Reportable Segments - NOI from Our Rental Real Estate for Each Segment Specific to Continuing Operations (Parenthetical) (Details) - Property	3 Months Ended	9 Months Ended
Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]
Units in same store properties	77,698	77,698	76,789	76,789

Total number of units associated with properties acquired or completed and stabilized two or more fiscal years ago, less properties subsequently sold.

No definition available.

Name:	eqr_NumberOfUnitsInSameStoreProperties
Namespace Prefix:	eqr_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration