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v3.19.1

Commitments to Acquire/Dispose of Real Estate - Separate Agreements to Dispose (Parenthetical) (Details) | 3 Months Ended
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Mar. 31, 2019
Discontinued Operations And Disposal Groups [Abstract] |
Ownership percentage | 20.00%

X
- Definition Percentage of ownership interest in unconsolidated entity. + References No definition available. + Details
Name: | eqr_PercentageOfOwnershipInterestInUnconsolidatedEntity
Namespace Prefix: | eqr_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

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- References No definition available. + Details
Name: | us-gaap_DiscontinuedOperationsAndDisposalGroupsAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration