v2.4.1.9

Commitments to Acquire/Dispose of Real Estate (Details) (USD $) In Thousands, unless otherwise specified	Apr. 30, 2015
Commitments to Acquire Real Estate
Properties Acquired-Total	0eqr_PropertiesContractedToBeAcquired
Rental Units Acquired - Total	0eqr_UnitsContractedToBeAcquired
Purchase Price - Total	$ 25,132
Commitments to Dispose of Real Estate
Properties Disposed - Total	2eqr_PropertiesContractedToBeDisposed
Rental Units Disposed-Total	513eqr_UnitsContractedToBeDisposed
Sales Price For Commitments To Dispose	71,350eqr_SalesPriceForCommitmentsToDispose
Rental Properties Disposed of [Member]
Commitments to Dispose of Real Estate
Properties Disposed - Total	2
Rental Units Disposed-Total	513
Sales Price For Commitments To Dispose	68,650
Land [Member]
Commitments to Dispose of Real Estate
Sales Price For Commitments To Dispose	2,700
Land Parcels Contracted To Be Disposed	1
Land [Member]
Commitments to Acquire Real Estate
Purchase Price - Total	$ 25,132
Land Parcels Contracted To Be Acquired	3

- Details

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

- Details

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

- Definition

Total number of land parcels to be acquired subsequent to the balance sheet date per separate agreements entered into prior to the balance sheet date.

+ References

No definition available.

+ Details

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

- Definition

Total number of land parcels to be disposed subsequent to the balance sheet date per separate agreements entered into prior to the balance sheet date.

+ References

No definition available.

+ Details

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

- Definition

Total number of rental properties to be acquired subsequent to the balance sheet date per separate agreements entered into prior to the balance sheet date.

+ References

No definition available.

+ Details

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

- Definition

Total number of rental properties to be disposed of subsequent to the balance sheet date per separate agreements entered into prior to the balance sheet date.

+ References

No definition available.

+ Details

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

- Definition

The amount of the fixed and determinable portion of an unrecorded purchase commitment for the acquisition of a rental property or land parcel subsequent to the balance sheet date.

+ References

No definition available.

+ Details

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

- Definition

The amount of the fixed and determinable portion of an unrecorded sales commitment for the disposition of a rental property, land parcel or other property subsequent to the balance sheet date.

+ References

No definition available.

+ Details

Name:	eqr_SalesPriceForCommitmentsToDispose
Namespace Prefix:	eqr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Total number of rental units to be acquired subsequent to the balance sheet date per separate agreements entered into prior to the balance sheet date.

+ References

No definition available.

+ Details

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

- Definition

Total number of rental units to be disposed of subsequent to the balance sheet date per separate agreements entered into prior to the balance sheet date.

+ References

No definition available.

+ Details

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

- Details

Name:	eqr_CommitmentsToAcquireAxis=us-gaap_LandMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	eqr_CommitmentsToDisposeOfAxis=eqr_RentalPropertiesDisposedOfMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	eqr_CommitmentsToDisposeOfAxis=us-gaap_LandMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

ERP OPERATING LTD PARTNERSHIP 10-Q