Distribution Reinvestment and Share Purchase Plan (Details)	Dec. 31, 2015 shares
Common Shares registered with Distribution Reinvestment and Share Purchase Plan (2011 DRIP)	4,850,000
Number of shares available for issuance	4,775,789
Distribution Reinvestment Plan 2014 [Member]
Common Shares registered with Distribution Reinvestment and Share Purchase Plan (2011 DRIP)	4,790,000

Represents the number of shares authorized for issuance under the company's dividend reinvestment plan at the registration date.

No definition available.

Name:	eqr_StockRegisteredDuringPeriodSharesDividendReinvestmentPlan
Namespace Prefix:	eqr_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant