Name:	eqr_CommonSharesAndUnitsOutstanding
Namespace Prefix:	eqr_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

Number of units issued during the period as a result of a long-term incentive plan.

No definition available.

Name:	eqr_IssuanceOfLtips
Namespace Prefix:	eqr_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

Partners capital units shares repurchased and retired.

No definition available.

Name:	eqr_PartnersCapitalUnitsSharesRepurchasedAndRetired
Namespace Prefix:	eqr_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

The number of restricted shares granted during the reporting period, net of cancellations.

No definition available.

Name:	eqr_RestrictedShareGrantsNet
Namespace Prefix:	eqr_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

OP Units converted into shares of stock during the period. An example of a convertible unit is an umbrella partnership real estate investment trust unit (UPREIT unit). Subject to certain exceptions, this unit can be exchanged for Common Shares on a one-for-one basis.

No definition available.

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Namespace Prefix:	eqr_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

Units outstanding.

No definition available.

Name:	eqr_UnitsOutstanding
Namespace Prefix:	eqr_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

Represents the noncontrolling interests (comprised of Units and LTIP Units) ownership interest in the Operating Partnership.

No definition available.

Name:	eqr_UnitsOwnershipInterestInOperatingPartnership
Namespace Prefix:	eqr_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- References

No definition available.

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

Name:	us-gaap_LimitedPartnersCapitalAccountAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Number of shares issued during the period as a result of an employee stock purchase plan.

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Number of share options (or share units) exercised during the current period.

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