Equity, Capital and Other Interests ERP Units (Details) - shares	6 Months Ended
	Jun. 30, 2015	Dec. 31, 2014
Capital Unit [Line Items]
Common Shares And Units Outstanding	378,517,017
Exercise of EQR share options	814,827
EQR's Employee Share Purchase Plan (ESPP)	40,873
Restricted Share Grants, net	169,667
Conversion of restricted shares to restricted units	(1,284)
Shares Issued During Period Shares Conversion Of Units To Common Shares	171,353
Units Ownership Interest in Operating Partnership	3.80%
Limited Partner [Member]
Capital Unit [Line Items]
Limited Partners' Capital Account, Units Outstanding	14,466,127	14,298,691
Restricted units, net	337,505
Conversion of restricted shares to restricted units	1,284
Shares Issued During Period Shares Conversion Of Units To Common Shares	(171,353)
General And Limited Partner [Member]
Capital Unit [Line Items]
Common Shares And Units Outstanding	378,517,017	377,154,145
Exercise of EQR share options	814,827
EQR's Employee Share Purchase Plan (ESPP)	40,873
Restricted Share Grants, net	169,667
Restricted units, net	337,505