Capital and Redeemable Limited Partners of ERP Operating Limited Partnership (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
Common Shares And Units Outstanding	380,199,636
Exercise of EQR share options	582,435
EQR’s Employee Share Purchase Plan (ESPP)	15,506
Restricted share grants, net	137,057
Conversion of Limited Partner OP Units to EQR Common Shares	5,577
Units Ownership Interest in Operating Partnership	3.90%
ERPOP [Member]
Common Shares And Units Outstanding	380,199,636	379,182,608
Exercise of EQR share options	582,435
EQR’s Employee Share Purchase Plan (ESPP)	15,506
Restricted share grants, net	137,057
Restricted unit grants, net	282,030
Total Units Outstanding	14,703,617	14,427,164
Conversion of Limited Partner OP Units to EQR Common Shares	(5,577)
Units Ownership Interest in Operating Partnership	3.90%
Redeemable Limited Partners	$ 521,080	$ 566,783
Limited Partners Change In Redemption Value	(55,478)
Limited Partners Change In Carrying Value	$ 9,775