CONSOLIDATED STATEMENTS OF CASH FLOWS OF ERP OPERATING LIMITED PARTNERSHIP (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 152,167	$ 133,066
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	175,108	169,363
Amortization of deferred financing costs	2,974	3,074
Amortization of discounts and premiums on debt	(1,567)	373
Amortization of deferred settlements on derivative instruments	3,429	822
Write-off of pursuit costs	1,034	1,683
Distributions from unconsolidated entities - return on capital	89	41
Net (gain) on sales of discontinued operations	(132,956)	(123,754)
Unrealized (gain) on derivative instruments	(1)	0
Compensation paid with Company Common Shares	8,968	6,524
Changes in assets and liabilities:
(Increase) decrease in deposits - restricted	(2,768)	1,557
Decrease in other assets	12,262	5,771
Increase in accounts payable and accrued expenses	41,616	44,531
(Decrease) in accrued interest payable	(8,632)	(26,659)
(Decrease) in other liabilities	(16,878)	(28,836)
Increase in security deposits	182	(28)
Net cash provided by operating activities	235,027	187,528
CASH FLOWS FROM INVESTING ACTIVITIES:
Investment in real estate - acquisitions	(183,112)	(123,868)
Investment in real estate - development/other	(35,876)	(29,840)
Improvements to real estate	(30,225)	(29,891)
Additions to non-real estate property	(2,229)	(2,677)
Interest capitalized for real estate and unconsolidated entities under development	(4,996)	(1,700)
Proceeds from disposition of real estate, net	204,272	258,212
Investments in unconsolidated entities	(2,396)	(366)
(Increase) in deposits on real estate acquisitions and investments, net	(27,386)	(107,878)
(Increase) decrease in mortgage deposits	(736)	506
Acquisition of Noncontrolling Interests - Partially Owned Properties	0	(504)
Net cash (used for) investing activities	(82,684)	(38,006)
CASH FLOWS FROM FINANCING ACTIVITIES:
Loan and bond acquisition costs	(4,227)	(223)
Mortgage notes payable:
Proceeds	0	707
Restricted cash	209	(22,297)
Scheduled principal repayments	(3,970)	(4,223)
Notes, net:
Lump sum payoffs	(253,858)	(93,096)
Proceeds from Employee Stock Purchase Plan	4,210	2,742
Proceeds from exercise of EQR options	18,938	32,719
Payment of offering costs	(1,887)	(2,352)
Contributions - Noncontrolling Interests - Partially Owned Properties	921	0
Contributions - Limited Partners	5	0
Distributions:
Noncontrolling Interests - Partially Owned Properties	(1,762)	(264)
Net cash (used for) financing activities	(316,636)	(274,858)
Net (decrease) in cash and cash equivalents	(164,293)	(125,336)
Cash and cash equivalents, beginning of period	383,921	431,408
Cash and cash equivalents, end of period	219,628	306,072
SUPPLEMENTAL INFORMATION:
Cash paid for interest, net of amounts capitalized	125,435	146,514
Net cash paid for income and other taxes	560	341
Real estate acquisitions/dispositions/other:
Mortgage loans assumed	0	26,900
Amortization of discounts and premiums on debt:
Mortgage notes payable	(2,153)	(1,858)
Notes, net	586	2,231
Amortization of deferred settlements on derivative instruments:
Other liabilities	(134)	(134)
Accumulated other comprehensive income	3,563	956
Unrealized loss (gain) on derivative instruments:
Other assets	1,300	810
Mortgage notes payable	(588)	(144)
Notes, net	(712)	(1,348)
Other liabilities	(3,219)	(5,400)
Accumulated other comprehensive income	3,218	6,082
Interest capitalized for real estate and unconsolidated entities under development:
Investment in real estate, net	(4,827)	(1,659)
Investments in unconsolidated entities	(169)	(41)
OPERATING PARTNERSHIP
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	152,167	133,066
