Name:	eqr_MasterLeasedPropertiesAcquired
Namespace Prefix:	eqr_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

Total number of units associated with rental properties that are subject to a master lease.

No definition available.

Name:	eqr_MasterLeasedUnits
Namespace Prefix:	eqr_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

Total number of rental properties that represent military housing and are not consolidated by the Company.

No definition available.

Name:	eqr_MilitaryHousingProperties
Namespace Prefix:	eqr_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

Total number of units associated with rental properties that represent military housing and are not consolidated by the Company.

No definition available.

Name:	eqr_MilitaryHousingUnits
Namespace Prefix:	eqr_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

Total number of rental properties that are partially owned and consolidated by the Company.

No definition available.

Name:	eqr_PartiallyOwnedConsolidatedProperties
Namespace Prefix:	eqr_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

Total number of units associated with rental properties that are partially owned and consolidated by the Company.

No definition available.

Name:	eqr_PartiallyOwnedConsolidatedUnits
Namespace Prefix:	eqr_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

Total number of rental properties that are partially owned and not consolidated by the Company.

No definition available.

Name:	eqr_PartiallyOwnedUnconsolidatedProperties
Namespace Prefix:	eqr_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

Total number of units associated with rental properties that are partially owned and not consolidated by the Company.

No definition available.

Name:	eqr_PartiallyOwnedUnconsolidatedUnits
Namespace Prefix:	eqr_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	eqr_ScheduleOfPropertiesAndUnitsAbstract
Namespace Prefix:	eqr_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Total number of rental properties that are wholly owned and consolidated by the Company.

No definition available.

Name:	eqr_WhollyOwnedProperties
Namespace Prefix:	eqr_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

Total number of units associated with rental properties that are wholly owned and consolidated by the Company.

No definition available.

Name:	eqr_WhollyOwnedUnits
Namespace Prefix:	eqr_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

The parent entity's interest in net assets of the subsidiary, expressed as a percentage.

No definition available.

Name:	us-gaap_MinorityInterestOwnershipPercentageByParent
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

The number of real estate properties owned as of the balance sheet date.

No definition available.

Name:	us-gaap_NumberOfRealEstateProperties
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

The number of states the entity operates in as of the balance sheet date.

No definition available.

Name:	us-gaap_NumberOfStatesInWhichEntityOperates
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

The number of units in a real estate property owned as of the balance sheet date.

No definition available.