Equity, Capital and Other Interests ERP Units (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Capital Unit [Line Items]
Common Shares And Units Outstanding	374,659,636	339,023,412	311,000,728
Exercise of EQR share options	586,017	1,608,427	2,945,948
EQR's Employee Share Purchase Plan (ESPP)	73,468	110,054	113,107
Restricted Share Grants Net	229,097	128,252	145,616
Conversion of restricted shares to LTIP Units	0	0	(101,988)
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
General And Limited Partner [Member]
Capital Unit [Line Items]
Common Shares And Units Outstanding	374,659,636	339,023,412	311,000,728	303,809,279
Issuance of OP Units	34,468,085	25,023,919
Exercise of EQR share options	586,017	1,608,427	2,945,948
EQR's Employee Share Purchase Plan (ESPP)	73,468	110,054	113,107
Restricted Share Grants Net	229,097	128,252	145,616
Issuance Of LTIPs	279,557	70,235	120,112
Issuance Of Units	0	1,081,797	0
Limited Partner [Member]
Capital Unit [Line Items]
Issuance Of LTIPs	279,557	70,235	120,112
Issuance Of Units	0	1,081,797	0
Total Units Outstanding	14,180,376	13,968,758	13,492,543	13,612,037
Conversion of restricted shares to LTIP Units	0	0	101,988
Shares Issued During Period Shares Conversion Of Units To Common Shares	(67,939)	(675,817)	(341,594)
Units Ownership Interest in Operating Partnership	3.80%	4.10%	4.30%
OP Units Issued:
Issue Price Per OP Unit	$ 0	$ 61.57	$ 0