XML 54 R36.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Business - Additional Information (Details) | Sep. 30, 2018 State Property ApartmentUnit | Apr. 02, 2018 ApartmentUnit | Feb. 01, 2018 ApartmentUnit
--- | --- | --- | ---
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items] |  |  |
Number of states in which entity operates | State | 11 |  |
Properties | Property | 306 |  |
Apartment units | 79,260 |  |
Master-Leased Properties - Consolidated |  |  |
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items] |  |  |
Properties | Property | 1 |  |
Apartment units | 162 |  |
Master-Leased Properties - Consolidated | Boston |  |  |
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items] |  |  |
Number of self managed apartments |  |  | 94
Master-Leased Properties - Consolidated | Los Angeles |  |  |
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items] |  |  |
Number of self managed apartments |  | 597 |
ERPOP [Member] |  |  |
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items] |  |  |
Noncontrolling interest, ownership percentage by parent | 96.30% |  |

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

X
- Definition Organization consolidation and presentation of financial statements disclosure. + References No definition available. + Details
Name: | eqr_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureLineItems
Namespace Prefix: | eqr_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The parent entity's interest in net assets of the subsidiary, expressed as a percentage. + References No definition available. + Details
Name: | us-gaap_MinorityInterestOwnershipPercentageByParent
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The number of real estate properties owned as of the balance sheet date. + References No definition available. + Details
Name: | us-gaap_NumberOfRealEstateProperties
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition The number of states the entity operates in as of the balance sheet date. + References No definition available. + Details
Name: | us-gaap_NumberOfStatesInWhichEntityOperates
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition The number of units in a real estate property owned as of the balance sheet date. + References No definition available. + Details
Name: | us-gaap_NumberOfUnitsInRealEstateProperty
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_RealEstatePropertiesAxis=eqr_MasterLeasedPropertiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

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

X
- Details
Name: | srt_OwnershipAxis=eqr_ERPOPMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |