CONSOLIDATED STATEMENT OF CHANGES IN EQUITY (Unaudited) - 9 months ended Sep. 30, 2015 - USD ($) $ in Thousands	Total	PREFERRED SHARES	COMMON SHARES, $0.01 PAR VALUE	Additional Paid-in Capital [Member]	RETAINED EARNINGS	Accumulated Other Comprehensive (Loss)	Noncontrolling Interest [Member]	Partially Owned [Domain]
Balance, beginning of year at Dec. 31, 2014	$ 10,368,456	$ 50,000	$ 3,629	$ 8,536,340	$ 1,950,639	$ (172,152)
Balance, beginning of year at Dec. 31, 2014	339,320						$ 214,411	$ 124,909
PREFERRED SHARES
Partial redemption of 8.29% Series K Cumulative Redeemable	9,820	(9,820)
Common Share Issuance:
Conversion of OP Units into Common Shares			2	4,376			(4,378)
Exercise of share options			8	37,039
PAID IN CAPITAL
EQR's Employee Share Purchase Plan (ESPP)				3,376
Conversion of restricted shares to restricted units				(70)			70
Share-based employee compensation expense:
Restricted shares			2	12,689
Share options				2,887
ESPP discount				692
Offering costs				(69)
Supplemental Executive Retirement Plan (SERP)				(1,325)
Change in market value of Redeemable Noncontrolling Interests – Operating Partnership	20,262			(20,262)
Adjustment for Noncontrolling Interests ownership in Operating Partnership				8,470			(8,470)
Net income attributable to controlling interests	665,634				665,634
Common Share distributions					(603,337)
Preferred Share distributions					(2,557)
Premium on redemption of Preferred Shares	(2,789)				(2,789)
Other comprehensive income (loss) – derivative instruments:
Unrealized holding gains arising during the period	1,796					1,796
Losses reclassified into earnings from other comprehensive income	(13,647)					13,647
Currency translation adjustments arising during the period	(311)					(311)
Issuance of restricted units to Noncontrolling Interests							3
Equity compensation associated with Noncontrolling Interests							18,969
Net income attributable to Noncontrolling Interests	(26,191)						26,191
Distributions to Noncontrolling Interests							(23,719)	(5,389)
Change in carrying value of Redeemable Noncontrolling Interests – Operating Partnership	1,590						(1,590)
Net income attributable to Noncontrolling Interests	2,473							2,473
Deconsolidation of previously consolidated Noncontrolling Interests								(117,350)
Balance, end of period at Sep. 30, 2015	10,478,534	$ 40,180	$ 3,641	$ 8,584,143	$ 2,007,590	$ (157,020)
Balance, end of period at Sep. 30, 2015	$ 226,130						$ 221,487	$ 4,643