Equity and Redeemable Noncontrolling Interests of Equity Residential - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Common Stock, Shares, Outstanding	365,870,924	364,755,444	362,855,454	360,479,260
Common Shares Issued:
Conversion of OP Units	88,838	208,307	94,671
Exercise of share options	815,044	1,456,363	2,086,380
Employee Share Purchase Plan (ESPP)	63,909	68,462	68,807
Restricted share grants, net	147,689	168,142	169,722
Common Shares Other:
Conversion of restricted shares to restricted units	0	(1,284)	(12,146)
Stock Repurchased and Retired During Period, Shares	0	0	(31,240)
Units
Units Ownership Interest in Operating Partnership	3.80%	3.80%	3.80%
Redeemable Noncontrolling Interests – Operating Partnership	$ 442,092	$ 566,783	$ 500,733	$ 363,144
Change in market value of Redeemable Noncontrolling Interests – Operating Partnership	$ (115,093)	$ 64,378	$ 139,818
Common Shares And Units Outstanding	380,496,999	379,182,608	377,154,145
Change in carrying value	$ (9,598)	$ 1,672	$ (2,229)
ERPOP [Member]
Common Shares Issued:
Exercise of share options	815,044	1,456,363	2,086,380
Employee Share Purchase Plan (ESPP)	63,909	68,462	68,807
Restricted share grants, net	147,689	168,142	169,722
Common Shares Other:
Conversion of restricted shares to restricted units	0	1,284	12,146
Stock Repurchased and Retired During Period, Shares	0	0	(31,240)
Units
Total Units Outstanding	14,626,075	14,427,164	14,298,691	14,180,376
Restricted unit grants, net	287,749	335,496	200,840
Shares Issued During Period Shares Conversion Of Units To Common Shares	(88,838)	(208,307)	(94,671)
Units Ownership Interest in Operating Partnership	3.80%	3.80%	3.80%
Common Shares And Units Outstanding	380,496,999	379,182,608	377,154,145	374,659,636