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

Number of consolidated projects in various stages of development.

No definition available.

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

Total number of open development projects. May include projects that are held for and/or under development, completed and not stabilized or completed and stabilized. These projects are consolidated.

No definition available.

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

Number of unconsolidated projects in various stages of development.

No definition available.

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

Total number of units that are associated with open development projects. May include projects that are held for and/or under development, completed and not stabilized or completed and stabilized. These units are consolidated.

No definition available.

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

Project under development commitment fund.

No definition available.

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

Unconsolidated project under development commitment fund.

No definition available.

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

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.