Leases - Summary of Residential Bad Debt for Company's Properties (Parenthetical) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Leases [Abstract]
Bad debt, net from resident payments	$ 0.5	$ 7.3	$ 2.4	$ 32.3

Operating lease lease income bad debt net from resident payments.

No definition available.

Name:	eqr_OperatingLeaseLeaseIncomeBadDebtNetFromResidentPayments
Namespace Prefix:	eqr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration