CONSOLIDATED STATEMENTS OF CASH FLOWS OF ERP OPERATING LIMITED PARTNERSHIP (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 694,298	$ 431,642
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	584,862	565,772
Amortization of deferred financing costs	7,734	8,554
Amortization of above/below market leases	2,534	2,376
Amortization of discounts and premiums on debt	(7,718)	(8,750)
Amortization of deferred settlements on derivative instruments	13,483	12,205
Write-off of pursuit costs	2,322	2,067
(Income) loss from investments in unconsolidated entities	(14,388)	10,201
Distributions from unconsolidated entities – return on capital	3,564	4,557
Net (gain) on sale of investment securities	(387)	(57)
Net (gain) on sales of real estate properties	(295,692)	(128,544)
Net loss (gain) on sales of land parcels	1	(1,846)
Net (gain) on sales of discontinued operations	0	(223)
Realized/unrealized loss (gain) on derivative instruments	3,055	(66)
Compensation paid with Company Common Shares	29,269	24,647
Changes in assets and liabilities:
(Increase) in deposits – restricted	(1,268)	(2,223)
Decrease in mortgage deposits	756	1,638
(Increase) decrease in other assets	(25,428)	3,854
Increase in accounts payable and accrued expenses	63,385	76,331
(Decrease) increase in accrued interest payable	(3,457)	8,163
Increase (decrease) in other liabilities	5,120	(173)
Increase in security deposits	1,301	4,146
Net cash provided by operating activities	1,063,346	1,014,271
CASH FLOWS FROM INVESTING ACTIVITIES:
Investment in real estate – acquisitions	(159,575)	(404,658)
Investment in real estate – development/other	(485,758)	(380,691)
Capital expenditures to real estate	(134,438)	(133,181)
Non-real estate capital additions	(2,384)	(2,446)
Interest capitalized for real estate and unconsolidated entities under development	(45,850)	(38,140)
Proceeds from disposition of real estate, net	457,499	224,538
Investments in unconsolidated entities	(22,998)	(14,568)
Distributions from unconsolidated entities – return of capital	45,245	77,042
Proceeds from sale of investment securities	387	57
(Increase) decrease in deposits on real estate acquisitions and investments, net	(62,433)	20,845
(Increase) decrease in mortgage deposits	(407)	560
Net cash (used for) investing activities	(410,712)	(650,642)
CASH FLOWS FROM FINANCING ACTIVITIES:
Debt financing costs	(6,355)	(10,598)
Mortgage deposits	(6,335)	(5,557)
Mortgage notes payable:
Lump sum payoffs	(177,564)	(63,772)
Scheduled principal repayments	(7,161)	(8,919)
Notes, net:
Proceeds	746,391	1,194,278
Lump sum payoffs	(300,000)	(1,250,000)
Line of credit and commercial paper:
Line of credit proceeds	3,569,000	5,324,000
Line of credit repayments	(3,902,000)	(4,993,000)
Commercial paper proceeds	2,491,848	0
Commercial paper repayments	(2,462,500)	0
(Payments on) settlement of derivative instruments	(13,938)	(758)
Proceeds from exercise of options	37,047	56,554
Partial redemption of 8.29% Series K Cumulative Redeemable	(9,820)	0
Premium on redemption of Preference Units	(2,789)	0
Payment of offering costs	(69)	0
Other financing activities, net	(33)	(33)
Acquisition of Noncontrolling Interests – Partially Owned Properties	0	(5,501)
Contributions – Noncontrolling Interests – Partially Owned Properties	0	5,684
Contributions – Limited Partners	3	3
Distributions:
Noncontrolling Interests – Partially Owned Properties	(5,356)	(6,762)
Net cash (used for) financing activities	(655,348)	(385,685)
Net (decrease) in cash and cash equivalents	(2,714)	(22,056)
Cash and cash equivalents, beginning of period	40,080	53,534
Cash and cash equivalents, end of period	37,366	31,478
SUPPLEMENTAL INFORMATION:
Cash paid for interest, net of amounts capitalized	328,400	335,646
Net cash paid for income and other taxes	1,052	866
Amortization of discounts and premiums on debt:
Mortgage notes payable	(10,261)	(10,515)
Notes, net	1,895	1,765
Line of credit and commercial paper	648	0
Amortization of deferred settlements on derivative instruments:
Other liabilities	(164)	(401)
Accumulated other comprehensive income	13,647	12,606
Write-off of pursuit costs:
Investment in real estate, net	1,929	1,965
Other assets	63	102
(Income) loss from investments in unconsolidated entities:
Investments in unconsolidated entities	(16,309)	7,684
Other liabilities	1,921	2,517
Distributions from unconsolidated entities – return on capital:
Investments in unconsolidated entities	3,462	4,399
Other liabilities	102	158
Realized/unrealized loss (gain) on derivative instruments:
Other assets	(9,677)	11,409
Notes, net	8,162	(2,485)
Other liabilities	2,774	12,794
Unrealized holding gains (losses) arising during the period	1,796	(21,784)
Interest capitalized for real estate and unconsolidated entities under development:
Investment in real estate, net	(45,850)	(38,086)
Investments in unconsolidated entities	0	(54)
Investments in unconsolidated entities:
Investments in unconsolidated entities	(1,383)	(5,118)
Other liabilities	(21,615)	(9,450)
Other:
Foreign currency translation adjustments	311	466
ERPOP [Member]
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	694,298	431,642
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	584,862	565,772
Amortization of deferred financing costs	7,734	8,554
Amortization of above/below market leases	2,534	2,376
Amortization of discounts and premiums on debt	(7,718)	(8,750)
Amortization of deferred settlements on derivative instruments	13,483	12,205
Write-off of pursuit costs	2,322	2,067
(Income) loss from investments in unconsolidated entities	(14,388)	10,201
Distributions from unconsolidated entities – return on capital	3,564	4,557
Net (gain) on sale of investment securities	(387)	(57)
Net (gain) on sales of real estate properties	(295,692)	(128,544)
Net loss (gain) on sales of land parcels	1	(1,846)
Net (gain) on sales of discontinued operations	0	(223)
Realized/unrealized loss (gain) on derivative instruments	3,055	(66)
Compensation paid with Company Common Shares	29,269	24,647
Changes in assets and liabilities:
(Increase) in deposits – restricted	(1,268)	(2,223)
Decrease in mortgage deposits	756	1,638
(Increase) decrease in other assets	(25,428)	3,854
Increase in accounts payable and accrued expenses	63,385	76,331
(Decrease) increase in accrued interest payable	(3,457)	8,163
Increase (decrease) in other liabilities	5,120	(173)
Increase in security deposits	1,301	4,146
Net cash provided by operating activities	1,063,346	1,014,271
CASH FLOWS FROM INVESTING ACTIVITIES:
Investment in real estate – acquisitions	(159,575)	(404,658)
Investment in real estate – development/other	(485,758)	(380,691)
Capital expenditures to real estate	(134,438)	(133,181)
Non-real estate capital additions	(2,384)	(2,446)
Interest capitalized for real estate and unconsolidated entities under development	(45,850)	(38,140)
Proceeds from disposition of real estate, net	457,499	224,538
Investments in unconsolidated entities	(22,998)	(14,568)
Distributions from unconsolidated entities – return of capital	45,245	77,042
Proceeds from sale of investment securities	387	57
(Increase) decrease in deposits on real estate acquisitions and investments, net	(62,433)	20,845
(Increase) decrease in mortgage deposits	(407)	560
Net cash (used for) investing activities	(410,712)	(650,642)
CASH FLOWS FROM FINANCING ACTIVITIES:
Debt financing costs	(6,355)	(10,598)
Mortgage deposits	(6,335)	(5,557)
Mortgage notes payable:
Lump sum payoffs	(177,564)	(63,772)
Scheduled principal repayments	(7,161)	(8,919)
Notes, net:
Proceeds	746,391	1,194,278
Lump sum payoffs	(300,000)	(1,250,000)
Line of credit and commercial paper:
Line of credit proceeds	3,569,000	5,324,000
Line of credit repayments	(3,902,000)	(4,993,000)
Commercial paper proceeds	2,491,848	0
Commercial paper repayments	(2,462,500)	0
(Payments on) settlement of derivative instruments	(13,938)	(758)
Proceeds from EQR's Employee Share Purchase Plan (ESPP)	3,376	2,728
Proceeds from exercise of options	37,047	56,554
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
Payment of offering costs	(69)	0
Other financing activities, net	(33)	(33)
Acquisition of Noncontrolling Interests – Partially Owned Properties	0	(5,501)
Contributions – Noncontrolling Interests – Partially Owned Properties	0	5,684
Contributions – Limited Partners	3	3
Distributions:
OP Units – General Partner	(583,568)	(595,564)
Preference Units	(2,557)	(3,109)
OP Units – Limited Partners	(22,968)	(23,582)
Noncontrolling Interests – Partially Owned Properties	(5,356)	(6,762)
Net cash (used for) financing activities	(655,348)	(385,685)
Net (decrease) in cash and cash equivalents	(2,714)	(22,056)
Cash and cash equivalents, beginning of period	40,080	53,534
Cash and cash equivalents, end of period	37,366	31,478
SUPPLEMENTAL INFORMATION:
Cash paid for interest, net of amounts capitalized	328,400	335,646
Net cash paid for income and other taxes	1,052	866
Amortization of discounts and premiums on debt:
Mortgage notes payable	(10,261)	(10,515)
Notes, net	1,895	1,765
Line of credit and commercial paper	648	0
Amortization of deferred settlements on derivative instruments:
Other liabilities	(164)	(401)
Accumulated other comprehensive income	13,647	12,606
Write-off of pursuit costs:
Investment in real estate, net	1,929	1,965
Other assets	63	102
(Income) loss from investments in unconsolidated entities:
Investments in unconsolidated entities	(16,309)	7,684
Other liabilities	1,921	2,517
Distributions from unconsolidated entities – return on capital:
Investments in unconsolidated entities	3,462	4,399
Other liabilities	102	158
Realized/unrealized loss (gain) on derivative instruments:
Other assets	(9,677)	11,409
Notes, net	8,162	(2,485)
Other liabilities	2,774	12,794
Unrealized holding gains (losses) arising during the period	1,796	(21,784)
Interest capitalized for real estate and unconsolidated entities under development:
Investment in real estate, net	(45,850)	(38,086)
Investments in unconsolidated entities	0	(54)
Investments in unconsolidated entities:
Investments in unconsolidated entities	(1,383)	(5,118)
Other liabilities	(21,615)	(9,450)
Other:
Foreign currency translation adjustments	311	466
Land [Member]
Adjustments to reconcile net income to net cash provided by operating activities:
Write-off of pursuit costs	330	0
Land [Member] | ERPOP [Member]
Adjustments to reconcile net income to net cash provided by operating activities:
Write-off of pursuit costs	$ 330	$ 0