Erp Operating LTD Partnership 10-Q 6 May 15 2015 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Mar. 31, 2015	Apr. 30, 2015
Entity Registrant Name	EQUITY RESIDENTIAL
Entity Central Index Key	906107
Document Type	10-Q
Document Period End Date	31-Mar-15
Amendment Flag	FALSE
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q1
Current Fiscal Year End Date	-19
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		363,988,765
OPERATING PARTNERSHIP
Entity Registrant Name	ERP OPERATING LIMITED PARTNERSHIP
Entity Central Index Key	931182
Document Type	10-Q
Document Period End Date	31-Mar-15
Amendment Flag	FALSE
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q1
Current Fiscal Year End Date	-19
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, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Investment in real estate
Land	$6,357,580	$6,295,404
Depreciable property	20,024,497	19,851,504
Projects under development	1,269,784	1,343,919
Land held for development	143,997	184,556
Investment in real estate	27,795,858	27,675,383
Real Estate Investment Property, Accumulated Depreciation	-5,600,485	-5,432,805
Investment in real estate, net	22,195,373	22,242,578
Cash and cash equivalents	49,418	40,080
Investments in unconsolidated entities	89,284	105,434
Deposits - restricted	203,800	72,303
Escrow deposits - mortgage	50,659	48,085
Deferred financing costs, net	55,791	58,380
Other assets	384,723	383,754
Total assets	23,029,048	22,950,614
Liabilities:
Mortgage notes payable	4,957,876	5,086,515
Notes, net	5,430,806	5,425,346
Line of credit and commercial paper	470,826	333,000
Accounts payable and accrued expenses	202,110	153,590
Accrued interest payable	84,670	89,540
Other liabilities	383,057	389,915
Security deposits	75,294	75,633
Distributions payable	208,954	188,566
Total liabilities	11,813,593	11,742,105
Commitments and contingencies
Redeemable Noncontrolling Interests - Operating Partnership	541,866	500,733
Shareholders' equity:
Preferred Shares of beneficial interest, $0.01 par value; 100,000,000 shares authorized; 803,600 shares issued and outstanding as of March 31, 2015 and 1,000,000 shares issued and outstanding as of December 31, 2014	40,180	50,000
Common Shares of beneficial interest, $0.01 par value; 1,000,000,000 shares authorized; 363,968,420 shares issued and outstanding as of March 31, 2015 and 362,855,454 shares issued and outstanding as of December 31, 2014	3,640	3,629
Paid in capital	8,539,115	8,536,340
Retained earnings	1,928,449	1,950,639
Accumulated other comprehensive (loss)	-180,022	-172,152
Total shareholders' equity	10,331,362	10,368,456
Noncontrolling Interests:
Operating Partnership	219,566	214,411
Noncontrolling Interests - Partially Owned Properties	122,661	124,909
Total Noncontrolling Interests	342,227	339,320
Total equity	10,673,589	10,707,776
Total liabilities and equity	$23,029,048	$22,950,614

CONSOLIDATED_BALANCE_SHEETS_Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) (Unaudited) (USD $)	Mar. 31, 2015	Dec. 31, 2014
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	803,600	1,000,000
Preferred Shares of beneficial interest, shares outstanding	803,600	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	363,968,420	362,855,454
Common Shares of beneficial interest, shares outstanding	363,968,420	362,855,454

CONSOLIDATED_BALANCE_SHEETS_OF

CONSOLIDATED BALANCE SHEETS OF ERP OPERATING LIMITED PARTNERSHIP (Unaudited) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Investment in real estate
Land	$6,357,580	$6,295,404
Depreciable property	20,024,497	19,851,504
Projects under development	1,269,784	1,343,919
Land held for development	143,997	184,556
Investment in real estate	27,795,858	27,675,383
Real Estate Investment Property, Accumulated Depreciation	-5,600,485	-5,432,805
Investment in real estate, net	22,195,373	22,242,578
Cash and cash equivalents	49,418	40,080
Investments in unconsolidated entities	89,284	105,434
Deposits - restricted	203,800	72,303
Escrow deposits - mortgage	50,659	48,085
Deferred financing costs, net	55,791	58,380
Other assets	384,723	383,754
Total assets	23,029,048	22,950,614
Liabilities:
Mortgage notes payable	4,957,876	5,086,515
Notes, net	5,430,806	5,425,346
Line of credit and commercial paper	470,826	333,000
Accounts payable and accrued expenses	202,110	153,590
Accrued interest payable	84,670	89,540
Other liabilities	383,057	389,915
Security deposits	75,294	75,633
Distributions payable	208,954	188,566
Total liabilities	11,813,593	11,742,105
Commitments and contingencies
Partnersb Capital:
Accumulated other comprehensive (loss)	-180,022	-172,152
Noncontrolling Interests - Partially Owned Properties	122,661	124,909
Total liabilities and equity	23,029,048	22,950,614
OPERATING PARTNERSHIP
Investment in real estate
Land	6,357,580	6,295,404
Depreciable property	20,024,497	19,851,504
Projects under development	1,269,784	1,343,919
Land held for development	143,997	184,556
Investment in real estate	27,795,858	27,675,383
Real Estate Investment Property, Accumulated Depreciation	-5,600,485	-5,432,805
Investment in real estate, net	22,195,373	22,242,578
Cash and cash equivalents	49,418	40,080
Investments in unconsolidated entities	89,284	105,434
Deposits - restricted	203,800	72,303
Escrow deposits - mortgage	50,659	48,085
Deferred financing costs, net	55,791	58,380
Other assets	384,723	383,754
Total assets	23,029,048	22,950,614
Liabilities:
Mortgage notes payable	4,957,876	5,086,515
Notes, net	5,430,806	5,425,346
Line of credit and commercial paper	470,826	333,000
Accounts payable and accrued expenses	202,110	153,590
Accrued interest payable	84,670	89,540
Other liabilities	383,057	389,915
Security deposits	75,294	75,633
Distributions payable	208,954	188,566
Total liabilities	11,813,593	11,742,105
Commitments and contingencies
Redeemable Limited Partners	541,866	500,733
Partnersb Capital:
Preferred Units	40,180	50,000
General Partner	10,471,204	10,490,608
Limited Partners	219,566	214,411
Accumulated other comprehensive (loss)	-180,022	-172,152
Total partnersb capital	10,550,928	10,582,867
Noncontrolling Interests - Partially Owned Properties	122,661	124,909
Total capital	10,673,589	10,707,776
Total liabilities and equity	$23,029,048	$22,950,614

CONSOLIDATED_STATEMENTS_OF_OPE

CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
REVENUES
Rental income	$664,606	$630,725
Fee and asset management	1,765	2,717
Total revenues	666,371	633,442
EXPENSES
Property and maintenance	124,560	125,566
Real estate taxes and insurance	86,432	82,094
Property management	21,444	22,118
Fee and asset management	1,321	1,662
Depreciation	194,521	185,167
General and administrative	19,922	17,576
Total expenses	448,200	434,183
Operating Income	218,171	199,259
Interest and other income	120	605
Other expenses	70	-664
Interest:
Expense incurred, net	-108,622	-113,049
Amortization of deferred financing costs	-2,589	-2,792
Income before income and other taxes, income (loss) from investments in unconsolidated entities, net gain (loss) on sales of real estate properties and land parcels and discontinued operations	107,150	83,359
Income and other tax (expense) benefit	-43	-240
Income (loss) from investments in unconsolidated entities	2,963	-1,409
Net gain on sales of real estate properties	79,951	0
Net (loss) on sales of land parcels	-1	-30
Income from continuing operations	190,020	81,680
Discontinued operations, net	204	1,052
Net income	190,224	82,732
Net (income) attributable to Noncontrolling Interests:
Net (income) attributable to Noncontrolling Interests - Operating Partnership	-7,059	-3,093
Net (income) attributable to Noncontrolling Interests b Partially Owned Properties	-643	-504
Net income attributable to controlling interests	182,522	79,135
Preferred distributions	-891	-1,036
Premium on redemption of Preferred Shares	-2,789	0
Net income available to Common Shares	$178,842	$78,099
Earnings per share - basic:
Income from continuing operations available to Common Shares	$0.49	$0.21
Net income available to Common Shares	$0.49	$0.22
Weighted average Common Shares outstanding	363,098	360,470
Earnings per share - diluted:
Income from continuing operations available to Common Shares	$0.49	$0.21
Net income available to Common Shares	$0.49	$0.22
Weighted average Common Shares outstanding	380,327	376,384
Distributions declared per Common Share outstanding	$0.55	$0.50

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, 2015	Mar. 31, 2014
REVENUES
Rental income	$664,606,000	$630,725,000
Fee and asset management	1,765,000	2,717,000
Total revenues	666,371,000	633,442,000
EXPENSES
Property and maintenance	124,560,000	125,566,000
Real estate taxes and insurance	86,432,000	82,094,000
Property management	21,444,000	22,118,000
Fee and asset management	1,321,000	1,662,000
Depreciation	194,521,000	185,167,000
General and administrative	19,922,000	17,576,000
Total expenses	448,200,000	434,183,000
Operating Income	218,171,000	199,259,000
Interest and other income	120,000	605,000
Other expenses	70,000	-664,000
Interest:
Expense incurred, net	-108,622,000	-113,049,000
Amortization of deferred financing costs	-2,589,000	-2,792,000
Income before income and other taxes, income (loss) from investments in unconsolidated entities, net gain (loss) on sales of real estate properties and land parcels and discontinued operations	107,150,000	83,359,000
Income and other tax (expense) benefit	-43,000	-240,000
Income (loss) from investments in unconsolidated entities	2,963,000	-1,409,000
Net gain on sales of real estate properties	79,951,000	0
Net (loss) on sales of land parcels	-1,000	-30,000
Income from continuing operations	190,020,000	81,680,000
Discontinued operations, net	204,000	1,052,000
Net income	190,224,000	82,732,000
Net (income) attributable to Noncontrolling Interests b Partially Owned Properties	-643,000	-504,000
Net income attributable to controlling interests	182,522,000	79,135,000
ALLOCATION OF NET INCOME:
Premium on redemption of Preferred Shares	-2,789,000	0
Earnings per Unit - basic:
Income from continuing operations available to Units	$0.49	$0.21
Net income available to Units	$0.49	$0.22
Earnings per Unit - diluted:
Income from continuing operations available to Units	$0.49	$0.21
Net income available to Units	$0.49	$0.22
OPERATING PARTNERSHIP
REVENUES
Rental income	664,606,000	630,725,000
Fee and asset management	1,765,000	2,717,000
Total revenues	666,371,000	633,442,000
EXPENSES
Property and maintenance	124,560,000	125,566,000
Real estate taxes and insurance	86,432,000	82,094,000
Property management	21,444,000	22,118,000
Fee and asset management	1,321,000	1,662,000
Depreciation	194,521,000	185,167,000
General and administrative	19,922,000	17,576,000
Total expenses	448,200,000	434,183,000
Operating Income	218,171,000	199,259,000
Interest and other income	120,000	605,000
Other expenses	70,000	-664,000
Interest:
Expense incurred, net	-108,622,000	-113,049,000
Amortization of deferred financing costs	-2,589,000	-2,792,000
Income before income and other taxes, income (loss) from investments in unconsolidated entities, net gain (loss) on sales of real estate properties and land parcels and discontinued operations	107,150,000	83,359,000
Income and other tax (expense) benefit	-43,000	-240,000
Income (loss) from investments in unconsolidated entities	2,963,000	-1,409,000
Net gain on sales of real estate properties	79,951,000	0
Net (loss) on sales of land parcels	-1,000	-30,000
Income from continuing operations	190,020,000	81,680,000
Discontinued operations, net	204,000	1,052,000
Net income	190,224,000	82,732,000
Net (income) attributable to Noncontrolling Interests b Partially Owned Properties	-643,000	-504,000
Net income attributable to controlling interests	189,581,000	82,228,000
ALLOCATION OF NET INCOME:
Preference Units	891,000	1,036,000
Premium on redemption of Preferred Shares	2,789,000	0
General Partner	178,842,000	78,099,000
Limited Partners	7,059,000	3,093,000
Net income available to Units	$185,901,000	$81,192,000
Earnings per Unit - basic:
Income from continuing operations available to Units	$0.49	$0.21
Net income available to Units	$0.49	$0.22
Weighted average Units outstanding	376,696	374,201
Earnings per Unit - diluted:
Income from continuing operations available to Units	$0.49	$0.21
Net income available to Units	$0.49	$0.22
Weighted average Units outstanding	380,327	376,384
Distributions declared per Unit outstanding	$0.55	$0.50

CONSOLIDATED_STATEMENTS_OF_COM

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Comprehensive income:
Net income	$190,224	$82,732
Other comprehensive (loss) income b derivative instruments:
Unrealized holding (losses) arising during the period	-11,788	-11,952
Losses reclassified into earnings from other comprehensive income	4,338	4,129
Other comprehensive (loss) income b foreign currency:
Currency translation adjustments arising during the period	-420	91
Other comprehensive (loss)	-7,870	-7,732
Comprehensive income	182,354	75,000
Comprehensive (income) attributable to Noncontrolling Interests	-7,402	-3,302
Comprehensive income attributable to controlling interests	$174,952	$71,698

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, 2015	Mar. 31, 2014
Comprehensive income:
Net income	$190,224	$82,732
Other comprehensive (loss) income b derivative instruments:
Unrealized holding (losses) arising during the period	-11,788	-11,952
Losses reclassified into earnings from other comprehensive income	4,338	4,129
Other comprehensive (loss) income b foreign currency:
Currency translation adjustments arising during the period	-420	91
Other comprehensive (loss)	-7,870	-7,732
Comprehensive income	182,354	75,000
Comprehensive (income) attributable to Noncontrolling Interests b Partially Owned Properties	-7,402	-3,302
Comprehensive income attributable to controlling interests	174,952	71,698
OPERATING PARTNERSHIP
Comprehensive income:
Net income	190,224	82,732
Other comprehensive (loss) income b derivative instruments:
Unrealized holding (losses) arising during the period	-11,788	-11,952
Losses reclassified into earnings from other comprehensive income	4,338	4,129
Other comprehensive (loss) income b foreign currency:
Currency translation adjustments arising during the period	-420	91
Other comprehensive (loss)	-7,870	-7,732
Comprehensive income	182,354	75,000
Comprehensive (income) attributable to Noncontrolling Interests b Partially Owned Properties	-643	-504
Comprehensive income attributable to controlling interests	$181,711	$74,496

CONSOLIDATED_STATEMENTS_OF_CAS

CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$190,224	$82,732
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	194,521	185,167
Amortization of deferred financing costs	2,589	2,792
Amortization of above/below market leases	846	829
Amortization of discounts and premiums on debt	-3,751	-2,938
Amortization of deferred settlements on derivative instruments	4,205	3,996
Write-off of pursuit costs	493	452
(Income) loss from investments in unconsolidated entities	-2,963	1,409
Distributions from unconsolidated entities - return on capital	516	914
Net (gain) on sale of investment securities	0	-21
Net (gain) on sales of real estate properties	-79,951	0
Net loss on sales of land parcels	1	30
Net (gain) on sales of discontinued operations	0	-71
Unrealized loss (gain) on derivative instruments	24	-3
Compensation paid with Company Common Shares	13,610	12,981
Changes in assets and liabilities:
Decrease (increase) in deposits b restricted	290	-418
(Increase) decrease in mortgage deposits	-456	375
(Increase) decrease in other assets	-4,237	18,613
Increase in accounts payable and accrued expenses	45,450	55,263
(Decrease) in accrued interest payable	-4,870	-169
(Decrease) in other liabilities	-8,307	-26,194
(Decrease) increase in security deposits	-339	1,143
Net cash provided by operating activities	347,895	336,882
CASH FLOWS FROM INVESTING ACTIVITIES:
Investment in real estate b acquisitions	-6,720	-148,535
Investment in real estate - development/other	-146,194	-122,340
Capital expenditures to real estate	-38,170	-32,191
Non-real estate capital additions	-469	-159
Interest capitalized for real estate and unconsolidated entities under development	-15,313	-12,792
Proceeds from disposition of real estate, net	142,931	0
Investments in unconsolidated entities	-2,410	-6,254
Distributions from unconsolidated entities - return of capital	18,969	7,680
Proceeds from sale of investment securities	0	21
(Increase) decrease in deposits on real estate acquisitions and investments, net	-131,787	12,904
(Increase) in mortgage deposits	-59	-91
Net cash (used for) investing activities	-179,222	-301,757
CASH FLOWS FROM FINANCING ACTIVITIES:
Debt financing costs	0	-60
Mortgage Deposits	-2,059	-1,643
Mortgage notes payable:
Lump sum payoffs	-121,326	0
Scheduled principal repayments	-2,746	-3,034
Line of credit and commercial paper:
Line of credit proceeds	1,997,000	1,751,000
Line of credit repayments	-2,200,000	-1,568,000
Commercial paper proceeds	1,155,228	0
Commercial paper repayments	-814,600	0
(Payments on) settlement of derivative instruments	-25	0
Proceeds from Employee Stock Purchase Plan (ESPP)	1,927	1,741
Proceeds from exercise of options	32,213	15,785
Common Shares repurchased and retired	0	-1,777
Partial redemption of 8.29% Series K Cumulative Redeemable	-9,820	0
Premium on redemption of Preferred Shares	-2,789	0
Acquisition of Noncontrolling Interests - Partially Owned Properties	0	-2,501
Contributions - Noncontrolling Interests - Partially Owned Properties	0	5,684
Contributions - Noncontrolling Interests - Operating Partnership	1	3
Distributions:
Common Shares	-181,408	-234,282
Preferred Shares	-891	-1,036
Noncontrolling Interests b Operating Partnership	-7,149	-9,217
Noncontrolling Interests b Partially Owned Properties	-2,891	-4,113
Net Cash (used for) Financing Activities	-159,335	-51,450
Net increase (decrease) in cash and cash equivalents	9,338	-16,325
Cash and cash equivalents, beginning of period	40,080	53,534
Cash and cash equivalents, end of period	49,418	37,209
SUPPLEMENTAL INFORMATION:
Cash paid for interest, net of amounts capitalized	113,113	112,152
Net cash paid for income and other taxes	718	596
Amortization of discounts and premiums on debt:
Mortgage notes payable	-4,567	-3,506
Notes, net	618	568
Line of credit and commercial paper	198	0
Amortization of deferred settlements on derivative instruments:
Other liabilities	-133	-133
Losses reclassified into earnings from other comprehensive income	4,338	4,129
(Income) Loss From Investments In Unconsolidated Entities [Abstract]
(Income) loss from investment in unconsolidated entities	-3,625	472
Other Liabilities Loss From Investments in unconsolidated entities	662	937
Distributions from unconsolidated entities return on capital [Abstract]
Distributions from unconsolidated entities investments in unconsolidated entities	516	862
Distributions from unconsolidated entities other liabilities	0	52
Unrealized loss (gain) on derivative instruments:
Other assets	-4,963	7,279
Notes, net	4,842	0
Other liabilities	11,933	4,670
Unrealized holding (losses) arising during the period	-11,788	-11,952
Interest capitalized for real estate and unconsolidated entities under development:
Investment in real estate, net	-15,313	-12,774
Investments in unconsolidated entities	0	-18
Investments in unconsolidated entities [Abstract]
Investments in unconsolidated entities	-130	-1,454
Investments in unconsolidated entities other liabilities	-2,280	-4,800
Other:
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax	$420	($91)

