Leases - Summary of Reconciliation of Lease Liabilities (Details) $ in Thousands	Dec. 31, 2020 USD ($)
Leases [Abstract]
Total minimum rent payments	$ 1,076,108
Less: Lease discount	746,978
Lease liabilities	$ 329,130

Lessee operating and financing lease liability undiscounted excess amount.

No definition available.

Name:	eqr_LesseeOperatingAndFinancingLeaseLiabilityUndiscountedExcessAmount
Namespace Prefix:	eqr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant