Equity, Capital and Other Interest Redeemable (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
Sep. 30, 2013	Dec. 31, 2012
Redeemable Noncontrolling Interests - Operating Partnership	$ 376,057	$ 398,372
Change in market value	(69,344)
Change in carrying value	47,029
Limited Partners Change In Redemption Value	(69,344)
Limited Partners Change In Carrying Value	47,029
Partnership Interest [Member]
Redeemable Limited Partners	$ 376,057	$ 398,372

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