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, 2015	Mar. 31, 2014
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$190,224	$82,732
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	194,521	185,167
Amortization of deferred financing costs	2,589	2,792
Amortization of above/below market leases	846	829
Amortization of discounts and premiums on debt	-3,751	-2,938
Amortization of deferred settlements on derivative instruments	4,205	3,996
Write-off of pursuit costs	493	452
(Income) loss from investments in unconsolidated entities	-2,963	1,409
Distributions from unconsolidated entities - return on capital	516	914
Net (gain) on sale of investment securities	0	-21
Net (gain) on sales of real estate properties	-79,951	0
Net (gain) on sales of discontinued operations	0	-71
Unrealized loss (gain) on derivative instruments	24	-3
Compensation paid with Company Common Shares	13,610	12,981
Changes in assets and liabilities:
Decrease (increase) in deposits b restricted	290	-418
(Increase) decrease in mortgage deposits	-456	375
(Increase) decrease in other assets	-4,237	18,613
Increase in accounts payable and accrued expenses	45,450	55,263
(Decrease) in accrued interest payable	-4,870	-169
(Decrease) in other liabilities	-8,307	-26,194
(Decrease) increase in security deposits	-339	1,143
Net cash provided by operating activities	347,895	336,882
CASH FLOWS FROM INVESTING ACTIVITIES:
Investment in real estate - acquisitions	-6,720	-148,535
Investment in real estate - development/other	-146,194	-122,340
Capital expenditures to real estate	-38,170	-32,191
Non-real estate capital additions	-469	-159
Interest capitalized for real estate and unconsolidated entities under development	-15,313	-12,792
Proceeds from disposition of real estate, net	142,931	0
Investments in unconsolidated entities	-2,410	-6,254
Distributions from unconsolidated entities - return of capital	18,969	7,680
Proceeds from sale of investment securities	0	21
(Increase) decrease in deposits on real estate acquisitions and investments, net	-131,787	12,904
(Increase) in mortgage deposits	-59	-91
Net cash (used for) investing activities	-179,222	-301,757
CASH FLOWS FROM FINANCING ACTIVITIES:
Debt financing costs	0	-60
Mortgage Deposits	-2,059	-1,643
Mortgage notes payable:
Scheduled principal repayments	-2,746	-3,034
Line of credit and commercial paper:
Line of credit proceeds	1,997,000	1,751,000
Line of credit repayments	-2,200,000	-1,568,000
Commercial paper proceeds	1,155,228	0
Commercial paper repayments	-814,600	0
(Payments on) settlement of derivative instruments	-25	0
Proceeds from exercise of options	32,213	15,785
Partial redemption of 8.29% Series K Cumulative Redeemable	-9,820	0
Premium on redemption of Preference Units	2,789	0
Acquisition of Noncontrolling Interests - Partially Owned Properties	0	-2,501
Contributions - Noncontrolling Interests - Partially Owned Properties	0	5,684
Contributions - Limited Partners	1	3
Distributions:
Noncontrolling Interests b Partially Owned Properties	-2,891	-4,113
Net Cash (used for) Financing Activities	-159,335	-51,450
Net increase (decrease) in cash and cash equivalents	9,338	-16,325
Cash and cash equivalents, beginning of period	40,080	53,534
Cash and cash equivalents, end of period	49,418	37,209
SUPPLEMENTAL INFORMATION:
Cash paid for interest, net of amounts capitalized	113,113	112,152
Net cash paid for income and other taxes	718	596
Amortization of discounts and premiums on debt:
Mortgage notes payable	4,567	3,506
Notes, net	618	568
Line of credit and commercial paper	198	0
Amortization of deferred settlements on derivative instruments:
Other liabilities	-133	-133
Losses reclassified into earnings from other comprehensive income	4,338	4,129
(Income) Loss From Investments In Unconsolidated Entities [Abstract]
(Income) loss from investment in unconsolidated entities	-3,625	472
Other Liabilities Loss From Investments in unconsolidated entities	662	937
Distributions from unconsolidated entities return on capital [Abstract]
Distributions from unconsolidated entities investments in unconsolidated entities	516	862
Distributions from unconsolidated entities other liabilities	0	52
Unrealized loss (gain) on derivative instruments:
Other assets	-4,963	7,279
Notes, net	4,842	0
Other liabilities	11,933	4,670
Unrealized holding (losses) arising during the period	-11,788	-11,952
Interest capitalized for real estate and unconsolidated entities under development:
Investment in real estate, net	-15,313	-12,774
Investments in unconsolidated entities	0	-18
Investments in unconsolidated entities [Abstract]
Investments in unconsolidated entities	130	1,454
Investments in unconsolidated entities other liabilities	2,280	4,800
Other:
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax	420	-91
OPERATING PARTNERSHIP
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	190,224	82,732
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	194,521	185,167
Amortization of deferred financing costs	2,589	2,792
Amortization of above/below market leases	846	829
Amortization of discounts and premiums on debt	-3,751	-2,938
Amortization of deferred settlements on derivative instruments	4,205	3,996
Write-off of pursuit costs	493	452
(Income) loss from investments in unconsolidated entities	-2,963	1,409
Distributions from unconsolidated entities - return on capital	516	914
Net (gain) on sale of investment securities	0	-21
Net (gain) on sales of real estate properties	-79,951	0
Net loss on sales of land parcels	1	30
Net (gain) on sales of discontinued operations	0	-71
Unrealized loss (gain) on derivative instruments	24	-3
Compensation paid with Company Common Shares	13,610	12,981
Changes in assets and liabilities:
Decrease (increase) in deposits b restricted	290	-418
(Increase) decrease in mortgage deposits	-456	375
(Increase) decrease in other assets	-4,237	18,613
Increase in accounts payable and accrued expenses	45,450	55,263
(Decrease) in accrued interest payable	-4,870	-169
(Decrease) in other liabilities	-8,307	-26,194
(Decrease) increase in security deposits	-339	1,143
Net cash provided by operating activities	347,895	336,882
CASH FLOWS FROM INVESTING ACTIVITIES:
Investment in real estate - acquisitions	-6,720	-148,535
Investment in real estate - development/other	-146,194	-122,340
Capital expenditures to real estate	-38,170	-32,191
Non-real estate capital additions	-469	-159
Interest capitalized for real estate and unconsolidated entities under development	-15,313	-12,792
Proceeds from disposition of real estate, net	142,931	0
Investments in unconsolidated entities	-2,410	-6,254
Distributions from unconsolidated entities - return of capital	18,969	7,680
Proceeds from sale of investment securities	0	21
(Increase) decrease in deposits on real estate acquisitions and investments, net	-131,787	12,904
(Increase) in mortgage deposits	-59	-91
Net cash (used for) investing activities	-179,222	-301,757
CASH FLOWS FROM FINANCING ACTIVITIES:
Debt financing costs	0	-60
Mortgage Deposits	-2,059	-1,643
Mortgage notes payable:
Lump sum payoffs	-121,326	0
Scheduled principal repayments	-2,746	-3,034
Line of credit and commercial paper:
Line of credit proceeds	1,997,000	1,751,000
Line of credit repayments	-2,200,000	-1,568,000
Commercial paper proceeds	1,155,228	0
Commercial paper repayments	-814,600	0
(Payments on) settlement of derivative instruments	-25	0
EQR's Employee Share Purchase Plan (ESPP)	1,927	1,741
Proceeds from exercise of options	32,213	15,785
OP Units repurchased and retired	0	-1,777
Partial redemption of 8.29% Series K Cumulative Redeemable	-9,820	0
Premium on redemption of Preference Units	-2,789	0
Acquisition of Noncontrolling Interests - Partially Owned Properties	0	-2,501
Contributions - Noncontrolling Interests - Partially Owned Properties	0	5,684
Contributions - Limited Partners	1	3
Distributions:
OP Units - General Partner	-181,408	-234,282
Preference Units	-891	-1,036
OP Units - Limited Partners	-7,149	-9,217
Noncontrolling Interests b Partially Owned Properties	-2,891	-4,113
Net Cash (used for) Financing Activities	-159,335	-51,450
Net increase (decrease) in cash and cash equivalents	9,338	-16,325
Cash and cash equivalents, beginning of period	40,080	53,534
Cash and cash equivalents, end of period	49,418	37,209
SUPPLEMENTAL INFORMATION:
Cash paid for interest, net of amounts capitalized	113,113	112,152
Net cash paid for income and other taxes	718	596
Amortization of discounts and premiums on debt:
Mortgage notes payable	-4,567	-3,506
Notes, net	618	568
Line of credit and commercial paper	198	0
Amortization of deferred settlements on derivative instruments:
Other liabilities	-133	-133
Losses reclassified into earnings from other comprehensive income	4,338	4,129
(Income) Loss From Investments In Unconsolidated Entities [Abstract]
(Income) loss from investment in unconsolidated entities	-3,625	472
Other Liabilities Loss From Investments in unconsolidated entities	662	937
Distributions from unconsolidated entities return on capital [Abstract]
Distributions from unconsolidated entities investments in unconsolidated entities	516	862
Distributions from unconsolidated entities other liabilities	0	52
Unrealized loss (gain) on derivative instruments:
Other assets	-4,963	7,279
Notes, net	4,842	0
Other liabilities	11,933	4,670
Unrealized holding (losses) arising during the period	-11,788	-11,952
Interest capitalized for real estate and unconsolidated entities under development:
Investment in real estate, net	-15,313	-12,774
Investments in unconsolidated entities	0	-18
Investments in unconsolidated entities [Abstract]
Investments in unconsolidated entities	-130	-1,454
Investments in unconsolidated entities other liabilities	-2,280	-4,800
Other:
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax	$420	($91)

CONSOLIDATED_STATEMENT_OF_CHAN

CONSOLIDATED STATEMENT OF CHANGES IN EQUITY (Unaudited) (USD $)	Total	Additional Paid-in Capital [Member]	PREFERRED SHARES	COMMON SHARES, $0.01 PAR VALUE	RETAINED EARNINGS	Accumulated Other Comprehensive (Loss)	OPERATING PARTNERSHIP	Partially Owned Properties [Member]
In Thousands, unless otherwise specified
Beginning Balance, Noncontrolling Interest at Dec. 31, 2014	$339,320						$214,411	$124,909
Beginning Balance, Parent at Dec. 31, 2014	10,368,456	8,536,340	50,000	3,629	1,950,639	-172,152
Preferred Shares [Abstract]
Partial redemption of 8.29% Series K Cumulative Redeemable	-9,820		-9,820
Common Share Issuance:
Conversion of OP Units into Common Shares		3,712		1			-3,713
Exercise of share options		32,205		8
EQR's Employee Share Purchase Plan (ESPP)		1,927
Share-based employee compensation expense:
Restricted Shares		6,720		2
Share options		997
ESPP discount		412
Supplemental Executive Retirement Plan (SERP)		-2,307
Change in market value of Redeemable Noncontrolling Interests - Operating Partnership	41,763	-41,763
Adjustment for Noncontrolling Interests ownership in Operating Partnership		872					-872
Net income attributable to controlling interests	182,522				182,522
Common Share distributions					-201,032
Preferred Share distributions					-891
Premium on redemption of Preferred Shares	-2,789				-2,789
Other comprehensive (loss) income b derivative instruments:
Unrealized holding (losses) arising during the period	-11,788					-11,788
Losses reclassified into earnings from other comprehensive income	-4,338					4,338
Currency translation adjustments arising during the period	-420					-420
Issuance of restricted units to Noncontrolling Interests							1
Equity Compensation associated with Noncontrolling Interests							9,963
Net (income) attributable to Noncontrolling Interests - Operating Partnership	-7,059						7,059
Distributions to Noncontrolling Interests							-7,913	-2,891
Change in carrying value	-630						630
Net (income) attributable to Noncontrolling Interests b Partially Owned Properties	643							643
Ending Balance, Noncontrolling Interest at Mar. 31, 2015	342,227						219,566	122,661
Ending Balance, Parent at Mar. 31, 2015	$10,331,362	$8,539,115	$40,180	$3,640	$1,928,449	($180,022)

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, 2014						$124,909
Balance, beginning of year at Dec. 31, 2014		50,000	10,490,608	214,411	-172,152
Partial redemption of 8.29% Series K Cumulative Redeemable	-9,820	-9,820
OP Unit Issuance:
Conversion of OP Units held by Limited Partners into OP Units held by General Partner			3,713	-3,713
Exercise of EQR share options			32,213
EQR's Employee Share Purchase Plan (ESPP)			1,927
Share-based employee compensation expense:
EQR restricted shares			6,722
EQR share options			997
EQR ESPP discount			412
Net income available to Units - General Partner			178,842
OP Units - General Partner distributions			-201,032
Supplemental Executive Retirement Plan (SERP)			-2,307
Change in market value of Redeemable Limited Partners			-41,763
Adjustment for Limited Partners ownership in Operating Partnership			872	-872
Issuance of restricted units to Noncontrolling Interests				1
Equity compensation associated with Units - Limited Partners				9,963
Net income available to Units - Limited Partners				7,059
Units Limited Partners Distributions				7,913
Net (income) attributable to Noncontrolling Interests b Partially Owned Properties	643					643
Distributions to Noncontrolling Interests						-2,891
Change in carrying value	-630			630
Other comprehensive (loss) income b derivative instruments:
Unrealized holding (losses) arising during the period	-11,788				-11,788
Losses reclassified into earnings from other comprehensive income	-4,338				4,338
Currency translation adjustments arising during the period	-420				-420
Balance, end of period - Noncontrolling Interest at Mar. 31, 2015						122,661
Balance, end of period at Mar. 31, 2015		$40,180	$10,471,204	$219,566	($180,022)

Business

Business	3 Months Ended
	Mar. 31, 2015
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, 2015 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, 2015, the Company, directly or indirectly through investments in title holding entities, owned all or a portion of 389 properties located in 12 states and the District of Columbia consisting of 108,793 apartment units. The ownership breakdown includes (table does not include various uncompleted development properties):
			Properties	Apartment
				Units
	Wholly Owned Properties		362	97,825
	Master-Leased Properties – Consolidated		3	853
	Partially Owned Properties – Consolidated		19	3,771
	Partially Owned Properties – Unconsolidated		3	1,281
	Military Housing		2	5,063
			389	108,793

Summary_of_Significant_Account

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2015
Summary of Significant Accounting Policies [Abstract]
Summary of Significant Accounting Policies
	2	Summary of Significant Accounting Policies
	Basis of Presentation
	The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by accounting principles generally accepted in the United States for complete financial statements. In the opinion of management, all adjustments (consisting of normal recurring accruals) and certain reclassifications considered necessary for a fair presentation have been included. Certain reclassifications have been made to the prior period financial statements in order to conform to the current year presentation. These reclassifications did not have an impact on net income previously reported. Operating results for the quarter ended March 31, 2015 are not necessarily indicative of the results that may be expected for the year ending December 31, 2015.
	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, 2014 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, 2014.
	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, 2015, 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 19 properties and 3,771 apartment units and various completed and uncompleted development properties having a noncontrolling interest book value of $122.7 million at March 31, 2015. 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 $11.0 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, 2015, the Company estimates the value of Noncontrolling Interest distributions for these six properties would have been approximately $63.3 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, 2015 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.
	In April 2014, the Financial Accounting Standards Board (the "FASB") issued new guidance for reporting discontinued operations. Only disposals representing a strategic shift in operations that has a major effect on a company’s operations and financial results will be presented as discontinued operations. Companies are required to expand their disclosures about discontinued operations to provide more information on the assets, liabilities, income and expenses of the discontinued operations. Companies are also required to disclose the pre-tax income attributable to a disposal of a significant part of a company that does not qualify for discontinued operations reporting. Application of this guidance is prospective from the date of adoption and early adoption was permitted, but only for disposals (or classifications as held for sale) that had not been reported in financial statements previously issued. The new standard was effective January 1, 2015, but the Company early adopted it as allowed effective January 1, 2014. Adoption of this standard resulted in and will likely continue to result in substantially fewer of the Company's dispositions meeting the discontinued operations qualifications. See Note 11 for further discussion.
	In May 2014, the FASB issued a comprehensive new revenue recognition standard entitled Revenue from Contracts with Customers that will supersede nearly all existing revenue recognition guidance. The new standard specifically excludes lease contracts. The new standard’s core principle is that a company will recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. Companies will likely need to use more judgment and make more estimates than under current revenue recognition guidance. These may include identifying performance obligations in the contract, estimating the amount of variable consideration, if any, to include in the transaction price and allocating the transaction price to each separate performance obligation. The new standard will be effective for the Company beginning on January 1, 2017 and early adoption is not permitted. The new standard may be applied retrospectively to each prior period presented or retrospectively with the cumulative effect recognized as of the date of adoption. The Company has not yet selected a transition method and is currently evaluating the impact of adopting the new standard on its consolidated results of operations and financial position.
	In August 2014, the FASB issued a new standard that will explicitly require management to assess an entity's ability to continue as a going concern and to provide related footnote disclosures in certain circumstances. In connection with each annual and interim period, management will assess whether there is substantial doubt about an entity's ability to continue as a going concern within one year after the issuance date. Disclosures will be required if conditions give rise to substantial doubt, however to determine the specific disclosures, management will need to assess whether its plans will alleviate substantial doubt. The new standard is effective for the annual period ending after December 15, 2016. The Company does not expect that this will have a material effect on its consolidated results of operations or financial position.
	In February 2015, the FASB issued new consolidation guidance which makes changes to both the variable interest model and the voting model. Among other changes, the new standard specifically eliminates the presumption in the current voting model that a general partner controls a limited partnership or similar entity unless that presumption can be overcome. Generally, only a single limited partner that is able to exercise substantive kick-out rights will consolidate. The new standard will be effective for the Company beginning on January 1, 2016 and early adoption is permitted, including adoption in an interim period. The new standard must be applied using a modified retrospective approach by recording a cumulative-effect adjustment to equity/capital as of the beginning of the period of adoption or retrospectively to each period presented. The Company has not yet selected a transition method and is currently evaluating the impact of adopting the new standard on its consolidated results of operations and financial position.
	In April 2015, the FASB issued a new standard which requires companies to present debt financing costs as a direct deduction from the carrying amount of the associated debt liability rather than as an asset, consistent with the presentation of debt discounts on the consolidated balance sheets.  The new standard will be effective for the Company beginning on January 1, 2016 and early adoption is permitted.  The new standard must be applied retrospectively to all prior periods presented in the consolidated financial statements.  The Company does not expect that this will have a material effect on its consolidated results of operations or financial position.