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	175,108	169,363
Amortization of deferred financing costs	2,974	3,074
Amortization of discounts and premiums on debt	(1,567)	373
Amortization of deferred settlements on derivative instruments	3,429	822
Write-off of pursuit costs	1,034	1,683
Distributions from unconsolidated entities - return on capital	89	41
Net (gain) on sales of discontinued operations	(132,956)	(123,754)
Unrealized (gain) on derivative instruments	(1)	0
Compensation paid with Company Common Shares	8,968	6,524
Changes in assets and liabilities:
(Increase) decrease in deposits - restricted	(2,768)	1,557
Decrease in other assets	12,262	5,771
Increase in accounts payable and accrued expenses	41,616	44,531
(Decrease) in accrued interest payable	(8,632)	(26,659)
(Decrease) in other liabilities	(16,878)	(28,836)
Increase in security deposits	182	(28)
Net cash provided by operating activities	235,027	187,528
CASH FLOWS FROM INVESTING ACTIVITIES:
Investment in real estate - acquisitions	(183,112)	(123,868)
Investment in real estate - development/other	(35,876)	(29,840)
Improvements to real estate	(30,225)	(29,891)
Additions to non-real estate property	(2,229)	(2,677)
Interest capitalized for real estate and unconsolidated entities under development	(4,996)	(1,700)
Proceeds from disposition of real estate, net	204,272	258,212
Investments in unconsolidated entities	(2,396)	(366)
(Increase) in deposits on real estate acquisitions and investments, net	(27,386)	(107,878)
(Increase) decrease in mortgage deposits	(736)	506
Acquisition of Noncontrolling Interests - Partially Owned Properties	0	(504)
Net cash (used for) investing activities	(82,684)	(38,006)
CASH FLOWS FROM FINANCING ACTIVITIES:
Loan and bond acquisition costs	(4,227)	(223)
Mortgage notes payable:
Proceeds	0	707
Restricted cash	209	(22,297)
Lump sum payoffs	(47,800)	(200,733)
Scheduled principal repayments	(3,970)	(4,223)
Notes, net:
Lump sum payoffs	(253,858)	(93,096)
Proceeds from sale of OP Units	152,058	154,508
Proceeds from Employee Stock Purchase Plan	4,210	2,742
Proceeds from exercise of EQR options	18,938	32,719
Payment of offering costs	(1,887)	(2,352)
Contributions - Noncontrolling Interests - Partially Owned Properties	921	0
Contributions - Limited Partners	5	0
Distributions:
OP Units - General Partner	(168,350)	(132,655)
Preference Units	(3,466)	(3,466)
OP Units - Limited Partners	(7,657)	(6,225)
Noncontrolling Interests - Partially Owned Properties	(1,762)	(264)
Net cash (used for) financing activities	(316,636)	(274,858)
Net (decrease) in cash and cash equivalents	(164,293)	(125,336)
Cash and cash equivalents, beginning of period	383,921	431,408
Cash and cash equivalents, end of period	219,628	306,072
SUPPLEMENTAL INFORMATION:
Cash paid for interest, net of amounts capitalized	125,435	146,514
Net cash paid for income and other taxes	560	341
Real estate acquisitions/dispositions/other:
Mortgage loans assumed	0	26,900
Amortization of discounts and premiums on debt:
Mortgage notes payable	(2,153)	(1,858)
Notes, net	586	2,231
Amortization of deferred settlements on derivative instruments:
Other liabilities	(134)	(134)
Accumulated other comprehensive income	3,563	956
Unrealized loss (gain) on derivative instruments:
Other assets	1,300	810
Mortgage notes payable	(588)	(144)
Notes, net	(712)	(1,348)
Other liabilities	(3,219)	(5,400)
Accumulated other comprehensive income	3,218	6,082
Interest capitalized for real estate and unconsolidated entities under development:
Investment in real estate, net	(4,827)	(1,659)
Investments in unconsolidated entities	(169)	(41)
Other:
Receivable on sale of OP Units	$ 28,457	$ 0