Capital and Redeemable Limited Partners of ERP Operating Limited Partnership (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Common Shares And Units Outstanding	380,284,810
Exercise of EQR share options	619,232
EQR’s Employee Share Purchase Plan (ESPP)	46,399
Restricted share grants, net	148,822
Conversion of Limited Partner OP Units to EQR Common Shares	87,168
Units Ownership Interest in Operating Partnership	3.80%
ERPOP [Member]
Common Shares And Units Outstanding	380,284,810	379,182,608
Exercise of EQR share options	619,232
EQR’s Employee Share Purchase Plan (ESPP)	46,399
Restricted share grants, net	148,822
Restricted unit grants, net	287,749
Total Units Outstanding	14,627,745	14,427,164
Conversion of Limited Partner OP Units to EQR Common Shares	(87,168)
Units Ownership Interest in Operating Partnership	3.80%
Redeemable Limited Partners	$ 441,892	$ 566,783
Limited Partners Change In Redemption Value	(113,308)
Limited Partners Change In Carrying Value	$ (11,583)