Equity_Capital_and_Other_Inter

Equity, Capital and Other Interests	3 Months Ended
	Mar. 31, 2015
Equity, Capital and other Interests [Abstract]
Equity Capital And Other Interests [Text Block]
	3	Equity, Capital and Other Interests
	Equity and Redeemable Noncontrolling Interests of Equity Residential
	The following tables present the changes in the Company’s issued and outstanding Common Shares and “Units” (which includes OP Units and restricted units (formerly known as Long-Term Incentive Plan (“LTIP”) Units)) for the quarter ended March 31, 2015:
			2015
	Common Shares
	Common Shares outstanding at January 1,		362,855,454
	Common Shares Issued:
	Conversion of OP Units		154,050
	Exercise of share options		770,012
	Employee Share Purchase Plan (ESPP)		30,151
	Restricted share grants, net		158,753
	Common Shares outstanding at March 31,		363,968,420
	Units
	Units outstanding at January 1,		14,298,691
	Restricted units, net		333,304
	Conversion of OP Units to Common Shares		(154,050	)
	Units outstanding at March 31,		14,477,945
	Total Common Shares and Units outstanding at March 31,		378,446,365
	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 restricted units, are collectively referred to as the “Noncontrolling Interests – Operating Partnership”. Subject to certain exceptions (including the “book-up” requirements of restricted units), the Noncontrolling Interests – Operating Partnership may exchange their Units with EQR for Common Shares on a one-for-one basis. The carrying value of the Noncontrolling Interests – Operating Partnership (including redeemable interests) is allocated based on the number of Noncontrolling Interests – Operating Partnership Units in total in proportion to the number of Noncontrolling Interests – Operating Partnership Units in total plus the number of Common Shares. Net income is allocated to the Noncontrolling Interests – Operating Partnership based on the weighted average ownership percentage during the period.
	The Operating Partnership has the right but not the obligation to make a cash payment instead of issuing Common Shares to any and all holders of Noncontrolling Interests – Operating Partnership Units requesting an exchange of their OP Units with EQR. Once the Operating Partnership elects not to redeem the Noncontrolling Interests – Operating Partnership Units for cash, EQR is obligated to deliver Common Shares to the exchanging holder of the Noncontrolling Interests – Operating Partnership Units.
	The Noncontrolling Interests – Operating Partnership Units are classified as either mezzanine equity or permanent equity. If EQR is required, either by contract or securities law, to deliver registered Common Shares, such Noncontrolling Interests – Operating Partnership are differentiated and referred to as “Redeemable Noncontrolling Interests – Operating Partnership”. Instruments that require settlement in registered shares 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, 2015 and December 31, 2014.
	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, 2015, the Redeemable Noncontrolling Interests – Operating Partnership have a redemption value of approximately $541.9 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, 2015 (amounts in thousands):
			2015
	Balance at January 1,		$	500,733
	Change in market value		41,763
	Change in carrying value		(630		)
	Balance at March 31,		$	541,866
	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, 2015 and December 31, 2014:
							Amounts in thousands
			Redemption		Annual		March 31,		December 31,
			Date (1)		Dividend per		2015		2014
					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	$	40,180	$	50,000
	value $50 per share; 803,600 shares issued and outstanding
	at March 31, 2015 and 1,000,000 shares issued and
	outstanding at December 31, 2014 (3)
							$	40,180	$	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.
	-3	Effective January 26, 2015, the Company repurchased and retired 196,400 Series K Preferred Shares with a par value of $9.82 million for total cash consideration of approximately $12.7 million. As a result of this partial redemption, the Company incurred a cash charge of approximately $2.8 million which was recorded as a premium on the redemption of Preferred Shares.
	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, 2015:
			2015
	General and Limited Partner Units
	General and Limited Partner Units outstanding at January 1,		377,154,145
	Issued to General Partner:
	Exercise of EQR share options		770,012
	EQR’s Employee Share Purchase Plan (ESPP)		30,151
	EQR's restricted share grants, net		158,753
	Issued to Limited Partners:
	Restricted units, net		333,304
	General and Limited Partner Units outstanding at March 31,		378,446,365
	Limited Partner Units
	Limited Partner Units outstanding at January 1,		14,298,691
	Limited Partner restricted units, net		333,304
	Conversion of Limited Partner OP Units to EQR Common Shares		(154,050	)
Limited Partner Units outstanding at March 31,		14,477,945
Limited Partner Units Ownership Interest in Operating Partnership		3.8	%
The Limited Partners of the Operating Partnership as of March 31, 2015 include various individuals and entities that contributed their properties to the Operating Partnership in exchange for OP Units, as well as the equity positions of the holders of restricted units. Subject to certain exceptions (including the “book-up” requirements of restricted units), Limited Partners may exchange their Units with EQR for Common Shares on a one-for-one basis. The carrying value of the Limited Partner Units (including redeemable interests) is allocated based on the number of Limited Partner Units in total in proportion to the number of Limited Partner Units in total plus the number of General Partner Units. Net income is allocated to the Limited Partner Units based on the weighted average ownership percentage during the period.
The Operating Partnership has the right but not the obligation to make a cash payment instead of issuing Common Shares to any and all holders of Limited Partner Units requesting an exchange of their OP Units with EQR. Once the Operating Partnership elects not to redeem the Limited Partner Units for cash, EQR is obligated to deliver Common Shares to the exchanging limited partner.
The Limited Partner Units are classified as either mezzanine equity or permanent equity. If EQR is required, either by contract or securities law, to deliver registered Common Shares, such Limited Partner Units are differentiated and referred to as “Redeemable Limited Partner Units”. Instruments that require settlement in registered shares 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, 2015 and December 31, 2014.
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, 2015, the Redeemable Limited Partner Units have a redemption value of approximately $541.9 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, 2015 (amounts in thousands):
		2015
Balance at January 1,		$	500,733
Change in market value		41,763
Change in carrying value		(630		)
Balance at March 31,		$	541,866
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, 2015 and December 31, 2014:
						Amounts in thousands
		Redemption		Annual		March 31,		December 31,
		Date (1)		Dividend per		2015		2014
				Unit (2)
Preference Units:
8.29% Series K Cumulative Redeemable Preference Units;		12/10/26			$4.14	$	40,180	$	50,000
liquidation value $50 per unit; 803,600 units issued and
outstanding at March 31, 2015 and 1,000,000 units
issued and outstanding at December 31, 2014 (3)
						$	40,180	$	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.
-3	Effective January 26, 2015, the Operating Partnership repurchased and retired 196,400 Series K Preference Units with a par value of $9.82 million for total cash consideration of approximately $12.7 million, in conjunction with the concurrent redemption of the corresponding Company Preferred Shares. As a result of this partial redemption, the Operating Partnership incurred a cash charge of approximately $2.8 million which was recorded as a premium on the redemption of Preference Units.
Other
In September 2009, the Company announced the establishment of an At-The-Market (“ATM”) share offering program which would allow EQR to sell Common Shares from time to time into the existing trading market at current market prices as well as through negotiated transactions. Per the terms of ERPOP's partnership agreement, EQR contributes the net proceeds from all equity offerings to the capital of ERPOP in exchange for additional OP Units (on a one-for-one Common Share per OP Unit basis). On July 30, 2013, the Board of Trustees approved an increase to the amount of shares which may be offered under the ATM program to 13.0 million Common Shares and extended the program maturity to July 2016. EQR has not issued any shares under this program since September 14, 2012.
Effective July 30, 2013, the Board of Trustees approved an increase and modification to the Company's share repurchase program to allow for the potential repurchase of up to 13.0 million Common Shares. No shares were repurchased during the quarter ended March 31, 2015. As of March 31, 2015, EQR has remaining authorization to repurchase an additional 12,968,760 of its shares.

Real_Estate

Real Estate	3 Months Ended
	Mar. 31, 2015
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, 2015 and December 31, 2014 (amounts in thousands):
			March 31,				December 31,
			2015				2014
	Land		$	6,357,580			$	6,295,404
	Depreciable property:
	Buildings and improvements		18,109,892				17,974,337
	Furniture, fixtures and equipment		1,401,801				1,365,276
	In-Place lease intangibles		512,804				511,891
	Projects under development:
	Land		423,359				466,764
	Construction-in-progress		846,425				877,155
	Land held for development:
	Land		109,726				145,366
	Construction-in-progress		34,271				39,190
	Investment in real estate		27,795,858				27,675,383
	Accumulated depreciation		(5,600,485		)		(5,432,805		)
	Investment in real estate, net		$	22,195,373			$	22,242,578
	The following table summarizes the carrying amounts for the Company's above and below market ground and retail lease intangibles as of March 31, 2015 and December 31, 2014 (amounts in thousands):
	Description		Balance Sheet Location		March 31,				December 31,
					2015				2014
	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				(10,050		)		(8,913		)
	Lease intangible assets, net				$	169,461			$	170,598
	Liabilities
	Ground lease intangibles – above market		Other Liabilities		$	2,400			$	2,400
	Retail lease intangibles – below market		Other Liabilities		5,270				5,270
	Lease intangible liabilities				7,670				7,670
	Accumulated amortization				(2,549		)		(2,258		)
	Lease intangible liabilities, net				$	5,121			$	5,412
	During the quarters ended March 31, 2015 and 2014, the Company amortized approximately $1.1 million and $1.1 million, respectively, of above and below market ground lease intangibles which is included (net increase) in property and maintenance expense in the accompanying consolidated statements of operations and comprehensive income and approximately $0.2 million and $0.3 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
			2015				2016				2017			2018			2019			2020
	Ground lease intangibles		$	3,241			$	4,321			$	4,321		$	4,321		$	4,321		$	4,321
	Retail lease intangibles		(705		)		(896		)		(540		)	(71		)	(71		)	(71		)
	Total		$	2,536			$	3,425			$	3,781		$	4,250		$	4,250		$	4,250
	During the quarter ended March 31, 2015, the Company acquired the entire equity interest in the following from an unaffiliated party (purchase price in thousands):
			Properties			Apartment Units			Purchase Price
	Land Parcel (one)		—			—			$	5,968
	Total		—			—			$	5,968
	During the quarter ended March 31, 2015, the Company disposed of the following to unaffiliated parties (sales price in thousands):
			Properties			Apartment Units			Sales Price
	Rental Properties		3			550			$	145,400
	Total		3			550			$	145,400
	The Company recognized a net gain on sales of real estate properties of approximately $80.0 million on the above sales.

Commitments_to_AcquireDispose_

Commitments to Acquire/Dispose of Real Estate	3 Months Ended
	Mar. 31, 2015
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
	In addition to the property that was subsequently acquired as discussed in Note 14, the Company has entered into separate agreements to acquire the following (purchase price in thousands):
			Properties	Apartment Units	Purchase Price
	Land Parcels (three)		—	—	$	25,132
	Total		—	—	$	25,132
	In addition to the property and office building that were 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		2	513	$	68,650
	Land Parcel (one)		—	—	2,700
	Total		2	513	$	71,350
	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, 2015
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, 2015 (amounts in thousands except for project and apartment unit amounts):
		Consolidated									Unconsolidated
		Development Projects
		Held for			Operating			Total			Operating			Total
		and/or Under
		Development
	Total projects (1)	—			19			19			3			3
	Total apartment units (1)	—			3,771			3,771			1,281			1,281
	Balance sheet information at 3/31/15 (at 100%):
	ASSETS
	Investment in real estate	$	347,809		$	684,686		$	1,032,495		$	290,077		$	290,077
	Accumulated depreciation	(991		)	(200,002		)	(200,993		)	(21,388		)	(21,388		)
	Investment in real estate, net	346,818			484,684			831,502			268,689			268,689
	Cash and cash equivalents	—			13,775			13,775			7,598			7,598
	Investments in unconsolidated entities	—			51,363			51,363			—			—
	Deposits – restricted	15,640			310			15,950			246			246
	Deferred financing costs, net	—			2,052			2,052			7			7
	Other assets	6,697			26,227			32,924			1,327			1,327
	Total assets	$	369,155		$	578,411		$	947,566		$	277,867		$	277,867
	LIABILITIES AND EQUITY/CAPITAL
	Mortgage notes payable (2)	$	—		$	360,567		$	360,567		$	175,276		$	175,276
	Accounts payable & accrued expenses	8,731			3,188			11,919			389			389
	Accrued interest payable	—			1,283			1,283			691			691
	Other liabilities	257			576			833			834			834
	Security deposits	150			1,976			2,126			531			531
	Total liabilities	9,138			367,590			376,728			177,721			177,721
	Noncontrolling Interests – Partially Owned	117,350			5,311			122,661			90,878			90,878
	Properties/Partners' equity
	Company equity/General and Limited	242,667			205,510			448,177			9,268			9,268
	Partners' Capital
	Total equity/capital	360,017			210,821			570,838			100,146			100,146
	Total liabilities and equity/capital	$	369,155		$	578,411		$	947,566		$	277,867		$	277,867
		Consolidated									Unconsolidated
		Development Projects
		Held for									Operating
		and/or Under
		Development			Operating			Total						Total
	Operating information for the quarter ended 3/31/15 (at 100%):
	Operating revenue	$	250		$	22,688		$	22,938		$	7,813		$	7,813
	Operating expenses	418			6,875			7,293			2,443			2,443
	Net operating (loss) income	(168		)	15,813			15,645			5,370			5,370
	Depreciation	991			5,520			6,511			3,076			3,076
	General and administrative/other	—			15			15			56			56
	Operating (loss) income	(1,159		)	10,278			9,119			2,238			2,238
	Interest and other income	—			4			4			—			—
	Other expenses	—			(50		)	(50		)	—			—
	Interest:
	Expense incurred, net	—			(3,884		)	(3,884		)	(2,346		)	(2,346		)
	Amortization of deferred financing costs	—			(89		)	(89		)	(1		)	(1		)
	(Loss) income before income and other taxes and (loss)	(1,159		)	6,259			5,100			(109		)	(109		)
	from investments in unconsolidated entities
	Income and other tax (expense) benefit	—			(35		)	(35		)	(18		)	(18		)
	(Loss) from investments in unconsolidated entities	—			(377		)	(377		)	—			—
	Net (loss) income	$	(1,159	)	$	5,847		$	4,688		$	(127	)	$	(127	)
	-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.
	Note:	The above tables exclude the Company's interests in unconsolidated joint ventures entered into with AvalonBay Communities, Inc. (“AVB”)in connection with the acquisition of certain real estate related assets from Archstone Enterprise LP (such assets are referred to herein as "Archstone"). These ventures own certain non-core Archstone assets that are held for sale and succeeded to certain residual Archstone liabilities/litigation, as well as responsibility for tax protection arrangements and third-party preferred interests in former Archstone subsidiaries. The preferred interests had an aggregate liquidation value of $72.6 million at March 31, 2015. 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 $122.7 million at March 31, 2015. The Company does not have any variable interest entities.
	Operating Properties
	On February 27, 2013, in conjunction with the acquisition of Archstone, the Company acquired an interest in the Wisconsin Place joint venture. 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.
	On February 27, 2013, in conjunction with the acquisition of Archstone, the Company acquired an interest in the Waterton Tenside joint venture. 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 $29.8 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.
	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 each of these entities. These projects are now unconsolidated. Details of these projects follow:
	•	Nexus Sawgrass – This development project was completed and stabilized during the quarter ended September 30, 2014. Total project costs were approximately $78.6 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 $48.7 million and a current unconsolidated outstanding balance of $48.6 million; the loan bears interest at 5.60% and matures January 1, 2021.
•	Domain – This development project was completed and stabilized during the quarter ended March 31, 2015. Total project costs were approximately $155.8 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 $96.8 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 had 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.
Development Project
Prism at Park Ave South – 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 master condominium association has been legally established, 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, 2015, the Company's and Toll Brothers' consolidated contributions to the joint venture were approximately $339.4 million, of which Toll Brothers' noncontrolling interest balance totaled $117.4 million.
Other
On February 27, 2013, in connection with the acquisition of Archstone, subsidiaries of the Company and AVB entered into three limited liability company agreements (collectively, the “Residual JV”). The Residual JV owns certain non-core Archstone assets, such as interests in a three property portfolio of apartment buildings and succeeded to certain residual Archstone liabilities/litigation. 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.
During the quarter ended March 31, 2015, the Company received approximately $19.0 million in distributions from the Residual JV as a result of the winddown/sale of remaining assets owned by the Residual JV and a partial litigation settlement received by the Residual JV. The Company's pro rata share of the distributions related to the winddown of the German dispositions that occurred in 2014 was approximately $2.0 million during the quarter ended March 31, 2015 and $100.5 million cumulatively since the acquisition of Archstone. The Company's pro rata share of the proceeds related to the sale of certain remaining assets owned by the Residual JV and the partial litigation settlement received by the Residual JV were approximately $10.4 million and $6.6 million, respectively.
On February 27, 2013, in connection with the acquisition of Archstone, a subsidiary of the Company and AVB entered into a limited liability company agreement (the “Legacy JV”), through which they assumed obligations of Archstone in the form of preferred interests, some of which are governed by tax protection arrangements. At March 31, 2015, the remaining preferred interests had an aggregate liquidation value of $72.6 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.

Deposits_Restricted

Deposits - Restricted	3 Months Ended
	Mar. 31, 2015
Deposits - Restricted [Abstract]
Restricted Cash And Cash Equivalents Disclosure [Text Block]	7.    Deposits – Restricted and Escrow Deposits – Mortgage
	The following table presents the Company’s restricted deposits as of March 31, 2015 and December 31, 2014 (amounts in thousands):
		March 31,		December 31,
		2015		2014
	Tax-deferred (1031) exchange proceeds	$	136,602	$	—
	Earnest money on pending acquisitions	2,830		580
	Restricted deposits on real estate investments	17,636		24,701
	Resident security and utility deposits	46,225		46,516
	Other	507		506
	Totals	$	203,800	$	72,303
	The following table presents the Company’s escrow deposits as of March 31, 2015 and December 31, 2014 (amounts in thousands):
		March 31,		December 31,
		2015		2014
	Real estate taxes and insurance	$	2,691	$	2,235
	Replacement reserves	3,490		3,431
	Mortgage principal reserves/sinking funds	43,626		41,567
	Other	852		852
	Totals	$	50,659	$	48,085

Debt

Debt	3 Months Ended
	Mar. 31, 2015
Debt Disclosure [Abstract]
Debt Disclosure [Text Block]	8.    Debt
	EQR does not have any indebtedness as all debt is incurred by the Operating Partnership. EQR guarantees the Operating Partnership’s revolving credit facility up to the maximum amount and for the full term of the facility.
	Mortgage Notes Payable
	As of March 31, 2015, the Company had outstanding mortgage debt of approximately $5.0 billion.
	During the quarter ended March 31, 2015, the Company:
	▪	Repaid $124.1 million of mortgage loans.
	The Company recorded $0.1 million of write-offs of unamortized deferred financing costs during the quarter ended March 31, 2015 as additional interest expense related to debt extinguishment of mortgages. The Company also recorded $1.4 million of write-offs of net unamortized premiums during the quarter ended March 31, 2015 as a reduction of interest expense related to debt extinguishment of mortgages.
	As of March 31, 2015, the Company had $700.5 million of secured debt subject to third party credit enhancement.
	As of March 31, 2015, scheduled maturities for the Company’s outstanding mortgage indebtedness were at various dates through May 1, 2061. At March 31, 2015, the interest rate range on the Company’s mortgage debt was 0.02% to 7.25%. During the quarter ended March 31, 2015, the weighted average interest rate on the Company’s mortgage debt was 4.13%.
	Notes
	As of March 31, 2015, the Company had outstanding unsecured notes of approximately $5.4 billion.
	As of March 31, 2015, scheduled maturities for the Company’s outstanding notes were at various dates through 2044. At March 31, 2015, the interest rate range on the Company’s notes was 2.375% to 7.57%. During the quarter ended March 31, 2015, the weighted average interest rate on the Company’s notes was 5.01%.
	Line of Credit and Commercial Paper
	On January 11, 2013, the Company replaced its existing $1.75 billion facility with a $2.5 billion unsecured revolving credit facility maturing April 1, 2018. The Company has the ability to increase available borrowings by an additional $500.0 million by adding additional banks to the facility or obtaining the agreement of existing banks to increase their commitments. The interest rate on advances under the facility will generally be LIBOR plus a spread (1.05% as of March 31, 2015) 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, 2015, the amount outstanding on the revolving credit facility was $130.0 million and the amount available was $1.986 billion (net of $43.3 million which was restricted/dedicated to support letters of credit, net of the $130.0 million outstanding on the revolving credit facility and net of $340.9 million outstanding on the commercial paper program). During the quarter ended March 31, 2015, the weighted average interest rate on the revolving credit facility was 1.02%.
	On February 2, 2015, the Company entered into an unsecured commercial paper note program in the United States. The Company may borrow up to a maximum of $500.0 million on this program subject to market conditions. The notes will be sold under customary terms in the United States commercial paper note market and will rank pari passu with all of the Company's other unsecured senior indebtedness. As of March 31, 2015, there was a balance of $340.8 million on the commercial paper program ($340.9 million in principal outstanding net of an unamortized discount of $0.1 million). The notes bear interest at various floating rates with a weighted average of 0.53% for the quarter ended March 31, 2015 and a weighted average maturity of 14 days as of March 31, 2015.

Derivative_and_Other_Fair_Valu

Derivative and Other Fair Value Instruments	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
Derivatives and Fair Value [Text Block]
	9	Derivative and Other Fair Value Instruments
	The valuation of financial instruments requires the Company to make estimates and judgments that affect the fair value of the instruments. The Company, where possible, bases the fair values of its financial instruments, including its derivative instruments, on listed market prices and third party quotes. Where these are not available, the Company bases its estimates on current instruments with similar terms and maturities or on other factors relevant to the financial instruments.
	In the normal course of business, the Company is exposed to the effect of interest rate changes. The Company seeks to manage these risks by following established risk management policies and procedures including the use of derivatives to hedge interest rate risk on debt instruments. The Company may also use derivatives to manage its exposure to foreign exchange rates or manage commodity prices in the daily operations of the business.
	A three-level valuation hierarchy exists for disclosure of fair value measurements. The valuation hierarchy is based upon the transparency of inputs to the valuation of an asset or liability as of the measurement date. A financial instrument’s categorization within the valuation hierarchy is based upon the lowest level of input that is significant to the fair value measurement. The three levels are defined as follows:
	•	Level 1 – Inputs to the valuation methodology are quoted prices (unadjusted) for identical assets or liabilities in active markets.
	•	Level 2 – Inputs to the valuation methodology include quoted prices for similar assets and liabilities in active markets, and inputs that are observable for the asset or liability, either directly or indirectly, for substantially the full term of the financial instrument.
	•	Level 3 – Inputs to the valuation methodology are unobservable and significant to the fair value measurement.
	The Company’s derivative positions are valued using models developed by the respective counterparty as well as models developed internally by the Company that use as their basis readily observable market parameters (such as forward yield curves and credit default swap data). Employee holdings other than Common Shares within the supplemental executive retirement plan (the “SERP”) are valued using quoted market prices for identical assets and are included in other assets and other liabilities on the consolidated balance sheets. Redeemable Noncontrolling Interests – Operating Partnership/Redeemable Limited Partners are valued using the quoted market price of Common Shares. The fair values disclosed for mortgage notes payable and unsecured debt (including its line of credit and commercial paper) were calculated using indicative rates provided by lenders of similar loans in the case of mortgage notes payable and the private unsecured debt (including its line of credit and commercial paper) and quoted market prices for each underlying issuance in the case of the public unsecured notes.
	The carrying values of the Company’s mortgage notes payable and unsecured debt (including its line of credit and commercial paper) were approximately $5.0 billion and $5.9 billion, respectively, at March 31, 2015. The fair values of the Company’s mortgage notes payable and unsecured debt (including its line of credit and commercial paper) were approximately $5.0 billion (Level 2) and $6.3 billion (Level 2), respectively, at March 31, 2015. The carrying values of the Company's mortgage notes payable and unsecured debt (including its line of credit) were approximately $5.1 billion and $5.8 billion, respectively, at December 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 December 31, 2014. The fair values of the Company’s financial instruments (other than mortgage notes payable, unsecured notes, line of credit, commercial paper and derivative instruments), including cash and cash equivalents and other financial instruments, approximate their carrying or contract values.
	The following table summarizes the Company’s consolidated derivative instruments at March 31, 2015 (dollar amounts are in thousands):
			Fair Value				Forward
			Hedges (1)				Starting
							Swaps (2)
	Current Notional Balance		$	450,000			$	450,000
	Lowest Possible Notional		$	450,000			$	450,000
	Highest Possible Notional		$	450,000			$	450,000
	Lowest Interest Rate		2.375		%		1.935		%
	Highest Interest Rate		2.375		%		3.191		%
	Earliest Maturity Date		2019				2025
	Latest Maturity Date		2019				2025
	-1	Fair Value Hedges – Converts outstanding fixed rate unsecured notes ($450.0 million 2.375% notes due July 1, 2019) to a floating interest rate of 90-Day LIBOR plus 0.61%.
	-2	Forward Starting Swaps – Designed to partially fix interest rates in advance of a planned future debt issuance. These swaps have mandatory counterparty terminations in 2016, and are targeted to 2015 issuances.
	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, 2015 and December 31, 2014, respectively (amounts in thousands):
									Fair Value Measurements at Reporting Date Using
	Description		Balance Sheet		3/31/15				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:
	Fair Value Hedges		Other Assets		$	6,438			$	—		$	6,438			$	—
	Forward Starting Swaps		Other Assets		454				—			454				—
	Supplemental Executive Retirement Plan		Other Assets		97,391				97,391			—				—
	Total				$	104,283			$	97,391		$	6,892			$	—
	Liabilities
	Derivatives designated as hedging instruments:
	Interest Rate Contracts:
	Forward Starting Swaps		Other Liabilities		$	26,014			$	—		$	26,014			$	—
	Supplemental Executive Retirement Plan		Other Liabilities		97,391				97,391			—				—
	Total				$	123,405			$	97,391		$	26,014			$	—
	Redeemable Noncontrolling Interests –
	Operating Partnership/Redeemable
	Limited Partners		Mezzanine		$	541,866			$	—		$	541,866			$	—
									Fair Value Measurements at Reporting Date Using
	Description		Balance Sheet		12/31/14				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:
	Fair Value Hedges		Other Assets		$	1,596			$	—		$	1,596			$	—
	Forward Starting Swaps		Other Assets		332				—			332				—
	Supplemental Executive Retirement Plan		Other Assets		104,463				104,463			—				—
	Total				$	106,391			$	104,463		$	1,928			$	—
	Liabilities
	Derivatives designated as hedging instruments:
	Interest Rate Contracts:
	Forward Starting Swaps		Other Liabilities		$	14,104			$	—		$	14,104			$	—
	Supplemental Executive Retirement Plan		Other Liabilities		104,463				104,463			—				—
	Total				$	118,567			$	104,463		$	14,104			$	—
	Redeemable Noncontrolling Interests –
Operating Partnership/Redeemable
Limited Partners		Mezzanine		$	500,733			$	—		$	500,733			$	—
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, 2015 and 2014, respectively (amounts in thousands):
31-Mar-15		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		Interest expense		$	4,842			Fixed rate debt		Interest expense	$	(4,842	)
Total				$	4,842						$	(4,842	)
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				$	—						$	—
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, 2015 and 2014, respectively (amounts in thousands):
		Effective Portion									Ineffective Portion
31-Mar-15		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				Reclassified from		Reclassified from			Recognized in		Reclassified from
		OCI on				Accumulated		Accumulated			Income on		Accumulated
		Derivative				OCI into Income		OCI into Income			Derivative		OCI into Income
Derivatives designated as hedging instruments:
Interest Rate Contracts:
Forward Starting Swaps		$	(11,788	)		Interest expense		$	(4,338	)	N/A		$	—
Total		$	(11,788	)				$	(4,338	)			$	—
		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				Reclassified from		Reclassified from			Recognized in		Reclassified from
		OCI on				Accumulated		Accumulated			Income on		Accumulated
		Derivative				OCI into Income		OCI into Income			Derivative		OCI into Income
Derivatives designated as hedging instruments:
Interest Rate Contracts:
Forward Starting Swaps		$	(11,952	)		Interest expense		$	(4,129	)	N/A		$	—
Total		$	(11,952	)				$	(4,129	)			$	—
As of March 31, 2015 and December 31, 2014, there were approximately $179.7 million and $172.2 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, 2015, the Company may recognize an estimated $22.2 million of accumulated other comprehensive (loss) as additional interest expense during the twelve months ending March 31, 2016.

Earnings_Per_Share

Earnings Per Share	3 Months Ended
	Mar. 31, 2015
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,
		2015			2014
	Numerator for net income per share – basic:
	Income from continuing operations	$	190,020		$	81,680
	Allocation to Noncontrolling Interests – Operating Partnership, net	(7,051		)	(3,053		)
	Net (income) attributable to Noncontrolling Interests – Partially Owned Properties	(643		)	(504		)
	Preferred distributions	(891		)	(1,036		)
	Premium on redemption of Preferred Shares	(2,789		)	—
	Income from continuing operations available to Common Shares, net of Noncontrolling Interests	178,646			77,087
	Discontinued operations, net of Noncontrolling Interests	196			1,012
	Numerator for net income per share – basic	$	178,842		$	78,099
	Numerator for net income per share – diluted:
	Income from continuing operations	$	190,020		$	81,680
	Net (income) attributable to Noncontrolling Interests – Partially Owned Properties	(643		)	(504		)
	Preferred distributions	(891		)	(1,036		)
	Premium on redemption of Preferred Shares	(2,789		)	—
	Income from continuing operations available to Common Shares	185,697			80,140
	Discontinued operations, net	204			1,052
	Numerator for net income per share – diluted	$	185,901		$	81,192
	Denominator for net income per share – basic and diluted:
	Denominator for net income per share – basic	363,098			360,470
	Effect of dilutive securities:
	OP Units	13,598			13,731
	Long-term compensation shares/units	3,631			2,183
	Denominator for net income per share – diluted	380,327			376,384
	Net income per share – basic	$	0.49		$	0.22
	Net income per share – diluted	$	0.49		$	0.22
	Net income per share – basic:
	Income from continuing operations available to Common Shares, net of Noncontrolling Interests	$	0.492		$	0.214
	Discontinued operations, net of Noncontrolling Interests	0.001			0.003
	Net income per share – basic	$	0.493		$	0.217
	Net income per share – diluted:
	Income from continuing operations available to Common Shares	$	0.488		$	0.213
	Discontinued operations, net	0.001			0.003
	Net income per share – diluted	$	0.489		$	0.216
	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,
		2015			2014
	Numerator for net income per Unit – basic and diluted:
	Income from continuing operations	$	190,020		$	81,680
	Net (income) attributable to Noncontrolling Interests – Partially Owned Properties	(643		)	(504		)
	Allocation to Preference Units	(891		)	(1,036		)
	Allocation to premium on redemption of Preference Units	(2,789		)	—
	Income from continuing operations available to Units	185,697			80,140
	Discontinued operations, net	204			1,052
	Numerator for net income per Unit – basic and diluted	$	185,901		$	81,192
	Denominator for net income per Unit – basic and diluted:
	Denominator for net income per Unit – basic	376,696			374,201
	Effect of dilutive securities:
	Dilution for Units issuable upon assumed exercise/vesting of the Company’s long-term	3,631			2,183
	compensation shares/units
	Denominator for net income per Unit – diluted	380,327			376,384
	Net income per Unit – basic	$	0.49		$	0.22
	Net income per Unit – diluted	$	0.49		$	0.22
	Net income per Unit – basic:
	Income from continuing operations available to Units	$	0.492		$	0.214
	Discontinued operations, net	0.001			0.003
	Net income per Unit – basic	$	0.493		$	0.217
	Net income per Unit – diluted:
	Income from continuing operations available to Units	$	0.488		$	0.213
Discontinued operations, net	0.001			0.003
Net income per Unit – diluted	$	0.489		$	0.216

Discontinued_Operations

Discontinued Operations	3 Months Ended
	Mar. 31, 2015
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, for properties sold in 2013 and prior years. The amounts included in discontinued operations for the quarters ended March 31, 2015 and 2014 represent trailing activity for properties sold in 2013 and prior years. None of the properties sold during the quarters ended March 31, 2015 and 2014 met the new criteria for reporting discontinued operations. See Note 2 for further discussion.
	The components of discontinued operations are outlined below and include the results of operations for the respective periods that the Company owned such assets for properties sold in 2013 and prior years during each of the quarters ended March 31, 2015 and 2014 (amounts in thousands).
			Quarter Ended March 31,
			2015			2014
	REVENUES
	Rental income		$	161		$	1,023
	Total revenues		161			1,023
	EXPENSES (1)
	Property and maintenance		(67		)	48
	Real estate taxes and insurance		52			13
	General and administrative		6			5
	Total expenses		(9		)	66
	Discontinued operating income		170			957
	Interest and other income		49			35
	Income and other tax (expense) benefit		(15		)	(11		)
	Discontinued operations		204			981
	Net gain on sales of discontinued operations		—			71
	Discontinued operations, net		$	204		$	1,052
	-1	Includes expenses paid in the current period for properties sold in prior periods related to the Company’s period of ownership.

Commitments_and_Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2015
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, 2015. While no assurances can be given, the Company does not believe that the suit, if adversely determined, would have a material adverse effect on the Company.
	The Company has established a reserve related to various litigation matters associated with its Massachusetts properties and periodically assesses the adequacy of the reserve and makes adjustments as necessary. During the quarter ended March 31, 2015, the Company recorded a reduction to the reserve of approximately $1.0 million, resulting in a total reserve of approximately $5.0 million at March 31, 2015. While no assurances can be given, the Company does not believe that the ultimate resolution of these litigation matters, if adversely determined, would have a material adverse effect on the Company.
	The Company does not believe there is any other litigation pending or threatened against it that, individually or in the aggregate, may reasonably be expected to have a material adverse effect on the Company.
	As of March 31, 2015, the Company has 15 consolidated projects (including Prism at Park Avenue South in New York City, which the Company is jointly developing with Toll Brothers as discussed below) totaling 5,273 apartment units in various stages of development with commitments to fund of approximately $1.3 billion and estimated completion dates ranging through September 30, 2017, as well as other completed development projects that are in various stages of lease up or are stabilized. 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, 2015, the Company has two completed unconsolidated development projects that are stabilized. Both projects were co-developed with the same third party development partner in different ventures. The development venture agreements with this partner are primarily deal-specific regarding profit-sharing, equity contributions, returns on investment, buy-sell agreements and other customary provisions. The Company currently has no further funding obligations related to these projects. 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 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.
	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 master condominium association has been legally established, 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, 2015, the Company's and Toll Brothers' consolidated contributions to the joint venture were approximately $339.4 million, of which Toll Brothers' noncontrolling interest balance totaled $117.4 million.

Reportable_Segments

Reportable Segments	3 Months Ended
	Mar. 31, 2015
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, 2015 and 2014, 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, 2015 and 2014, respectively, as well as total assets and capital expenditures at March 31, 2015 (amounts in thousands):
			Quarter Ended March 31, 2015									Quarter Ended March 31, 2014
			Rental Income			Operating Expenses			NOI			Rental Income		Operating Expenses		NOI
	Same store (1)
	Boston		$	64,033		$	22,541		$	41,492		$	61,907	$	22,129	$	39,778
	Denver		28,997			7,460			21,537			26,612		7,461		19,151
	New York		116,070			46,113			69,957			111,186		45,834		65,352
	San Francisco		89,850			27,103			62,747			81,261		26,609		54,652
	Seattle		40,390			12,667			27,723			37,621		12,734		24,887
	South Florida		49,302			17,968			31,334			46,896		17,525		29,371
	Southern California		105,193			34,126			71,067			99,776		33,545		66,231
	Washington D.C.		112,627			38,539			74,088			111,804		37,809		73,995
	Non-core		25,572			10,027			15,545			24,731		9,814		14,917
	Total same store		632,034			216,544			415,490			601,794		213,460		388,334
	Non-same store/other (2) (3)
	Boston		922			229			693			1,028		210		818
	Seattle		4,579			1,298			3,281			107		146		(39		)
	South Florida		1,932			675			1,257			803		454		349
	Southern California		17,777			6,528			11,249			8,905		3,690		5,215
	Washington D.C.		5,408			1,653			3,755			3,507		1,441		2,066
	Other (3)		1,954			5,509			(3,555		)	14,581		10,377		4,204
	Total non-same store/other		32,572			15,892			16,680			28,931		16,318		12,613
	Total		$	664,606		$	232,436		$	432,170		$	630,725	$	229,778	$	400,947
	-1	Same store primarily includes all properties acquired or completed and stabilized prior to January 1, 2014, less properties subsequently sold, which represented 97,586 apartment units.
	-2	Non-same store primarily includes properties acquired after January 1, 2014, plus any properties in lease-up and not stabilized as of January 1, 2014.
	-3	Other includes development, other corporate operations and operations prior to sale for properties sold in 2014 and 2015 that do not meet the new discontinued operations criteria.
			Quarter Ended March 31, 2015
			Total Assets			Capital Expenditures
	Same store (1)
	Boston		$	1,908,859		$	3,505
	Denver		514,958			1,120
	New York		4,637,217			3,797
	San Francisco		2,700,366			5,638
	Seattle		1,088,728			3,524
	South Florida		1,126,085			2,942
	Southern California		2,787,871			6,020
	Washington D.C.		4,250,738			7,113
	Non-core		405,017			1,649
	Total same store		19,419,839			35,308
	Non-same store/other (2) (3)
	Boston		47,996			34
	Seattle		231,258			466
	South Florida		66,906			14
	Southern California		845,902			1,163
	Washington D.C.		242,360			1,143
	Other (3)		2,174,787			42
	Total non-same store/other		3,609,209			2,862
	Total		$	23,029,048		$	38,170
	-1	Same store primarily includes all properties acquired or completed and stabilized prior to January 1, 2014, less properties subsequently sold, which represented 97,586 apartment units.
	-2	Non-same store primarily includes properties acquired after January 1, 2014, plus any properties in lease-up and not stabilized as of January 1, 2014.
	-3	Other includes development, other corporate operations and capital expenditures for properties sold.
	Note: Markets/Metro Areas aggregated 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, 2015 and 2014, respectively (amounts in thousands):
			Quarter Ended March 31,
			2015			2014
	Rental income		$	664,606		$	630,725
Property and maintenance expense		(124,560		)	(125,566		)
Real estate taxes and insurance expense		(86,432		)	(82,094		)
Property management expense		(21,444		)	(22,118		)
Total operating expenses		(232,436		)	(229,778		)
Net operating income		$	432,170		$	400,947

Subsequent_EventsOther

Subsequent Events/Other	3 Months Ended
	Mar. 31, 2015
Subsequent Events Other [Abstract]
Subsequent Events/Other
	14	Subsequent Events/Other
	Subsequent Events
	Subsequent to March 31, 2015, the Company:
	•	Acquired one property consisting of 202 apartment units for $130.3 million;
	•	Sold one property consisting of 314 apartment units for $49.6 million;
	•	Sold a 193,230 square foot office building for approximately $123.3 million which is adjacent to our Longfellow Place property located in Boston and acquired in 1999; and
	•	Repaid $300.0 million of 6.584% unsecured notes at maturity.
	Other
	During the quarters ended March 31, 2015 and 2014, the Company incurred charges of $0.1 million and none, respectively, related to property acquisition costs, such as survey, title and legal fees, on the acquisition of operating properties and $0.5 million and $0.5 million, respectively, related to the write-off of various pursuit and out-of-pocket costs for terminated acquisition, disposition and development transactions. These costs, totaling $0.6 million and $0.5 million, respectively, are included in other expenses in the accompanying consolidated statements of operations and comprehensive income.
	Effective January 1, 2015, the Company has revised its executive compensation program. The long-term incentive portion of the revised program will be performance based and determined by the Company’s absolute and relative total shareholder return over a three year performance period.  During the quarter ended March 31, 2015, the Company expensed approximately $2.3 million under the long-term incentive portion of the revised program, of which $0.3 million and $2.0 million was recorded to property management expense and general and administrative expense, respectively.
	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, 2015
Summary of Significant Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation
	The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by accounting principles generally accepted in the United States for complete financial statements. In the opinion of management, all adjustments (consisting of normal recurring accruals) and certain reclassifications considered necessary for a fair presentation have been included. Certain reclassifications have been made to the prior period financial statements in order to conform to the current year presentation. These reclassifications did not have an impact on net income previously reported. Operating results for the quarter ended March 31, 2015 are not necessarily indicative of the results that may be expected for the year ending December 31, 2015.
	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, 2014 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, 2014.
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, 2015, 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 19 properties and 3,771 apartment units and various completed and uncompleted development properties having a noncontrolling interest book value of $122.7 million at March 31, 2015. 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 $11.0 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, 2015, the Company estimates the value of Noncontrolling Interest distributions for these six properties would have been approximately $63.3 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, 2015 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.
	In April 2014, the Financial Accounting Standards Board (the "FASB") issued new guidance for reporting discontinued operations. Only disposals representing a strategic shift in operations that has a major effect on a company’s operations and financial results will be presented as discontinued operations. Companies are required to expand their disclosures about discontinued operations to provide more information on the assets, liabilities, income and expenses of the discontinued operations. Companies are also required to disclose the pre-tax income attributable to a disposal of a significant part of a company that does not qualify for discontinued operations reporting. Application of this guidance is prospective from the date of adoption and early adoption was permitted, but only for disposals (or classifications as held for sale) that had not been reported in financial statements previously issued. The new standard was effective January 1, 2015, but the Company early adopted it as allowed effective January 1, 2014. Adoption of this standard resulted in and will likely continue to result in substantially fewer of the Company's dispositions meeting the discontinued operations qualifications. See Note 11 for further discussion.
	In May 2014, the FASB issued a comprehensive new revenue recognition standard entitled Revenue from Contracts with Customers that will supersede nearly all existing revenue recognition guidance. The new standard specifically excludes lease contracts. The new standard’s core principle is that a company will recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. Companies will likely need to use more judgment and make more estimates than under current revenue recognition guidance. These may include identifying performance obligations in the contract, estimating the amount of variable consideration, if any, to include in the transaction price and allocating the transaction price to each separate performance obligation. The new standard will be effective for the Company beginning on January 1, 2017 and early adoption is not permitted. The new standard may be applied retrospectively to each prior period presented or retrospectively with the cumulative effect recognized as of the date of adoption. The Company has not yet selected a transition method and is currently evaluating the impact of adopting the new standard on its consolidated results of operations and financial position.
	In August 2014, the FASB issued a new standard that will explicitly require management to assess an entity's ability to continue as a going concern and to provide related footnote disclosures in certain circumstances. In connection with each annual and interim period, management will assess whether there is substantial doubt about an entity's ability to continue as a going concern within one year after the issuance date. Disclosures will be required if conditions give rise to substantial doubt, however to determine the specific disclosures, management will need to assess whether its plans will alleviate substantial doubt. The new standard is effective for the annual period ending after December 15, 2016. The Company does not expect that this will have a material effect on its consolidated results of operations or financial position.
	In February 2015, the FASB issued new consolidation guidance which makes changes to both the variable interest model and the voting model. Among other changes, the new standard specifically eliminates the presumption in the current voting model that a general partner controls a limited partnership or similar entity unless that presumption can be overcome. Generally, only a single limited partner that is able to exercise substantive kick-out rights will consolidate. The new standard will be effective for the Company beginning on January 1, 2016 and early adoption is permitted, including adoption in an interim period. The new standard must be applied using a modified retrospective approach by recording a cumulative-effect adjustment to equity/capital as of the beginning of the period of adoption or retrospectively to each period presented. The Company has not yet selected a transition method and is currently evaluating the impact of adopting the new standard on its consolidated results of operations and financial position.
	In April 2015, the FASB issued a new standard which requires companies to present debt financing costs as a direct deduction from the carrying amount of the associated debt liability rather than as an asset, consistent with the presentation of debt discounts on the consolidated balance sheets.  The new standard will be effective for the Company beginning on January 1, 2016 and early adoption is permitted.  The new standard must be applied retrospectively to all prior periods presented in the consolidated financial statements.  The Company does not expect that this will have a material effect on its consolidated results of operations or financial position.

Business_Tables

Business (Tables)	3 Months Ended
	Mar. 31, 2015
Business [Abstract]
Schedule of Real Estate Properties	The ownership breakdown includes (table does not include various uncompleted development properties):
		Properties	Apartment
			Units
	Wholly Owned Properties	362	97,825
	Master-Leased Properties – Consolidated	3	853
	Partially Owned Properties – Consolidated	19	3,771
	Partially Owned Properties – Unconsolidated	3	1,281
	Military Housing	2	5,063
		389	108,793

Equity_Capital_and_Other_Inter1

Equity, Capital and Other Interests (Tables)	3 Months Ended
	Mar. 31, 2015
Common shares and units rollforward	The following tables present the changes in the Company’s issued and outstanding Common Shares and “Units” (which includes OP Units and restricted units (formerly known as Long-Term Incentive Plan (“LTIP”) Units)) for the quarter ended March 31, 2015:
			2015
	Common Shares
	Common Shares outstanding at January 1,		362,855,454
	Common Shares Issued:
	Conversion of OP Units		154,050
	Exercise of share options		770,012
	Employee Share Purchase Plan (ESPP)		30,151
	Restricted share grants, net		158,753
	Common Shares outstanding at March 31,		363,968,420
	Units
	Units outstanding at January 1,		14,298,691
	Restricted units, net		333,304
	Conversion of OP Units to Common Shares		(154,050	)
	Units outstanding at March 31,		14,477,945
	Total Common Shares and Units outstanding at March 31,		378,446,365
	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, 2015 (amounts in thousands):
			2015
	Balance at January 1,		$	500,733
	Change in market value		41,763
	Change in carrying value		(630		)
	Balance at March 31,		$	541,866
Schedule Of Preferred Stock [Table Text Block]	The following table presents the Company’s issued and outstanding Preferred Shares as of March 31, 2015 and December 31, 2014:
							Amounts in thousands
			Redemption		Annual		March 31,		December 31,
			Date (1)		Dividend per		2015		2014
					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	$	40,180	$	50,000
	value $50 per share; 803,600 shares issued and outstanding
	at March 31, 2015 and 1,000,000 shares issued and
	outstanding at December 31, 2014 (3)
							$	40,180	$	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.
	-3	Effective January 26, 2015, the Company repurchased and retired 196,400 Series K Preferred Shares with a par value of $9.82 million for total cash consideration of approximately $12.7 million. As a result of this partial redemption, the Company incurred a cash charge of approximately $2.8 million which was recorded as a premium on the redemption of Preferred Shares.
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, 2015:
			2015
	General and Limited Partner Units
	General and Limited Partner Units outstanding at January 1,		377,154,145
	Issued to General Partner:
	Exercise of EQR share options		770,012
	EQR’s Employee Share Purchase Plan (ESPP)		30,151
	EQR's restricted share grants, net		158,753
	Issued to Limited Partners:
	Restricted units, net		333,304
	General and Limited Partner Units outstanding at March 31,		378,446,365
	Limited Partner Units
	Limited Partner Units outstanding at January 1,		14,298,691
	Limited Partner restricted units, net		333,304
	Conversion of Limited Partner OP Units to EQR Common Shares		(154,050	)
	Limited Partner Units outstanding at March 31,		14,477,945
	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, 2015 (amounts in thousands):
			2015
	Balance at January 1,		$	500,733
	Change in market value		41,763
	Change in carrying value		(630		)
	Balance at March 31,		$	541,866
Schedule Of Preferred Stock [Table Text Block]	The following table presents the Operating Partnership’s issued and outstanding “Preference Units” as of March 31, 2015 and December 31, 2014:
							Amounts in thousands
			Redemption		Annual		March 31,		December 31,
			Date (1)		Dividend per		2015		2014
					Unit (2)
	Preference Units:
	8.29% Series K Cumulative Redeemable Preference Units;		12/10/26			$4.14	$	40,180	$	50,000
	liquidation value $50 per unit; 803,600 units issued and
	outstanding at March 31, 2015 and 1,000,000 units
	issued and outstanding at December 31, 2014 (3)
							$	40,180	$	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.
	-3	Effective January 26, 2015, the Operating Partnership repurchased and retired 196,400 Series K Preference Units with a par value of $9.82 million for total cash consideration of approximately $12.7 million, in conjunction with the concurrent redemption of the corresponding Company Preferred Shares. As a result of this partial redemption, the Operating Partnership incurred a cash charge of approximately $2.8 million which was recorded as a premium on the redemption of Preference Units.

Real_Estate_Tables

Real Estate (Tables)	3 Months Ended
	Mar. 31, 2015
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, 2015 and December 31, 2014 (amounts in thousands):
		March 31,				December 31,
		2015				2014
	Land	$	6,357,580			$	6,295,404
	Depreciable property:
	Buildings and improvements	18,109,892				17,974,337
	Furniture, fixtures and equipment	1,401,801				1,365,276
	In-Place lease intangibles	512,804				511,891
	Projects under development:
	Land	423,359				466,764
	Construction-in-progress	846,425				877,155
	Land held for development:
	Land	109,726				145,366
	Construction-in-progress	34,271				39,190
	Investment in real estate	27,795,858				27,675,383
	Accumulated depreciation	(5,600,485		)		(5,432,805		)
	Investment in real estate, net	$	22,195,373			$	22,242,578
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, 2015 and December 31, 2014 (amounts in thousands):
	Description	Balance Sheet Location		March 31,				December 31,
				2015				2014
	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			(10,050		)		(8,913		)
	Lease intangible assets, net			$	169,461			$	170,598
	Liabilities
	Ground lease intangibles – above market	Other Liabilities		$	2,400			$	2,400
	Retail lease intangibles – below market	Other Liabilities		5,270				5,270
	Lease intangible liabilities			7,670				7,670
	Accumulated amortization			(2,549		)		(2,258		)
	Lease intangible liabilities, net			$	5,121			$	5,412
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
		2015				2016				2017			2018			2019			2020
	Ground lease intangibles	$	3,241			$	4,321			$	4,321		$	4,321		$	4,321		$	4,321
	Retail lease intangibles	(705		)		(896		)		(540		)	(71		)	(71		)	(71		)
	Total	$	2,536			$	3,425			$	3,781		$	4,250		$	4,250		$	4,250
Acquired and Disposed Properties [Table Text Block]	During the quarter ended March 31, 2015, the Company acquired the entire equity interest in the following from an unaffiliated party (purchase price in thousands):
		Properties			Apartment Units			Purchase Price
	Land Parcel (one)	—			—			$	5,968
	Total	—			—			$	5,968
	During the quarter ended March 31, 2015, the Company disposed of the following to unaffiliated parties (sales price in thousands):
		Properties			Apartment Units			Sales Price
	Rental Properties	3			550			$	145,400
	Total	3			550			$	145,400

Commitments_to_AcquireDispose_1

Commitments to Acquire/Dispose of Real Estate (Tables)	3 Months Ended
	Mar. 31, 2015
Commitments to Acquire Dispose of Real Estate [Abstract]
Real Estate to be Acquired Table Text Block	In addition to the property that was subsequently acquired as discussed in Note 14, the Company has entered into separate agreements to acquire the following (purchase price in thousands):
		Properties	Apartment Units	Purchase Price
	Land Parcels (three)	—	—	$	25,132
	Total	—	—	$	25,132
Real Estate To Be Disposed Of Text Block	In addition to the property and office building that were 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	2	513	$	68,650
	Land Parcel (one)	—	—	2,700
	Total	2	513	$	71,350

Investments_in_Partially_Owned1

Investments in Partially Owned Entities (Tables)	3 Months Ended
	Mar. 31, 2015
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, 2015 (amounts in thousands except for project and apartment unit amounts):
		Consolidated									Unconsolidated
		Development Projects
		Held for			Operating			Total			Operating			Total
		and/or Under
		Development
	Total projects (1)	—			19			19			3			3
	Total apartment units (1)	—			3,771			3,771			1,281			1,281
	Balance sheet information at 3/31/15 (at 100%):
	ASSETS
	Investment in real estate	$	347,809		$	684,686		$	1,032,495		$	290,077		$	290,077
	Accumulated depreciation	(991		)	(200,002		)	(200,993		)	(21,388		)	(21,388		)
	Investment in real estate, net	346,818			484,684			831,502			268,689			268,689
	Cash and cash equivalents	—			13,775			13,775			7,598			7,598
	Investments in unconsolidated entities	—			51,363			51,363			—			—
	Deposits – restricted	15,640			310			15,950			246			246
	Deferred financing costs, net	—			2,052			2,052			7			7
	Other assets	6,697			26,227			32,924			1,327			1,327
	Total assets	$	369,155		$	578,411		$	947,566		$	277,867		$	277,867
	LIABILITIES AND EQUITY/CAPITAL
	Mortgage notes payable (2)	$	—		$	360,567		$	360,567		$	175,276		$	175,276
	Accounts payable & accrued expenses	8,731			3,188			11,919			389			389
	Accrued interest payable	—			1,283			1,283			691			691
	Other liabilities	257			576			833			834			834
	Security deposits	150			1,976			2,126			531			531
	Total liabilities	9,138			367,590			376,728			177,721			177,721
	Noncontrolling Interests – Partially Owned	117,350			5,311			122,661			90,878			90,878
	Properties/Partners' equity
	Company equity/General and Limited	242,667			205,510			448,177			9,268			9,268
	Partners' Capital
	Total equity/capital	360,017			210,821			570,838			100,146			100,146
	Total liabilities and equity/capital	$	369,155		$	578,411		$	947,566		$	277,867		$	277,867
Partially Owned Property Income Statement Schedule [Table Text Block]
		Consolidated									Unconsolidated
		Development Projects
		Held for									Operating
		and/or Under
		Development			Operating			Total						Total
	Operating information for the quarter ended 3/31/15 (at 100%):
	Operating revenue	$	250		$	22,688		$	22,938		$	7,813		$	7,813
	Operating expenses	418			6,875			7,293			2,443			2,443
	Net operating (loss) income	(168		)	15,813			15,645			5,370			5,370
	Depreciation	991			5,520			6,511			3,076			3,076
	General and administrative/other	—			15			15			56			56
	Operating (loss) income	(1,159		)	10,278			9,119			2,238			2,238
	Interest and other income	—			4			4			—			—
	Other expenses	—			(50		)	(50		)	—			—
	Interest:
	Expense incurred, net	—			(3,884		)	(3,884		)	(2,346		)	(2,346		)
	Amortization of deferred financing costs	—			(89		)	(89		)	(1		)	(1		)
	(Loss) income before income and other taxes and (loss)	(1,159		)	6,259			5,100			(109		)	(109		)
	from investments in unconsolidated entities
	Income and other tax (expense) benefit	—			(35		)	(35		)	(18		)	(18		)
	(Loss) from investments in unconsolidated entities	—			(377		)	(377		)	—			—
	Net (loss) income	$	(1,159	)	$	5,847		$	4,688		$	(127	)	$	(127	)
	-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.
	Note:	The above tables exclude the Company's interests in unconsolidated joint ventures entered into with AvalonBay Communities, Inc. (“AVB”)in connection with the acquisition of certain real estate related assets from Archstone Enterprise LP (such assets are referred to herein as "Archstone"). These ventures own certain non-core Archstone assets that are held for sale and succeeded to certain residual Archstone liabilities/litigation, as well as responsibility for tax protection arrangements and third-party preferred interests in former Archstone subsidiaries. The preferred interests had an aggregate liquidation value of $72.6 million at March 31, 2015. The ventures are owned 60% by the Company and 40% by AVB.

Deposits_Restricted_Tables

Deposits - Restricted (Tables)	3 Months Ended
	Mar. 31, 2015
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, 2015 and December 31, 2014 (amounts in thousands):
		March 31,		December 31,
		2015		2014
	Tax-deferred (1031) exchange proceeds	$	136,602	$	—
	Earnest money on pending acquisitions	2,830		580
	Restricted deposits on real estate investments	17,636		24,701
	Resident security and utility deposits	46,225		46,516
	Other	507		506
	Totals	$	203,800	$	72,303
Escrow Deposits [Text Block]	The following table presents the Company’s escrow deposits as of March 31, 2015 and December 31, 2014 (amounts in thousands):
		March 31,		December 31,
		2015		2014
	Real estate taxes and insurance	$	2,691	$	2,235
	Replacement reserves	3,490		3,431
	Mortgage principal reserves/sinking funds	43,626		41,567
	Other	852		852
	Totals	$	50,659	$	48,085

Derivative_and_Other_Fair_Valu1

Derivative and Other Fair Value Instruments (Tables)	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
Derivative Instrument Table	The following table summarizes the Company’s consolidated derivative instruments at March 31, 2015 (dollar amounts are in thousands):
			Fair Value				Forward
			Hedges (1)				Starting
							Swaps (2)
	Current Notional Balance		$	450,000			$	450,000
	Lowest Possible Notional		$	450,000			$	450,000
	Highest Possible Notional		$	450,000			$	450,000
	Lowest Interest Rate		2.375		%		1.935		%
	Highest Interest Rate		2.375		%		3.191		%
	Earliest Maturity Date		2019				2025
	Latest Maturity Date		2019				2025
	-1	Fair Value Hedges – Converts outstanding fixed rate unsecured notes ($450.0 million 2.375% notes due July 1, 2019) to a floating interest rate of 90-Day LIBOR plus 0.61%.
	-2	Forward Starting Swaps – Designed to partially fix interest rates in advance of a planned future debt issuance. These swaps have mandatory counterparty terminations in 2016, and are targeted to 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, 2015 and December 31, 2014, respectively (amounts in thousands):
									Fair Value Measurements at Reporting Date Using
	Description		Balance Sheet		3/31/15				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:
	Fair Value Hedges		Other Assets		$	6,438			$	—		$	6,438			$	—
	Forward Starting Swaps		Other Assets		454				—			454				—
	Supplemental Executive Retirement Plan		Other Assets		97,391				97,391			—				—
	Total				$	104,283			$	97,391		$	6,892			$	—
	Liabilities
	Derivatives designated as hedging instruments:
	Interest Rate Contracts:
	Forward Starting Swaps		Other Liabilities		$	26,014			$	—		$	26,014			$	—
	Supplemental Executive Retirement Plan		Other Liabilities		97,391				97,391			—				—
	Total				$	123,405			$	97,391		$	26,014			$	—
	Redeemable Noncontrolling Interests –
	Operating Partnership/Redeemable
	Limited Partners		Mezzanine		$	541,866			$	—		$	541,866			$	—
									Fair Value Measurements at Reporting Date Using
	Description		Balance Sheet		12/31/14				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:
	Fair Value Hedges		Other Assets		$	1,596			$	—		$	1,596			$	—
	Forward Starting Swaps		Other Assets		332				—			332				—
	Supplemental Executive Retirement Plan		Other Assets		104,463				104,463			—				—
	Total				$	106,391			$	104,463		$	1,928			$	—
	Liabilities
	Derivatives designated as hedging instruments:
	Interest Rate Contracts:
	Forward Starting Swaps		Other Liabilities		$	14,104			$	—		$	14,104			$	—
	Supplemental Executive Retirement Plan		Other Liabilities		104,463				104,463			—				—
	Total				$	118,567			$	104,463		$	14,104			$	—
	Redeemable Noncontrolling Interests –
	Operating Partnership/Redeemable
	Limited Partners		Mezzanine		$	500,733			$	—		$	500,733			$	—
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, 2015 and 2014, respectively (amounts in thousands):
	31-Mar-15		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		Interest expense		$	4,842			Fixed rate debt		Interest expense	$	(4,842	)
	Total				$	4,842						$	(4,842	)
	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				$	—						$	—
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, 2015 and 2014, respectively (amounts in thousands):
			Effective Portion									Ineffective Portion
	31-Mar-15		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				Reclassified from		Reclassified from			Recognized in		Reclassified from
			OCI on				Accumulated		Accumulated			Income on		Accumulated
			Derivative				OCI into Income		OCI into Income			Derivative		OCI into Income
	Derivatives designated as hedging instruments:
	Interest Rate Contracts:
	Forward Starting Swaps		$	(11,788	)		Interest expense		$	(4,338	)	N/A		$	—
	Total		$	(11,788	)				$	(4,338	)			$	—
			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				Reclassified from		Reclassified from			Recognized in		Reclassified from
			OCI on				Accumulated		Accumulated			Income on		Accumulated
			Derivative				OCI into Income		OCI into Income			Derivative		OCI into Income
	Derivatives designated as hedging instruments:
	Interest Rate Contracts:
	Forward Starting Swaps		$	(11,952	)		Interest expense		$	(4,129	)	N/A		$	—
	Total		$	(11,952	)				$	(4,129	)			$	—

Earnings_Per_Share_Tables

Earnings Per Share (Tables)	3 Months Ended
	Mar. 31, 2015
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,
		2015			2014
	Numerator for net income per share – basic:
	Income from continuing operations	$	190,020		$	81,680
	Allocation to Noncontrolling Interests – Operating Partnership, net	(7,051		)	(3,053		)
	Net (income) attributable to Noncontrolling Interests – Partially Owned Properties	(643		)	(504		)
	Preferred distributions	(891		)	(1,036		)
	Premium on redemption of Preferred Shares	(2,789		)	—
	Income from continuing operations available to Common Shares, net of Noncontrolling Interests	178,646			77,087
	Discontinued operations, net of Noncontrolling Interests	196			1,012
	Numerator for net income per share – basic	$	178,842		$	78,099
	Numerator for net income per share – diluted:
	Income from continuing operations	$	190,020		$	81,680
	Net (income) attributable to Noncontrolling Interests – Partially Owned Properties	(643		)	(504		)
	Preferred distributions	(891		)	(1,036		)
	Premium on redemption of Preferred Shares	(2,789		)	—
	Income from continuing operations available to Common Shares	185,697			80,140
	Discontinued operations, net	204			1,052
	Numerator for net income per share – diluted	$	185,901		$	81,192
	Denominator for net income per share – basic and diluted:
	Denominator for net income per share – basic	363,098			360,470
	Effect of dilutive securities:
	OP Units	13,598			13,731
	Long-term compensation shares/units	3,631			2,183
	Denominator for net income per share – diluted	380,327			376,384
	Net income per share – basic	$	0.49		$	0.22
	Net income per share – diluted	$	0.49		$	0.22
	Net income per share – basic:
	Income from continuing operations available to Common Shares, net of Noncontrolling Interests	$	0.492		$	0.214
	Discontinued operations, net of Noncontrolling Interests	0.001			0.003
	Net income per share – basic	$	0.493		$	0.217
	Net income per share – diluted:
	Income from continuing operations available to Common Shares	$	0.488		$	0.213
	Discontinued operations, net	0.001			0.003
	Net income per share – diluted	$	0.489		$	0.216
OPERATING PARTNERSHIP
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,
		2015			2014
	Numerator for net income per Unit – basic and diluted:
	Income from continuing operations	$	190,020		$	81,680
	Net (income) attributable to Noncontrolling Interests – Partially Owned Properties	(643		)	(504		)
	Allocation to Preference Units	(891		)	(1,036		)
	Allocation to premium on redemption of Preference Units	(2,789		)	—
	Income from continuing operations available to Units	185,697			80,140
	Discontinued operations, net	204			1,052
	Numerator for net income per Unit – basic and diluted	$	185,901		$	81,192
	Denominator for net income per Unit – basic and diluted:
	Denominator for net income per Unit – basic	376,696			374,201
	Effect of dilutive securities:
	Dilution for Units issuable upon assumed exercise/vesting of the Company’s long-term	3,631			2,183
	compensation shares/units
	Denominator for net income per Unit – diluted	380,327			376,384
	Net income per Unit – basic	$	0.49		$	0.22
	Net income per Unit – diluted	$	0.49		$	0.22
	Net income per Unit – basic:
	Income from continuing operations available to Units	$	0.492		$	0.214
	Discontinued operations, net	0.001			0.003
	Net income per Unit – basic	$	0.493		$	0.217
	Net income per Unit – diluted:
	Income from continuing operations available to Units	$	0.488		$	0.213
	Discontinued operations, net	0.001			0.003
	Net income per Unit – diluted	$	0.489		$	0.216

Discontinued_Operations_Tables

Discontinued Operations (Tables)	3 Months Ended
	Mar. 31, 2015
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 for properties sold in 2013 and prior years during each of the quarters ended March 31, 2015 and 2014 (amounts in thousands).
			Quarter Ended March 31,
			2015			2014
	REVENUES
	Rental income		$	161		$	1,023
	Total revenues		161			1,023
	EXPENSES (1)
	Property and maintenance		(67		)	48
	Real estate taxes and insurance		52			13
	General and administrative		6			5
	Total expenses		(9		)	66
	Discontinued operating income		170			957
	Interest and other income		49			35
	Income and other tax (expense) benefit		(15		)	(11		)
	Discontinued operations		204			981
	Net gain on sales of discontinued operations		—			71
	Discontinued operations, net		$	204		$	1,052
	-1	Includes expenses paid in the current period for properties sold in prior periods related to the Company’s period of ownership.

Reportable_Segments_Tables

Reportable Segments (Tables)	3 Months Ended
	Mar. 31, 2015
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, 2015 and 2014, respectively, as well as total assets and capital expenditures at March 31, 2015 (amounts in thousands):
			Quarter Ended March 31, 2015									Quarter Ended March 31, 2014
			Rental Income			Operating Expenses			NOI			Rental Income		Operating Expenses		NOI
	Same store (1)
	Boston		$	64,033		$	22,541		$	41,492		$	61,907	$	22,129	$	39,778
	Denver		28,997			7,460			21,537			26,612		7,461		19,151
	New York		116,070			46,113			69,957			111,186		45,834		65,352
	San Francisco		89,850			27,103			62,747			81,261		26,609		54,652
	Seattle		40,390			12,667			27,723			37,621		12,734		24,887
	South Florida		49,302			17,968			31,334			46,896		17,525		29,371
	Southern California		105,193			34,126			71,067			99,776		33,545		66,231
	Washington D.C.		112,627			38,539			74,088			111,804		37,809		73,995
	Non-core		25,572			10,027			15,545			24,731		9,814		14,917
	Total same store		632,034			216,544			415,490			601,794		213,460		388,334
	Non-same store/other (2) (3)
	Boston		922			229			693			1,028		210		818
	Seattle		4,579			1,298			3,281			107		146		(39		)
	South Florida		1,932			675			1,257			803		454		349
	Southern California		17,777			6,528			11,249			8,905		3,690		5,215
	Washington D.C.		5,408			1,653			3,755			3,507		1,441		2,066
	Other (3)		1,954			5,509			(3,555		)	14,581		10,377		4,204
	Total non-same store/other		32,572			15,892			16,680			28,931		16,318		12,613
	Total		$	664,606		$	232,436		$	432,170		$	630,725	$	229,778	$	400,947
	-1	Same store primarily includes all properties acquired or completed and stabilized prior to January 1, 2014, less properties subsequently sold, which represented 97,586 apartment units.
	-2	Non-same store primarily includes properties acquired after January 1, 2014, plus any properties in lease-up and not stabilized as of January 1, 2014.
	-3	Other includes development, other corporate operations and operations prior to sale for properties sold in 2014 and 2015 that do not meet the new discontinued operations criteria.
			Quarter Ended March 31, 2015
			Total Assets			Capital Expenditures
	Same store (1)
	Boston		$	1,908,859		$	3,505
	Denver		514,958			1,120
	New York		4,637,217			3,797
	San Francisco		2,700,366			5,638
	Seattle		1,088,728			3,524
	South Florida		1,126,085			2,942
	Southern California		2,787,871			6,020
	Washington D.C.		4,250,738			7,113
	Non-core		405,017			1,649
	Total same store		19,419,839			35,308
	Non-same store/other (2) (3)
	Boston		47,996			34
	Seattle		231,258			466
	South Florida		66,906			14
	Southern California		845,902			1,163
	Washington D.C.		242,360			1,143
	Other (3)		2,174,787			42
	Total non-same store/other		3,609,209			2,862
	Total		$	23,029,048		$	38,170
	-1	Same store primarily includes all properties acquired or completed and stabilized prior to January 1, 2014, less properties subsequently sold, which represented 97,586 apartment units.
	-2	Non-same store primarily includes properties acquired after January 1, 2014, plus any properties in lease-up and not stabilized as of January 1, 2014.
	-3	Other includes development, other corporate operations and capital expenditures for properties sold.
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, 2015 and 2014, respectively (amounts in thousands):
			Quarter Ended March 31,
			2015			2014
	Rental income		$	664,606		$	630,725
	Property and maintenance expense		(124,560		)	(125,566		)
	Real estate taxes and insurance expense		(86,432		)	(82,094		)
	Property management expense		(21,444		)	(22,118		)
	Total operating expenses		(232,436		)	(229,778		)
	Net operating income		$	432,170		$	400,947

Business_Details

Business (Details)	Mar. 31, 2015
Noncontrolling Interest, Ownership Percentage by Parent	96.20%
Number of Real Estate Properties	389
Number of States in which Entity Operates	12
Number of Units in Real Estate Property	108,793
Consolidated Properties [Member]
Number of Real Estate Properties	362
Number of Units in Real Estate Property	97,825
Master-Leased Properties [Member]
Number of Real Estate Properties	3
Number of Units in Real Estate Property	853
Partially Owned Properties [Member]
Number of Real Estate Properties	19
Number of Units in Real Estate Property	3,771
Unconsolidated Properties [Member]
Number of Real Estate Properties	3
Number of Units in Real Estate Property	1,281
Military Housing [Member]
Number of Real Estate Properties	2
Number of Units in Real Estate Property	5,063

Summary_of_Significant_Account2

Summary of Significant Accounting Policies (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
Number of Real Estate Properties	389
Number of Units in Real Estate Property	108,793
Noncontrolling Interests - Partially Owned Properties	$122,661,000	$124,909,000
Partially Owned Properties [Member]
Number of Real Estate Properties	19
Number of Units in Real Estate Property	3,771
Limited Life Partnership Properties [Member]
Number of Real Estate Properties	6
Noncontrolling Interests - Partially Owned Properties	10,992,000
Noncontrolling Interests Settlement Value	$63,300,000

Equity_Capital_and_Other_Inter2

Equity, Capital and Other Interests EQR Common Shares (Details)	3 Months Ended
	Mar. 31, 2015	Dec. 31, 2014
Common Shares of beneficial interest, shares outstanding	363,968,420	362,855,454
Common Shares Issued:
Conversion of OP Units	154,050
Exercise of share options	770,012
Employee Share Purchase Plan (ESPP)	30,151
Restricted Share Grants, net	158,753
Units
Common Shares And Units Outstanding	378,446,365
Units Ownership Interest in Operating Partnership	3.80%
Limited Partner [Member]
Limited Partners' Capital Account, Units Outstanding	14,477,945	14,298,691
Common Shares Issued:
Conversion of OP Units	-154,050
Units
Restricted units, net	333,304

Equity_Capital_and_Other_Inter3

Equity, Capital and Other Interests Redeemable (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Redeemable Noncontrolling Interests Operating Partnership	$541,866	$500,733
Change in market value of Redeemable Noncontrolling Interests - Operating Partnership	41,763
Change in carrying value	-630
OPERATING PARTNERSHIP
Limited Partners Change In Redemption Value	41,763
Limited Partners Change In Carrying Value	-630
Redeemable Limited Partners	$541,866	$500,733

Equity_Capital_and_Other_Inter4

Equity, Capital and Other Interests Preferred (Details) (USD $)	3 Months Ended		12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Class of Stock [Line Items]
Preferred Shares of beneficial interest, $0.01 par value; 100,000,000 shares authorized; 803,600 shares issued and outstanding as of March 31, 2015 and 1,000,000 shares issued and outstanding as of December 31, 2014	$40,180,000		$50,000,000
Partial redemption of 8.29% Series K Cumulative Redeemable	9,820,000	0
Redemption Premium	2,789,000	0
OPERATING PARTNERSHIP
Class of Stock [Line Items]
Partial redemption of 8.29% Series K Cumulative Redeemable	9,820,000	0
Redemption Premium	-2,789,000	0
Preferred Units	40,180,000		50,000,000
Series K Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Stock Preference Units Dividend Rate Percentage	8.29%		8.29%
Preferred Stock Preference Units Redemption Price Per Share Unit	$50		$50
Preferred Stock Preference Units Issued	803,600		1,000,000
Preferred Stock Preference Units Outstanding	803,600		1,000,000
Preferred Stocks Preference Units Redemption Date	10-Dec-26
Annual Dividend Per Preferred Share Preference Unit	$4.14
Preferred Shares of beneficial interest, $0.01 par value; 100,000,000 shares authorized; 803,600 shares issued and outstanding as of March 31, 2015 and 1,000,000 shares issued and outstanding as of December 31, 2014	40,180,000		50,000,000
Preferred Stock Preference Units Repurchased and Retired	196,400
Partial redemption of 8.29% Series K Cumulative Redeemable	9,820,000
Payments For Repurchase Of Preference Units	12,700,000
Redemption Premium	2,789,000
Series K Preferred Stock [Member] | OPERATING PARTNERSHIP
Class of Stock [Line Items]
Preferred Stock Preference Units Dividend Rate Percentage	8.29%		8.29%
Preferred Stock Preference Units Redemption Price Per Share Unit	$50		$50
Preferred Stock Preference Units Issued	803,600		1,000,000
Preferred Stock Preference Units Outstanding	803,600		1,000,000
Preferred Stocks Preference Units Redemption Date	10-Dec-26
Annual Dividend Per Preferred Share Preference Unit	$4.14
Preferred Units	$40,180,000		$50,000,000

Equity_Capital_and_Other_Inter5

Equity, Capital and Other Interests ERP Units (Details)	3 Months Ended
	Mar. 31, 2015	Dec. 31, 2014
Capital Unit [Line Items]
Common Shares And Units Outstanding	378,446,365
Exercise of EQR share options	770,012
EQR's Employee Share Purchase Plan (ESPP)	30,151
Restricted Share Grants, net	158,753
Shares Issued During Period Shares Conversion Of Units To Common Shares	154,050
Units Ownership Interest in Operating Partnership	3.80%
Limited Partner [Member]
Capital Unit [Line Items]
Limited Partners' Capital Account, Units Outstanding	14,477,945	14,298,691
Restricted units, net	333,304
Shares Issued During Period Shares Conversion Of Units To Common Shares	-154,050
General And Limited Partner [Member]
Capital Unit [Line Items]
Common Shares And Units Outstanding	378,446,365	377,154,145
Exercise of EQR share options	770,012
EQR's Employee Share Purchase Plan (ESPP)	30,151
Restricted Share Grants, net	158,753
Restricted units, net	333,304

Equity_Capital_and_Other_Inter6

Equity, Capital and Other Interests Text (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
Preferred Stock, Shares Authorized	100,000,000	100,000,000
Preferred Stock, Par or Stated Value Per Share	$0.01	$0.01
Additional Common Shares Authorized	13,000,000
Stock Repurchase Program, Number of Shares Authorized to be Repurchased	13,000,000
Stock Repurchase Program, Remaining Number of Shares Authorized to be Repurchased	12,968,760

Real_Estate_Details

Real Estate (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Land	$6,357,580		$6,295,404
Property, Plant and Equipment, Gross [Abstract]
Investment Building and Building Improvements	18,109,892		17,974,337
Fixtures and Equipment, Gross	1,401,801		1,365,276
Finite-Lived Intangible Asset, Acquired-in-Place Leases	512,804		511,891
Projects under development -CIP	1,269,784		1,343,919
Land Available for Development	143,997		184,556
Investment in real estate	27,795,858		27,675,383
Real Estate Investment Property, Accumulated Depreciation	-5,600,485		-5,432,805
Investment in real estate, net	22,195,373		22,242,578
Finite-Lived Intangible Assets, Gross	179,511		179,511
Amortization of Intangible Assets	-10,050		-8,913
Lease Intangible Assets, Net	169,461		170,598
Lease Intangible Liabilities	7,670		7,670
Amortization Of Intangible Liabilities	-2,549		-2,258
Lease Intangible Liabilities, net	5,121		5,412
Amortization of above/below market leases	846	829
Weighted Average Ground Lease Amortization Period	49.8
Weighted Average Retail Lease Amortization Period	2.8
Finite-Lived Intangible Assets, Amortization Expense, Remainder of Fiscal Year	2,536
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months	3,425
Finite-Lived Intangible Assets, Amortization Expense, Year Two	3,781
Finite-Lived Intangible Assets, Amortization Expense, Year Three	4,250
Finite-Lived Intangible Assets, Amortization Expense, Year Four	4,250
Finite-Lived Intangible Assets, Amortization Expense, Year Five	4,250
Retail Site [Member]
Property, Plant and Equipment, Gross [Abstract]
Amortization of above/below market leases	200	300
Finite-Lived Intangible Assets, Amortization Expense, Remainder of Fiscal Year	-705
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months	-896
Finite-Lived Intangible Assets, Amortization Expense, Year Two	-540
Finite-Lived Intangible Assets, Amortization Expense, Year Three	-71
Finite-Lived Intangible Assets, Amortization Expense, Year Four	-71
Finite-Lived Intangible Assets, Amortization Expense, Year Five	-71
Assets [Member]
Property, Plant and Equipment, Gross [Abstract]
Below Market Lease, Gross	178,251		178,251
Finite-Lived Intangible Asset, Off-market Lease, Favorable, Gross	1,260		1,260
Liability [Member]
Property, Plant and Equipment, Gross [Abstract]
Below Market Lease, Gross	5,270		5,270
Off-market Lease, Unfavorable	2,400		2,400
Ground Lease [Member]
Property, Plant and Equipment, Gross [Abstract]
Amortization of above/below market leases	1,100	1,100
Finite-Lived Intangible Assets, Amortization Expense, Remainder of Fiscal Year	3,241
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months	4,321
Finite-Lived Intangible Assets, Amortization Expense, Year Two	4,321
Finite-Lived Intangible Assets, Amortization Expense, Year Three	4,321
Finite-Lived Intangible Assets, Amortization Expense, Year Four	4,321
Finite-Lived Intangible Assets, Amortization Expense, Year Five	4,321
Projects under development [Member]
Property, Plant and Equipment, Gross [Abstract]
Projects under development - Land	423,359		466,764
Projects under development -CIP	846,425		877,155
Land held for development [Member]
Property, Plant and Equipment, Gross [Abstract]
Projects under development -CIP	34,271		39,190
Land Available for Development	$109,726		$145,366

Real_Estate_Details_2

Real Estate (Details 2) (USD $)	1 Months Ended	3 Months Ended
In Thousands, unless otherwise specified	Apr. 30, 2015	Mar. 31, 2015	Mar. 31, 2014
Properties acquired	1	0
Property Units Acquired	202	0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	$130,300	$5,968
Disposed Properties	1	3
Disposed Units	314	550
Proceeds From Sale Of Property	49,600	145,400
Net gain on sales of real estate properties		79,951	0
Consolidated Rental Properties [Member]
Disposed Properties		3
Disposed Units		550
Proceeds From Sale Of Property		145,400
Land [Member]
Land parcels acquired		1
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets		$5,968

