Name:	eqr_LimitedPartnersChangeInCarryingValue
Namespace Prefix:	eqr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Change in the value of Redeemable Limited Partners Units as a result of changes in the fair value of the company's common shares during the period.

No definition available.

Name:	eqr_LimitedPartnersChangeInRedemptionValue
Namespace Prefix:	eqr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Represents the change in the proportional relationship between the carrying values of equity associated with common shares relative to that of the noncontrolling interests.

No definition available.

Name:	eqr_MinorityInterestChangeInCarryingValue
Namespace Prefix:	eqr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

The greater of carrying value (book value) or fair market value of an entity's issued and outstanding stock which is not included within permanent equity in Stockholders Equity. Temporary equity is a security with redemption features that are outside the control of the issuer, is not classified as an asset or liability in conformity with GAAP, and is not mandatorily redeemable. Includes any type of security that is redeemable at a fixed or determinable price or on a fixed or determinable date or dates, is redeemable at the option of the holder, or has conditions for redemption which are not solely within the control of the issuer. If convertible, the issuer does not control the actions or events necessary to issue the maximum number of shares that could be required to be delivered under the conversion option if the holder exercises the option to convert the stock to another class of equity.

No definition available.

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

Value of parent company common shares that would be issued in exchange for Redeemable Limited Partner Units at the ending of the period.

No definition available.

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

Change in noncontrolling interest during the period as a result of a change in the redemption value of redeemable noncontrolling interest.

No definition available.