Distribution Reinvestment Plan - Additional Information (Details) - shares	Dec. 31, 2020	Sep. 30, 2014
Distribution Reinvestment And Share Purchase Plan [Abstract]
Common shares registered with distribution reinvestment and share purchase Plan (2014 DRIP)		4,790,000
Number of shares available for issuance	4,650,334

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