Reportable Segments - NOI from Our Rental Real Estate for Each Segment Specific to Continuing Operations (Parenthetical) (Details) - Property	3 Months Ended	6 Months Ended
Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]
Units in same store properties	77,545	77,545	76,952	76,952

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