Real Estate - Acquired Properties From Unaffiliated Parties (Details) $ in Thousands	9 Months Ended
Sep. 30, 2023 USD ($) Property ApartmentUnit
Properties \| Property	4
Apartment Units \| ApartmentUnit	1,183
Purchase Price	$ 366,334
Land	41,142
Depreciable Property	$ 325,611
Rental Properties - Consolidated [Member]
Properties \| Property	4
Apartment Units \| ApartmentUnit	1,183
Purchase Price	$ 366,334
Land	41,142
Depreciable Property	$ 325,611

Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Depreciable Property

No definition available.

Name:	eqr_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDepreciableProperty
Namespace Prefix:	eqr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Total number of property or properties acquired from unaffiliated third parties during the period.

+ References

No definition available.

+ Details

Name:	eqr_PropertiesAcquired
Namespace Prefix:	eqr_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Total number of units associated with the property or properties acquired from unaffiliated third parties during the period.

+ References

No definition available.

+ Details

Name:	eqr_PropertyUnitsAcquired
Namespace Prefix:	eqr_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of assets acquired at the acquisition date.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 805
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479907/805-20-50-1

+ Details

Name:	us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of real estate acquired, at the acquisition date.

+ References

+ Details

Name:	us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLand
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=eqr_ConsolidatedRentalPropertiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: