Schedule III - Real Estate and Accumulated Depreciation-Encumbrances Reconciliation (Details)	Dec. 31, 2022 USD ($) Property
Total Consolidated Investment in Real Estate [Member]
Overall summary of real estate and accumulated depreciation
Encumbrances	$ 1,953,438,085
Archstone Master Property [Member]
Real Estate and Accumulated Depreciation Encumbrances Reconciliation [Abstract]
Number of Properties Encumbered \| Property	13
Overall summary of real estate and accumulated depreciation
Encumbrances	$ 799,609,043
Portfolio Entity Encumbrances [Member]
Real Estate and Accumulated Depreciation Encumbrances Reconciliation [Abstract]
Number of Properties Encumbered \| Property	13
Overall summary of real estate and accumulated depreciation
Encumbrances	$ 799,609,043
Individual Property Encumbrances [Member]
Overall summary of real estate and accumulated depreciation
Encumbrances	$ 1,153,829,042

Represents the number of rental properties encumbered by a lien or mortgage.

No definition available.

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

- Definition

Overall summary of real estate and accumulated depreciation.

+ References

No definition available.

+ Details

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

- Definition

Real estate and accumulated depreciation encumbrances reconciliation.

+ References

No definition available.

+ Details

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

- Definition

Amount of lien or mortgage outstanding on real estate investment properties for entities with a substantial portion of business acquiring and holding investment real estate.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 12
-Paragraph Column B
-Subsection 28

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 970
-SubTopic 360
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-28(Column B))
-URI https://asc.fasb.org/extlink&oid=120402810&loc=d3e638233-123024

+ Details

Name:	srt_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances
Namespace Prefix:	srt_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=eqr_TotalConsolidatedInvestmentInRealEstateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=eqr_ArchstoneMasterPropertyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=eqr_PortfolioEntityEncumbrancesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=eqr_IndividualPropertyEncumbrancesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: