Capital and Redeemable Limited Partners of ERP Operating Limited Partnership - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Common Shares And Units Outstanding	380,496,999	379,182,608	377,154,145
Exercise of EQR share options	815,044	1,456,363	2,086,380
EQR's Employee Share Purchase Plan (ESPP)	63,909	68,462	68,807
EQR's restricted share grants, net	147,689	168,142	169,722
Stock Repurchased and Retired During Period, Shares	0	0	(31,240)
Conversion of restricted shares to restricted units	0	(1,284)	(12,146)
Units Ownership Interest in Operating Partnership	3.80%	3.80%	3.80%
ERPOP [Member]
Common Shares And Units Outstanding	380,496,999	379,182,608	377,154,145	374,659,636
Exercise of EQR share options	815,044	1,456,363	2,086,380
EQR's Employee Share Purchase Plan (ESPP)	63,909	68,462	68,807
EQR's restricted share grants, net	147,689	168,142	169,722
Restricted unit grants, net	287,749	335,496	200,840
Stock Repurchased and Retired During Period, Shares	0	0	(31,240)
Conversion of restricted shares to restricted units	0	1,284	12,146
Shares Issued During Period Shares Conversion Of Units To Common Shares	(88,838)	(208,307)	(94,671)
Total Units Outstanding	14,626,075	14,427,164	14,298,691	14,180,376
Units Ownership Interest in Operating Partnership	3.80%	3.80%	3.80%
Redeemable Limited Partners	$ 442,092	$ 566,783	$ 500,733	$ 363,144
Limited Partners Change In Redemption Value	(115,093)	64,378	139,818
Limited Partners Change In Carrying Value	$ (9,598)	$ 1,672	$ (2,229)