CONSOLIDATED STATEMENT OF CHANGES IN CAPITAL OF ERP OPERATING LIMITED PARTNERSHIP (Unaudited) - 6 months ended Jun. 30, 2015 - USD ($) $ in Thousands	Total	PREFERRED UNITS	General Partner [Member]	Limited Partner [Member]	Accumulated Other Comprehensive (Loss)	Partially Owned Properties [Member]
Balance, beginning of year at Dec. 31, 2014		$ 50,000	$ 10,490,608	$ 214,411	$ (172,152)
Balance, beginning of year - Noncontrolling Interest at Dec. 31, 2014						$ 124,909
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			4,119	(4,119)
Exercise of EQR share options			33,984
EQR's Employee Share Purchase Plan (ESPP)			2,610
Conversion of restricted shares to restricted units			(70)	70
Share-based employee compensation expense:
EQR restricted shares			10,345
EQR share options			2,028
EQR ESPP discount			533
Net income available to Units - General Partner			464,429
OP Units - General Partner distributions			(402,159)
Offering costs			(40)
Supplemental Executive Retirement Plan (SERP)			(2,227)
Change in market value of Redeemable Limited Partners			13,966
Adjustment for Limited Partners ownership in Operating Partnership			6,313	(6,313)
Issuance of restricted units to Noncontrolling Interests				1
Equity compensation associated with Units - Limited Partners				16,368
Net income available to Units - Limited Partners				18,413
Units Limited Partners Distributions				(15,819)
Change in carrying value				(1,411)
Net (income) attributable to Noncontrolling Interests – Partially Owned Properties	1,487					1,487
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders						(4,028)
Other comprehensive (loss) income – derivative instruments:
Unrealized holding (losses) arising during the period	(112)				(112)
Losses reclassified into earnings from other comprehensive income	(8,911)				8,911
Currency translation adjustments arising during the period	$ (502)				(502)
Balance, end of period at Jun. 30, 2015		$ 40,180	$ 10,624,439	$ 221,601	$ (163,855)
Balance, end of period - Noncontrolling Interest at Jun. 30, 2015						$ 122,368