Equity, Capital and Other Interests ERP Units (Details)	3 Months Ended
	Mar. 31, 2015	Dec. 31, 2014
Capital Unit [Line Items]
Common Shares And Units Outstanding	378,446,365
Exercise of EQR share options	770,012
EQR's Employee Share Purchase Plan (ESPP)	30,151
Restricted Share Grants, net	158,753
Shares Issued During Period Shares Conversion Of Units To Common Shares	154,050
Units Ownership Interest in Operating Partnership	3.80%
Limited Partner [Member]
Capital Unit [Line Items]
Limited Partners' Capital Account, Units Outstanding	14,477,945	14,298,691
Restricted units, net	333,304
Shares Issued During Period Shares Conversion Of Units To Common Shares	(154,050)
General And Limited Partner [Member]
Capital Unit [Line Items]
Common Shares And Units Outstanding	378,446,365	377,154,145
Exercise of EQR share options	770,012
EQR's Employee Share Purchase Plan (ESPP)	30,151
Restricted Share Grants, net	158,753
Restricted units, net	333,304