Reportable Segments - Schedule of Reconciliation of Total Assets and Capital Expenditures (Parenthetical) (Details) - Property	3 Months Ended	6 Months Ended
Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]
Units in same store properties	75,950	75,950	75,072	75,072

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