CONSOLIDATED STATEMENTS OF CASH FLOWS OF ERP OPERATING LIMITED PARTNERSHIP (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 488,842	$ 200,452
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	388,803	375,303
Amortization of deferred financing costs	5,127	5,926
Amortization of above/below market leases	1,691	1,530
Amortization of discounts and premiums on debt	(5,611)	(5,876)
Amortization of deferred settlements on derivative instruments	8,751	8,068
Write-off of pursuit costs	1,651	1,492
(Income) loss from investments in unconsolidated entities	(15,429)	9,025
Distributions from unconsolidated entities - return on capital	2,193	2,390
Net (gain) on sale of investment securities	(387)	(57)
Net (gain) on sales of real estate properties	(228,753)	(14,903)
Net (gain) on sales of discontinued operations	0	(224)
Unrealized loss (gain) on derivative instruments	51	(90)
Compensation paid with Company Common Shares	24,017	21,905
Changes in assets and liabilities:
(Increase) in deposits – restricted	(288)	(1,820)
(Increase) decrease in mortgage deposits	(382)	187
(Increase) in other assets	(4,553)	(7,745)
Increase in accounts payable and accrued expenses	22,350	38,951
(Decrease) increase in accrued interest payable	(2,409)	80
(Decrease) in other liabilities	(11,097)	(17,237)
Increase in security deposits	479	2,916
Net cash provided by operating activities	675,047	619,479
CASH FLOWS FROM INVESTING ACTIVITIES:
Investment in real estate - acquisitions	(136,995)	(265,466)
Investment in real estate - development/other	(324,343)	(245,657)
Capital expenditures to real estate	(81,962)	(76,912)
Non-real estate capital additions	(1,955)	(1,818)
Interest capitalized for real estate and unconsolidated entities under development	(30,432)	(25,037)
Proceeds from disposition of real estate, net	379,863	48,359
Investments in unconsolidated entities	(4,786)	(9,554)
Distributions from unconsolidated entities - return of capital	26,147	64,669
Proceeds from sale of investment securities	387	57
(Increase) decrease in deposits on real estate acquisitions and investments, net	(31,247)	20,979
(Increase) decrease in mortgage deposits	(226)	760
Net cash (used for) investing activities	(205,549)	(489,620)
CASH FLOWS FROM FINANCING ACTIVITIES:
Debt financing costs	(6,352)	(10,881)
Mortgage Deposits	(4,169)	(3,580)
Mortgage notes payable:
Scheduled principal repayments	(5,028)	(6,000)
Notes, net:
Proceeds	746,391	1,194,277
Lump sum payoffs	(300,000)	(750,000)
Line of credit and commercial paper:
Line of credit proceeds	3,553,000	3,374,000
Line of credit repayments	(3,886,000)	(3,489,000)
Commercial paper proceeds	2,266,924	0
Commercial paper repayments	(2,267,500)	0
(Payments on) settlement of derivative instruments	(13,938)	(733)
Proceeds from exercise of options	33,984	25,685
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	(40)	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	1	3
Distributions:
Noncontrolling Interests – Partially Owned Properties	(3,995)	(5,239)
Net Cash (used for) Financing Activities	(417,469)	(107,261)
Net increase in cash and cash equivalents	52,029	22,598
Cash and cash equivalents, beginning of period	40,080	53,534
Cash and cash equivalents, end of period	92,109	76,132
SUPPLEMENTAL INFORMATION:
Cash paid for interest, net of amounts capitalized	218,965	226,785
Net cash paid for income and other taxes	895	843
Amortization of discounts and premiums on debt:
Mortgage notes payable	7,420	7,011
Notes, net	1,233	1,135
Line of credit and commercial paper	576	0
Amortization of deferred settlements on derivative instruments:
Other liabilities	(160)	(267)
Losses reclassified into earnings from other comprehensive income	8,911	8,335
Write-off of pursuit costs [Abstract]
Write-off of pursuit costs - investment in real estate, net	1,260	1,435
Deposits – restricted	330	0
Write-off of pursuit costs - other assets	61	57
(Income) Loss From Investments In Unconsolidated Entities [Abstract]
(Income) loss from investment in unconsolidated entities	(16,767)	7,354
Other Liabilities Loss From Investments in unconsolidated entities	1,338	1,671
Distributions from unconsolidated entities return on capital [Abstract]
Distributions from unconsolidated entities investments in unconsolidated entities	2,125	2,285
Distributions from unconsolidated entities other liabilities	68	105
Unrealized loss (gain) on derivative instruments:
Other assets	(3,873)	10,611
Notes, net	2,358	1,452
Other liabilities	1,678	9,728
Unrealized holding (losses) gains arising during the period	(112)	(21,881)
Interest capitalized for real estate and unconsolidated entities under development:
Investment in real estate, net	(30,432)	(25,002)
Investments in unconsolidated entities	0	(35)
Investments in unconsolidated entities [Abstract]
Investments in unconsolidated entities	1,291	2,354
Investments in unconsolidated entities other liabilities	3,495	7,200
Other:
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax	502	(1,718)
OPERATING PARTNERSHIP
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	488,842	200,452
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	388,803	375,303
Amortization of deferred financing costs	5,127	5,926
Amortization of above/below market leases	1,691	1,530
Amortization of discounts and premiums on debt	(5,611)	(5,876)
Amortization of deferred settlements on derivative instruments	8,751	8,068
Write-off of pursuit costs	1,651	1,492
(Income) loss from investments in unconsolidated entities	(15,429)	9,025
Distributions from unconsolidated entities - return on capital	2,193	2,390
Net (gain) on sale of investment securities	(387)	(57)
Net (gain) on sales of real estate properties	(228,753)	(14,903)
Net loss (gain) on sales of land parcels	1	(794)
Net (gain) on sales of discontinued operations	0	(224)
Unrealized loss (gain) on derivative instruments	51	(90)
Compensation paid with Company Common Shares	24,017	21,905
Changes in assets and liabilities:
(Increase) in deposits – restricted	(288)	(1,820)
(Increase) decrease in mortgage deposits	(382)	187
(Increase) in other assets	(4,553)	(7,745)
Increase in accounts payable and accrued expenses	22,350	38,951
(Decrease) increase in accrued interest payable	(2,409)	80
(Decrease) in other liabilities	(11,097)	(17,237)
Increase in security deposits	479	2,916
Net cash provided by operating activities	675,047	619,479
CASH FLOWS FROM INVESTING ACTIVITIES:
Investment in real estate - acquisitions	(136,995)	(265,466)
Investment in real estate - development/other	(324,343)	(245,657)
Capital expenditures to real estate	(81,962)	(76,912)
Non-real estate capital additions	(1,955)	(1,818)
Interest capitalized for real estate and unconsolidated entities under development	(30,432)	(25,037)
Proceeds from disposition of real estate, net	379,863	48,359
Investments in unconsolidated entities	(4,786)	(9,554)
Distributions from unconsolidated entities - return of capital	26,147	64,669
Proceeds from sale of investment securities	387	57
(Increase) decrease in deposits on real estate acquisitions and investments, net	(31,247)	20,979
(Increase) decrease in mortgage deposits	(226)	760
Net cash (used for) investing activities	(205,549)	(489,620)
CASH FLOWS FROM FINANCING ACTIVITIES:
Debt financing costs	(6,352)	(10,881)
Mortgage Deposits	(4,169)	(3,580)
Mortgage notes payable:
Lump sum payoffs	(121,488)	(3,064)
Scheduled principal repayments	(5,028)	(6,000)
Notes, net:
Proceeds	746,391	1,194,277
Lump sum payoffs	(300,000)	(750,000)
Line of credit and commercial paper:
Line of credit proceeds	3,553,000	3,374,000
Line of credit repayments	(3,886,000)	(3,489,000)
Commercial paper proceeds	2,266,924	0
Commercial paper repayments	(2,267,500)	0
(Payments on) settlement of derivative instruments	(13,938)	(733)
EQR's Employee Share Purchase Plan (ESPP)	2,610	2,218
Proceeds from exercise of options	33,984	25,685
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	(40)	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	1	3
Distributions:
OP Units - General Partner	(382,441)	(414,843)
Preference Units	(1,724)	(2,072)
OP Units - Limited Partners	(15,062)	(16,405)
Noncontrolling Interests – Partially Owned Properties	(3,995)	(5,239)
Net Cash (used for) Financing Activities	(417,469)	(107,261)
Net increase in cash and cash equivalents	52,029	22,598
Cash and cash equivalents, beginning of period	40,080	53,534
Cash and cash equivalents, end of period	92,109	76,132
SUPPLEMENTAL INFORMATION:
Cash paid for interest, net of amounts capitalized	218,965	226,785
Net cash paid for income and other taxes	895	843
Amortization of discounts and premiums on debt:
Mortgage notes payable	(7,420)	(7,011)
Notes, net	1,233	1,135
Line of credit and commercial paper	576	0
Amortization of deferred settlements on derivative instruments:
Other liabilities	(160)	(267)
Losses reclassified into earnings from other comprehensive income	8,911	8,335
Write-off of pursuit costs [Abstract]
Write-off of pursuit costs - investment in real estate, net	1,260	1,435
Deposits – restricted	330	0
Write-off of pursuit costs - other assets	61	57
(Income) Loss From Investments In Unconsolidated Entities [Abstract]
(Income) loss from investment in unconsolidated entities	(16,767)	7,354
Other Liabilities Loss From Investments in unconsolidated entities	1,338	1,671
Distributions from unconsolidated entities return on capital [Abstract]
Distributions from unconsolidated entities investments in unconsolidated entities	2,125	2,285
Distributions from unconsolidated entities other liabilities	68	105
Unrealized loss (gain) on derivative instruments:
Other assets	(3,873)	10,611
Notes, net	2,358	1,452
Other liabilities	1,678	9,728
Unrealized holding (losses) gains arising during the period	(112)	(21,881)
Interest capitalized for real estate and unconsolidated entities under development:
Investment in real estate, net	(30,432)	(25,002)
Investments in unconsolidated entities	0	(35)
Investments in unconsolidated entities [Abstract]
Investments in unconsolidated entities	(1,291)	(2,354)
Investments in unconsolidated entities other liabilities	(3,495)	(7,200)
Other:
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax	$ 502	$ (1,718)