Equity, Capital and Other Interests EQR Common Shares (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Common Stock, Shares, Outstanding January 1,	360,479,260	325,054,654	297,508,185	290,197,242
Common Shares Issued:
Conversion of OP Units	67,939	675,817	341,594
Stock Issued During Period, Shares, New Issues	34,468,085	25,023,919	3,866,666
Exercise of share options	586,017	1,608,427	2,945,948
Employee Share Purchase Plan (ESPP)	73,468	110,054	113,107
Restricted Share Grants Net	229,097	128,252	145,616
Common Shares Other:
Conversion of restricted shares to LTIP Units	0	0	(101,988)
Units
Common Shares And Units Outstanding	374,659,636	339,023,412	311,000,728
Units Ownership Interest in Operating Partnership	3.78%	4.10%	4.30%
OP Units Issued:
Issue Price Per OP Unit	$ 0	$ 61.57	$ 0
Valuation Operating Partnership Unit		$ 66,600,000
Limited Partner [Member]
Common Shares Other:
Conversion of restricted shares to LTIP Units	0	0	101,988
Units
Total Units Outstanding	14,180,376	13,968,758	13,492,543	13,612,037
Issuance Of LTIPs	279,557	70,235	120,112
Issuance Of Units	0	1,081,797	0
Shares Issued During Period Shares Conversion Of Units To Common Shares	(67,939)	(675,817)	(341,594)
OP Units Issued:
Valuation Operating Partnership Unit		$ 66,600,000
ATM Program [Member]
Common Shares Issued:
Stock Issued During Period, Shares, New Issues		3,200,000