Equity, Capital and Other Interests ERP Units (Details)	6 Months Ended
	Jun. 30, 2013	Dec. 31, 2012
Capital Unit [Line Items]
Common Shares And Units Outstanding	374,526,476
Issuance of OP Units	34,468,085
Exercise of EQR share options	468,203
EQR's Employee Share Purchase Plan (ESPP)	50,148
Restricted Share Grants Net	234,697
Units Ownership Interest in Operating Partnership	3.80%
General And Limited Partner [Member]
Capital Unit [Line Items]
Common Shares And Units Outstanding	374,526,476	339,023,412
Issuance of OP Units	34,468,085
Exercise of EQR share options	468,203
EQR's Employee Share Purchase Plan (ESPP)	50,148
Restricted Share Grants Net	234,697
Issuance Of LTIPs	281,931
Limited Partner [Member]
Capital Unit [Line Items]
Issuance Of LTIPs	281,931
Shares Issued During Period Shares Conversion Of Units To Common Shares	(36,262)
Total Units Outstanding	14,214,427	13,968,758
Limited Partner [Member]
Capital Unit [Line Items]
Issuance Of LTIPs	281,931
Shares Issued During Period Shares Conversion Of Units To Common Shares	(36,262)
Total Units Outstanding	14,214,427	13,968,758