Reportable Segments - Schedule of Reconciliation of Total Assets and Capital Expenditures (Parenthetical) (Details) - Property	3 Months Ended	6 Months Ended
Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Segment Reporting, Descriptive Information [Abstract]
Units in same store properties	78,612	78,612	78,385	78,385

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