Debt - Notes - Additional Information (Details)	12 Months Ended
Dec. 31, 2020
Debt Disclosure [Abstract]
Shelf registration statement effective date	2019-06
Shelf registration statement expiry date	2022-06

Expiry date of securities remaining under the shelf registration statement.

No definition available.

Name:	eqr_ExpiryDateOfSecuritiesRemainingUnderShelfRegistrationStatement
Namespace Prefix:	eqr_
Data Type:	xbrli:gYearMonthItemType
Balance Type:	na
Period Type:	duration