Land held for development:
	Land		253,350				341,389
	Construction-in-progress		42,007				52,133
	Investment in real estate		27,065,130				26,800,948
	Accumulated depreciation		(4,992,877		)		(4,807,709		)
	Investment in real estate, net		$	22,072,253			$	21,993,239
	The following table summarizes the carrying amounts for the Company's above and below market ground and retail lease intangibles as of March 31, 2014 and December 31, 2013 (amounts in thousands):
	Description		Balance Sheet Location		March 31,				December 31,
					2014				2013
	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				(5,502		)		(4,364		)
	Lease intangible assets, net				$	174,009			$	175,147
	Liabilities
	Ground lease intangibles – above market		Other Liabilities		$	2,400			$	2,400
	Retail lease intangibles – below market		Other Liabilities		5,500				5,500
	Lease intangible liabilities				7,900				7,900
	Accumulated amortization				(1,471		)		(1,161		)
	Lease intangible liabilities, net				$	6,429			$	6,739
	During the quarters ended March 31, 2014 and 2013, the Company amortized approximately $1.1 million and $0.4 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 $0.3 million and $0.1 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 weighted average amortization period for above and below market ground lease intangibles and retail lease intangibles is 49.8 years and 2.8 years, respectively.
	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
			2014				2015				2016			2017			2018			2019
	Ground lease intangibles		$	3,241			$	4,321			$	4,321		$	4,321		$	4,321		$	4,321
	Retail lease intangibles		(758		)		(1,016		)		(908		)	(540		)	(71		)	(71		)
	Total		$	2,483			$	3,305			$	3,413		$	3,781		$	4,250		$	4,250
	Archstone Acquisition
	On February 27, 2013, the Company, AvalonBay Communities, Inc. (“AVB”) and certain of their respective subsidiaries completed their previously announced acquisition (the “Archstone Acquisition” or the “Archstone Transaction”) from Archstone Enterprise LP (“Enterprise”) (which subsequently changed its name to Jupiter Enterprise LP), an affiliate of Lehman Brothers Holdings, Inc. (“Lehman”) and its affiliates, of all of the assets of Enterprise (including interests in various entities affiliated with Enterprise), constituting a portfolio of apartment properties and other assets (the “Archstone Portfolio”).
	The Company acquired assets representing approximately 60% of the Archstone Portfolio which consisted principally of high-quality apartment properties in major markets in the United States. The acquisition allowed the Company to accelerate the completion of its strategic shift into coastal apartment markets. Pursuant to the Archstone Transaction, the Company acquired directly or indirectly, 71 wholly owned, stabilized properties consisting of 20,160 apartment units, one partially owned and consolidated stabilized property consisting of 432 apartment units, one partially owned and unconsolidated stabilized property consisting of 336 apartment units, three consolidated master-leased properties consisting of 853 apartment units, four projects in various stages of construction (two consolidated and two unconsolidated) for 964 apartment units and fourteen land sites for approximately $9.0 billion. During the quarter ended March 31, 2013, the Company recorded revenues and net operating income ("NOI") of $52.6 million and $36.2 million, respectively, from the acquired assets.
	The consideration paid by the Company in connection with the Archstone Acquisition consisted of cash of approximately $4.0 billion (inclusive of $2.0 billion of Archstone secured mortgage principal paid off in conjunction with the closing), 34,468,085 Common Shares (which shares had a total value of $1.9 billion based on the February 27, 2013 closing price of EQR common shares of $55.99 per share) issued to the seller and the assumption of approximately $3.1 billion of mortgage debt (inclusive of a net mark-to-market premium of $127.9 million) and approximately 60% of all of the other assets and liabilities related to the Archstone Portfolio. The cash consideration was funded with proceeds from the issuance of 21,850,000 Common Shares (which shares had a total value of approximately $1.2 billion based on a price of $54.75 per share) in the November/December 2012 public equity offering, asset sales of approximately $4.5 billion that were completed during the year ended December 31, 2013, the Company's $750.0 million unsecured term loan facility and the Company's revolving credit facility.
	The Company owns the building and improvements and leases the land underlying the improvements under long-term ground leases that expire beginning in 2042 and running through 2103 for nine of the operating properties acquired and discussed above. These properties are consolidated and reflected as real estate assets while the ground leases are accounted for as operating leases. The Company also leases the three master-leased properties discussed above to third party operators and earns monthly net rental income.
	The Company accounted for the acquisition under the acquisition method in accordance with Accounting Standards Codification ("ASC") 805, Business Combinations (“ASC 805”), and the accounting for this business combination is complete and final. The following table summarizes the acquisition date fair values of the assets acquired and liabilities assumed, which the Company determined using Level 1, Level 2 and Level 3 inputs (amounts in thousands):
	Land		$	2,239,000
	Depreciable property:
	Buildings and improvements		5,765,538
	Furniture, fixtures and equipment		61,470
	In-Place lease intangibles		304,830
	Projects under development		36,583
	Land held for development		244,097
	Investments in unconsolidated entities		230,608
	Other assets		195,260
	Other liabilities		(108,997		)
	Net assets acquired		$	8,968,389
	The allocation of fair values of the assets acquired and liabilities assumed has changed from the allocation reported in “Note 4 – Real Estate and Lease Intangibles” in the Notes to Consolidated Financial Statements included in Part II of our Annual Report on Form 10-K for the year ended December 31, 2013 filed with the SEC on February 27, 2014. The changes to our valuation assumptions were based on more accurate information concerning the subject assets and liabilities and resulted from information not readily available at the acquisition date, final purchase price settlement with our partner in accordance with the terms of the purchase agreement and reclassification adjustments for presentation. None of these changes had a material impact on our Consolidated Financial Statements. The Company's assessment of the fair values and the allocation of the purchase price to the identified tangible and intangible assets/liabilities is its final and best estimate of fair value.
	The fair values of investment in real estate were determined using internally developed models that were based on market assumptions and comparable sales data as well as external valuations performed by unrelated third parties. The market assumptions used as inputs to the Company’s fair value model include construction costs, leasing assumptions, growth rates, discount rates, terminal capitalization rates and development yields. The Company used data on its existing portfolio of properties and its recent acquisition and development properties, as well as similar market data from third party sources, when available, in determining these inputs (Level 2 and 3). The fair value of Noncontrolling Interests was calculated similar to the investment in real estate described above. The fair value of mortgage debt was calculated using indicative rates, leverage and coverage provided by lenders of similar loans (Level 2). The Common Shares issued to an affiliate of Lehman Brothers Holdings, Inc. were valued using the quoted market price of Common Shares (Level 1).
	The following table summarizes the acquisition date fair values of the above and below market ground and retail lease intangibles, which we determined using Level 2 and Level 3 inputs (amounts in thousands):
	Description		Balance Sheet Location		Fair Value
	Ground lease intangibles – below market		Other Assets		$	178,251
Retail lease intangibles – above market		Other Assets		1,260
Ground lease intangibles – above market		Other Liabilities		2,400
Retail lease intangibles – below market		Other Liabilities		8,040
As of March 31, 2014, the Company has incurred cumulative Archstone-related expenses of approximately $94.7 million, of which approximately $13.5 million of this total was financing-related and approximately $81.2 million was merger costs. During the quarter ended March 31, 2014, the Company expensed nominal amounts of direct and indirect merger costs. During the quarter ended March 31, 2013, the Company expensed $19.1 million of direct merger costs primarily related to investment banking and legal/accounting fees, which were included in other expenses in the accompanying consolidated statements of operations and comprehensive income. During the quarter ended March 31, 2013, the Company also expensed $46.0 million of indirect merger costs primarily related to severance and retention obligations through our 60% interest in an unconsolidated joint venture with AVB, which were included in (loss) from investments in unconsolidated entities in the accompanying consolidated statements of operations and comprehensive income. Finally, during the quarter ended March 31, 2013, the Company also expensed $2.5 million of financing-related costs, which were included in interest expense in the accompanying consolidated statements of operations and comprehensive income.
Unaudited Pro Forma Financial Information
Equity Residential
The following table illustrates the effect on net income, earnings per share – basic and earnings per share – diluted as if the Company had consummated the Archstone Acquisition as of January 1, 2012 (amounts in thousands, except per share amounts):
		Quarter Ended
		31-Mar-13
Total revenues		$	638,499
(Loss) from continuing operations (1)		(34,473		)
Discontinued operations, net		1,213,615
Net income		1,179,142
Net income available to Common Shares		1,130,671
Earnings per share - basic:
Net income available to Common Shares		$	3.15
Weighted average Common Shares outstanding (2)		359,362
Earnings per share - diluted (1):
Net income available to Common Shares		$	3.15
Weighted average Common Shares outstanding (2)		359,362
-1	Potential common shares issuable from the assumed conversion of OP Units and the exercise/vesting of long-term compensation shares/units are automatically anti-dilutive and therefore excluded from the diluted earnings per share calculation as the Company had a pro forma loss from continuing operations for the quarter ended March 31, 2013.
-2	Includes an adjustment for Common Shares issued to the public in November/December 2012 and to an affiliate of Lehman Brothers Holdings Inc. in February 2013 as partial consideration for the Archstone Acquisition.
ERP Operating Limited Partnership
The following table illustrates the effect on net income, earnings per Unit – basic and earnings per Unit – diluted as if the Operating Partnership had consummated the Archstone Acquisition as of January 1, 2012 (amounts in thousands, except per Unit amounts):
		Quarter Ended
		31-Mar-13
Total revenues		$	638,499
(Loss) from continuing operations (1)		(34,473		)
Discontinued operations, net		1,213,615
Net income		1,179,142
Net income available to Units		1,178,887
Earnings per Unit - basic:
Net income available to Units		$	3.15
Weighted average Units outstanding (2)		373,085
Earnings per Unit - diluted (1):
Net income available to Units		$	3.15
Weighted average Units outstanding (2)		373,085
-1	Potential Units issuable from the assumed exercise/vesting of the Company's long-term compensation shares/units are automatically anti-dilutive and therefore excluded from the diluted earnings per Unit calculation as the Operating Partnership had a pro forma loss from continuing operations for the quarter ended March 31, 2013.
-2	Includes an adjustment for Common Shares issued to the public in November/December 2012 and to an affiliate of Lehman Brothers Holdings Inc. in February 2013 as partial consideration for the Archstone Acquisition. Concurrent with these transactions, ERPOP issued the same number of OP Units to EQR.
For the quarter ended March 31, 2013, acquisition costs of $19.1 million and severance/retention and other costs of $44.8 million related to the Archstone Acquisition are not expected to have a continuing impact on the Company's financial results and therefore have been excluded from these pro forma results. The pro forma results also do not include the impact of any synergies or lower borrowing costs that the Company has or may achieve as a result of the acquisition or any strategies that management has or may consider in order to more efficiently manage the Company's operations, nor do they give pro forma effect to any other acquisitions, dispositions or capital markets transactions (excluding the equity offering in November/December 2012 which proceeds were used for the Archstone Acquisition) that the Company completed during the periods presented. These pro forma results are not necessarily indicative of the operating results that would have been obtained had the Archstone Acquisition occurred at the beginning of the periods presented, nor are they necessarily indicative of future operating results.
Other
During the quarter ended March 31, 2014, 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			430			$	143,000
Land Parcel – Consolidated		—			—			5,500
Total		1			430			$	148,500
During the quarter ended March 31, 2014, the Company did not dispose of any rental properties or land parcels.

Commitments_to_AcquireDispose_

Commitments to Acquire/Dispose of Real Estate	3 Months Ended
	Mar. 31, 2014
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 entered into a separate agreement to acquire the following (purchase price in thousands):
			Properties	Apartment Units	Purchase Price
	Land Parcel (one)		—	—	$	16,300
	Total		—	—	$	16,300
	In addition to the portion of the land parcel that was subsequently disposed of as discussed in Note 14, the Company has entered into separate agreements to dispose of the following (sales price in thousands):
			Properties	Apartment Units	Sales Price
	Rental Properties		4	1,360	$	192,050
	Land Parcel		—	—	32,100
	Total		4	1,360	$	224,150
	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, 2014
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, 2014 (amounts in thousands except for project and apartment unit amounts):
		Consolidated											Unconsolidated
		Development Projects											Development Projects
		Held for			Completed, Not Stabilized (3)		Operating			Total			Held for			Completed, Not Stabilized (3)			Operating			Total
		and/or Under											and/or Under
		Development											Development
	Total projects (1)	—			1		19			20			—			3			1			4
	Total apartment units (1)	—			268		3,752			4,020			—			1,333			336			1,669
	Balance sheet information at
	3/31/14 (at 100%):
	ASSETS
	Investment in real estate	$	310,147		$	48,319	$	674,916		$	1,033,382		$	49,332		$	285,191		$	55,585		$	390,108
	Accumulated depreciation	—			—		(178,165		)	(178,165		)	—			(4,669		)	(5,052		)	(9,721		)
	Investment in real estate, net	310,147			48,319		496,751			855,217			49,332			280,522			50,533			380,387
	Cash and cash equivalents	4,226			698		11,611			16,535			450			1,803			1,378			3,631
	Investments in	—			—		53,844			53,844			—			—			—			—
	unconsolidated entities
	Deposits – restricted	42,045			32		220			42,297			—			120			48			168
	Deferred financing costs, net	—			—		2,407			2,407			65			126			4			195
	Other assets	5,670			2		26,641			32,313			—			365			1,032			1,397
	Total assets	$	362,088		$	49,051	$	591,474		$	1,002,613		$	49,847		$	282,936		$	52,995		$	385,778
	LIABILITIES AND
	EQUITY/CAPITAL
	Mortgage notes payable (2)	$	—		$	—	$	360,217		$	360,217		$	16,154		$	176,232		$	30,410		$	222,796
	Accounts payable & accrued	17,438			1,413		2,806			21,657			4,078			915			210			5,203
	expenses
	Accrued interest payable	—			—		1,283			1,283			32			725			—			757
	Other liabilities	120			49		1,114			1,283			339			867			863			2,069
	Security deposits	—			21		1,839			1,860			—			258			109			367
	Total liabilities	17,558			1,483		367,259			386,300			20,603			178,997			31,592			231,192
	Noncontrolling Interests –	117,689			1,244		8,725			127,658			27,858			73,412			20,450			121,720
	Partially Owned Properties/
	Partners' equity
	Company equity/General and	226,841			46,324		215,490			488,655			1,386			30,527			953			32,866
	Limited Partners' Capital
	Total equity/capital	344,530			47,568		224,215			616,313			29,244			103,939			21,403			154,586
	Total liabilities and	$	362,088		$	49,051	$	591,474		$	1,002,613		$	49,847		$	282,936		$	52,995		$	385,778
	equity/capital
		Consolidated											Unconsolidated
		Development Projects											Development Projects
		Held for											Held for						Operating
		and/or Under			Completed, Not								and/or Under			Completed, Not Stabilized (3)
		Development			Stabilized (3)		Operating			Total			Development									Total
	Operating information for the quarter
	ended 3/31/14 (at 100%):
	Operating revenue	$	—		$	468	$	21,308		$	21,776		$	—		$	4,528		$	1,353		$	5,881
	Operating expenses	77			204		6,453			6,734			44			1,917			559			2,520
	Net operating (loss) income	(77		)	264		14,855			15,042			(44		)	2,611			794			3,361
	Depreciation	—			—		5,363			5,363			—			2,782			447			3,229
	General and administrative/other	(9		)	116		12			119			—			12			43			55
	Operating (loss) income	(68		)	148		9,480			9,560			(44		)	(183		)	304			77
	Interest and other income	—			—		3			3			—			—			—			—
	Other expenses	(42		)	—		(7		)	(49		)	—			—			—			—
	Interest:
	Expense incurred, net	—			—		(3,887		)	(3,887		)	—			(1,992		)	(279		)	(2,271		)
	Amortization of deferred	—			—		(88		)	(88		)	—			(3		)	—			(3		)
	financing costs
	(Loss) income before income and	(110		)	148		5,501			5,539			(44		)	(2,178		)	25			(2,197		)
	other taxes and (loss) from
	investments in unconsolidated
	entities
	Income and other tax (expense)	—			—		(36		)	(36		)	—			—			—			—
benefit
(Loss) from investments in	—			—		(419		)	(419		)	—			—			—			—
unconsolidated entities
Net (loss) income	$	(110	)	$	148	$	5,046		$	5,084		$	(44	)	$	(2,178	)	$	25		$	(2,197	)
-1	Project and apartment unit counts exclude all uncompleted development projects until those projects are substantially completed.
-2	All debt is non-recourse to the Company with the exception of 50% of the current $16.2 million outstanding debt balance on one unconsolidated development project.
-3	Projects included here are substantially complete. However, they may still require additional exterior and interior work for all units to be available for leasing.
Note:	The above tables exclude the Company's interests in unconsolidated joint ventures entered into with AVB in connection with the Archstone Transaction. These ventures own certain non-core Archstone assets that are held for sale and succeeded to certain residual Archstone liabilities, such as liability for various employment-related matters as well as responsibility for tax protection arrangements and third-party preferred interests in former Archstone subsidiaries. The preferred interests have an aggregate liquidation value of $79.3 million at March 31, 2014. The ventures are owned 60% by the Company and 40% by AVB.
The Company is the controlling partner in various consolidated partnership properties and development properties having a noncontrolling interest book value of $127.7 million at March 31, 2014. The Company does not have any VIEs.
Archstone Acquisition
On February 27, 2013, in conjunction with the Archstone Acquisition, the Company acquired interests in several joint ventures. Details of these interests follow by project:
Park Aire (formerly known as Enclave at Wellington) – This venture developed certain land parcels into a 268 unit apartment building located in Wellington, Florida. The Company has a 95% equity interest with an initial basis of $26.2 million. Total project costs are approximately $50.0 million. The Company is the managing member, was responsible for constructing the project and its partner does not have substantive kick-out or participating rights. As a result, the entity is required to be consolidated on the Company's balance sheet.
East Palmetto Park – This venture was formed to ultimately develop certain land parcels into a 377 unit apartment building located in Boca Raton, Florida. The Company has a 90% equity interest with an initial basis of $20.2 million. The Company is the managing member, is responsible for constructing the project and its partner does not have substantive kick-out or participating rights. As a result, the entity is required to be consolidated on the Company's balance sheet.
Wisconsin Place – This project contains a mixed-use site located in Chevy Chase, Maryland consisting of residential, retail, office and accessory uses, including underground parking facilities. The Company has a 75% equity interest with an initial basis of $198.5 million in the 432 unit residential component. The Company is the managing member, was responsible for constructing the residential project and its partner does not have substantive kick-out or participating rights. As a result, the entity that owns the residential component of this mixed-use site is required to be consolidated on the Company's balance sheet. Such entity also retains an unconsolidated interest in an entity that owns the land underlying the entire project and owns and operates the parking facility. The initial fair value of this investment is $56.5 million. The Company does not have any ownership interest in the retail and office components.
San Norterra – This venture developed certain land parcels into a 388 unit apartment building located in Phoenix, Arizona. The Company has an 85% equity interest with an initial basis of $16.9 million. Total project costs are approximately $53.3 million and construction was partially funded with a construction loan that is guaranteed by the partner and non-recourse to the Company. The loan has a maximum debt commitment of $34.8 million and a current unconsolidated outstanding balance of $33.0 million; the loan bears interest at LIBOR plus 2.00% and matures January 6, 2015. The partner is the managing member and developed the project. The Company does not have substantive kick-out or participating rights. As a result, the entity is unconsolidated and recorded using the equity method of accounting.
Waterton Tenside – This venture was formed to develop and operate a 336 unit apartment property located in Atlanta, Georgia. The Company has a 20% equity interest with an initial basis of $5.1 million. The partner is the managing member and developed the project. The project is encumbered by a non-recourse mortgage loan that has a current outstanding balance of $30.4 million, bears interest at 3.66% and matures December 1, 2018. The Company does not have substantive kick-out or participating rights. As a result, the entity is unconsolidated and recorded using the equity method of accounting.
1333 Powell (formerly known as Parkside at Emeryville) – This venture is currently developing certain land parcels into a 176 unit apartment building located in Emeryville, California. The Company has a 5% equity interest with an initial obligation of approximately $2.1 million. Total project costs are expected to be approximately $75.0 million and construction is being partially funded with a construction loan. The loan has a maximum debt commitment of $39.5 million and a current unconsolidated outstanding balance of $16.2 million; the loan bears interest at LIBOR plus 2.25% and matures August 14, 2015. The Company has given a repayment guaranty on the construction loan of 50% of the outstanding balance, up to a maximum of $19.7 million, and has given certain construction cost overrun guarantees. The partner is the managing member. The Company does not have substantive kick-out or participating rights. As a result, the entity is unconsolidated and recorded using the equity method of accounting.
On February 27, 2013, in connection with the Archstone Acquisition, subsidiaries of the Company and AVB entered into three limited liability company agreements (collectively, the “Residual JV”). The Residual JV owns certain non-core Archstone assets that are held for sale, such as interests in a German portfolio of apartment buildings (see Note 14 for further discussion on the German portfolio), and succeeded to certain residual Archstone liabilities, such as liability for various employment-related matters. The Residual JV is owned 60% by the Company and 40% by AVB and the Company's initial investment was $147.6 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 is unconsolidated and recorded using the equity method of accounting.
On February 27, 2013, in connection with the Archstone Acquisition, 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. During the year ended December 31, 2013, the Company purchased with AVB $65.0 million (of which the Company's 60% share was $39.0 million) of the preferred interests assumed by Legacy JV. At March 31, 2014, the remaining preferred interests have an aggregate liquidation value of $79.3 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 is unconsolidated and recorded using the equity method of accounting.
Other
In December 2011, the Company and Toll Brothers (NYSE: TOL) jointly acquired a vacant land parcel at 400 Park Avenue South in New York City. The Company's and Toll Brothers' allocated portions of the purchase price were approximately $76.1 million and $57.9 million, respectively. The Company is the managing member and Toll Brothers does not have substantive kick-out or participating rights. Until the core and shell of the building is complete, the building and land will be owned jointly and are required to be consolidated on the Company's balance sheet. Thereafter, the Company will solely own and control the rental portion of the building (floors 2-22) and Toll Brothers will solely own and control the for sale portion of the building (floors 23-40). Once the core and shell are complete, the Toll Brothers' portion of the property will be deconsolidated from the Company's balance sheet. The acquisition was financed through contributions by the Company and Toll Brothers of approximately $102.5 million and $75.7 million, respectively, which included the land purchase noted above, restricted deposits and taxes and fees. As of March 31, 2014, the Company's and Toll Brothers' consolidated contributions to the joint venture were approximately $311.6 million, of which Toll Brothers' noncontrolling interest balance totaled $117.4 million.
The Company admitted an 80% institutional partner to two separate entities/transactions (Nexus Sawgrass in December 2010 and Domain in August 2011), each owning a developable land parcel, in exchange for $40.1 million in cash and retained a 20% equity interest in both of these entities. These projects are now unconsolidated. Details of these projects follow:
•	Nexus Sawgrass – This development project is substantially complete. Total project costs are expected to be approximately $79.0 million and construction was predominantly funded with a long-term, non-recourse secured loan from the partner. The mortgage loan has a maximum debt commitment of $48.7 million and a current unconsolidated outstanding balance of $48.2 million; the loan bears interest at 5.60% and matures January 1, 2021.
•	Domain – This development project is substantially complete. Total project costs are expected to be approximately $154.6 million and construction was predominantly funded with a long-term, non-recourse secured loan from the partner. The mortgage loan has a maximum debt commitment of $98.6 million and a current unconsolidated outstanding balance of $95.0 million; the loan 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 projects and has given certain construction cost overrun guarantees, the joint venture partner has significant participating rights and has active involvement in and oversight of the ongoing projects. The Company currently has no further funding obligations related to these projects.

Deposits_Restricted

Deposits - Restricted	3 Months Ended
	Mar. 31, 2014
Deposits - Restricted [Abstract]	'
Restricted Cash And Cash Equivalents Disclosure [Text Block]	'
	7	Deposits – Restricted
	The following table presents the Company’s restricted deposits as of March 31, 2014 and December 31, 2013 (amounts in thousands):
			March 31,		December 31,
			2014		2013
	Earnest money on pending acquisitions		$	1,344	$	4,514
	Restricted deposits on real estate investments		44,037		53,771
	Resident security and utility deposits		45,195		44,777
	Other		505		505
	Totals		$	91,081	$	103,567

Debt

Debt	3 Months Ended
	Mar. 31, 2014
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 $750.0 million unsecured term loan facility and also guarantees the Operating Partnership’s revolving credit facility up to the maximum amount and for the full term of the facility.
	Mortgage Notes Payable
	As of March 31, 2014, the Company had outstanding mortgage debt of approximately $5.2 billion.
	During the quarter ended March 31, 2014, the Company:
	▪	Repaid $3.0 million of mortgage loans.
	As of March 31, 2014, the Company had $700.5 million of secured debt subject to third party credit enhancement.
	As of March 31, 2014, scheduled maturities for the Company’s outstanding mortgage indebtedness were at various dates through May 1, 2061. At March 31, 2014, the interest rate range on the Company’s mortgage debt was 0.04% to 7.25%. During the quarter ended March 31, 2014, the weighted average interest rate on the Company’s mortgage debt was 4.22%.
	Notes
	As of March 31, 2014, the Company had outstanding unsecured notes of approximately $5.5 billion.
	As of March 31, 2014, scheduled maturities for the Company’s outstanding notes were at various dates through 2026. At March 31, 2014, the interest rate range on the Company’s notes was 1.32% to 7.57%. During the quarter ended March 31, 2014, the weighted average interest rate on the Company’s notes was 4.92%.
	Lines of Credit
	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 new credit facility will generally be LIBOR plus a spread (currently 1.05%) 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.
	As of March 31, 2014, the amount available on the credit facility was $2.17 billion (net of $34.7 million which was restricted/dedicated to support letters of credit and net of $298.0 million outstanding). During the quarter ended March 31, 2014, the weighted average interest rate was 0.98%.

Derivative_and_Other_Fair_Valu

Derivative and Other Fair Value Instruments	3 Months Ended
	Mar. 31, 2014
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.
	The carrying values of the Company’s mortgage notes payable and unsecured debt (including its line of credit) were approximately $5.2 billion and $5.8 billion, respectively, at March 31, 2014. The fair values of the Company’s mortgage notes payable and unsecured debt (including its line of credit) were approximately $5.1 billion (Level 2) and $6.1 billion (Level 2), respectively, at March 31, 2014. The carrying values of the Company's mortgage notes payable and unsecured debt (including its line of credit) were approximately $5.2 billion and $5.6 billion, respectively, at December 31, 2013. The fair values of the Company’s mortgage notes payable and unsecured debt (including its line of credit) were approximately $5.1 billion (Level 2) and $5.9 billion (Level 2), respectively, at December 31, 2013. The fair values of the Company’s financial instruments (other than mortgage notes payable, unsecured notes, lines of credit and derivative instruments), including cash and cash equivalents and other financial instruments, approximate their carrying or contract values.
	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.
	The following table summarizes the Company’s consolidated derivative instruments at March 31, 2014 (dollar amounts are in thousands):
			Forward
			Starting
			Swaps (1)
	Current Notional Balance		$	450,000
	Lowest Possible Notional		$	450,000
	Highest Possible Notional		$	450,000
	Lowest Interest Rate		2.125		%
	Highest Interest Rate		3.23		%
	Earliest Maturity Date		2024
	Latest Maturity Date		2025
	-1	Forward Starting Swaps – Designed to partially fix interest rates in advance of planned future debt issuances. These swaps have mandatory counterparty terminations in 2015 and 2016, and are targeted to 2014 and 2015 issuances.
	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 sheet. 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 line of credit) 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 line of credit) and quoted market prices for each underlying issuance in the case of the public unsecured notes.
	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, 2014 and December 31, 2013, respectively (amounts in thousands):
								Fair Value Measurements at Reporting Date Using
	Description		Balance Sheet		3/31/14			Quoted Prices in			Significant  Other				Significant
			Location					Active Markets for			Observable Inputs				Unobservable Inputs
								Identical Assets/Liabilities			(Level 2)				(Level  3)
								(Level 1)
	Assets
	Derivatives designated as hedging instruments:
	Interest Rate Contracts:
	Forward Starting Swaps		Other Assets		$	11,428		$	—		$	11,428			$	—
	Supplemental Executive Retirement Plan		Other Assets		88,010			88,010			—				—
	Total				$	99,438		$	88,010		$	11,428			$	—
	Liabilities
	Derivatives designated as hedging instruments:
	Interest Rate Contracts:
	Forward Starting Swaps		Other Liabilities		$	4,670		$	—		$	4,670			$	—
	Supplemental Executive Retirement Plan		Other Liabilities		88,010			88,010			—				—
	Total				$	92,680		$	88,010		$	4,670			$	—
	Redeemable Noncontrolling Interests –
	Operating Partnership/Redeemable
	Limited Partners		Mezzanine		$	405,276		$	—		$	405,276			$	—
								Fair Value Measurements at Reporting Date Using
	Description		Balance Sheet		12/31/13			Quoted Prices in			Significant  Other				Significant
			Location					Active Markets for			Observable Inputs				Unobservable Inputs
								Identical Assets/Liabilities			(Level 2)				(Level  3)
								(Level 1)
	Assets
	Derivatives designated as hedging instruments:
	Interest Rate Contracts:
	Forward Starting Swaps		Other Assets		$	18,710		$	—		$	18,710			$	—
	Supplemental Executive Retirement Plan		Other Assets		83,845			83,845			—				—
	Total				$	102,555		$	83,845		$	18,710			$	—
	Liabilities
	Supplemental Executive Retirement Plan		Other Liabilities		$	83,845		$	83,845		$	—			$	—
	Total				$	83,845		$	83,845		$	—			$	—
	Redeemable Noncontrolling Interests –
	Operating Partnership/Redeemable
	Limited Partners		Mezzanine		$	363,144		$	—		$	363,144			$	—
	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, 2014 and 2013, respectively (amounts in thousands):
	31-Mar-14		Location of		Amount of			Hedged Item		Income Statement	Amount of
	Type of Fair Value Hedge		Gain/(Loss)		Gain/(Loss)					Location of	Gain/(Loss)
			Recognized in		Recognized in					Hedged Item	Recognized in
	Income on		Income on			Gain/(Loss)	Income
	Derivative		Derivative				on Hedged Item
Derivatives designated as hedging instruments:
Interest Rate Contracts:
Interest Rate Swaps		N/A		$	—		N/A		N/A	$	—
Total				$	—					$	—
31-Mar-13		Location of		Amount of			Hedged Item		Income Statement	Amount of
Type of Fair Value Hedge		Gain/(Loss)		Gain/(Loss)					Location of	Gain/(Loss)
		Recognized in		Recognized in					Hedged	Recognized in
		Income		Income					Item Gain/(Loss)	Income
		on Derivative		on Derivative						on Hedged Item
Derivatives designated as hedging instruments:
Interest Rate Contracts:
Interest Rate Swaps		Interest expense		$	(1,471	)	Fixed rate debt		Interest expense	$	1,471
Total				$	(1,471	)				$	1,471
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, 2014 and 2013, respectively (amounts in thousands):
		Effective Portion								Ineffective Portion
31-Mar-14		Amount of				Location of Gain/	Amount of Gain/			Location of		Amount of Gain/
Type of Cash Flow Hedge		Gain/(Loss)				(Loss)	(Loss)			Gain/(Loss)		(Loss)
		Recognized in OCI				Reclassified from	Reclassified from			Recognized in		Reclassified from
		on Derivative				Accumulated	Accumulated			Income		Accumulated
						OCI	OCI into Income			on Derivative		OCI into Income
						into Income
Derivatives designated as hedging instruments:
Interest Rate Contracts:
Forward Starting Swaps/Treasury Locks		$	(11,952	)		Interest expense	$	(4,129	)	N/A		$	—
Total		$	(11,952	)			$	(4,129	)			$	—
		Effective Portion								Ineffective Portion
31-Mar-13		Amount of				Location of Gain/	Amount of Gain/			Location of		Amount of Gain/
Type of Cash Flow Hedge		Gain/(Loss)				(Loss)	(Loss)			Gain/(Loss)		(Loss)
		Recognized in OCI				Reclassified from	Reclassified from			Recognized in		Reclassified from
		on Derivative				Accumulated	Accumulated			Income		Accumulated
						OCI	OCI			on Derivative		OCI
						into Income	into Income					into Income
Derivatives designated as hedging instruments:
Interest Rate Contracts:
Forward Starting Swaps/Treasury Locks		$	2,814			Interest expense	$	(8,272	)	N/A		$	—
Total		$	2,814				$	(8,272	)			$	—
As of March 31, 2014 and December 31, 2013, there were approximately $163.6 million and $155.8 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, 2014, the Company may recognize an estimated $21.9 million of accumulated other comprehensive (loss) as additional interest expense during the twelve months ending March 31, 2015.

Earnings_Per_Share

Earnings Per Share	3 Months Ended
	Mar. 31, 2014
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,
			2014			2013
	Numerator for net income per share – basic:
	Income (loss) from continuing operations		$	81,698		$	(165,339	)
	Allocation to Noncontrolling Interests – Operating Partnership, net		(3,053		)	6,836
	Net (income) attributable to Noncontrolling Interests – Partially		(504		)	(25		)
	Owned Properties
	Preferred distributions		(1,036		)	(1,036		)
	Income (loss) from continuing operations available to Common Shares,		77,105			(159,564		)
	net of Noncontrolling Interests
	Discontinued operations, net of Noncontrolling Interests		994			1,176,214
	Numerator for net income per share – basic		$	78,099		$	1,016,650
	Numerator for net income per share – diluted (1):
	Income from continuing operations		$	81,698
	Net (income) attributable to Noncontrolling Interests – Partially		(504		)
	Owned Properties
	Preferred distributions		(1,036		)
	Income from continuing operations available to Common Shares		80,158
	Discontinued operations, net		1,034
	Numerator for net income per share – diluted (1)		$	81,192		$	1,016,650
	Denominator for net income per share – basic and diluted (1):
	Denominator for net income per share – basic		360,470			337,532
	Effect of dilutive securities:
	OP Units		13,731
	Long-term compensation shares/units		2,183
	Denominator for net income per share – diluted (1)		376,384			337,532
	Net income per share – basic		$	0.22		$	3.01
	Net income per share – diluted		$	0.22		$	3.01
	Net income per share – basic:
	Income (loss) from continuing operations available to Common Shares,		$	0.214		$	(0.473	)
	net of Noncontrolling Interests
	Discontinued operations, net of Noncontrolling Interests		0.003			3.485
	Net income per share – basic		$	0.217		$	3.012
	Net income per share – diluted (1):
	Income (loss) from continuing operations available to Common Shares		$	0.213		$	(0.473	)
	Discontinued operations, net		0.003			3.485
	Net income per share – diluted		$	0.216		$	3.012
	-1	Potential common shares issuable from the assumed conversion of OP Units and the exercise/vesting of long-term compensation shares/units are automatically anti-dilutive and therefore excluded from the diluted earnings per share calculation as the Company had a loss from continuing operations for the quarter ended March 31, 2013.
	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,
			2014			2013
	Numerator for net income per Unit – basic and diluted (1):
	Income (loss) from continuing operations		$	81,698		$	(165,339	)
	Net (income) attributable to Noncontrolling Interests – Partially		(504		)	(25		)
	Owned Properties
	Allocation to Preference Units		(1,036		)	(1,036		)
	Income (loss) from continuing operations available to Units		80,158			(166,400		)
	Discontinued operations, net		1,034			1,226,373
	Numerator for net income per Unit – basic and diluted (1)		$	81,192		$	1,059,973
	Denominator for net income per Unit – basic and diluted (1):
	Denominator for net income per Unit - basic		374,201			351,255
	Effect of dilutive securities:
	Dilution for Units issuable upon assumed exercise/vesting of the Company’s long-term		2,183
	compensation shares/units
	Denominator for net income per Unit – diluted (1)		376,384			351,255
	Net income per Unit – basic		$	0.22		$	3.01
	Net income per Unit – diluted		$	0.22		$	3.01
	Net income per Unit – basic:
	Income (loss) from continuing operations available to Units		$	0.214		$	(0.473	)
Discontinued operations, net		0.003			3.485
Net income per Unit – basic		$	0.217		$	3.012
Net income per Unit – diluted (1):
Income (loss) from continuing operations available to Units		$	0.213		$	(0.473	)
Discontinued operations, net		0.003			3.485
Net income per Unit – diluted		$	0.216		$	3.012
-1	Potential Units issuable from the assumed exercise/vesting of the Company's long-term compensation shares/units are automatically anti-dilutive and therefore excluded from the diluted earnings per Unit calculation as the Operating Partnership had a loss from continuing operations for the quarter ended March 31, 2013.

Discontinued_Operations

Discontinued Operations	3 Months Ended
	Mar. 31, 2014
Discontinued Operations and Disposal Groups [Abstract]	'
Discontinued Operations	'
	11	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.
	The components of discontinued operations are outlined below and include the results of operations for the respective periods that the Company owned such assets during the quarters ended March 31, 2014 and 2013 (amounts in thousands).
			Quarter Ended March 31,
			2014			2013
	REVENUES
	Rental income		$	1,023		$	81,782
	Total revenues		1,023			81,782
	EXPENSES (1)
	Property and maintenance		48			20,424
	Real estate taxes and insurance		13			8,594
	Property management		—			1
	Depreciation		—			23,816
	General and administrative		5			8
	Total expenses		66			52,843
	Discontinued operating income		957			28,939
	Interest and other income		35			52
	Other expenses		—			(2		)
	Interest (2):
	Expense incurred, net		—			(1,252		)
	Amortization of deferred financing costs		—			(228		)
	Income and other tax (expense) benefit		(29		)	(58		)
	Discontinued operations		963			27,451
	Net gain on sales of discontinued operations		71			1,198,922
	Discontinued operations, net		$	1,034		$	1,226,373
	-1	Includes expenses paid in the current period for properties sold in prior periods related to the Company’s period of ownership.
	-2	Includes only interest expense specific to secured mortgage notes payable for properties sold.
	During the quarter ended March 31, 2014, the Company did not dispose of any rental properties or land parcels. The amounts included in discontinued operations in the first quarter of 2014 represent trailing activity for properties sold in 2013 and prior years.

Commitments_and_Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2014
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 alleges that the Company designed and built approximately 300 of its properties in violation of the accessibility requirements of the Fair Housing Act and Americans With Disabilities Act. The suit seeks actual and punitive damages, injunctive relief (including modification of non-compliant properties), costs and attorneys' fees. The Company believes it has a number of viable defenses, including that a majority of the named properties were completed before the operative dates of the statutes in question and/or were not designed or built by the Company. Accordingly, the Company is defending the suit vigorously. Due to the pendency of the Company’s defenses and the uncertainty of many other 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, 2014. 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 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, 2014, the Company has 12 consolidated projects (including 400 Park Avenue South in New York City which the Company is jointly developing with Toll Brothers that is discussed below) totaling 3,871 apartment units in various stages of development with commitments to fund of approximately $1.1 billion and estimated completion dates ranging through September 30, 2016, as well as other completed development projects that are in various stages of lease up or are stabilized. Some of the projects are being developed solely by the Company, while others are being co-developed with various third party development partners. The development venture agreements with these partners are primarily deal-specific, with differing terms regarding profit-sharing, equity contributions, returns on investment, buy-sell agreements and other customary provisions. The Company is the "general" or "managing" partner of the development ventures.
	As of March 31, 2014, the Company has one unconsolidated project totaling 176 apartment units under development with an estimated completion date of December 31, 2014, as well as three completed development projects that are currently in lease up. These projects are all being co-developed with various third party development partners. The development venture agreements with these partners are primarily deal-specific, with differing terms regarding profit-sharing, equity contributions, returns on investment, buy-sell agreements and other customary provisions. The Company currently has no further funding obligations for Domain, Nexus Sawgrass and San Norterra. While the Company is the managing member of the Domain and Nexus Sawgrass joint ventures, was responsible for constructing both projects and has given certain construction cost overrun guarantees, the joint venture partner has significant participating rights and has active involvement in and oversight of the ongoing projects. The Domain and Nexus Sawgrass 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. The respective partner for San Norterra and 1333 Powell (formerly known as Parkside at Emeryville) is the “general” or “managing” partner of the development venture and the Company does not have substantive kick-out or participating rights. The Company has given a repayment guaranty on the construction loan for 1333 Powell of 50% of the outstanding balance, up to a maximum of $19.7 million, and has given certain construction cost overrun guarantees.
	In December 2011, the Company and Toll Brothers (NYSE: TOL) jointly acquired a vacant land parcel at 400 Park Avenue South in New York City. The Company's and Toll Brothers' allocated portions of the purchase price were approximately $76.1 million and $57.9 million, respectively. The Company is the managing member and Toll Brothers does not have substantive kick-out or participating rights. Until the core and shell of the building is complete, the building and land will be owned jointly and are required to be consolidated on the Company's balance sheet. Thereafter, the Company will solely own and control the rental portion of the building (floors 2-22) and Toll Brothers will solely own and control the for sale portion of the building (floors 23-40). Once the core and shell are complete, the Toll Brothers' portion of the property will be deconsolidated from the Company's balance sheet. The acquisition was financed through contributions by the Company and Toll Brothers of approximately $102.5 million and $75.7 million, respectively, which included the land purchase noted above, restricted deposits and taxes and fees. As of March 31, 2014, the Company's and Toll Brothers' consolidated contributions to the joint venture were approximately $311.6 million, of which Toll Brothers' noncontrolling interest balance totaled $117.4 million.

Reportable_Segments

Reportable Segments	3 Months Ended
	Mar. 31, 2014
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 core markets represent its reportable segments (with the aggregation of Los Angeles, Orange County and San Diego into the Southern California reportable segment). The Company's operating segments located in its non-core markets that are not material have also been aggregated in the tables presented below.
	The Company’s fee and asset management and development (including its partially owned properties) activities are other business activities that do not constitute an operating segment and as such, have been aggregated in the "Other" category in the tables presented below.
	All 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, 2014 and 2013, 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; 2) real estate taxes and insurance expense; and 3) property management expense (all as reflected in the accompanying consolidated statements of operations and comprehensive income). 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 communities. Current year NOI is compared to prior year NOI and current year budgeted NOI as a measure of financial performance. The following tables present NOI for each segment from our rental real estate specific to continuing operations for the quarters ended March 31, 2014 and 2013, respectively, as well as total assets and capital expenditures at March 31, 2014 (amounts in thousands):
			Quarter Ended March 31, 2014									Quarter Ended March 31, 2013
			Rental Income			Operating Expenses			NOI			Rental Income			Operating Expenses			NOI
	Same store (1)
	Boston		$	61,907		$	22,154		$	39,753		$	59,054		$	20,207		$	38,847
	Denver		26,611			7,449			19,162			24,970			7,217			17,753
	New York		111,185			46,202			64,983			107,997			43,111			64,886
	San Francisco		81,261			26,655			54,606			74,945			28,156			46,789
	Seattle		37,725			12,768			24,957			35,372			12,237			23,135
	South Florida		48,437			18,184			30,253			46,239			17,643			28,596
	Southern California		102,665			34,347			68,318			98,210			34,587			63,623
	Washington DC		110,396			37,396			73,000			110,993			35,884			75,109
	Non-core		33,691			13,084			20,607			32,672			12,443			20,229
	Total same store		613,878			218,239			395,639			590,452			211,485			378,967
	Non-same store/other (2) (3)
	Boston		1,028			211			817			256			53			203
	Seattle		1,687			690			997			25			1			24
	South Florida		800			466			334			14			78			(64		)
	Southern California		7,174			3,122			4,052			1,292			617			675
	Washington DC		4,934			1,863			3,071			1,806			653			1,153
	Other (3)		1,224			5,194			(3,970		)	1,140			9,955			(8,815		)
	Total non-same store/other		16,847			11,546			5,301			4,533			11,357			(6,824		)
	Archstone pre-ownership (4)		—			—			—			(92,423		)	(36,729		)	(55,694		)
	Total		$	630,725		$	229,785		$	400,940		$	502,562		$	186,113		$	316,449
	-1	Same store primarily includes all properties acquired or completed and stabilized prior to January 1, 2013, less properties subsequently sold, which represented 100,984 apartment units. Also includes 18,465 stabilized apartment units acquired in the Archstone Acquisition that are owned and managed by the Company.
	-2	Non-same store primarily includes properties acquired after January 1, 2013, plus any properties in lease-up and not stabilized as of January 1, 2013, but excludes 18,465 stabilized apartment units acquired in the Archstone Acquisition that are owned and managed by the Company.
	-3	Other includes development and other corporate operations.
	-4	Represents pro forma Archstone pre-ownership results for the period January 1, 2013 to February 27, 2013 that is included in 2013 same store results.
			Quarter Ended March 31, 2014
			Total Assets			Capital Expenditures
	Same store (1)
	Boston		$	1,968,613		$	4,078
	Denver		536,226			762
	New York		4,727,805			3,051
	San Francisco		2,769,826			5,716
	Seattle		1,053,600			2,205
	South Florida		1,178,426			3,119
	Southern California		3,000,465			5,142
	Washington DC		4,299,085			5,529
	Non-core		640,141			1,544
	Total same store		20,174,187			31,146
	Non-same store/other (2) (3)
	Boston		48,971			263
	Seattle		190,041			160
	South Florida		70,725			(1		)
	Southern California		446,912			173
	Washington DC		305,668			449
	Other (3)		1,653,127			1
	Total non-same store/other		2,715,444			1,045
	Total		$	22,889,631		$	32,191
	-1	Same store primarily includes all properties acquired or completed and stabilized prior to January 1, 2013, less properties subsequently sold, which represented 100,984 apartment units. Also includes 18,465 stabilized apartment units acquired in the Archstone Acquisition that are owned and managed by the Company.
	-2	Non-same store primarily includes properties acquired after January 1, 2013, plus any properties in lease-up and not stabilized as of January 1, 2013, but excludes 18,465 stabilized apartment units acquired in the Archstone Acquisition that are owned and managed by the Company.
	-3	Other includes development and other corporate operations.
	Note: Markets/Metro Areas included in the above Southern California and Non-core segments are as follows:
	(a) Southern California – Los Angeles, Orange County and San Diego.
	(b) Non-core – Inland Empire, CA, New England (excluding Boston), Orlando and Phoenix.
	The following table presents a reconciliation of NOI from our rental real estate specific to continuing operations for the quarters ended March 31, 2014 and 2013, respectively (amounts in thousands):
			Quarter Ended March 31,
		2014			2013
Rental income		$	630,725		$	502,562
Property and maintenance expense		(125,573		)	(98,529		)
Real estate taxes and insurance expense		(82,094		)	(65,095		)
Property management expense		(22,118		)	(22,489		)
Total operating expenses		(229,785		)	(186,113		)
Net operating income		$	400,940		$	316,449

Subsequent_EventsOther

Subsequent Events/Other	3 Months Ended
	Mar. 31, 2014
Subsequent Events Other [Abstract]	'
Subsequent Events/Other	'
	14	Subsequent Events/Other
	Subsequent Events
	Subsequent to March 31, 2014, the Company:
	•	Acquired one land parcel for $10.3 million;
	•	Disposed of a portion of a land parcel for $8.2 million;
	•	Repaid $3.1 million of mortgage loans;
	•	Entered into $50.0 million of forward starting swaps to hedge changes in interest rates related to future secured or unsecured debt issuances; and
	•	Closed on the sale of its unconsolidated interest in the German portfolio fund and the German management company, representing the sale of the majority of the remaining German assets that were acquired as part of the Archstone Acquisition.
	Other
	During the quarters ended March 31, 2014 and 2013, the Company incurred charges of $0.5 million and $2.6 million, respectively, related to the write-off of various pursuit and out-of-pocket costs for terminated acquisition, disposition and development transactions. These costs are included in other expenses in the accompanying consolidated statements of operations and comprehensive income. See Note 4 for details on the property acquisition costs related to the Archstone Transaction.
	During the quarter ended March 31, 2014, the Company settled a dispute with the seller/co-developer of a land parcel located in Florida and received $0.5 million, which is included in interest and other income in the accompanying consolidated statements of operations and comprehensive income.

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2014
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. Operating results for the quarter ended March 31, 2014 are not necessarily indicative of the results that may be expected for the year ending December 31, 2014.
	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, 2013 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, 2013.
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, 2014, the Company has recorded a deferred tax asset, which is fully offset by a valuation allowance due to the uncertainty in forecasting future TRS taxable income.
Other	'
	Other
	The Company is the controlling partner in various consolidated partnerships owning 20 properties and 4,020 apartment units and various completed and uncompleted development properties having a noncontrolling interest book value of $127.7 million at March 31, 2014. 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 six properties having a noncontrolling interest deficit balance of $10.0 million. These six 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, 2014, the Company estimates the value of Noncontrolling Interest distributions for these six properties would have been approximately $52.5 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 six 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, 2014 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.
	Effective January 1, 2013, companies are required to report, in one place, information about reclassifications out of accumulated other comprehensive income ("AOCI"). Companies are also required to report changes in AOCI balances. For significant items reclassified out of AOCI to net income in their entirety in the same reporting period, reporting is required about the effect of the reclassifications on the respective line items in the statement where net income is presented. For items that are not reclassified to net income in their entirety in the same reporting period, a cross reference to other disclosures currently required under US GAAP is required in the notes. This does not have a material effect on the Company's consolidated results of operations or financial position. See Note 9 for further discussion.
	Effective January 1, 2014, companies are required to measure obligations resulting from joint and several liability arrangements for which the total amount of the obligation is fixed at the reporting date as the sum of the amount a company agreed to pay on the basis of its arrangement among its co-obligors and any additional amount a company expects to pay on behalf of its co-obligors. Companies are required to disclose the nature and amount of the obligation as well as other information about those obligations. This does not have a material effect on the Company's consolidated results of operations or financial position.
	Effective January 1, 2015, the criteria for reporting discontinued operations will change. 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 will be required to expand their disclosures about discontinued operations to provide more information on the assets, liabilities, income and expenses of the discontinued operations. Companies will also be 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 is permitted, but only for disposals (or classifications as held for sale) that have not been reported in financial statements previously issued. The Company adopted this standard effective January 1, 2014 but did not have any dispositions in the first quarter of 2014. Adoption of this standard did not have a material effect on the Company's overall consolidated results of operations or financial position. However, adoption will result in substantially fewer of the Company's dispositions meeting the discontinued operations qualifications.

Business_Tables

Business (Tables)	3 Months Ended
	Mar. 31, 2014
Business [Abstract]	'
Property/Unit schedule	'
	The ownership breakdown includes (table does not include various uncompleted development properties):
		Properties	Apartment
			Units
	Wholly Owned Properties	367	99,936
	Master-Leased Properties – Consolidated	3	853
	Partially Owned Properties – Consolidated	20	4,020
	Partially Owned Properties – Unconsolidated	4	1,669
	Military Housing	2	5,059
		396	111,537

Equity_Capital_and_Other_Inter1

Equity, Capital and Other Interests (Tables)	3 Months Ended
	Mar. 31, 2014
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 Long-Term Incentive Plan (“LTIP”) Units) for the quarter ended March 31, 2014:
			2014
	Common Shares
	Common Shares outstanding at January 1,		360,479,260
	Common Shares Issued:
	Conversion of OP Units		18,043
	Exercise of share options		493,995
	Employee Share Purchase Plan (ESPP)		37,928
	Restricted share grants, net		162,349
	Common Shares Other:
	Conversion of restricted shares to LTIP Units		(12,146	)
	Repurchased and retired		(31,240	)
	Common Shares outstanding at March 31,		361,148,189
	Units
	Units outstanding at January 1,		14,180,376
	LTIP Units, net		200,840
	Conversion of restricted shares to LTIP Units		12,146
	Conversion of OP Units to Common Shares		(18,043	)
	Units outstanding at March 31,		14,375,319
	Total Common Shares and Units outstanding at March 31,		375,523,508
	Units Ownership Interest in Operating Partnership		3.8	%
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, 2014 (amounts in thousands):
			2014
	Balance at January 1,		$	363,144
	Change in market value		44,530
	Change in carrying value		(2,398		)
	Balance at March 31,		$	405,276
Schedule Of Preferred Stock [Table Text Block]	'
	The following table presents the Company’s issued and outstanding Preferred Shares as of March 31, 2014 and December 31, 2013:
							Amounts in thousands
			Redemption		Annual		March 31,		December 31,
			Date (1)		Dividend per		2014		2013
					Share (2)
	Preferred Shares of beneficial interest, $0.01 par value;
	100,000,000 shares authorized:
	8.29% Series K Cumulative Redeemable Preferred; liquidation		12/10/26			$4.14	$	50,000	$	50,000
	value $50 per share; 1,000,000 shares issued and outstanding
	at March 31, 2014 and December 31, 2013
							$	50,000	$	50,000
	-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.
Limited Partner [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, 2014:
			2014
	General and Limited Partner Units
	General and Limited Partner Units outstanding at January 1,		374,659,636
	Issued to General Partner:
	Exercise of EQR share options		493,995
	EQR’s Employee Share Purchase Plan (ESPP)		37,928
	EQR's restricted share grants, net		162,349
	Issued to Limited Partners:
	LTIP Units, net		200,840
	OP Units Other:
	Repurchased and retired		(31,240	)
	General and Limited Partner Units outstanding at March 31,		375,523,508
	Limited Partner Units
	Limited Partner Units outstanding at January 1,		14,180,376
	Limited Partner LTIP Units, net		200,840
	Conversion of EQR restricted shares to LTIP Units		12,146
	Conversion of Limited Partner OP Units to EQR Common Shares		(18,043	)
	Limited Partner Units outstanding at March 31,		14,375,319
	Limited Partner Units Ownership Interest in Operating Partnership		3.8	%
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, 2014 (amounts in thousands):
			2014
	Balance at January 1,		$	363,144
	Change in market value		44,530
	Change in carrying value		(2,398		)
	Balance at March 31,		$	405,276
Schedule Of Preferred Stock [Table Text Block]	'
	The following table presents the Operating Partnership’s issued and outstanding “Preference Units” as of March 31, 2014 and December 31, 2013:
							Amounts in thousands
			Redemption		Annual		March 31,		December 31,
			Date (1)		Dividend per		2014		2013
					Unit (2)
	Preference Units:
	8.29% Series K Cumulative Redeemable Preference Units;		12/10/26			$4.14	$	50,000	$	50,000
	liquidation value $50 per unit; 1,000,000 units issued and
	outstanding at March 31, 2014 and December 31, 2013
							$	50,000	$	50,000
	-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, 2014
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, 2014 and December 31, 2013 (amounts in thousands):
			March 31,				December 31,
			2014				2013
	Land		$	6,281,124			$	6,192,512
	Depreciable property:
	Buildings and improvements		17,843,201				17,509,609
	Furniture, fixtures and equipment		1,273,171				1,214,220
	In-Place lease intangibles		507,100				502,218
	Projects under development:
	Land		390,850				353,574
	Construction-in-progress		474,327				635,293
	Land held for development:
	Land		253,350				341,389
	Construction-in-progress		42,007				52,133
	Investment in real estate		27,065,130				26,800,948
	Accumulated depreciation		(4,992,877		)		(4,807,709		)
	Investment in real estate, net		$	22,072,253			$	21,993,239
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, 2014 and December 31, 2013 (amounts in thousands):
	Description		Balance Sheet Location		March 31,				December 31,
					2014				2013
	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				(5,502		)		(4,364		)
	Lease intangible assets, net				$	174,009			$	175,147
	Liabilities
	Ground lease intangibles – above market		Other Liabilities		$	2,400			$	2,400
	Retail lease intangibles – below market		Other Liabilities		5,500				5,500
	Lease intangible liabilities				7,900				7,900
	Accumulated amortization				(1,471		)		(1,161		)
	Lease intangible liabilities, net				$	6,429			$	6,739
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
			2014				2015				2016			2017			2018			2019
	Ground lease intangibles		$	3,241			$	4,321			$	4,321		$	4,321		$	4,321		$	4,321
	Retail lease intangibles		(758		)		(1,016		)		(908		)	(540		)	(71		)	(71		)
	Total		$	2,483			$	3,305			$	3,413		$	3,781		$	4,250		$	4,250
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block]	'
	The following table summarizes the acquisition date fair values of the assets acquired and liabilities assumed, which the Company determined using Level 1, Level 2 and Level 3 inputs (amounts in thousands):
	Land		$	2,239,000
	Depreciable property:
	Buildings and improvements		5,765,538
	Furniture, fixtures and equipment		61,470
	In-Place lease intangibles		304,830
	Projects under development		36,583
	Land held for development		244,097
	Investments in unconsolidated entities		230,608
	Other assets		195,260
	Other liabilities		(108,997		)
	Net assets acquired		$	8,968,389
Schedule of Finite-Lived Intangible Assets Acquired as Part of Business Combination [Text Block]	'
	The following table summarizes the acquisition date fair values of the above and below market ground and retail lease intangibles, which we determined using Level 2 and Level 3 inputs (amounts in thousands):
	Description		Balance Sheet Location		Fair Value
	Ground lease intangibles – below market		Other Assets		$	178,251
	Retail lease intangibles – above market		Other Assets		1,260
	Ground lease intangibles – above market		Other Liabilities		2,400
	Retail lease intangibles – below market		Other Liabilities		8,040
Business Acquisition, Pro Forma Information [Table Text Block]	'
	The following table illustrates the effect on net income, earnings per share – basic and earnings per share – diluted as if the Company had consummated the Archstone Acquisition as of January 1, 2012 (amounts in thousands, except per share amounts):
			Quarter Ended
			31-Mar-13
	Total revenues		$	638,499
	(Loss) from continuing operations (1)		(34,473		)
	Discontinued operations, net		1,213,615
	Net income		1,179,142
	Net income available to Common Shares		1,130,671
	Earnings per share - basic:
	Net income available to Common Shares		$	3.15
	Weighted average Common Shares outstanding (2)		359,362
	Earnings per share - diluted (1):
	Net income available to Common Shares		$	3.15
	Weighted average Common Shares outstanding (2)		359,362
	-1	Potential common shares issuable from the assumed conversion of OP Units and the exercise/vesting of long-term compensation shares/units are automatically anti-dilutive and therefore excluded from the diluted earnings per share calculation as the Company had a pro forma loss from continuing operations for the quarter ended March 31, 2013.
	-2	Includes an adjustment for Common Shares issued to the public in November/December 2012 and to an affiliate of Lehman Brothers Holdings Inc. in February 2013 as partial consideration for the Archstone Acquisition.
Acquired Properties Table Text Block	'
	During the quarter ended March 31, 2014, 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			430			$	143,000
	Land Parcel – Consolidated		—			—			5,500
	Total		1			430			$	148,500
Partnership Interest [Member]	'
Business Acquisition, Pro Forma Information [Table Text Block]	'
	The following table illustrates the effect on net income, earnings per Unit – basic and earnings per Unit – diluted as if the Operating Partnership had consummated the Archstone Acquisition as of January 1, 2012 (amounts in thousands, except per Unit amounts):
			Quarter Ended
			31-Mar-13
	Total revenues		$	638,499
	(Loss) from continuing operations (1)		(34,473		)
	Discontinued operations, net		1,213,615
	Net income		1,179,142
	Net income available to Units		1,178,887
	Earnings per Unit - basic:
	Net income available to Units		$	3.15
	Weighted average Units outstanding (2)		373,085
	Earnings per Unit - diluted (1):
	Net income available to Units		$	3.15
	Weighted average Units outstanding (2)		373,085
	-1	Potential Units issuable from the assumed exercise/vesting of the Company's long-term compensation shares/units are automatically anti-dilutive and therefore excluded from the diluted earnings per Unit calculation as the Operating Partnership had a pro forma loss from continuing operations for the quarter ended March 31, 2013.
	-2	Includes an adjustment for Common Shares issued to the public in November/December 2012 and to an affiliate of Lehman Brothers Holdings Inc. in February 2013 as partial consideration for the Archstone Acquisition. Concurrent with these transactions, ERPOP issued the same number of OP Units to EQR.

Commitments_to_AcquireDispose_1

Commitments to Acquire/Dispose of Real Estate (Tables)	3 Months Ended
	Mar. 31, 2014
Commitments to Acquire Dispose of Real Estate [Abstract]	'
Real Estate to be Acquired Table Text Block	'
	The Company has entered into a separate agreement to acquire the following (purchase price in thousands):
		Properties	Apartment Units	Purchase Price
	Land Parcel (one)	—	—	$	16,300
	Total	—	—	$	16,300
Disposed Properties Table Text Block	'
	In addition to the portion of the land parcel that was subsequently disposed of as discussed in Note 14, the Company has entered into separate agreements to dispose of the following (sales price in thousands):
		Properties	Apartment Units	Sales Price
	Rental Properties	4	1,360	$	192,050
	Land Parcel	—	—	32,100
	Total	4	1,360	$	224,150

Investments_in_Partially_Owned1

Investments in Partially Owned Entities (Tables)	3 Months Ended
	Mar. 31, 2014
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, 2014 (amounts in thousands except for project and apartment unit amounts):
		Consolidated											Unconsolidated
		Development Projects											Development Projects
		Held for			Completed, Not Stabilized (3)		Operating			Total			Held for			Completed, Not Stabilized (3)			Operating			Total
		and/or Under											and/or Under
		Development											Development
	Total projects (1)	—			1		19			20			—			3			1			4
	Total apartment units (1)	—			268		3,752			4,020			—			1,333			336			1,669
	Balance sheet information at
	3/31/14 (at 100%):
	ASSETS
	Investment in real estate	$	310,147		$	48,319	$	674,916		$	1,033,382		$	49,332		$	285,191		$	55,585		$	390,108
	Accumulated depreciation	—			—		(178,165		)	(178,165		)	—			(4,669		)	(5,052		)	(9,721		)
	Investment in real estate, net	310,147			48,319		496,751			855,217			49,332			280,522			50,533			380,387
	Cash and cash equivalents	4,226			698		11,611			16,535			450			1,803			1,378			3,631
	Investments in	—			—		53,844			53,844			—			—			—			—
	unconsolidated entities
	Deposits – restricted	42,045			32		220			42,297			—			120			48			168
	Deferred financing costs, net	—			—		2,407			2,407			65			126			4			195
	Other assets	5,670			2		26,641			32,313			—			365			1,032			1,397
	Total assets	$	362,088		$	49,051	$	591,474		$	1,002,613		$	49,847		$	282,936		$	52,995		$	385,778
	LIABILITIES AND
	EQUITY/CAPITAL
	Mortgage notes payable (2)	$	—		$	—	$	360,217		$	360,217		$	16,154		$	176,232		$	30,410		$	222,796
	Accounts payable & accrued	17,438			1,413		2,806			21,657			4,078			915			210			5,203
	expenses
	Accrued interest payable	—			—		1,283			1,283			32			725			—			757
	Other liabilities	120			49		1,114			1,283			339			867			863			2,069
	Security deposits	—			21		1,839			1,860			—			258			109			367
	Total liabilities	17,558			1,483		367,259			386,300			20,603			178,997			31,592			231,192
	Noncontrolling Interests –	117,689			1,244		8,725			127,658			27,858			73,412			20,450			121,720
	Partially Owned Properties/
	Partners' equity
	Company equity/General and	226,841			46,324		215,490			488,655			1,386			30,527			953			32,866
	Limited Partners' Capital
	Total equity/capital	344,530			47,568		224,215			616,313			29,244			103,939			21,403			154,586
	Total liabilities and	$	362,088		$	49,051	$	591,474		$	1,002,613		$	49,847		$	282,936		$	52,995		$	385,778
	equity/capital
Partially Owned Property Income Statement Schedule [Table Text Block]	'
		Consolidated											Unconsolidated
		Development Projects											Development Projects
		Held for											Held for						Operating
		and/or Under			Completed, Not								and/or Under			Completed, Not Stabilized (3)
		Development			Stabilized (3)		Operating			Total			Development									Total
	Operating information for the quarter
	ended 3/31/14 (at 100%):
	Operating revenue	$	—		$	468	$	21,308		$	21,776		$	—		$	4,528		$	1,353		$	5,881
	Operating expenses	77			204		6,453			6,734			44			1,917			559			2,520
	Net operating (loss) income	(77		)	264		14,855			15,042			(44		)	2,611			794			3,361
	Depreciation	—			—		5,363			5,363			—			2,782			447			3,229
	General and administrative/other	(9		)	116		12			119			—			12			43			55
	Operating (loss) income	(68		)	148		9,480			9,560			(44		)	(183		)	304			77
	Interest and other income	—			—		3			3			—			—			—			—
	Other expenses	(42		)	—		(7		)	(49		)	—			—			—			—
	Interest:
	Expense incurred, net	—			—		(3,887		)	(3,887		)	—			(1,992		)	(279		)	(2,271		)
	Amortization of deferred	—			—		(88		)	(88		)	—			(3		)	—			(3		)
	financing costs
	(Loss) income before income and	(110		)	148		5,501			5,539			(44		)	(2,178		)	25			(2,197		)
	other taxes and (loss) from
	investments in unconsolidated
	entities
	Income and other tax (expense)	—			—		(36		)	(36		)	—			—			—			—
	benefit
	(Loss) from investments in	—			—		(419		)	(419		)	—			—			—			—
	unconsolidated entities
	Net (loss) income	$	(110	)	$	148	$	5,046		$	5,084		$	(44	)	$	(2,178	)	$	25		$	(2,197	)
	-1	Project and apartment unit counts exclude all uncompleted development projects until those projects are substantially completed.
	-2	All debt is non-recourse to the Company with the exception of 50% of the current $16.2 million outstanding debt balance on one unconsolidated development project.
	-3	Projects included here are substantially complete. However, they may still require additional exterior and interior work for all units to be available for leasing.
	Note:	The above tables exclude the Company's interests in unconsolidated joint ventures entered into with AVB in connection with the Archstone Transaction. These ventures own certain non-core Archstone assets that are held for sale and succeeded to certain residual Archstone liabilities, such as liability for various employment-related matters as well as responsibility for tax protection arrangements and third-party preferred interests in former Archstone subsidiaries. The preferred interests have an aggregate liquidation value of $79.3 million at March 31, 2014. The ventures are owned 60% by the Company and 40% by AVB.

Deposits_Restricted_Tables

Deposits - Restricted (Tables)	3 Months Ended
	Mar. 31, 2014
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, 2014 and December 31, 2013 (amounts in thousands):
		March 31,		December 31,
		2014		2013
	Earnest money on pending acquisitions	$	1,344	$	4,514
	Restricted deposits on real estate investments	44,037		53,771
	Resident security and utility deposits	45,195		44,777
	Other	505		505
	Totals	$	91,081	$	103,567

Derivative_and_Other_Fair_Valu1

Derivative and Other Fair Value Instruments (Tables)	3 Months Ended
	Mar. 31, 2014
Fair Value Disclosures [Abstract]	'
Derivative Instrument Table	'
	The following table summarizes the Company’s consolidated derivative instruments at March 31, 2014 (dollar amounts are in thousands):
			Forward
			Starting
			Swaps (1)
	Current Notional Balance		$	450,000
	Lowest Possible Notional		$	450,000
	Highest Possible Notional		$	450,000
	Lowest Interest Rate		2.125		%
	Highest Interest Rate		3.23		%
	Earliest Maturity Date		2024
	Latest Maturity Date		2025
	-1	Forward Starting Swaps – Designed to partially fix interest rates in advance of planned future debt issuances. These swaps have mandatory counterparty terminations in 2015 and 2016, and are targeted to 2014 and 2015 issuances.
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, 2014 and December 31, 2013, respectively (amounts in thousands):
								Fair Value Measurements at Reporting Date Using
	Description		Balance Sheet		3/31/14			Quoted Prices in			Significant  Other				Significant
			Location					Active Markets for			Observable Inputs				Unobservable Inputs
								Identical Assets/Liabilities			(Level 2)				(Level  3)
								(Level 1)
	Assets
	Derivatives designated as hedging instruments:
	Interest Rate Contracts:
	Forward Starting Swaps		Other Assets		$	11,428		$	—		$	11,428			$	—
	Supplemental Executive Retirement Plan		Other Assets		88,010			88,010			—				—
	Total				$	99,438		$	88,010		$	11,428			$	—
	Liabilities
	Derivatives designated as hedging instruments:
	Interest Rate Contracts:
	Forward Starting Swaps		Other Liabilities		$	4,670		$	—		$	4,670			$	—
	Supplemental Executive Retirement Plan		Other Liabilities		88,010			88,010			—				—
	Total				$	92,680		$	88,010		$	4,670			$	—
	Redeemable Noncontrolling Interests –
	Operating Partnership/Redeemable
	Limited Partners		Mezzanine		$	405,276		$	—		$	405,276			$	—
								Fair Value Measurements at Reporting Date Using
	Description		Balance Sheet		12/31/13			Quoted Prices in			Significant  Other				Significant
			Location					Active Markets for			Observable Inputs				Unobservable Inputs
								Identical Assets/Liabilities			(Level 2)				(Level  3)
								(Level 1)
	Assets
	Derivatives designated as hedging instruments:
	Interest Rate Contracts:
	Forward Starting Swaps		Other Assets		$	18,710		$	—		$	18,710			$	—
	Supplemental Executive Retirement Plan		Other Assets		83,845			83,845			—				—
	Total				$	102,555		$	83,845		$	18,710			$	—
	Liabilities
	Supplemental Executive Retirement Plan		Other Liabilities		$	83,845		$	83,845		$	—			$	—
	Total				$	83,845		$	83,845		$	—			$	—
	Redeemable Noncontrolling Interests –
	Operating Partnership/Redeemable
	Limited Partners		Mezzanine		$	363,144		$	—		$	363,144			$	—
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, 2014 and 2013, respectively (amounts in thousands):
	31-Mar-14		Location of		Amount of			Hedged Item		Income Statement	Amount of
	Type of Fair Value Hedge		Gain/(Loss)		Gain/(Loss)					Location of	Gain/(Loss)
			Recognized in		Recognized in					Hedged Item	Recognized in
			Income on		Income on					Gain/(Loss)	Income
			Derivative		Derivative						on Hedged Item
	Derivatives designated as hedging instruments:
	Interest Rate Contracts:
	Interest Rate Swaps		N/A		$	—		N/A		N/A	$	—
	Total				$	—					$	—
	31-Mar-13		Location of		Amount of			Hedged Item		Income Statement	Amount of
	Type of Fair Value Hedge		Gain/(Loss)		Gain/(Loss)					Location of	Gain/(Loss)
			Recognized in		Recognized in					Hedged	Recognized in
			Income		Income					Item Gain/(Loss)	Income
			on Derivative		on Derivative						on Hedged Item
	Derivatives designated as hedging instruments:
	Interest Rate Contracts:
	Interest Rate Swaps		Interest expense		$	(1,471	)	Fixed rate debt		Interest expense	$	1,471
	Total				$	(1,471	)				$	1,471
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, 2014 and 2013, respectively (amounts in thousands):
			Effective Portion								Ineffective Portion
	31-Mar-14		Amount of				Location of Gain/	Amount of Gain/			Location of		Amount of Gain/
	Type of Cash Flow Hedge		Gain/(Loss)				(Loss)	(Loss)			Gain/(Loss)		(Loss)
			Recognized in OCI				Reclassified from	Reclassified from			Recognized in		Reclassified from
			on Derivative				Accumulated	Accumulated			Income		Accumulated
							OCI	OCI into Income			on Derivative		OCI into Income
							into Income
	Derivatives designated as hedging instruments:
	Interest Rate Contracts:
	Forward Starting Swaps/Treasury Locks		$	(11,952	)		Interest expense	$	(4,129	)	N/A		$	—
	Total		$	(11,952	)			$	(4,129	)			$	—
			Effective Portion								Ineffective Portion
	31-Mar-13		Amount of				Location of Gain/	Amount of Gain/			Location of		Amount of Gain/
	Type of Cash Flow Hedge		Gain/(Loss)				(Loss)	(Loss)			Gain/(Loss)		(Loss)
			Recognized in OCI				Reclassified from	Reclassified from			Recognized in		Reclassified from
			on Derivative				Accumulated	Accumulated			Income		Accumulated
							OCI	OCI			on Derivative		OCI
							into Income	into Income					into Income
	Derivatives designated as hedging instruments:
	Interest Rate Contracts:
	Forward Starting Swaps/Treasury Locks		$	2,814			Interest expense	$	(8,272	)	N/A		$	—
	Total		$	2,814				$	(8,272	)			$	—

Earnings_Per_Share_Tables

Earnings Per Share (Tables)	3 Months Ended
	Mar. 31, 2014
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,
			2014			2013
	Numerator for net income per share – basic:
	Income (loss) from continuing operations		$	81,698		$	(165,339	)
	Allocation to Noncontrolling Interests – Operating Partnership, net		(3,053		)	6,836
	Net (income) attributable to Noncontrolling Interests – Partially		(504		)	(25		)
	Owned Properties
	Preferred distributions		(1,036		)	(1,036		)
	Income (loss) from continuing operations available to Common Shares,		77,105			(159,564		)
	net of Noncontrolling Interests
	Discontinued operations, net of Noncontrolling Interests		994			1,176,214
	Numerator for net income per share – basic		$	78,099		$	1,016,650
	Numerator for net income per share – diluted (1):
	Income from continuing operations		$	81,698
	Net (income) attributable to Noncontrolling Interests – Partially		(504		)
	Owned Properties
	Preferred distributions		(1,036		)
	Income from continuing operations available to Common Shares		80,158
	Discontinued operations, net		1,034
	Numerator for net income per share – diluted (1)		$	81,192		$	1,016,650
	Denominator for net income per share – basic and diluted (1):
	Denominator for net income per share – basic		360,470			337,532
	Effect of dilutive securities:
	OP Units		13,731
	Long-term compensation shares/units		2,183
	Denominator for net income per share – diluted (1)		376,384			337,532
	Net income per share – basic		$	0.22		$	3.01
	Net income per share – diluted		$	0.22		$	3.01
	Net income per share – basic:
	Income (loss) from continuing operations available to Common Shares,		$	0.214		$	(0.473	)
	net of Noncontrolling Interests
	Discontinued operations, net of Noncontrolling Interests		0.003			3.485
	Net income per share – basic		$	0.217		$	3.012
	Net income per share – diluted (1):
	Income (loss) from continuing operations available to Common Shares		$	0.213		$	(0.473	)
	Discontinued operations, net		0.003			3.485
	Net income per share – diluted		$	0.216		$	3.012
	-1	Potential common shares issuable from the assumed conversion of OP Units and the exercise/vesting of long-term compensation shares/units are automatically anti-dilutive and therefore excluded from the diluted earnings per share calculation as the Company had a loss from continuing operations for the quarter ended March 31, 2013.
Operating Partnership [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,
			2014			2013
	Numerator for net income per Unit – basic and diluted (1):
	Income (loss) from continuing operations		$	81,698		$	(165,339	)
	Net (income) attributable to Noncontrolling Interests – Partially		(504		)	(25		)
	Owned Properties
	Allocation to Preference Units		(1,036		)	(1,036		)
	Income (loss) from continuing operations available to Units		80,158			(166,400		)
	Discontinued operations, net		1,034			1,226,373
	Numerator for net income per Unit – basic and diluted (1)		$	81,192		$	1,059,973
	Denominator for net income per Unit – basic and diluted (1):
	Denominator for net income per Unit - basic		374,201			351,255
	Effect of dilutive securities:
	Dilution for Units issuable upon assumed exercise/vesting of the Company’s long-term		2,183
	compensation shares/units
	Denominator for net income per Unit – diluted (1)		376,384			351,255
	Net income per Unit – basic		$	0.22		$	3.01
	Net income per Unit – diluted		$	0.22		$	3.01
	Net income per Unit – basic:
	Income (loss) from continuing operations available to Units		$	0.214		$	(0.473	)
	Discontinued operations, net		0.003			3.485
	Net income per Unit – basic		$	0.217		$	3.012
	Net income per Unit – diluted (1):
	Income (loss) from continuing operations available to Units		$	0.213		$	(0.473	)
	Discontinued operations, net		0.003			3.485
	Net income per Unit – diluted		$	0.216		$	3.012
	-1	Potential Units issuable from the assumed exercise/vesting of the Company's long-term compensation shares/units are automatically anti-dilutive and therefore excluded from the diluted earnings per Unit calculation as the Operating Partnership had a loss from continuing operations for the quarter ended March 31, 2013.

Discontinued_Operations_Tables

Discontinued Operations (Tables)	3 Months Ended
	Mar. 31, 2014
Discontinued Operations and Disposal Groups [Abstract]	'
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 during the quarters ended March 31, 2014 and 2013 (amounts in thousands).
			Quarter Ended March 31,
			2014			2013
	REVENUES
	Rental income		$	1,023		$	81,782
	Total revenues		1,023			81,782
	EXPENSES (1)
	Property and maintenance		48			20,424
	Real estate taxes and insurance		13			8,594
	Property management		—			1
	Depreciation		—			23,816
	General and administrative		5			8
	Total expenses		66			52,843
	Discontinued operating income		957			28,939
	Interest and other income		35			52
	Other expenses		—			(2		)
	Interest (2):
	Expense incurred, net		—			(1,252		)
	Amortization of deferred financing costs		—			(228		)
	Income and other tax (expense) benefit		(29		)	(58		)
	Discontinued operations		963			27,451
	Net gain on sales of discontinued operations		71			1,198,922
	Discontinued operations, net		$	1,034		$	1,226,373
	-1	Includes expenses paid in the current period for properties sold in prior periods related to the Company’s period of ownership.
	-2	Includes only interest expense specific to secured mortgage notes payable for properties sold.

Reportable_Segments_Tables

Reportable Segments (Tables)	3 Months Ended
	Mar. 31, 2014
Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]	'
Reportable Segments Schedule	'
	The following tables present NOI for each segment from our rental real estate specific to continuing operations for the quarters ended March 31, 2014 and 2013, respectively, as well as total assets and capital expenditures at March 31, 2014 (amounts in thousands):
			Quarter Ended March 31, 2014									Quarter Ended March 31, 2013
			Rental Income			Operating Expenses			NOI			Rental Income			Operating Expenses			NOI
	Same store (1)
	Boston		$	61,907		$	22,154		$	39,753		$	59,054		$	20,207		$	38,847
	Denver		26,611			7,449			19,162			24,970			7,217			17,753
	New York		111,185			46,202			64,983			107,997			43,111			64,886
	San Francisco		81,261			26,655			54,606			74,945			28,156			46,789
	Seattle		37,725			12,768			24,957			35,372			12,237			23,135
	South Florida		48,437			18,184			30,253			46,239			17,643			28,596
	Southern California		102,665			34,347			68,318			98,210			34,587			63,623
	Washington DC		110,396			37,396			73,000			110,993			35,884			75,109
	Non-core		33,691			13,084			20,607			32,672			12,443			20,229
	Total same store		613,878			218,239			395,639			590,452			211,485			378,967
	Non-same store/other (2) (3)
	Boston		1,028			211			817			256			53			203
	Seattle		1,687			690			997			25			1			24
	South Florida		800			466			334			14			78			(64		)
	Southern California		7,174			3,122			4,052			1,292			617			675
	Washington DC		4,934			1,863			3,071			1,806			653			1,153
	Other (3)		1,224			5,194			(3,970		)	1,140			9,955			(8,815		)
	Total non-same store/other		16,847			11,546			5,301			4,533			11,357			(6,824		)
	Archstone pre-ownership (4)		—			—			—			(92,423		)	(36,729		)	(55,694		)
	Total		$	630,725		$	229,785		$	400,940		$	502,562		$	186,113		$	316,449
	-1	Same store primarily includes all properties acquired or completed and stabilized prior to January 1, 2013, less properties subsequently sold, which represented 100,984 apartment units. Also includes 18,465 stabilized apartment units acquired in the Archstone Acquisition that are owned and managed by the Company.
	-2	Non-same store primarily includes properties acquired after January 1, 2013, plus any properties in lease-up and not stabilized as of January 1, 2013, but excludes 18,465 stabilized apartment units acquired in the Archstone Acquisition that are owned and managed by the Company.
	-3	Other includes development and other corporate operations.
	-4	Represents pro forma Archstone pre-ownership results for the period January 1, 2013 to February 27, 2013 that is included in 2013 same store results.
			Quarter Ended March 31, 2014
			Total Assets			Capital Expenditures
	Same store (1)
	Boston		$	1,968,613		$	4,078
	Denver		536,226			762
	New York		4,727,805			3,051
	San Francisco		2,769,826			5,716
	Seattle		1,053,600			2,205
	South Florida		1,178,426			3,119
	Southern California		3,000,465			5,142
	Washington DC		4,299,085			5,529
	Non-core		640,141			1,544
	Total same store		20,174,187			31,146
	Non-same store/other (2) (3)
	Boston		48,971			263
	Seattle		190,041			160
	South Florida		70,725			(1		)
	Southern California		446,912			173
	Washington DC		305,668			449
	Other (3)		1,653,127			1
	Total non-same store/other		2,715,444			1,045
	Total		$	22,889,631		$	32,191
	-1	Same store primarily includes all properties acquired or completed and stabilized prior to January 1, 2013, less properties subsequently sold, which represented 100,984 apartment units. Also includes 18,465 stabilized apartment units acquired in the Archstone Acquisition that are owned and managed by the Company.
	-2	Non-same store primarily includes properties acquired after January 1, 2013, plus any properties in lease-up and not stabilized as of January 1, 2013, but excludes 18,465 stabilized apartment units acquired in the Archstone Acquisition that are owned and managed by the Company.
	-3	Other includes development and other corporate operations.
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, 2014 and 2013, respectively (amounts in thousands):
			Quarter Ended March 31,
			2014			2013
	Rental income		$	630,725		$	502,562
	Property and maintenance expense		(125,573		)	(98,529		)
	Real estate taxes and insurance expense		(82,094		)	(65,095		)
	Property management expense		(22,118		)	(22,489		)
	Total operating expenses		(229,785		)	(186,113		)
	Net operating income		$	400,940		$	316,449

Business_Details

Business (Details)	Mar. 31, 2014	Mar. 31, 2013
Noncontrolling Interest, Ownership Percentage by Parent	96.20%	'
Number of States in which Entity Operates	12	'
Number of Real Estate Properties	396	'
Number of Units in Real Estate Property	111,537	'
Property/Unit schedule	'	'
Wholly Owned Properties	367	'
Master Leased Properties Acquired	'	3
Partially Owned Consolidated Properties	20	'
Partially Owned Unconsolidated Properties	4	'
Military Housing Properties	2	'
Wholly Owned Units	99,936	'
Master Leased Units	853	'
Partially Owned Consolidated Units	4,020	'
Partially Owned Unconsolidated Units	1,669	'
Military Housing Units	5,059	'

Summary_of_Significant_Account2

Summary of Significant Accounting Policies (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
Partially Owned Consolidated Properties	20	'
Partially Owned Consolidated Units	4,020	'
Noncontrolling Interests - Partially Owned Properties	$127,658,000	$126,583,000
Partially Owned Limited Life Partnership Properties	6	'
Noncontrolling Interest Balance Limited Life Partnerships	-10,000,000	'
Noncontrolling Interests Settlement Value	$52,524,206	'

Equity_Capital_and_Other_Inter2

Equity, Capital and Other Interests EQR Common Shares (Details)	3 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Common Shares outstanding at January 1,	361,148,189	360,479,260
Common Shares Issued:	'	'
Conversion of OP Units	18,043	'
Exercise of share options	493,995	'
Employee Share Purchase Plan (ESPP)	37,928	'
Restricted Share Grants Net	162,349	'
Conversion Of Restricted Shares To Ltip Units Shares	-12,146	'
Stock Repurchased And Retired	-31,240	'
Units	'	'
Common Shares And Units Outstanding	375,523,508	'
Units Ownership Interest in Operating Partnership	3.80%	'
Limited Partner [Member]	'	'
Common Shares Issued:	'	'
Conversion Of Restricted Shares To Ltip Units Shares	12,146	'
Units	'	'
Total Units Outstanding	14,375,319	14,180,376
Issuance Of LTIPs	200,840	'
Shares Issued During Period Shares Conversion Of Units To Common Shares	-18,043	'

Equity_Capital_and_Other_Inter3

Equity, Capital and Other Interests Redeemable (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Redeemable Noncontrolling Interests - Operating Partnership	$405,276	$363,144
Change in market value	44,530	'
Change in carrying value	-2,398	'
Limited Partners Change In Redemption Value	44,530	'
Limited Partners Change In Carrying Value	($2,398)	'

Equity_Capital_and_Other_Inter4

Equity, Capital and Other Interests Preferred (Details) (USD $)	3 Months Ended	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
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
100,000,000 shares authorized; 1,000,000 shares issued and outstanding as of March 31, 2014 and December 31, 2013	$50,000	$50,000
Series K Preferred Stock [Member]	'	'
Class of Stock [Line Items]	'	'
Preferred Stock Preference Units Issued	1,000,000	1,000,000
Preferred Stock Preference Units Outstanding	1,000,000	1,000,000
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	10-Dec-26	'
Annual Dividend Per Preferred Share Preference Unit	$4.14	'
100,000,000 shares authorized; 1,000,000 shares issued and outstanding as of March 31, 2014 and December 31, 2013	50,000	50,000
Preference Units	$50,000	$50,000

Equity_Capital_and_Other_Inter5

Equity, Capital and Other Interests ERP Units (Details)	3 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Capital Unit [Line Items]	'	'
Common Shares And Units Outstanding	375,523,508	'
Exercise of EQR share options	493,995	'
EQR's Employee Share Purchase Plan (ESPP)	37,928	'
Restricted Share Grants Net	162,349	'
OP Units repurchased and retired	-31,240	'
Conversion Of Restricted Shares To Ltip Units Shares	-12,146	'
Units Ownership Interest in Operating Partnership	3.80%	'
General And Limited Partner [Member]	'	'
Capital Unit [Line Items]	'	'
Common Shares And Units Outstanding	375,523,508	374,659,636
Exercise of EQR share options	493,995	'
EQR's Employee Share Purchase Plan (ESPP)	37,928	'
Restricted Share Grants Net	162,349	'
Issuance Of LTIPs	200,840	'
OP Units repurchased and retired	-31,240	'
Limited Partner [Member]	'	'
Capital Unit [Line Items]	'	'
Issuance Of LTIPs	200,840	'
Conversion Of Restricted Shares To Ltip Units Shares	12,146	'
Shares Issued During Period Shares Conversion Of Units To Common Shares	-18,043	'
Total Units Outstanding	14,375,319	14,180,376

Equity_Capital_and_Other_Inter6

Equity, Capital and Other Interests Text (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
		Archstone Transaction [Member]
Issuance of Common Shares	'	34,468,085
Stock Issued During Period, Value, New Issues	'	$1,900,000,000
Average Price Per Common Share Issued	$56.87	$55.99
Units Issued During Period New Issues	'	34,468,085
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	'
Stock Repurchased And Retired	-31,240	'
Value Of Stock Repurchased And Retired	1,800,000	'
Payments to Acquire Interest in Subsidiaries and Affiliates	2,500,000	'
Increase To Reduction Of Paid In Capital	500,000	'
Reduction In Partially Owned Properties	1,000,000	'
Reduction In Other Liabilities	$1,000,000	'

Real_Estate_Details

Real Estate (Details) (USD $)

3 Months Ended

3 Months Ended

3 Months Ended

3 Months Ended

3 Months Ended

12 Months Ended

3 Months Ended

3 Months Ended

12 Months Ended

1 Months Ended

Mar. 31, 2014

Mar. 31, 2013

Dec. 31, 2013

Mar. 31, 2013

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2013

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2013

Mar. 31, 2014

Mar. 31, 2013

Mar. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2013

Mar. 31, 2014

Mar. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Mar. 31, 2013

Mar. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

8-May-14

Consolidated Properties [Member]

2014 [Member]

2015 [Member]

2016 [Member]

2017 [Member]

2018 [Member]

2019 [Member]

Archstone [Member]

Archstone [Member]

Building and Building Improvements [Member]

Furniture and Fixtures [Member]

Archstone Transaction [Member]

Archstone Transaction [Member]

Unconsolidated Properties [Member]

Investment Banking and Legal/Accounting Fees [Member]

Projects under development [Member]

Projects under development [Member]

Land held for development [Member]

Land held for development [Member]

Archstone Transaction [Member]

OPERATING PARTNERSHIP

OPERATING PARTNERSHIP

OPERATING PARTNERSHIP

Public Offering [Member]

Archstone Transaction [Member]

Term Loan [Member]

Consolidated Rental Properties [Member]

Consolidated Rental Properties [Member]

Land [Member]

Land

$6,281,124,000

'

$6,192,512,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$6,281,124,000

'

$6,192,512,000

'

'

'

'

'

'

Property, Plant and Equipment, Gross [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Investment Building and Building Improvements

17,843,201,000

'

17,509,609,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Fixtures and Equipment, Gross

1,273,171,000

'

1,214,220,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Finite-Lived Intangible Assets, Gross

507,100,000

'

502,218,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Land Under Development

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

390,850,000

353,574,000

'

'

'

'

'

'

'

'

'

'

'

'

Projects under development

865,177,000

'

988,867,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

474,327,000

635,293,000

42,007,000

52,133,000

'

865,177,000

'

988,867,000

'

'

'

'

'

'

Land held for development

295,357,000

'

393,522,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

253,350,000

341,389,000

'

295,357,000

'

393,522,000

'

'

'

'

'

'

Real Estate Investment Property, at Cost

27,065,130,000

'

26,800,948,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

27,065,130,000

'

26,800,948,000

'

'

'

'

'

'

Real Estate Investment Property, Accumulated Depreciation

-4,992,877,000

'

-4,807,709,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

-4,992,877,000

'

-4,807,709,000

'

'

'

'

'

'

Investment in real estate, net

22,072,253,000

'

21,993,239,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

22,072,253,000

'

21,993,239,000

'

'

'

'

'

'

Ground Lease Intangibles Below Market

178,251,000

'

178,251,000

'

'

'

'

'

'

'

'

'

'

'

'

178,251,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Retail Lease Intangibles Above Market

1,260,000

'

1,260,000

'

'

'

'

'

'

'

'

'

'

'

'

1,260,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Lease Intangible Assets

179,511,000

'

179,511,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Amortization of Intangible Assets

-5,502,000

'

-4,364,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Lease Intangible Assets, Net

174,009,000

'

175,147,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Ground Lease Intangibles Above Market

2,400,000

'

2,400,000

'

'

'

'

'

'

'

'

'

'

'

'

2,400,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Retail Lease Intangibles Below Market

5,500,000

'

5,500,000

'

'

'

'

'

'

'

'

'

'

'

'

8,040,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Lease Intangible Liabilities

7,900,000

'

7,900,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Amortization Of Intangible Liabilities

-1,471,000

'

-1,161,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Lease Intangible Liabilities, net

6,429,000

'

6,739,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Ground Lease Amortization

1,100,000

400,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Retail Lease Amortization

300,000

100,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Weighted Average Ground Lease Amortization Period

49.8

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Weighted Average Retail Lease Amortization Period

2.8

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Ground Lease Intangibles Amortization

'

'

'

'

3,241,000

4,321,000

4,321,000

4,321,000

4,321,000

4,321,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Retail Lease Intangibles Amortization

'

'

'

'

-758,000

-1,016,000

-908,000

-540,000

-71,000

-71,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Total Above And Below Market Ground Lease Intangibles And Retail Lease Intangibles

'

'

'

'

2,483,000

3,305,000

3,413,000

3,781,000

4,250,000

4,250,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Business Acquisition, Percentage of Voting Interests Acquired

'

'

'

'

'

'

'

'

'

'

'

'

'

'

60.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Properties acquired

1

'

'

'

'

'

'

'

'

'

'

'

'

'

71

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1

'

'

Property Units Acquired

430

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

20,160

'

'

'

'

'

'

430

'

'

Partially Owned Properties Acquired Properties

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Partially Owned Units Acquired Units

'

'

'

'

'

'

'

'

'

'

'

'

'

'

432

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Partially Owned Unconsolidated Properties Acquired

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Partially Owned Unconsolidated Units Acquired

'

'

'

'

'

'

'

'

'

'

'

'

'

'

336

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Master Leased Properties Acquired

'

3

'

'

'

'

'

'

'

'

'

'

'

'

3

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Master Leased Units Acquired

'

'

'

'

'

'

'

'

'

'

'

'

'

'

853

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Uncompleted Development Properties Acquired

'

'

'

2

'

'

'

'

'

'

'

'

'

'

4

'

2

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Uncompleted Development Units Acquired

'

'

'

'

'

'

'

'

'

'

'

'

'

'

964

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Land parcels acquired

'

'

'

'

'

'

'

'

'

'

'

'

'

'

14

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

8,968,389,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Payments to Acquire Businesses, Net of Cash Acquired

0

4,000,643,000

'

'

'

'

'

'

'

'

'

4,000,000,000

'

'

'

'

'

'

'

'

'

'

'

0

4,000,643,000

'

'

'

'

'

'

'

Mortgage notes payable

5,167,626,000

'

5,174,166,000

'

'

'

'

'

'

'

'

2,000,000,000

'

'

'

'

'

'

'

'

'

'

'

5,167,626,000

'

5,174,166,000

'

'

'

'

'

'

Issuance of Common Shares

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

21,850,000

34,468,085

'

'

'

'

Stock Issued During Period, Value, New Issues

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1,200,000,000

1,900,000,000

'

'

'

'

Average Price Per Common Share Issued

$56.87

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$54.75

$55.99

'

'

'

'

Noncash or Part Noncash Acquisition, Debt Assumed

'

'

'

'

'

'

'

'

'

'

3,100,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Mark-to-Market Debt Premiums

'

127,900,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Proceeds From Sale Of Property

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

4,500,000,000

'

Term Loan Principal Amount

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

750,000,000

'

'

'

Number of Properties Subject to Ground Leases

'

9

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Business Acquisition, Purchase Price Allocation, Land

'

'

'

'

'

'

'

'

'

'

2,239,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment

'

'

'

'

'

'

'

'

'

'

'

'

5,765,538,000

61,470,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Business Acquisition, Purchase Price Allocation, Amortizable Intangible Assets

'

'

'

'

'

'

'

'

'

'

304,830,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Business Combination Purchase Price Allocation Projects Under Development

'

'

'

'

'

'

'

'

'

'

36,583,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Business Combination Purchase Price Allocation Land Held for Development

'

'

'

'

'

'

'

'

'

'

244,097,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Business Combination Purchase Price Allocation Investments in Unconsolidated Entities

'

'

'

'

'

'

'

'

'

'

230,608,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Business Acquisition, Purchase Price Allocation, Other Assets

'

'

'

'

'

'

'

'

'

'

195,260,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Business Acquisition, Purchase Price Allocation, Other Liabilities

'

'

'

'

'

'

'

'

'

'

-108,997,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Business Combination, Acquisition Related Costs

94,700,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Payments of Financing Costs

60,000

13,869,000

'

'

'

'

'

'

'

'

-13,500,000

2,500,000

'

'

'

'

'

'

'

'

'

'

'

60,000

13,869,000

'

'

'

'

'

'

'

Merger Expenses

81,200,000

19,100,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

19,100,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Income Loss From Equity Method Investments Merger Expenses

'

46,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Business Acquisition, Pro Forma Revenue

'

638,499,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

638,499,000

'

'

'

'

'

'

'

Business Acquisition, Proforma Income Loss From Continuing Operations

'

-34,473,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

-34,473,000

'

'

'

'

'

'

'

Business Acquisition, Proforma Income Loss From Discontinued Operations Net Of Tax

'

1,213,615,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1,213,615,000

'

'

'

'

'

'

'

Business Acquisition, Pro Forma Net Income (Loss)

'

1,179,142,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1,179,142,000

'

'

'

'

'

'

'

Business Acquisition, Proforma Net Income Available to Common Shares

'

1,130,671,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Business Acquisition, Proforma Net Income Available to Units

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1,178,887,000

'

'

'

'

'

'

'

Business Acquisition, Pro Forma Earnings Per Share, Basic

'

$3.15

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$3.15

'

'

'

'

'

'

'

Business Acquisition, Pro Forma Earnings Per Share, Diluted

'

$3.15

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$3.15

'

'

'

'

'

'

'

Business Acquisition, Proforma Weighted Average Common Shares Basic

'

359,362,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Business Acquisition, Proforma Weighted Average Number Of Shares Diluted

'

359,362,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Business Acquisition, Proforma Weighted Average Limited Partnership And General Partnership Units Outstanding Basic

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

373,085,000

'

'

'

'

'

'

'

Business Acquisition, Proforma Weighted Average Number Of Limited Partnership And General Partnership Unit Outstanding Diluted

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

373,085,000

'

'

'

'

'

'

'

Severance Costs

'

'

'

'

'

'

'

'

'

'

'

44,800,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual

'

'

'

'

'

'

'

'

'

'

'

'

'

'

52,600,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$36,200,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Real_Estate_Details_2

Real Estate (Details 2) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2014	2-May-14	Mar. 31, 2014
		Consolidated Rental Properties [Member]	Land [Member]	Land [Member]
Properties acquired	1	1	'	'
Property Units Acquired	430	430	'	'
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	$148,500	$143,000	$10,300	$5,500

Commitments_to_AcquireDispose_2

Commitments to Acquire/Dispose of Real Estate (Details) (USD $)	Mar. 31, 2014
In Thousands, unless otherwise specified
Commitments to Acquire Real Estate	'
Properties Acquired-Total	0
Rental Units Acquired - Total	0
Purchase Price - Total	$16,300
Commitments to Dispose of Real Estate	'
Properties Disposed - Total	4
Rental Units Disposed-Total	1,360
Sales Price For Commitments To Dispose	224,150
Land Parcel [Member]	'
Commitments to Acquire Real Estate	'
Purchase Price - Total	16,300
Land Parcels Contracted to be Acquired	1
Rental Properties Disposed of [Member]	'
Commitments to Dispose of Real Estate	'
Properties Disposed - Total	4
Rental Units Disposed-Total	1,360
Sales Price For Commitments To Dispose	192,050
Land Parcel [Member]	'
Commitments to Dispose of Real Estate	'
Sales Price For Commitments To Dispose	$32,100

Investments_in_Partially_Owned2

Investments in Partially Owned Entities (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013	Dec. 31, 2012
Investments In Partially Owned Entities (Textuals) [Abstract]	'	'	'	'
Joint Venture Partner Ownership Percentage	80.00%	'	'	'
Equity Method Investment, Ownership Percentage	20.00%	'	'	'
Debt Instrument, Maturity Date	1-May-61	'	'	'
Preferred Interests	$65,000,000	'	'	'
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	148,500,000	'	'	'
Investment in Joint Venture	311,597,290	'	'	'
Number of Joint Ventures	2	'	'	'
Partners Payments To Acquire Equity Method Investments	40,100,000	'	'	'
Partially Owned Property Balance Sheet Schedule	'	'	'	'
Partially Owned Consolidated Properties	20	'	'	'
Partially Owned Unconsolidated Properties	4	'	'	'
Partially Owned Consolidated Units	4,020	'	'	'
Partially Owned Unconsolidated Units	1,669	'	'	'
ASSETS	'	'	'	'
Real Estate Investment Property, at Cost	27,065,130,000	'	26,800,948,000	'
Real Estate Investment Property, Accumulated Depreciation	-4,992,877,000	'	-4,807,709,000	'
Investment in real estate, net	22,072,253,000	'	21,993,239,000	'
Cash and Cash Equivalents, at Carrying Value	37,209,000	56,087,000	53,534,000	612,590,000
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	205,068,000	'	178,526,000	'
Restricted Cash and Cash Equivalents	91,081,000	'	103,567,000	'
Deferred Finance Costs, Net	55,754,000	'	58,486,000	'
Other Assets	384,271,000	'	404,557,000	'
Total assets	22,889,631,000	'	22,834,545,000	'
LIABILITIES AND EQUITY	'	'	'	'
Secured Debt	5,167,626,000	'	5,174,166,000	'
Accounts Payable And Accrued Liabilities Current And Noncurrent Other Than Interest And Dividend Payable	161,838,000	'	118,791,000	'
Interest Payable	78,140,000	'	78,309,000	'
Other Liabilities	321,043,000	'	347,748,000	'
Security Deposit Liability	72,735,000	'	71,592,000	'
Total liabilities	11,764,797,000	'	11,626,205,000	'
Noncontrolling Interests Partially Owned Properties	127,658,000	'	126,583,000	'
Total liabilities and equity	22,889,631,000	'	22,834,545,000	'
Partially Owned Property Income Statement Schedule	'	'	'	'
Operating revenue	633,442,000	504,722,000	'	'
Depreciation	185,167,000	196,222,000	'	'
General and Administrative Expense	17,576,000	16,495,000	'	'
Operating Income	199,252,000	104,246,000	'	'
Interest and Other Income	605,000	320,000	'	'
Interest:	'	'	'	'
Interest Expense, Debt	113,049,000	194,467,000	'	'
Amortization of Financing Costs	2,792,000	6,948,000	'	'
Income (loss) before income and other taxes, (loss) from investments in unconsolidated entities, net (loss) on sales of land parcels and discontinued operations	83,359,000	-118,568,000	'	'
Income and other tax (expense) benefit	-222,000	-405,000	'	'
(Loss) from investments in unconsolidated entities	-1,409,000	-46,366,000	'	'
Net income	82,732,000	1,061,034,000	'	'
Consolidated Development Projects Held for and or Under Development [Member]	'	'	'	'
Partially Owned Property Balance Sheet Schedule	'	'	'	'
Partially Owned Consolidated Properties	0	'	'	'
Partially Owned Consolidated Units	0	'	'	'
ASSETS	'	'	'	'
Real Estate Investment Property, at Cost	310,147,000	'	'	'
Real Estate Investment Property, Accumulated Depreciation	0	'	'	'
Investment in real estate, net	310,147,000	'	'	'
Cash and Cash Equivalents, at Carrying Value	4,226,000	'	'	'
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	0	'	'	'
Restricted Cash and Cash Equivalents	42,045,000	'	'	'
Deferred Finance Costs, Net	0	'	'	'
Other Assets	5,670,000	'	'	'
Total assets	362,088,000	'	'	'
LIABILITIES AND EQUITY	'	'	'	'
Secured Debt	0	'	'	'
Accounts Payable And Accrued Liabilities Current And Noncurrent Other Than Interest And Dividend Payable	17,438,000	'	'	'
Interest Payable	0	'	'	'
Other Liabilities	120,000	'	'	'
Security Deposit Liability	0	'	'	'
Total liabilities	17,558,000	'	'	'
Noncontrolling Interests Partially Owned Properties	117,689,000	'	'	'
Parent Equity Interest	226,841,000	'	'	'
Total Equity Interest	344,530,000	'	'	'
Total liabilities and equity	362,088,000	'	'	'
Partially Owned Property Income Statement Schedule	'	'	'	'
Operating revenue	0	'	'	'
Operating Expenses	77,000	'	'	'
Gross Profit	-77,000	'	'	'
Depreciation	0	'	'	'
General and Administrative Expense	-9,000	'	'	'
Operating Income	-68,000	'	'	'
Interest and Other Income	0	'	'	'
Other Nonoperating Income (Expense)	-42,000	'	'	'
Interest:	'	'	'	'
Interest Expense, Debt	0	'	'	'
Amortization of Financing Costs	0	'	'	'
Income (loss) before income and other taxes, (loss) from investments in unconsolidated entities, net (loss) on sales of land parcels and discontinued operations	-110,000	'	'	'
Income and other tax (expense) benefit	0	'	'	'
(Loss) from investments in unconsolidated entities	0	'	'	'
Net income	-110,000	'	'	'
Consolidated Completed, Not Stabilized [Member]	'	'	'	'
Partially Owned Property Balance Sheet Schedule	'	'	'	'
Partially Owned Consolidated Properties	1	'	'	'
Partially Owned Consolidated Units	268	'	'	'
ASSETS	'	'	'	'
Real Estate Investment Property, at Cost	48,319,000	'	'	'
Real Estate Investment Property, Accumulated Depreciation	0	'	'	'
Investment in real estate, net	48,319,000	'	'	'
Cash and Cash Equivalents, at Carrying Value	698,000	'	'	'
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	0	'	'	'
Restricted Cash and Cash Equivalents	32,000	'	'	'
Deferred Finance Costs, Net	0	'	'	'
Other Assets	2,000	'	'	'
Total assets	49,051,000	'	'	'
LIABILITIES AND EQUITY	'	'	'	'
Secured Debt	0	'	'	'
Accounts Payable And Accrued Liabilities Current And Noncurrent Other Than Interest And Dividend Payable	1,413,000	'	'	'
Interest Payable	0	'	'	'
Other Liabilities	49,000	'	'	'
Security Deposit Liability	21,000	'	'	'
Total liabilities	1,483,000	'	'	'
Noncontrolling Interests Partially Owned Properties	1,244,000	'	'	'
Parent Equity Interest	46,324,000	'	'	'
Total Equity Interest	47,568,000	'	'	'
Total liabilities and equity	49,051,000	'	'	'
Partially Owned Property Income Statement Schedule	'	'	'	'
Operating revenue	468,000	'	'	'
Operating Expenses	204,000	'	'	'
Gross Profit	264,000	'	'	'
Depreciation	0	'	'	'
General and Administrative Expense	116,000	'	'	'
Operating Income	148,000	'	'	'
Interest and Other Income	0	'	'	'
Other Nonoperating Income (Expense)	0	'	'	'
Interest:	'	'	'	'
Interest Expense, Debt	0	'	'	'
Amortization of Financing Costs	0	'	'	'
Income (loss) before income and other taxes, (loss) from investments in unconsolidated entities, net (loss) on sales of land parcels and discontinued operations	148,000	'	'	'
Income and other tax (expense) benefit	0	'	'	'
(Loss) from investments in unconsolidated entities	0	'	'	'
Net income	148,000	'	'	'
Consolidated Operating [Domain]	'	'	'	'
Partially Owned Property Balance Sheet Schedule	'	'	'	'
Partially Owned Consolidated Properties	19	'	'	'
Partially Owned Consolidated Units	3,752	'	'	'
ASSETS	'	'	'	'
Real Estate Investment Property, at Cost	674,916,000	'	'	'
Real Estate Investment Property, Accumulated Depreciation	-178,165,000	'	'	'
Investment in real estate, net	496,751,000	'	'	'
Cash and Cash Equivalents, at Carrying Value	11,611,000	'	'	'
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	53,844,000	'	'	'
Restricted Cash and Cash Equivalents	220,000	'	'	'
Deferred Finance Costs, Net	2,407,000	'	'	'
Other Assets	26,641,000	'	'	'
Total assets	591,474,000	'	'	'
LIABILITIES AND EQUITY	'	'	'	'
Secured Debt	360,217,000	'	'	'
Accounts Payable And Accrued Liabilities Current And Noncurrent Other Than Interest And Dividend Payable	2,806,000	'	'	'
Interest Payable	1,283,000	'	'	'
Other Liabilities	1,114,000	'	'	'
Security Deposit Liability	1,839,000	'	'	'
Total liabilities	367,259,000	'	'	'
Noncontrolling Interests Partially Owned Properties	8,725,000	'	'	'
Parent Equity Interest	215,490,000	'	'	'
Total Equity Interest	224,215,000	'	'	'
Total liabilities and equity	591,474,000	'	'	'
Partially Owned Property Income Statement Schedule	'	'	'	'
Operating revenue	21,308,000	'	'	'
Operating Expenses	6,453,000	'	'	'
Gross Profit	14,855,000	'	'	'
Depreciation	5,363,000	'	'	'
General and Administrative Expense	12,000	'	'	'
Operating Income	9,480,000	'	'	'
Interest and Other Income	3,000	'	'	'
Other Nonoperating Income (Expense)	-7,000	'	'	'
Interest:	'	'	'	'
Interest Expense, Debt	-3,887,000	'	'	'
Amortization of Financing Costs	-88,000	'	'	'
Income (loss) before income and other taxes, (loss) from investments in unconsolidated entities, net (loss) on sales of land parcels and discontinued operations	5,501,000	'	'	'
Income and other tax (expense) benefit	-36,000	'	'	'
(Loss) from investments in unconsolidated entities	-419,000	'	'	'
Net income	5,046,000	'	'	'
Consolidated Total [Domain]	'	'	'	'
Partially Owned Property Balance Sheet Schedule	'	'	'	'
Partially Owned Consolidated Properties	20	'	'	'
Partially Owned Consolidated Units	4,020	'	'	'
ASSETS	'	'	'	'
Real Estate Investment Property, at Cost	1,033,382,000	'	'	'
Real Estate Investment Property, Accumulated Depreciation	-178,165,000	'	'	'
Investment in real estate, net	855,217,000	'	'	'
Cash and Cash Equivalents, at Carrying Value	16,535,000	'	'	'
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	53,844,000	'	'	'
Restricted Cash and Cash Equivalents	42,297,000	'	'	'
Deferred Finance Costs, Net	2,407,000	'	'	'
Other Assets	32,313,000	'	'	'
Total assets	1,002,613,000	'	'	'
LIABILITIES AND EQUITY	'	'	'	'
Secured Debt	360,217,000	'	'	'
Accounts Payable And Accrued Liabilities Current And Noncurrent Other Than Interest And Dividend Payable	21,657,000	'	'	'
Interest Payable	1,283,000	'	'	'
Other Liabilities	1,283,000	'	'	'
Security Deposit Liability	1,860,000	'	'	'
Total liabilities	386,300,000	'	'	'
Noncontrolling Interests Partially Owned Properties	127,658,000	'	'	'
Parent Equity Interest	488,655,000	'	'	'
Total Equity Interest	616,313,000	'	'	'
Total liabilities and equity	1,002,613,000	'	'	'
Partially Owned Property Income Statement Schedule	'	'	'	'
Operating revenue	21,776,000	'	'	'
Operating Expenses	6,734,000	'	'	'
Gross Profit	15,042,000	'	'	'
Depreciation	5,363,000	'	'	'
General and Administrative Expense	119,000	'	'	'
Operating Income	9,560,000	'	'	'
Interest and Other Income	3,000	'	'	'
Other Nonoperating Income (Expense)	-49,000	'	'	'
Interest:	'	'	'	'
Interest Expense, Debt	-3,887,000	'	'	'
Amortization of Financing Costs	-88,000	'	'	'
Income (loss) before income and other taxes, (loss) from investments in unconsolidated entities, net (loss) on sales of land parcels and discontinued operations	5,539,000	'	'	'
Income and other tax (expense) benefit	-36,000	'	'	'
(Loss) from investments in unconsolidated entities	-419,000	'	'	'
Net income	5,084,000	'	'	'
Unconsolidated Development Projects Held for and or Under Development [Domain]	'	'	'	'
Partially Owned Property Balance Sheet Schedule	'	'	'	'
Partially Owned Unconsolidated Properties	0	'	'	'
Partially Owned Unconsolidated Units	0	'	'	'
ASSETS	'	'	'	'
Real Estate Investment Property, at Cost	49,332,000	'	'	'
Real Estate Investment Property, Accumulated Depreciation	0	'	'	'
Investment in real estate, net	49,332,000	'	'	'
Cash and Cash Equivalents, at Carrying Value	450,000	'	'	'
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	0	'	'	'
Restricted Cash and Cash Equivalents	0	'	'	'
Deferred Finance Costs, Net	65,000	'	'	'
Other Assets	0	'	'	'
Total assets	49,847,000	'	'	'
LIABILITIES AND EQUITY	'	'	'	'
Secured Debt	16,154,000	'	'	'
Accounts Payable And Accrued Liabilities Current And Noncurrent Other Than Interest And Dividend Payable	4,078,000	'	'	'
Interest Payable	32,000	'	'	'
Other Liabilities	339,000	'	'	'
Security Deposit Liability	0	'	'	'
Total liabilities	20,603,000	'	'	'
Noncontrolling Interests Partially Owned Properties	27,858,000	'	'	'
Parent Equity Interest	1,386,000	'	'	'
Total Equity Interest	29,244,000	'	'	'
Total liabilities and equity	49,847,000	'	'	'
Partially Owned Property Income Statement Schedule	'	'	'	'
Operating revenue	0	'	'	'
Operating Expenses	44,000	'	'	'
Gross Profit	-44,000	'	'	'
Depreciation	0	'	'	'
General and Administrative Expense	0	'	'	'
Operating Income	-44,000	'	'	'
Interest and Other Income	0	'	'	'
Other Nonoperating Income (Expense)	0	'	'	'
Interest:	'	'	'	'
Interest Expense, Debt	0	'	'	'
Amortization of Financing Costs	0	'	'	'
Income (loss) before income and other taxes, (loss) from investments in unconsolidated entities, net (loss) on sales of land parcels and discontinued operations	-44,000	'	'	'
Income and other tax (expense) benefit	0	'	'	'
(Loss) from investments in unconsolidated entities	0	'	'	'
Net income	-44,000	'	'	'
Unconsolidated Completed, Not Stabilized [Domain]	'	'	'	'
Partially Owned Property Balance Sheet Schedule	'	'	'	'
Partially Owned Unconsolidated Properties	3	'	'	'
Partially Owned Unconsolidated Units	1,333	'	'	'
ASSETS	'	'	'	'
Real Estate Investment Property, at Cost	285,191,000	'	'	'
Real Estate Investment Property, Accumulated Depreciation	-4,669,000	'	'	'
Investment in real estate, net	280,522,000	'	'	'
Cash and Cash Equivalents, at Carrying Value	1,803,000	'	'	'
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	0	'	'	'
Restricted Cash and Cash Equivalents	120,000	'	'	'
Deferred Finance Costs, Net	126,000	'	'	'
Other Assets	365,000	'	'	'
Total assets	282,936,000	'	'	'
LIABILITIES AND EQUITY	'	'	'	'
Secured Debt	176,232,000	'	'	'
Accounts Payable And Accrued Liabilities Current And Noncurrent Other Than Interest And Dividend Payable	915,000	'	'	'
Interest Payable	725,000	'	'	'
Other Liabilities	867,000	'	'	'
Security Deposit Liability	258,000	'	'	'
Total liabilities	178,997,000	'	'	'
Noncontrolling Interests Partially Owned Properties	73,412,000	'	'	'
Parent Equity Interest	30,527,000	'	'	'
Total Equity Interest	103,939,000	'	'	'
Total liabilities and equity	282,936,000	'	'	'
Partially Owned Property Income Statement Schedule	'	'	'	'
Operating revenue	4,528,000	'	'	'
Operating Expenses	1,917,000	'	'	'
Gross Profit	2,611,000	'	'	'
Depreciation	2,782,000	'	'	'
General and Administrative Expense	12,000	'	'	'
Operating Income	-183,000	'	'	'
Interest and Other Income	0	'	'	'
Other Nonoperating Income (Expense)	0	'	'	'
Interest:	'	'	'	'
Interest Expense, Debt	-1,992,000	'	'	'
Amortization of Financing Costs	-3,000	'	'	'
Income (loss) before income and other taxes, (loss) from investments in unconsolidated entities, net (loss) on sales of land parcels and discontinued operations	-2,178,000	'	'	'
Income and other tax (expense) benefit	0	'	'	'
(Loss) from investments in unconsolidated entities	0	'	'	'
Net income	-2,178,000	'	'	'
Unconsolidated Operating [Domain]	'	'	'	'
Partially Owned Property Balance Sheet Schedule	'	'	'	'
Partially Owned Unconsolidated Properties	1	'	'	'
Partially Owned Unconsolidated Units	336	'	'	'
ASSETS	'	'	'	'
Real Estate Investment Property, at Cost	55,585,000	'	'	'
Real Estate Investment Property, Accumulated Depreciation	-5,052,000	'	'	'
Investment in real estate, net	50,533,000	'	'	'
Cash and Cash Equivalents, at Carrying Value	1,378,000	'	'	'
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	0	'	'	'
Restricted Cash and Cash Equivalents	48,000	'	'	'
Deferred Finance Costs, Net	4,000	'	'	'
Other Assets	1,032,000	'	'	'
Total assets	52,995,000	'	'	'
LIABILITIES AND EQUITY	'	'	'	'
Secured Debt	30,410,000	'	'	'
Accounts Payable And Accrued Liabilities Current And Noncurrent Other Than Interest And Dividend Payable	210,000	'	'	'
Interest Payable	0	'	'	'
Other Liabilities	863,000	'	'	'
Security Deposit Liability	109,000	'	'	'
Total liabilities	31,592,000	'	'	'
Noncontrolling Interests Partially Owned Properties	20,450,000	'	'	'
Parent Equity Interest	953,000	'	'	'
Total Equity Interest	21,403,000	'	'	'
Total liabilities and equity	52,995,000	'	'	'
Partially Owned Property Income Statement Schedule	'	'	'	'
Operating revenue	1,353,000	'	'	'
Operating Expenses	559,000	'	'	'
Gross Profit	794,000	'	'	'
Depreciation	447,000	'	'	'
General and Administrative Expense	43,000	'	'	'
Operating Income	304,000	'	'	'
Interest and Other Income	0	'	'	'
Other Nonoperating Income (Expense)	0	'	'	'
Interest:	'	'	'	'
Interest Expense, Debt	-279,000	'	'	'
Amortization of Financing Costs	0	'	'	'
Income (loss) before income and other taxes, (loss) from investments in unconsolidated entities, net (loss) on sales of land parcels and discontinued operations	25,000	'	'	'
Income and other tax (expense) benefit	0	'	'	'
(Loss) from investments in unconsolidated entities	0	'	'	'
Net income	25,000	'	'	'
Unconsolidated Total [Domain]	'	'	'	'
Partially Owned Property Balance Sheet Schedule	'	'	'	'
Partially Owned Unconsolidated Properties	4	'	'	'
Partially Owned Unconsolidated Units	1,669	'	'	'
ASSETS	'	'	'	'
Real Estate Investment Property, at Cost	390,108,000	'	'	'
Real Estate Investment Property, Accumulated Depreciation	-9,721,000	'	'	'
Investment in real estate, net	380,387,000	'	'	'
Cash and Cash Equivalents, at Carrying Value	3,631,000	'	'	'
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	0	'	'	'
Restricted Cash and Cash Equivalents	168,000	'	'	'
Deferred Finance Costs, Net	195,000	'	'	'
Other Assets	1,397,000	'	'	'
Total assets	385,778,000	'	'	'
LIABILITIES AND EQUITY	'	'	'	'
Secured Debt	222,796,000	'	'	'
Accounts Payable And Accrued Liabilities Current And Noncurrent Other Than Interest And Dividend Payable	5,203,000	'	'	'
Interest Payable	757,000	'	'	'
Other Liabilities	2,069,000	'	'	'
Security Deposit Liability	367,000	'	'	'
Total liabilities	231,192,000	'	'	'
Noncontrolling Interests Partially Owned Properties	121,720,000	'	'	'
Parent Equity Interest	32,866,000	'	'	'
Total Equity Interest	154,586,000	'	'	'
Total liabilities and equity	385,778,000	'	'	'
Partially Owned Property Income Statement Schedule	'	'	'	'
Operating revenue	5,881,000	'	'	'
Operating Expenses	2,520,000	'	'	'
Gross Profit	3,361,000	'	'	'
Depreciation	3,229,000	'	'	'
General and Administrative Expense	55,000	'	'	'
Operating Income	77,000	'	'	'
Interest and Other Income	0	'	'	'
Other Nonoperating Income (Expense)	0	'	'	'
Interest:	'	'	'	'
Interest Expense, Debt	-2,271,000	'	'	'
Amortization of Financing Costs	-3,000	'	'	'
Income (loss) before income and other taxes, (loss) from investments in unconsolidated entities, net (loss) on sales of land parcels and discontinued operations	-2,197,000	'	'	'
Income and other tax (expense) benefit	0	'	'	'
(Loss) from investments in unconsolidated entities	0	'	'	'
Net income	-2,197,000	'	'	'
Residual JV [Domain]	'	'	'	'
ASSETS	'	'	'	'
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	147,600,000	'	'	'
Joint Venture Partner [Member]	'	'	'	'
Investments In Partially Owned Entities (Textuals) [Abstract]	'	'	'	'
Land purchase price	57,900,000	'	'	'
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	75,700,000	'	'	'
LIABILITIES AND EQUITY	'	'	'	'
Noncontrolling Interests Partially Owned Properties	117,350,387	'	'	'
Company's Portion [Member]	'	'	'	'
Investments In Partially Owned Entities (Textuals) [Abstract]	'	'	'	'
Land purchase price	76,100,000	'	'	'
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	102,500,000	'	'	'
Nexus Sawgrass [Member]	'	'	'	'
Investments In Partially Owned Entities (Textuals) [Abstract]	'	'	'	'
Project Cost	79,000,000	'	'	'
Maximum Debt Commitment	48,700,000	'	'	'
Debt Instrument, Maturity Date	1-Jan-21	'	'	'
Debt Instrument, Interest Rate, Stated Percentage	5.60%	'	'	'
LIABILITIES AND EQUITY	'	'	'	'
Secured Debt	48,200,000	'	'	'
Domain [Member]	'	'	'	'
Investments In Partially Owned Entities (Textuals) [Abstract]	'	'	'	'
Project Cost	154,600,000	'	'	'
Maximum Debt Commitment	98,600,000	'	'	'
Debt Instrument, Maturity Date	1-Jan-22	'	'	'
Debt Instrument, Interest Rate, Stated Percentage	5.75%	'	'	'
LIABILITIES AND EQUITY	'	'	'	'
Secured Debt	95,000,000	'	'	'
Archstone Transaction [Member]	'	'	'	'
Investments In Partially Owned Entities (Textuals) [Abstract]	'	'	'	'
Liquidation Value Preferred Interests	79,300,000	'	'	'
Business Acquisition, Percentage of Voting Interests Acquired	'	60.00%	'	'
Joint Venture Partner Ownership Percentage	40.00%	'	'	'
Company's Portion [Member]	'	'	'	'
Investments In Partially Owned Entities (Textuals) [Abstract]	'	'	'	'
Preferred Interests	39,000,000	'	'	'
Enclave at Wellington [Domain]	'	'	'	'
Investments In Partially Owned Entities (Textuals) [Abstract]	'	'	'	'
Business Acquisition, Percentage of Voting Interests Acquired	95.00%	'	'	'
Initial Basis of Real Estate, Consolidated	26,200,000	'	'	'
Project Cost	50,000,000	'	'	'
Partially Owned Property Balance Sheet Schedule	'	'	'	'
Partially Owned Consolidated Units	268	'	'	'
East Palmetto Park [Domain]	'	'	'	'
Investments In Partially Owned Entities (Textuals) [Abstract]	'	'	'	'
Business Acquisition, Percentage of Voting Interests Acquired	90.00%	'	'	'
Initial Basis of Real Estate, Consolidated	20,200,000	'	'	'
Partially Owned Consolidated Units to be Developed	377	'	'	'
Wisconsin Place [Domain]	'	'	'	'
Investments In Partially Owned Entities (Textuals) [Abstract]	'	'	'	'
Business Acquisition, Percentage of Voting Interests Acquired	75.00%	'	'	'
Initial Basis of Real Estate, Consolidated	198,500,000	'	'	'
Partially Owned Property Balance Sheet Schedule	'	'	'	'
Partially Owned Consolidated Units	432	'	'	'
ASSETS	'	'	'	'
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	56,500,000	'	'	'
San Norterra [Domain]	'	'	'	'
Investments In Partially Owned Entities (Textuals) [Abstract]	'	'	'	'
Project Cost	53,300,000	'	'	'
Equity Method Investment, Ownership Percentage	85.00%	'	'	'
Initial Basis of Land, Unconsolidated	16,900,000	'	'	'
Maximum Debt Commitment	34,800,000	'	'	'
Debt Instrument, Description of Variable Rate Basis	'LIBOR plus 2.00%	'	'	'
Debt Instrument, Maturity Date	6-Jan-15	'	'	'
Partially Owned Property Balance Sheet Schedule	'	'	'	'
Partially Owned Unconsolidated Units	388	'	'	'
LIABILITIES AND EQUITY	'	'	'	'
Secured Debt	33,000,000	'	'	'
Waterton Tenside [Domain]	'	'	'	'
Investments In Partially Owned Entities (Textuals) [Abstract]	'	'	'	'
Equity Method Investment, Ownership Percentage	20.00%	'	'	'
Initial Basis of Land, Unconsolidated	5,100,000	'	'	'
Debt Instrument, Maturity Date	1-Dec-18	'	'	'
Debt Instrument, Interest Rate, Stated Percentage	3.66%	'	'	'
Partially Owned Property Balance Sheet Schedule	'	'	'	'
Partially Owned Unconsolidated Units	336	'	'	'
LIABILITIES AND EQUITY	'	'	'	'
Secured Debt	30,400,000	'	'	'
1333 Powell (formerly Parkside at Emeryville) [Domain]	'	'	'	'
Investments In Partially Owned Entities (Textuals) [Abstract]	'	'	'	'
Project Cost	75,000,000	'	'	'
Equity Method Investment, Ownership Percentage	5.00%	'	'	'
Initial Basis of Land, Unconsolidated	-2,100,000	'	'	'
Maximum Debt Commitment	39,500,000	'	'	'
Debt Instrument, Description of Variable Rate Basis	'LIBOR plus 2.25%	'	'	'
Debt Instrument, Maturity Date	14-Aug-15	'	'	'
Partially Owned Unconsolidated Units To Be Developed	176	'	'	'
Guarantor Obligations, Maximum Exposure	19,700,000	'	'	'
LIABILITIES AND EQUITY	'	'	'	'
Secured Debt	$16,200,000	'	'	'
London Interbank Offered Rate (LIBOR) [Member] | San Norterra [Domain]	'	'	'	'
Investments In Partially Owned Entities (Textuals) [Abstract]	'	'	'	'
Debt Instrument, Basis Spread on Variable Rate	2.00%	'	'	'
London Interbank Offered Rate (LIBOR) [Member] | 1333 Powell (formerly Parkside at Emeryville) [Domain]	'	'	'	'
Investments In Partially Owned Entities (Textuals) [Abstract]	'	'	'	'
Debt Instrument, Basis Spread on Variable Rate	2.25%	'	'	'

Deposits_Restricted_Details

Deposits - Restricted (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Restricted Cash and Cash Equivalents Items [Line Items]	'	'
Earnest Money On Acquisitions	$1,344	$4,514
Restricted deposits on real estate investments	44,037	53,771
Resident security and utility deposits	45,195	44,777
Other Restricted Cash	505	505
Restricted Cash and Cash Equivalents	$91,081	$103,567

Debt_Mortgage_Notes_Payable_De

Debt Mortgage Notes Payable (Details) (USD $)	3 Months Ended				1 Months Ended	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013	Mar. 31, 2014	8-May-14	Mar. 31, 2014
				Credit enhanced debt [Member]	Secured Debt [Member]	Secured Debt [Member]
Debt Instrument [Line Items]	'	'	'	'	'	'
Mortgage notes payable	$5,167,626	'	$5,174,166	$700,500	'	'
Repayments Of Mortgage Notes Payable	$3,034	$3,244	'	'	$3,100	$3,000
Debt Instrument, Maturity Date	1-May-61	'	'	'	'	'
Debt Instrument, Interest Rate, Stated Percentage Rate Range, Minimum	0.04%	'	'	'	'	'
Interest rate range to maximum	7.25%	'	'	'	'	'
Weighted Average Mortgage Debt Interest Rate	4.22%	'	'	'	'	'

Debt_Notes_Details

Debt Notes (Details) (USD $)	3 Months Ended			3 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013	Mar. 31, 2014
			Term Loan [Member]	Unsecured Debt [Member]
Debt Instrument [Line Items]	'	'	'	'
Term Loan Principal Amount	'	'	$750,000,000	'
Notes, net	$5,477,656,000	$5,477,088,000	'	'
Debt Instrument, Maturity Date Range, End	31-Dec-26	'	'	'
Debt Instrument, Interest Rate, Stated Percentage Rate Range, Minimum	0.04%	'	'	1.32%
Debt Instrument, Interest Rate, Stated Percentage Rate Range, Maximum	7.25%	'	'	7.57%
Weighted Average Interest Rate	4.92%	'	'	'

Debt_Lines_of_Credit_Details

Debt Lines of Credit (Details) (USD $)	3 Months Ended
	Mar. 31, 2014
Line of Credit Facility [Line Items]	'
Debt Instrument, Maturity Date	1-May-61
500.0 million ability to increase	$500,000,000
A 250 billion LOC [Member] [Domain]	'
Line of Credit Facility [Line Items]	'
Unsecured revolving credit facility	2,500,000,000
Debt Instrument, Maturity Date	1-Apr-18
Remaining borrowing capacity	2,170,000,000
Amount restricted/dedicated to support letters of credit	34,674,455
Line of Credit Facility Amount Outstanding Period End	298,000,000
Weighted Average Interest Rate Revolving Credit Facility	0.98%
A 175 billion LOC [Member]	'
Line of Credit Facility [Line Items]	'
Unsecured revolving credit facility	$1,750,000,000
Revolving Credit Facility [Member]	'
Line of Credit Facility [Line Items]	'
Line Of Credit Spread	1.05%
Line of Credit [Member] | London Interbank Offered Rate (LIBOR) [Member]	'
Line of Credit Facility [Line Items]	'
Line Of Credit Facility Commitment Fee	'15 Basis Points
Debt Instrument, Description of Variable Rate Basis	'LIBOR plus 1.05%

Derivative_and_Other_Fair_Valu2

Derivative and Other Fair Value Instruments (Details) (Forward Starting Swaps [Member], USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	2-May-14
Forward Starting Swaps [Member]	'	'
Derivative [Line Items]	'	'
Current Notional Balance	$450,000	$50,000
Lowest Possible Notional	450,000	'
Highest Possible Notional	$450,000	'
Lowest Interest Rate	2.13%	'
Highest Interest Rate	3.23%	'
Earliest Maturity Date	'2024	'
Latest Maturity Date	'2025	'

Derivative_and_Other_Fair_Valu3

Derivative and Other Fair Value Instruments (Details 1) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Derivatives, Fair Value [Line Items]	'	'
Derivative asset, fair value	$11,428	$18,710
Fair Value Of Serp Investments	88,010	83,845
Assets, Fair Value Disclosure	99,438	102,555
Derivative liability, fair value	4,670	'
Other Liabilities, Fair Value Disclosure	88,010	83,845
Liabilities, Fair Value Disclosure	92,680	83,845
Redeemable Noncontrolling Interest Operating Partnership Liability Fair Value Disclosure	405,276	363,144
Fair Value, Inputs, Level 1 [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative asset, fair value	0	0
Fair Value Of Serp Investments	88,010	83,845
Assets, Fair Value Disclosure	88,010	83,845
Derivative liability, fair value	0	'
Other Liabilities, Fair Value Disclosure	88,010	83,845
Liabilities, Fair Value Disclosure	88,010	83,845
Redeemable Noncontrolling Interest Operating Partnership Liability Fair Value Disclosure	0	0
Fair Value, Inputs, Level 2 [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative asset, fair value	11,428	18,710
Fair Value Of Serp Investments	0	0
Assets, Fair Value Disclosure	11,428	18,710
Derivative liability, fair value	4,670	'
Other Liabilities, Fair Value Disclosure	0	0
Liabilities, Fair Value Disclosure	4,670	0
Redeemable Noncontrolling Interest Operating Partnership Liability Fair Value Disclosure	405,276	363,144
Fair Value, Inputs, Level 3 [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative asset, fair value	0	0
Fair Value Of Serp Investments	0	0
Assets, Fair Value Disclosure	0	0
Derivative liability, fair value	0	'
Other Liabilities, Fair Value Disclosure	0	0
Liabilities, Fair Value Disclosure	0	0
Redeemable Noncontrolling Interest Operating Partnership Liability Fair Value Disclosure	$0	$0

Derivative_and_Other_Fair_Valu4

Derivative and Other Fair Value Instruments (Details 3) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Derivative Instruments, Gain (Loss) [Line Items]	'	'
Increase (Decrease) in Fair Value of Interest Rate Fair Value Hedging Instruments	$0	($1,471)
Increase (Decrease) in Fair Value of Hedged Item in Interest Rate Fair Value Hedge	0	1,471
Effective Portion - Amount of Gain/ (Loss) Recognized in OCI on Derivative	-11,952	2,814
Effective Portion - Amount of Gain/ (Loss) Reclassified from Accumulated OCI into Income	-4,129	-8,272
Ineffective Portion - Amount of Gain/ (Loss) Reclassifed from Accumulated OCI into Income	0	0
Interest Rate Swap [Member]	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'
Increase (Decrease) in Fair Value of Interest Rate Fair Value Hedging Instruments	0	-1,471
Increase (Decrease) in Fair Value of Hedged Item in Interest Rate Fair Value Hedge	0	1,471
Derivative, Description of Hedged Item	'N/A	'Fixed rate debt
Forward Starting Swaps/Treasury Locks [Member]	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'
Effective Portion - Amount of Gain/ (Loss) Recognized in OCI on Derivative	-11,952	2,814
Effective Portion - Amount of Gain/ (Loss) Reclassified from Accumulated OCI into Income	-4,129	-8,272
Ineffective Portion - Amount of Gain/ (Loss) Reclassifed from Accumulated OCI into Income	$0	$0

Derivative_and_Other_Fair_Valu5

Derivative and Other Fair Value Instruments (Details Textuals) (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Derivative [Line Items]	'	'
Mortgage notes payable	$5,167,626,000	$5,174,166,000
Notes, net	5,477,656,000	5,477,088,000
Fair value of mortgage notes payable	5,100,000,000	5,100,000,000
Fair value of unsecured notes payable including line of credit	6,100,000,000	5,900,000,000
Unrealized Gain (Loss) on Interest Rate Cash Flow Hedges, Pretax, Accumulated Other Comprehensive Income (Loss)	-163,598,151	-155,800,000
Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net	21,900,000	'
Total Note Payable and Long-Term Line of Credit [Member]	'	'
Derivative [Line Items]	'	'
Notes, net	$5,775,656,000	$5,600,000,000

Earnings_Per_Share_Details

Earnings Per Share (Details) (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest	$81,698	($165,339)
Income (Loss) Attributable to Noncontrolling Interest	-3,053	6,836
Allocation Of Net Income Loss To Noncontrolling Interests Partially Owned Properties	-504	-25
Dividends, Preferred Stock	-1,036	-1,036
Income (Loss) from Continuing Operations Attributable to Parent	77,105	-159,564
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	994	1,176,214
Net Income Loss Available To Common Stockholder Basic	78,099	1,016,650
Income From Continuing Operations Available To Common Shares	80,158	'
Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	1,034	1,226,373
Net Income (Loss) Available to Common Stockholders, Diluted	81,192	1,016,650
Weighted Average Number of Shares Outstanding, Basic	360,470	337,532
Dilutive Op Units	13,731	'
Dilutive Securities Options	2,183	'
Weighted Average Number of Shares Outstanding, Diluted	376,384	337,532
Earnings Per Share, Basic	$0.22	$3.01
Earnings Per Share, Diluted	$0.22	$3.01
Income (loss) from continuing operations available to Common Shares	$0.21	($0.47)
Income (Loss) from Discontinued Operations, Net of Tax, Per Basic Share	$0.00	$3.48
Income (loss) from continuing operations available to Common Shares	$0.21	($0.47)
Income (Loss) from Discontinued Operations, Net of Tax, Per Diluted Share	$0.00	$3.48
OPERATING PARTNERSHIP	'	'
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest	81,698	-165,339
Allocation Of Net Income Loss To Noncontrolling Interests Partially Owned Properties	-504	-25
Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	1,034	1,226,373
Dilutive Securities Options	2,183	'
Earnings Per Share, Basic	$0.22	$3.01
Earnings Per Share, Diluted	$0.22	$3.01
Income (loss) from continuing operations available to Common Shares	$0.21	($0.47)
Income (loss) from continuing operations available to Common Shares	$0.21	($0.47)
Dividend preference units	-1,036	-1,036
Income Loss From Continuing Operations Available To Units	80,158	-166,400
Net Income loss available to Op unitholders basic diluted numerator	$81,192	$1,059,973
Weighted Average Limited Partnership and General Partnership Units Outstanding, Basic	374,201	351,255
Weighted Average Number Of Limited Partnership And General Partnership Unit Outstanding Diluted	376,384	351,255
Income (Loss) from Discontinued Operations, Net of Tax, Per Outstanding Limited Partnership and General Partnership Unit, Basic	$0.00	$3.48
Income Loss From Discontinued Operations Net Of Tax Per Outstanding Limited Partnership And General Partnership Diluted	$0.00	$3.48

Discontinued_Operations_Detail

Discontinued Operations (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014		Mar. 31, 2013
REVENUES	'		'
Disposal Group Including Discontinued Operation Rental Revenue	$1,023		$81,782
Disposal Group, Including Discontinued Operation, Revenue	1,023		81,782
EXPENSES (1)	'		'
Disposal Group Including Discontinued Operation Property And Maintenance	48	[1]	20,424	[1]
Disposal Group Including Discontinued Operation Real Estate Taxes And Insurance	13	[1]	8,594	[1]
Disposal Group Including Discontinued Operations Property Management	0		1	[1]
Disposal Group Including Discontinued Operation Depreciation	0	[1]	23,816	[1]
Disposal Group Including Discontinued Operation General And Administrative	5	[1]	8	[1]
Disposal Group, Including Discontinued Operation, Operating Expense	66	[1]	52,843	[1]
Disposal Group, Including Discontinued Operation, Operating Income (Loss)	957		28,939
Disposal Group Including Discontinued Operation Interest And Other Income	35		52
Disposal Group Including Discontinued Operation Other Expenses	0		-2
Interest (2)	'		'
Expense Incurred, Net	0	[2]	-1,252	[2]
Disposal Group Including Discontinued Operation Amortization Of Deferred Financing Costs	0	[2]	-228	[2]
Discontinued Operation, Tax Effect of Discontinued Operation	-29		-58
Income Loss From Discontinued Operations	963		27,451
Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax	71		1,198,922
Discontinued operations, net	$1,034		$1,226,373
[1]	Includes expenses paid in the current period for properties sold in prior periods related to the Companybs period of ownership.
[2]	Includes only interest expense specific to secured mortgage notes payable for properties sold.

Commitments_and_Contingencies_

Commitments and Contingencies (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
300 properties designed and built in violation of accessibility requirements	300	'
Projects in various stages of development	12	'
Units in various stages of development	3,871	'
Consolidated Project Under Development Commitment Fund	$1,142,758,000	'
Various stages of development with estimated completion dates ranging through September 30, 2016	30-Sep-16	'
Number Of Unconsolidated Projects	3	'
Number Of Apartments Units Under Development Unconsolidated Projects	176	'
Estimated completion period of project	31-Dec-14	'
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	148,500,000	'
Investment in Joint Venture	311,597,290	'
Noncontrolling Interests - Partially Owned Properties	127,658,000	126,583,000
Company's Portion [Member]	'	'
Land purchase price	76,100,000	'
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	102,500,000	'
Joint Venture Partner [Member]	'	'
Land purchase price	57,900,000	'
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	75,700,000	'
Noncontrolling Interests - Partially Owned Properties	117,350,387	'
Unconsolidated Development Projects Held for and or Under Development [Domain]	'	'
Number Of Unconsolidated Projects	1	'
1333 Powell (formerly Parkside at Emeryville) [Domain]	'	'
Guarantor Obligations, Maximum Exposure	$19,700,000	'

Reportable_Segments_Details

Reportable Segments (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Rental income:	'	'	'
Same store	$613,878	$590,452	'
Segment Reporting Segment Non Same Store Rental Income	16,847	4,533	'
Segment Reporting Information Revenues	630,725	502,562	'
Operating expenses:	'	'	'
Same store	218,239	211,485	'
Segment Reporting Segment Non Same Store Operating Expenses	11,546	11,357	'
Segment Reporting Segment Operating Expenses	229,785	186,113	'
NOI:	'	'	'
Same store	395,639	378,967	'
Segment Reporting Information Non Same Store Net Operating Income	5,301	-6,824	'
Segment Reporting Information Net Operating Income	400,940	316,449	'
Assets	22,889,631	'	22,834,545
Payments to Acquire Other Property, Plant, and Equipment	32,191	'	'
Reportable Segments (Textuals) [Abstract]	'	'	'
Units in same store properties	100,984	'	'
Rental income	630,725	502,562	'
Property Repairs and Maintenance	-125,573	-98,529	'
Real Estate Taxes and Insurance	-82,094	-65,095	'
Property management	-22,118	-22,489	'
Total Operating Expenses	-229,785	-186,113	'
Archstone [Member]	'	'	'
Reportable Segments (Textuals) [Abstract]	'	'	'
Units in same store properties	18,465	'	'
Same Store [Domain]	'	'	'
NOI:	'	'	'
Assets	20,174,187	'	'
Payments to Acquire Other Property, Plant, and Equipment	31,146	'	'
Non-same store [Domain]	'	'	'
NOI:	'	'	'
Assets	2,715,444	'	'
Payments to Acquire Other Property, Plant, and Equipment	1,045	'	'
Boston [Domain]	'	'	'
Rental income:	'	'	'
Same store	61,907	59,054	'
Segment Reporting Segment Non Same Store Rental Income	1,028	256	'
Operating expenses:	'	'	'
Same store	22,154	20,207	'
Segment Reporting Segment Non Same Store Operating Expenses	211	53	'
NOI:	'	'	'
Same store	39,753	38,847	'
Segment Reporting Information Non Same Store Net Operating Income	817	203	'
Boston [Domain] | Same Store [Domain]	'	'	'
NOI:	'	'	'
Assets	1,968,613	'	'
Payments to Acquire Other Property, Plant, and Equipment	4,078	'	'
Boston [Domain] | Non-same store [Domain]	'	'	'
NOI:	'	'	'
Assets	48,971	'	'
Payments to Acquire Other Property, Plant, and Equipment	263	'	'
Denver [Domain]	'	'	'
Rental income:	'	'	'
Same store	26,611	24,970	'
Operating expenses:	'	'	'
Same store	7,449	7,217	'
NOI:	'	'	'
Same store	19,162	17,753	'
Denver [Domain] | Same Store [Domain]	'	'	'
NOI:	'	'	'
Assets	536,226	'	'
Payments to Acquire Other Property, Plant, and Equipment	762	'	'
New York [Domain]	'	'	'
Rental income:	'	'	'
Same store	111,185	107,997	'
Operating expenses:	'	'	'
Same store	46,202	43,111	'
NOI:	'	'	'
Same store	64,983	64,886	'
New York [Domain] | Same Store [Domain]	'	'	'
NOI:	'	'	'
Assets	4,727,805	'	'
Payments to Acquire Other Property, Plant, and Equipment	3,051	'	'
San Francisco [Domain]	'	'	'
Rental income:	'	'	'
Same store	81,261	74,945	'
Operating expenses:	'	'	'
Same store	26,655	28,156	'
NOI:	'	'	'
Same store	54,606	46,789	'
San Francisco [Domain] | Same Store [Domain]	'	'	'
NOI:	'	'	'
Assets	2,769,826	'	'
Payments to Acquire Other Property, Plant, and Equipment	5,716	'	'
Seattle [Domain]	'	'	'
Rental income:	'	'	'
Same store	37,725	35,372	'
Segment Reporting Segment Non Same Store Rental Income	1,687	25	'
Operating expenses:	'	'	'
Same store	12,768	12,237	'
Segment Reporting Segment Non Same Store Operating Expenses	690	1	'
NOI:	'	'	'
Same store	24,957	23,135	'
Segment Reporting Information Non Same Store Net Operating Income	997	24	'
Seattle [Domain] | Same Store [Domain]	'	'	'
NOI:	'	'	'
Assets	1,053,600	'	'
Payments to Acquire Other Property, Plant, and Equipment	2,205	'	'
Seattle [Domain] | Non-same store [Domain]	'	'	'
NOI:	'	'	'
Assets	190,041	'	'
Payments to Acquire Other Property, Plant, and Equipment	160	'	'
South Florida [Domain]	'	'	'
Rental income:	'	'	'
Same store	48,437	46,239	'
Segment Reporting Segment Non Same Store Rental Income	800	14	'
Operating expenses:	'	'	'
Same store	18,184	17,643	'
Segment Reporting Segment Non Same Store Operating Expenses	466	78	'
NOI:	'	'	'
Same store	30,253	28,596	'
Segment Reporting Information Non Same Store Net Operating Income	334	-64	'
South Florida [Domain] | Same Store [Domain]	'	'	'
NOI:	'	'	'
Assets	1,178,426	'	'
Payments to Acquire Other Property, Plant, and Equipment	3,119	'	'
South Florida [Domain] | Non-same store [Domain]	'	'	'
NOI:	'	'	'
Assets	70,725	'	'
Payments to Acquire Other Property, Plant, and Equipment	-1	'	'
Southern California [Domain]	'	'	'
Rental income:	'	'	'
Same store	102,665	98,210	'
Segment Reporting Segment Non Same Store Rental Income	7,174	1,292	'
Operating expenses:	'	'	'
Same store	34,347	34,587	'
Segment Reporting Segment Non Same Store Operating Expenses	3,122	617	'
NOI:	'	'	'
Same store	68,318	63,623	'
Segment Reporting Information Non Same Store Net Operating Income	4,052	675	'
Southern California [Domain] | Same Store [Domain]	'	'	'
NOI:	'	'	'
Assets	3,000,465	'	'
Payments to Acquire Other Property, Plant, and Equipment	5,142	'	'
Southern California [Domain] | Non-same store [Domain]	'	'	'
NOI:	'	'	'
Assets	446,912	'	'
Payments to Acquire Other Property, Plant, and Equipment	173	'	'
Washington DC [Domain]	'	'	'
Rental income:	'	'	'
Same store	110,396	110,993	'
Segment Reporting Segment Non Same Store Rental Income	4,934	1,806	'
Operating expenses:	'	'	'
Same store	37,396	35,884	'
Segment Reporting Segment Non Same Store Operating Expenses	1,863	653	'
NOI:	'	'	'
Same store	73,000	75,109	'
Segment Reporting Information Non Same Store Net Operating Income	3,071	1,153	'
Washington DC [Domain] | Same Store [Domain]	'	'	'
NOI:	'	'	'
Assets	4,299,085	'	'
Payments to Acquire Other Property, Plant, and Equipment	5,529	'	'
Washington DC [Domain] | Non-same store [Domain]	'	'	'
NOI:	'	'	'
Assets	305,668	'	'
Payments to Acquire Other Property, Plant, and Equipment	449	'	'
Non-Core [Domain]	'	'	'
Rental income:	'	'	'
Same store	33,691	32,672	'
Operating expenses:	'	'	'
Same store	13,084	12,443	'
NOI:	'	'	'
Same store	20,607	20,229	'
Non-Core [Domain] | Same Store [Domain]	'	'	'
NOI:	'	'	'
Assets	640,141	'	'
Payments to Acquire Other Property, Plant, and Equipment	1,544	'	'
Archstone pre-ownership [Member]	'	'	'
Rental income:	'	'	'
Same store	0	-92,423	'
Operating expenses:	'	'	'
Same store	0	-36,729	'
NOI:	'	'	'
Same store	0	-55,694	'
Other [Domain]	'	'	'
Rental income:	'	'	'
Segment Reporting Segment Non Same Store Rental Income	1,224	1,140	'
Operating expenses:	'	'	'
Segment Reporting Segment Non Same Store Operating Expenses	5,194	9,955	'
NOI:	'	'	'
Segment Reporting Information Non Same Store Net Operating Income	-3,970	-8,815	'
Other [Domain] | Non-same store [Domain]	'	'	'
NOI:	'	'	'
Assets	1,653,127	'	'
Payments to Acquire Other Property, Plant, and Equipment	$1	'	'

Subsequent_EventsOther_Details

Subsequent Events/Other (Details) (USD $)	3 Months Ended				1 Months Ended	3 Months Ended	1 Months Ended			1 Months Ended	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	2-May-14	Mar. 31, 2014	8-May-14	Mar. 31, 2014	8-May-14	2-May-14	Mar. 31, 2014	8-May-14	Mar. 31, 2013
			Forward Starting Swaps [Member]	Forward Starting Swaps [Member]	Secured Debt [Member]	Secured Debt [Member]	Land [Member]	Land [Member]	Land [Member]	Land Parcel Portion [Member]	Other Expense [Member]
Subsequent Event [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Land parcels acquired	'	'	'	'	'	'	1	'	'	'	'
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	$148,500,000	'	'	'	'	'	'	$10,300,000	$5,500,000	'	'
Proceeds From Sale Of Property	'	'	'	'	'	'	'	'	'	8,200,000	'
Repayments Of Mortgage Notes Payable	3,034,000	3,244,000	'	'	3,100,000	3,000,000	'	'	'	'	'
Notional Amount of Hedge Instruments	'	'	50,000,000	450,000,000	'	'	'	'	'	'	'
Write-off of pursuit costs	452,000	2,533,000	'	'	'	'	'	'	'	'	2,600,000
Litigation Settlement, Amount	$500,000	'	'	'	'	'	'	'	'	'	'