Commitments_to_AcquireDispose_2

Commitments to Acquire/Dispose of Real Estate (Details) (USD $)	Apr. 30, 2015
In Thousands, unless otherwise specified
Commitments to Acquire Real Estate
Properties Acquired-Total	0
Rental Units Acquired - Total	0
Purchase Price - Total	$25,132
Commitments to Dispose of Real Estate
Properties Disposed - Total	2
Rental Units Disposed-Total	513
Sales Price For Commitments To Dispose	71,350
Rental Properties Disposed of [Member]
Commitments to Dispose of Real Estate
Properties Disposed - Total	2
Rental Units Disposed-Total	513
Sales Price For Commitments To Dispose	68,650
Land [Member]
Commitments to Dispose of Real Estate
Sales Price For Commitments To Dispose	2,700
Land Parcels Contracted To Be Disposed	1
Land [Member]
Commitments to Acquire Real Estate
Purchase Price - Total	$25,132
Land Parcels Contracted To Be Acquired	3

Investments_in_Partially_Owned2

Investments in Partially Owned Entities (Details) (USD $)	3 Months Ended		25 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2015	Apr. 30, 2015	Dec. 31, 2014	Dec. 31, 2013
Investments In Partially Owned Entities (Textuals) [Abstract]
Joint Venture Partner Ownership Percentage	80.00%		80.00%
Investments in unconsolidated entities	$89,284,000		$89,284,000		$105,434,000
Equity Method Investment, Ownership Percentage	20.00%		20.00%
Secured Debt	4,957,876,000		4,957,876,000		5,086,515,000
Debt Instrument, Interest Rate, Stated Percentage				6.58%
Debt Instrument, Maturity Date	1-May-61
Number of Joint Ventures	2		2
Partners Payments To Acquire Equity Method Investments	40,100,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	5,968,000		5,968,000	130,300,000
Investment in Joint Venture	339,400,000		339,400,000
Noncontrolling Interests - Partially Owned Properties/Partners' equity	122,661,000		122,661,000		124,909,000
Distributions from unconsolidated entities - return of capital	18,969,000	7,680,000
Partially Owned Property Balance Sheet Schedule
Number of Real Estate Properties	389		389
Number of Units in Real Estate Property	108,793		108,793
ASSETS
Investment in real estate	27,795,858,000		27,795,858,000		27,675,383,000
Real Estate Investment Property, Accumulated Depreciation	-5,600,485,000		-5,600,485,000		-5,432,805,000
Investment in real estate, net	22,195,373,000		22,195,373,000		22,242,578,000
Cash and cash equivalents	49,418,000	37,209,000	49,418,000		40,080,000	53,534,000
Investments in unconsolidated entities	89,284,000		89,284,000		105,434,000
Deposits - restricted	203,800,000		203,800,000		72,303,000
Deferred financing costs, net	55,791,000		55,791,000		58,380,000
Other Assets	384,723,000		384,723,000		383,754,000
Total assets	23,029,048,000		23,029,048,000		22,950,614,000
LIABILITIES AND EQUITY
Secured Debt	4,957,876,000		4,957,876,000		5,086,515,000
Accounts Payable And Accrued Liabilities Current And Noncurrent Other Than Interest And Dividend Payable	202,110,000		202,110,000		153,590,000
Accrued interest payable	84,670,000		84,670,000		89,540,000
Other liabilities	383,057,000		383,057,000		389,915,000
Security deposits	75,294,000		75,294,000		75,633,000
Total liabilities	11,813,593,000		11,813,593,000		11,742,105,000
Noncontrolling Interests - Partially Owned Properties/Partners' equity	122,661,000		122,661,000		124,909,000
Total liabilities and equity	23,029,048,000		23,029,048,000		22,950,614,000
Partially Owned Property Income Statement Schedule
Operating revenue	666,371,000	633,442,000
Depreciation	194,521,000	185,167,000
General and administrative/other	19,922,000	17,576,000
Operating Income	218,171,000	199,259,000
Interest and other income	120,000	605,000
Interest:
Expense incurred, net	108,622,000	113,049,000
Amortization of deferred financing costs	-2,589,000	-2,792,000
Income before income and other taxes, income (loss) from investments in unconsolidated entities, net gain (loss) on sales of real estate properties and land parcels and discontinued operations	107,150,000	83,359,000
Income and other tax (expense) benefit	-43,000	-240,000
Income (loss) from investments in unconsolidated entities	2,963,000	-1,409,000
Net income	190,224,000	82,732,000
Consolidated Development Projects Held for and or Under Development [Member]
Investments In Partially Owned Entities (Textuals) [Abstract]
Investments in unconsolidated entities	0		0
Secured Debt	0		0
Noncontrolling Interests - Partially Owned Properties/Partners' equity	117,350,000		117,350,000
Partially Owned Property Balance Sheet Schedule
Number of Real Estate Properties	0		0
Number of Units in Real Estate Property	0		0
ASSETS
Investment in real estate	347,809,000		347,809,000
Real Estate Investment Property, Accumulated Depreciation	-991,000		-991,000
Investment in real estate, net	346,818,000		346,818,000
Cash and cash equivalents	0		0
Investments in unconsolidated entities	0		0
Deposits - restricted	15,640,000		15,640,000
Deferred financing costs, net	0		0
Other Assets	6,697,000		6,697,000
Total assets	369,155,000		369,155,000
LIABILITIES AND EQUITY
Secured Debt	0		0
Accounts Payable And Accrued Liabilities Current And Noncurrent Other Than Interest And Dividend Payable	8,731,000		8,731,000
Accrued interest payable	0		0
Other liabilities	257,000		257,000
Security deposits	150,000		150,000
Total liabilities	9,138,000		9,138,000
Noncontrolling Interests - Partially Owned Properties/Partners' equity	117,350,000		117,350,000
Company equity/General and Limited Partners' Capital	242,667,000		242,667,000
Total equity/capital	360,017,000		360,017,000
Total liabilities and equity	369,155,000		369,155,000
Partially Owned Property Income Statement Schedule
Operating revenue	250,000
Operating expenses	418,000
Net operating (loss) income	-168,000
Depreciation	991,000
General and administrative/other	0
Operating Income	-1,159,000
Interest and other income	0
Other expenses	0
Interest:
Expense incurred, net	0
Amortization of deferred financing costs	0
Income before income and other taxes, income (loss) from investments in unconsolidated entities, net gain (loss) on sales of real estate properties and land parcels and discontinued operations	-1,159,000
Income and other tax (expense) benefit	0
Income (loss) from investments in unconsolidated entities	0
Net income	-1,159,000
Consolidated Operating [Domain]
Investments In Partially Owned Entities (Textuals) [Abstract]
Investments in unconsolidated entities	51,363,000		51,363,000
Secured Debt	360,567,000		360,567,000
Noncontrolling Interests - Partially Owned Properties/Partners' equity	5,311,000		5,311,000
Partially Owned Property Balance Sheet Schedule
Number of Real Estate Properties	19		19
Number of Units in Real Estate Property	3,771		3,771
ASSETS
Investment in real estate	684,686,000		684,686,000
Real Estate Investment Property, Accumulated Depreciation	-200,002,000		-200,002,000
Investment in real estate, net	484,684,000		484,684,000
Cash and cash equivalents	13,775,000		13,775,000
Investments in unconsolidated entities	51,363,000		51,363,000
Deposits - restricted	310,000		310,000
Deferred financing costs, net	2,052,000		2,052,000
Other Assets	26,227,000		26,227,000
Total assets	578,411,000		578,411,000
LIABILITIES AND EQUITY
Secured Debt	360,567,000		360,567,000
Accounts Payable And Accrued Liabilities Current And Noncurrent Other Than Interest And Dividend Payable	3,188,000		3,188,000
Accrued interest payable	1,283,000		1,283,000
Other liabilities	576,000		576,000
Security deposits	1,976,000		1,976,000
Total liabilities	367,590,000		367,590,000
Noncontrolling Interests - Partially Owned Properties/Partners' equity	5,311,000		5,311,000
Company equity/General and Limited Partners' Capital	205,510,000		205,510,000
Total equity/capital	210,821,000		210,821,000
Total liabilities and equity	578,411,000		578,411,000
Partially Owned Property Income Statement Schedule
Operating revenue	22,688,000
Operating expenses	6,875,000
Net operating (loss) income	15,813,000
Depreciation	5,520,000
General and administrative/other	15,000
Operating Income	10,278,000
Interest and other income	4,000
Other expenses	-50,000
Interest:
Expense incurred, net	-3,884,000
Amortization of deferred financing costs	-89,000
Income before income and other taxes, income (loss) from investments in unconsolidated entities, net gain (loss) on sales of real estate properties and land parcels and discontinued operations	6,259,000
Income and other tax (expense) benefit	-35,000
Income (loss) from investments in unconsolidated entities	-377,000
Net income	5,847,000
Consolidated Total [Domain]
Investments In Partially Owned Entities (Textuals) [Abstract]
Investments in unconsolidated entities	51,363,000		51,363,000
Secured Debt	360,567,000		360,567,000
Noncontrolling Interests - Partially Owned Properties/Partners' equity	122,661,000		122,661,000
Partially Owned Property Balance Sheet Schedule
Number of Real Estate Properties	19		19
Number of Units in Real Estate Property	3,771		3,771
ASSETS
Investment in real estate	1,032,495,000		1,032,495,000
Real Estate Investment Property, Accumulated Depreciation	-200,993,000		-200,993,000
Investment in real estate, net	831,502,000		831,502,000
Cash and cash equivalents	13,775,000		13,775,000
Investments in unconsolidated entities	51,363,000		51,363,000
Deposits - restricted	15,950,000		15,950,000
Deferred financing costs, net	2,052,000		2,052,000
Other Assets	32,924,000		32,924,000
Total assets	947,566,000		947,566,000
LIABILITIES AND EQUITY
Secured Debt	360,567,000		360,567,000
Accounts Payable And Accrued Liabilities Current And Noncurrent Other Than Interest And Dividend Payable	11,919,000		11,919,000
Accrued interest payable	1,283,000		1,283,000
Other liabilities	833,000		833,000
Security deposits	2,126,000		2,126,000
Total liabilities	376,728,000		376,728,000
Noncontrolling Interests - Partially Owned Properties/Partners' equity	122,661,000		122,661,000
Company equity/General and Limited Partners' Capital	448,177,000		448,177,000
Total equity/capital	570,838,000		570,838,000
Total liabilities and equity	947,566,000		947,566,000
Partially Owned Property Income Statement Schedule
Operating revenue	22,938,000
Operating expenses	7,293,000
Net operating (loss) income	15,645,000
Depreciation	6,511,000
General and administrative/other	15,000
Operating Income	9,119,000
Interest and other income	4,000
Other expenses	-50,000
Interest:
Expense incurred, net	-3,884,000
Amortization of deferred financing costs	-89,000
Income before income and other taxes, income (loss) from investments in unconsolidated entities, net gain (loss) on sales of real estate properties and land parcels and discontinued operations	5,100,000
Income and other tax (expense) benefit	-35,000
Income (loss) from investments in unconsolidated entities	-377,000
Net income	4,688,000
Unconsolidated Operating [Domain]
Investments In Partially Owned Entities (Textuals) [Abstract]
Investments in unconsolidated entities	0		0
Secured Debt	175,276,000		175,276,000
Noncontrolling Interests - Partially Owned Properties/Partners' equity	90,878,000		90,878,000
Partially Owned Property Balance Sheet Schedule
Number of Real Estate Properties	3		3
Number of Units in Real Estate Property	1,281		1,281
ASSETS
Investment in real estate	290,077,000		290,077,000
Real Estate Investment Property, Accumulated Depreciation	-21,388,000		-21,388,000
Investment in real estate, net	268,689,000		268,689,000
Cash and cash equivalents	7,598,000		7,598,000
Investments in unconsolidated entities	0		0
Deposits - restricted	246,000		246,000
Deferred financing costs, net	7,000		7,000
Other Assets	1,327,000		1,327,000
Total assets	277,867,000		277,867,000
LIABILITIES AND EQUITY
Secured Debt	175,276,000		175,276,000
Accounts Payable And Accrued Liabilities Current And Noncurrent Other Than Interest And Dividend Payable	389,000		389,000
Accrued interest payable	691,000		691,000
Other liabilities	834,000		834,000
Security deposits	531,000		531,000
Total liabilities	177,721,000		177,721,000
Noncontrolling Interests - Partially Owned Properties/Partners' equity	90,878,000		90,878,000
Company equity/General and Limited Partners' Capital	9,268,000		9,268,000
Total equity/capital	100,146,000		100,146,000
Total liabilities and equity	277,867,000		277,867,000
Partially Owned Property Income Statement Schedule
Operating revenue	7,813,000
Operating expenses	2,443,000
Net operating (loss) income	5,370,000
Depreciation	3,076,000
General and administrative/other	56,000
Operating Income	2,238,000
Interest and other income	0
Other expenses	0
Interest:
Expense incurred, net	-2,346,000
Amortization of deferred financing costs	-1,000
Income before income and other taxes, income (loss) from investments in unconsolidated entities, net gain (loss) on sales of real estate properties and land parcels and discontinued operations	-109,000
Income and other tax (expense) benefit	-18,000
Income (loss) from investments in unconsolidated entities	0
Net income	-127,000
Unconsolidated Total [Domain]
Investments In Partially Owned Entities (Textuals) [Abstract]
Investments in unconsolidated entities	0		0
Secured Debt	175,276,000		175,276,000
Noncontrolling Interests - Partially Owned Properties/Partners' equity	90,878,000		90,878,000
Partially Owned Property Balance Sheet Schedule
Number of Real Estate Properties	3		3
Number of Units in Real Estate Property	1,281		1,281
ASSETS
Investment in real estate	290,077,000		290,077,000
Real Estate Investment Property, Accumulated Depreciation	-21,388,000		-21,388,000
Investment in real estate, net	268,689,000		268,689,000
Cash and cash equivalents	7,598,000		7,598,000
Investments in unconsolidated entities	0		0
Deposits - restricted	246,000		246,000
Deferred financing costs, net	7,000		7,000
Other Assets	1,327,000		1,327,000
Total assets	277,867,000		277,867,000
LIABILITIES AND EQUITY
Secured Debt	175,276,000		175,276,000
Accounts Payable And Accrued Liabilities Current And Noncurrent Other Than Interest And Dividend Payable	389,000		389,000
Accrued interest payable	691,000		691,000
Other liabilities	834,000		834,000
Security deposits	531,000		531,000
Total liabilities	177,721,000		177,721,000
Noncontrolling Interests - Partially Owned Properties/Partners' equity	90,878,000		90,878,000
Company equity/General and Limited Partners' Capital	9,268,000		9,268,000
Total equity/capital	100,146,000		100,146,000
Total liabilities and equity	277,867,000		277,867,000
Partially Owned Property Income Statement Schedule
Operating revenue	7,813,000
Operating expenses	2,443,000
Net operating (loss) income	5,370,000
Depreciation	3,076,000
General and administrative/other	56,000
Operating Income	2,238,000
Interest and other income	0
Other expenses	0
Interest:
Expense incurred, net	-2,346,000
Amortization of deferred financing costs	-1,000
Income before income and other taxes, income (loss) from investments in unconsolidated entities, net gain (loss) on sales of real estate properties and land parcels and discontinued operations	-109,000
Income and other tax (expense) benefit	-18,000
Income (loss) from investments in unconsolidated entities	0
Net income	-127,000
Archstone Transaction [Member]
Investments In Partially Owned Entities (Textuals) [Abstract]
Liquidation Value Preferred Interests	72,600,000		72,600,000
Germany [Domain]
Investments In Partially Owned Entities (Textuals) [Abstract]
Distributions from unconsolidated entities - return of capital	2,000,000		100,500,000
Residual JV [Domain]
Investments In Partially Owned Entities (Textuals) [Abstract]
Business Acquisition, Percentage of Voting Interests Acquired	60.00%		60.00%
Joint Venture Partner Ownership Percentage	40.00%		40.00%
Investments in unconsolidated entities	147,600,000		147,600,000
Distributions from unconsolidated entities - return of capital	19,000,000
ASSETS
Investments in unconsolidated entities	147,600,000		147,600,000
Residual JV [Domain] | Rental Properties Disposed of [Member]
Investments In Partially Owned Entities (Textuals) [Abstract]
Distributions from unconsolidated entities - return of capital	10,400,000
Residual JV [Domain] | Settled Litigation [Member]
Investments In Partially Owned Entities (Textuals) [Abstract]
Distributions from unconsolidated entities - return of capital	6,600,000
Wisconsin Place [Domain]
Investments In Partially Owned Entities (Textuals) [Abstract]
Business Acquisition, Percentage of Voting Interests Acquired	75.00%		75.00%
Initial Basis of Real Estate, Consolidated	198,500,000		198,500,000
Investments in unconsolidated entities	56,500,000		56,500,000
Partially Owned Property Balance Sheet Schedule
Number of Units in Real Estate Property	432		432
ASSETS
Investments in unconsolidated entities	56,500,000		56,500,000
Waterton Tenside [Domain]
Investments In Partially Owned Entities (Textuals) [Abstract]
Equity Method Investment, Ownership Percentage	20.00%		20.00%
Initial Basis of Real Estate, Unconsolidated	5,100,000		5,100,000
Secured Debt	29,800,000		29,800,000
Debt Instrument, Interest Rate, Stated Percentage	3.66%		3.66%
Debt Instrument, Maturity Date	1-Dec-18
Partially Owned Property Balance Sheet Schedule
Number of Units in Real Estate Property	336		336
LIABILITIES AND EQUITY
Secured Debt	29,800,000		29,800,000
Joint Venture Partner [Member]
Investments In Partially Owned Entities (Textuals) [Abstract]
Land purchase price	57,900,000		57,900,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	75,700,000		75,700,000
Noncontrolling Interests - Partially Owned Properties/Partners' equity	117,400,000		117,400,000
LIABILITIES AND EQUITY
Noncontrolling Interests - Partially Owned Properties/Partners' equity	117,400,000		117,400,000
Company's Portion [Member]
Investments In Partially Owned Entities (Textuals) [Abstract]
Land purchase price	76,100,000		76,100,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	102,500,000		102,500,000
Nexus Sawgrass [Member]
Investments In Partially Owned Entities (Textuals) [Abstract]
Secured Debt	48,600,000		48,600,000
Debt Instrument, Interest Rate, Stated Percentage	5.60%		5.60%
Debt Instrument, Maturity Date	1-Jan-21
Project Cost	78,600,000		78,600,000
Maximum Debt Commitment	48,700,000		48,700,000
LIABILITIES AND EQUITY
Secured Debt	48,600,000		48,600,000
Domain [Member]
Investments In Partially Owned Entities (Textuals) [Abstract]
Secured Debt	96,800,000		96,800,000
Debt Instrument, Interest Rate, Stated Percentage	5.75%		5.75%
Debt Instrument, Maturity Date	1-Jan-22
Project Cost	155,800,000		155,800,000
Maximum Debt Commitment	98,600,000		98,600,000
LIABILITIES AND EQUITY
Secured Debt	$96,800,000		$96,800,000

Deposits_Restricted_Details

Deposits - Restricted (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Restricted Cash and Cash Equivalents Items [Line Items]
Tax-deferred (1031) exchange proceeds	$136,602	$0
Earnest money on pending acquisitions	2,830	580
Restricted deposits on real estate investments	17,636	24,701
Resident security and utility deposits	46,225	46,516
Other Restricted Cash	507	506
Restricted Cash and Cash Equivalents	203,800	72,303
Escrow deposits for real estate taxes and insurance	2,691	2,235
Replacement reserve	3,490	3,431
Mortgage principal reserves/sinking funds	43,626	41,567
Escrow deposits - other	852	852
Escrow Deposits For Mortgage And Replacement Reserves	$50,659	$48,085

Debt_Mortgage_Notes_Payable_De

Debt Mortgage Notes Payable (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Mortgage notes payable	$4,957,876,000	$5,086,515,000
Repayments Of Long-term Debt	124,100,000
Write Off Of Unamortized Deferred Financing Costs	100,000
Write off unamortized premium discount	1,400,000
Debt Instrument, Maturity Date	1-May-61
Debt Instrument, Interest Rate, Stated Percentage Rate Range, Minimum	0.02%
Debt Instrument, Interest Rate, Stated Percentage Rate Range, Maximum	7.25%
Weighted Average Mortgage Debt Interest Rate	4.13%
Credit enhanced debt [Member]
Debt Instrument [Line Items]
Mortgage notes payable	$700,500,000

Debt_Notes_Details

Debt Notes (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Notes, net	$5,430,806	$5,425,346
Debt Instrument, Maturity Date Range, End	31-Dec-44
Debt Instrument, Interest Rate, Stated Percentage Rate Range, Minimum	0.02%
Debt Instrument, Interest Rate, Stated Percentage Rate Range, Maximum	7.25%
Notes Payable, Other Payables [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage Rate Range, Minimum	2.38%
Debt Instrument, Interest Rate, Stated Percentage Rate Range, Maximum	7.57%
Weighted Average Interest Rate	5.01%

Debt_Line_of_Credit_and_Commer

Debt Line of Credit and Commercial Paper (Details) (USD $)	3 Months Ended
	Mar. 31, 2015
Line of Credit Facility [Line Items]
Debt Instrument, Maturity Date	1-May-61
Commercial Paper	$340,900,000
Commercial paper, maximum borrowing capacity	500,000,000
Short-term Debt, Description	14 days
A 175 billion LOC [Member]
Line of Credit Facility [Line Items]
Unsecured revolving credit facility	1,750,000,000
A 250 billion LOC [Member]
Line of Credit Facility [Line Items]
Unsecured revolving credit facility	2,500,000,000
Debt Instrument, Maturity Date	1-Apr-18
500.0 million ability to increase	500,000,000
Line Of Credit Facility Commitment Fee	15 Basis Points
Remaining borrowing capacity	1,986,000,000
Amount restricted/dedicated to support letters of credit	43,300,000
Weighted Average Interest Rate Revolving Credit Facility	1.02%
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Line of credit	130,000,000
Commercial Paper [Member]
Line of Credit Facility [Line Items]
Long-term Debt	340,800,000
Debt Instrument, Unamortized Discount	$100,000
Weighted Average Interest Rate	0.53%
Line of Credit [Member] | London Interbank Offered Rate (LIBOR) [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Description of Variable Rate Basis	LIBOR plus 1.05%

Derivative_and_Other_Fair_Valu2

Derivative and Other Fair Value Instruments (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Apr. 30, 2015
Derivative [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		6.58%
Debt Instrument, Maturity Date	1-May-61
2.375% Notes [Member]
Derivative [Line Items]
Proceeds from Issuance of Unsecured Debt	450,000,000
Debt Instrument, Interest Rate, Stated Percentage	2.38%
Derivative, Variable Interest Rate	0.61%
Debt Instrument, Maturity Date	1-Jul-19
Fair Value Hedging [Member]
Derivative [Line Items]
Current Notional Balance	450,000,000
Lowest Possible Notional	450,000,000
Highest Possible Notional	450,000,000
Lowest Interest Rate	2.38%
Highest Interest Rate	2.38%
Earliest Maturity Date	P2019Y0M0D
Latest Maturity Date	P2019Y0M0D
Forward Starting Swaps [Member]
Derivative [Line Items]
Current Notional Balance	450,000,000
Lowest Possible Notional	450,000,000
Highest Possible Notional	450,000,000
Lowest Interest Rate	1.94%
Highest Interest Rate	3.19%
Earliest Maturity Date	P2025Y0M0D
Latest Maturity Date	P2025Y0M0D

Derivative_and_Other_Fair_Valu3

Derivative and Other Fair Value Instruments (Details 1) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Derivatives, Fair Value [Line Items]
Fair Value Of Serp Investments	$97,391	$104,463
Assets, Fair Value Disclosure	104,283	106,391
Derivative liability, fair value	26,014	14,104
Other Liabilities, Fair Value Disclosure	97,391	104,463
Liabilities, Fair Value Disclosure	123,405	118,567
Redeemable Noncontrolling Interest Operating Partnership Fair Value Disclosure	541,866	500,733
Fair Value, Inputs, Level 1 [Member]
Derivatives, Fair Value [Line Items]
Fair Value Of Serp Investments	97,391	104,463
Assets, Fair Value Disclosure	97,391	104,463
Derivative liability, fair value	0	0
Other Liabilities, Fair Value Disclosure	97,391	104,463
Liabilities, Fair Value Disclosure	97,391	104,463
Redeemable Noncontrolling Interest Operating Partnership Fair Value Disclosure	0	0
Fair Value, Inputs, Level 2 [Member]
Derivatives, Fair Value [Line Items]
Fair Value Of Serp Investments	0	0
Assets, Fair Value Disclosure	6,892	1,928
Derivative liability, fair value	26,014	14,104
Other Liabilities, Fair Value Disclosure	0	0
Liabilities, Fair Value Disclosure	26,014	14,104
Redeemable Noncontrolling Interest Operating Partnership Fair Value Disclosure	541,866	500,733
Fair Value, Inputs, Level 3 [Member]
Derivatives, Fair Value [Line Items]
Fair Value Of Serp Investments	0	0
Assets, Fair Value Disclosure	0	0
Derivative liability, fair value	0	0
Other Liabilities, Fair Value Disclosure	0	0
Liabilities, Fair Value Disclosure	0	0
Redeemable Noncontrolling Interest Operating Partnership Fair Value Disclosure	0	0
Fair Value Hedging [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset	6,438	1,596
Fair Value Hedging [Member] | Fair Value, Inputs, Level 1 [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset	0	0
Fair Value Hedging [Member] | Fair Value, Inputs, Level 2 [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset	6,438	1,596
Fair Value Hedging [Member] | Fair Value, Inputs, Level 3 [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset	0	0
Forward Starting Swaps [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset	454	332
Forward Starting Swaps [Member] | Fair Value, Inputs, Level 1 [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset	0	0
Forward Starting Swaps [Member] | Fair Value, Inputs, Level 2 [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset	454	332
Forward Starting Swaps [Member] | Fair Value, Inputs, Level 3 [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset	$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, 2015	Mar. 31, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Increase (Decrease) in Fair Value of Interest Rate Fair Value Hedging Instruments	$4,842	$0
Increase (Decrease) in Fair Value of Hedged Item in Interest Rate Fair Value Hedge	-4,842	0
Effective Portion - Amount of Gain/ (Loss) Recognized in OCI on Derivative	-11,788	-11,952
Effective Portion - Amount of Gain/ (Loss) Reclassified from Accumulated OCI into Income	-4,338	-4,129
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	4,842	0
Derivative, Description of Hedged Item	Fixed rate debt	N/A
Increase (Decrease) in Fair Value of Hedged Item in Interest Rate Fair Value Hedge	-4,842	0
Forward Starting Swaps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Effective Portion - Amount of Gain/ (Loss) Recognized in OCI on Derivative	-11,788	-11,952
Effective Portion - Amount of Gain/ (Loss) Reclassified from Accumulated OCI into Income	-4,338	-4,129
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, 2015	Dec. 31, 2014	Dec. 31, 2016
Derivative [Line Items]
Mortgage notes payable	$4,957,876,000	$5,086,515,000
Unrealized Gain (Loss) on Interest Rate Cash Flow Hedges, Pretax, Accumulated Other Comprehensive Income (Loss)	-179,700,000	-172,200,000
Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net			22,200,000
Unsecured Debt [Member]
Derivative [Line Items]
Unsecured Debt	5,900,000,000	5,800,000,000
Debt Instrument, Fair Value Disclosure	6,300,000,000	6,100,000,000
Secured Debt [Member]
Derivative [Line Items]
Debt Instrument, Fair Value Disclosure	$5,000,000,000	$5,100,000,000

Earnings_Per_Share_Details

Earnings Per Share (Details) (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Income from continuing operations	$190,020	$81,680
Allocation to Noncontrolling Interests - Operating Partnership, net	-7,051	-3,053
Net (income) attributable to Noncontrolling Interests - Partially Owned Properties	-643	-504
Preferred distributions	-891	-1,036
Premium on redemption of Preferred Shares	-2,789	0
Income from continuing operations available to Common Shares, net of Noncontrolling Interests	178,646	77,087
Discontinued operations, net of Noncontrolling Interests	196	1,012
Numerator for net income per share - basic	178,842	78,099
Income from continuing operations available to Common Shares	185,697	80,140
Discontinued operations, net	204	1,052
Numerator for net income per share - diluted	185,901	81,192
Denominator for net income per share - basic	363,098	360,470
Effect of dilutive securities - OP Units	13,598	13,731
Effect of dilutive securities - Long-term compensation shares/units	3,631	2,183
Denominator for net income per share - diluted	380,327	376,384
Net income per share - basic	$0.49	$0.22
Net income per share - diluted	$0.49	$0.22
Income from continuing operations available to Common Shares	$0.49	$0.21
Net income per share - basic - Discontinued operations, net of Noncontrolling Interests	$0.00	$0.00
Income from continuing operations available to Common Shares	$0.49	$0.21
Net income per share - diluted - discontinued operations, net	$0.00	$0.00
OPERATING PARTNERSHIP
Income from continuing operations	190,020	81,680
Net (income) attributable to Noncontrolling Interests - Partially Owned Properties	-643	-504
Premium on redemption of Preferred Shares	-2,789	0
Discontinued operations, net	204	1,052
Effect of dilutive securities - Long-term compensation shares/units	3,631	2,183
Net income per share - basic	$0.49	$0.22
Net income per share - diluted	$0.49	$0.22
Income from continuing operations available to Common Shares	$0.49	$0.21
Income from continuing operations available to Common Shares	$0.49	$0.21
Dividend preference units	-891	-1,036
Income from continuing operations available to Units	185,697	80,140
Numerator for net income per Unit - basic and diluted	$185,901	$81,192
Denominator for net income per Unit - basic	376,696	374,201
Weighted Average Number Of Limited Partnership And General Partnership Unit Outstanding Diluted	380,327	376,384
Net income per Unit - basic - Discontinued operations, net	$0.00	$0.00
Net income per Unit - diluted - Discontinued operations, net	$0.00	$0.00

Discontinued_Operations_Detail

Discontinued Operations (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015		Mar. 31, 2014
REVENUES
Discontinued Operations - Rental income	$161		$1,023
Discontinued Operations - Total revenue	161		1,023
EXPENSES (1)
Discontinued Operations - Property and maintenance	-67	[1]	48	[1]
Discontinued Operations - Real estate taxes and insurance	52	[1]	13	[1]
Discontinued Operations - General and administrative	6	[1]	5	[1]
Discontinued Operations - Total expenses	-9	[1]	66	[1]
Discontinued operating income	170		957
Discontinued Operations - Interest and other income	49		35
Discontinued Operations - Income and other tax (expense) benefit	-15		-11
Income Loss From Discontinued Operations	204		981
Discontinued Operation - Net gain on sales of discontinued operations	0		71
Discontinued operations, net	$204		$1,052
[1]	Includes expenses paid in the current period for properties sold in prior periods related to the Companybs period of ownership.

Commitments_and_Contingencies_

Commitments and Contingencies (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Apr. 30, 2015	Dec. 31, 2014
300 properties designed and built in violation of accessibility requirements	300
Loss Contingency Accrual, Period Increase (Decrease)	$1,000,000
Loss Contingency Accrual	5,000,000
Projects in various stages of development	15
Units in various stages of development	5,273
Consolidated Project Under Development Commitment Fund	1,300,000,000
Various stages of development with estimated completion dates ranging through September 30, 2017	30-Sep-17
Number Of Unconsolidated Projects	2
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	5,968,000	130,300,000
Investment in Joint Venture	339,400,000
Noncontrolling Interests - Partially Owned Properties	122,661,000		124,909,000
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	$117,400,000

Reportable_Segments_Details

Reportable Segments (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Reportable Segments
Assets	$23,029,048		$22,950,614
Payments to Acquire Other Property, Plant, and Equipment	38,170
Rental income:
Total Rental Income	664,606	630,725
Operating expenses:
Total Operating Expenses	232,436	229,778
NOI:
Total NOI	432,170	400,947
Reportable Segments (Textuals) [Abstract]
Units in same store properties	97,586
Rental income	664,606	630,725
Property and maintenance expense	-124,560	-125,566
Real estate taxes and insurance expense	-86,432	-82,094
Property management expense	-21,444	-22,118
Total Operating Expenses	-232,436	-229,778
Non-same store [Domain]
Reportable Segments
Assets	3,609,209
Payments to Acquire Other Property, Plant, and Equipment	2,862
Same Store [Domain]
Rental income:
Same store - Rental Income	632,034	601,794
Operating expenses:
Same store - Operating Expenses	216,544	213,460
NOI:
Same store - NOI	415,490	388,334
Same Store [Domain] | Boston [Domain]
Reportable Segments
Assets	1,908,859
Payments to Acquire Other Property, Plant, and Equipment	3,505
Rental income:
Same store - Rental Income	64,033	61,907
Operating expenses:
Same store - Operating Expenses	22,541	22,129
NOI:
Same store - NOI	41,492	39,778
Same Store [Domain] | Denver [Domain]
Reportable Segments
Assets	514,958
Payments to Acquire Other Property, Plant, and Equipment	1,120
Rental income:
Same store - Rental Income	28,997	26,612
Operating expenses:
Same store - Operating Expenses	7,460	7,461
NOI:
Same store - NOI	21,537	19,151
Same Store [Domain] | New York [Domain]
Reportable Segments
Assets	4,637,217
Payments to Acquire Other Property, Plant, and Equipment	3,797
Rental income:
Same store - Rental Income	116,070	111,186
Operating expenses:
Same store - Operating Expenses	46,113	45,834
NOI:
Same store - NOI	69,957	65,352
Same Store [Domain] | San Francisco [Domain]
Reportable Segments
Assets	2,700,366
Payments to Acquire Other Property, Plant, and Equipment	5,638
Rental income:
Same store - Rental Income	89,850	81,261
Operating expenses:
Same store - Operating Expenses	27,103	26,609
NOI:
Same store - NOI	62,747	54,652
Same Store [Domain] | Seattle [Domain]
Reportable Segments
Assets	1,088,728
Payments to Acquire Other Property, Plant, and Equipment	3,524
Rental income:
Same store - Rental Income	40,390	37,621
Operating expenses:
Same store - Operating Expenses	12,667	12,734
NOI:
Same store - NOI	27,723	24,887
Same Store [Domain] | South Florida [Domain]
Reportable Segments
Assets	1,126,085
Payments to Acquire Other Property, Plant, and Equipment	2,942
Rental income:
Same store - Rental Income	49,302	46,896
Operating expenses:
Same store - Operating Expenses	17,968	17,525
NOI:
Same store - NOI	31,334	29,371
Same Store [Domain] | Southern California [Domain]
Reportable Segments
Assets	2,787,871
Payments to Acquire Other Property, Plant, and Equipment	6,020
Rental income:
Same store - Rental Income	105,193	99,776
Operating expenses:
Same store - Operating Expenses	34,126	33,545
NOI:
Same store - NOI	71,067	66,231
Same Store [Domain] | Washington DC [Domain]
Reportable Segments
Assets	4,250,738
Payments to Acquire Other Property, Plant, and Equipment	7,113
Rental income:
Same store - Rental Income	112,627	111,804
Operating expenses:
Same store - Operating Expenses	38,539	37,809
NOI:
Same store - NOI	74,088	73,995
Same Store [Domain] | Non-Core [Domain]
Reportable Segments
Assets	405,017
Payments to Acquire Other Property, Plant, and Equipment	1,649
Rental income:
Same store - Rental Income	25,572	24,731
Operating expenses:
Same store - Operating Expenses	10,027	9,814
NOI:
Same store - NOI	15,545	14,917
Same Store [Domain] | Same Store [Domain]
Reportable Segments
Assets	19,419,839
Payments to Acquire Other Property, Plant, and Equipment	35,308
Non-same store [Domain] | Boston [Domain]
Reportable Segments
Assets	47,996
Payments to Acquire Other Property, Plant, and Equipment	34
Rental income:
Non-same store - Rental Income	922	1,028
Operating expenses:
Non-same store - Operating Expenses	229	210
NOI:
Non-same store - NOI	693	818
Non-same store [Domain] | Seattle [Domain]
Reportable Segments
Assets	231,258
Payments to Acquire Other Property, Plant, and Equipment	466
Rental income:
Non-same store - Rental Income	4,579	107
Operating expenses:
Non-same store - Operating Expenses	1,298	146
NOI:
Non-same store - NOI	3,281	-39
Non-same store [Domain] | South Florida [Domain]
Reportable Segments
Assets	66,906
Payments to Acquire Other Property, Plant, and Equipment	14
Rental income:
Non-same store - Rental Income	1,932	803
Operating expenses:
Non-same store - Operating Expenses	675	454
NOI:
Non-same store - NOI	1,257	349
Non-same store [Domain] | Southern California [Domain]
Reportable Segments
Assets	845,902
Payments to Acquire Other Property, Plant, and Equipment	1,163
Rental income:
Non-same store - Rental Income	17,777	8,905
Operating expenses:
Non-same store - Operating Expenses	6,528	3,690
NOI:
Non-same store - NOI	11,249	5,215
Non-same store [Domain] | Washington DC [Domain]
Reportable Segments
Assets	242,360
Payments to Acquire Other Property, Plant, and Equipment	1,143
Rental income:
Non-same store - Rental Income	5,408	3,507
Operating expenses:
Non-same store - Operating Expenses	1,653	1,441
NOI:
Non-same store - NOI	3,755	2,066
Non-same store [Domain] | Other (3) [Domain]
Reportable Segments
Assets	2,174,787
Payments to Acquire Other Property, Plant, and Equipment	42
Rental income:
Non-same store - Rental Income	1,954	14,581
Operating expenses:
Non-same store - Operating Expenses	5,509	10,377
NOI:
Non-same store - NOI	-3,555	4,204
Non-same store [Domain] | Non-same store [Domain]
Rental income:
Non-same store - Rental Income	32,572	28,931
Operating expenses:
Non-same store - Operating Expenses	15,892	16,318
NOI:
Non-same store - NOI	$16,680	$12,613

Subsequent_EventsOther_Details

Subsequent Events/Other (Details) (USD $)	1 Months Ended	3 Months Ended
	Apr. 30, 2015	Mar. 31, 2015	Mar. 31, 2014
Subsequent Event [Line Items]
Properties acquired	1	0
Property Units Acquired	202	0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	$130,300,000	$5,968,000
Disposed Properties	1	3
Disposed Units	314	550
Proceeds From Sale Of Property	49,600,000	145,400,000
Repayments of Notes Payable	300,000,000
Debt Instrument, Interest Rate, Stated Percentage	6.58%
Business Combination, Acquisition Related Costs		100,000
Noncash Project Abandonment Costs		493,000	452,000
Other Expenses		600,000	500,000
Employee Benefits and Share-based Compensation		2,300,000
Owned Property Management Costs		21,444,000	22,118,000
General and administrative/other		19,922,000	17,576,000
Litigation Settlement, Amount			500,000
Consolidated Rental Properties [Member]
Subsequent Event [Line Items]
Disposed Properties		3
Disposed Units		550
Proceeds From Sale Of Property		145,400,000
Retail Site [Member]
Subsequent Event [Line Items]
Proceeds From Sale Of Property	123,300,000
Stock Compensation Plan [Member]
Subsequent Event [Line Items]
Owned Property Management Costs		300,000
General and administrative/other		$2,000,000