XML 92 R74.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Reportable Segments - Additional Information (Details) | Sep. 30, 2018 Property Customer | Sep. 30, 2017 Customer
--- | --- | ---
Segment Reporting Information [Line Items] |  |
Number of customer contributed 10% or more of total revenue | Customer | 0 | 0
Denver | Non-same store |  |
Segment Reporting Information [Line Items] |  |
Number of properties acquired | Property | 2 |

X
- Definition Number of customer. + References No definition available. + Details
Name: | eqr_NumberOfCustomer
Namespace Prefix: | eqr_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number of properties acquired. + References No definition available. + Details
Name: | eqr_NumberOfPropertiesAcquired
Namespace Prefix: | eqr_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

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

X
- Details
Name: | srt_StatementGeographicalAxis=eqr_DenverMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=eqr_NonSameStoreMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |