CONSOLIDATED STATEMENT OF CHANGES IN CAPITAL OF ERP OPERATING LIMITED PARTNERSHIP (Unaudited) (USD $) In Thousands	Total	ACCUMULATED OTHER COMPREHENSIVE (LOSS)	PARTIALLY OWNED PROPERTIES	OPERATING PARTNERSHIP	OPERATING PARTNERSHIP PREFERENCE UNITS	OPERATING PARTNERSHIP ACCUMULATED OTHER COMPREHENSIVE (LOSS)	OPERATING PARTNERSHIP PARTIALLY OWNED PROPERTIES	OPERATING PARTNERSHIP GENERAL PARTNER	OPERATING PARTNERSHIP LIMITED PARTNERS
Balance, beginning of year at Dec. 31, 2010					$ 200,000	$ (57,818)	$ 7,991	$ 4,948,004	$ 110,399
OP Unit Issuance:
Conversion of OP Units held by Limited Partners into OP Units held by General Partner								7,227	(7,227)
Issuance Of OP Units								154,508
Exercise of EQR share options								83,534
EQR's Employee Share Purchase Plan (ESPP)								3,501
Conversion of EQR restricted shares to LTIP Units				3,934				(3,934)	3,934
Share-based employee compensation expense:
EQR restricted shares								5,345
EQR share options								5,386
EQR ESPP discount								872
Offering costs								(2,611)
Net income available to Units - General Partner				676,322				676,322
OP Units - General Partner distributions								(199,284)
Supplemental Executive Retirement Plan (SERP)								2,984
Acquisition of Noncontrolling Interests - Partially Owned Properties			(3,000)				(3,000)	(5,575)
Change in market value of Redeemable Limited Partners								(41,377)
Equity compensation associated with Units - Limited Partners				1,988					1,988
Net income available to Units - Limited Partners				31,533					31,533
Units - Limited Partners distributions									(9,238)
Change in carrying value of Redeemable Limited Partners									(13,224)
Adjustment for Limited Partners ownership in Operating Partnership								(3,853)	3,853
Accumulated other comprehensive (loss) - derivative instruments:
Unrealized holding (losses) arising during the period	(25,119)	(25,119)		(25,119)		(25,199)
Losses reclassified into earnings from other comprehensive income	1,891	1,891		1,891		1,891
Accumulated other comprehensive income - other instruments:
Unrealized holding gains arising during the period						493
Net income (loss) attributable to Noncontrolling Interests							31
Distributions to Noncontrolling Interests			(487)	(9,238)			(487)
Other							(1,240)
Balance, end of period at Jun. 30, 2011					200,000	(80,553)	3,295	5,631,049	122,018
Balance, beginning of year at Mar. 31, 2011
Share-based employee compensation expense:
Net income available to Units - General Partner				552,457
Net income available to Units - Limited Partners				25,758
Accumulated other comprehensive (loss) - derivative instruments:
Unrealized holding (losses) arising during the period	(31,201)			(31,201)
Losses reclassified into earnings from other comprehensive income	935			935
Balance, end of period at Jun. 30, 2011					$ 200,000