Transactions With Related Parties	12 Months Ended
Transactions With Related Parties	Dec. 31, 2011
Transactions With Related Parties [Abstract]
Related Party Transactions Disclosure [Text Block]	Transactions with Related Parties Pursuant to the terms of the partnership agreement for the Operating Partnership, ERPOP is required to reimburse EQR for all expenses incurred by EQR in excess of income earned by EQR through its indirect 1% ownership of various entities. Amounts paid on behalf of EQR are reflected in the consolidated statements of operations as general and administrative expenses. The Company leases its corporate headquarters from an entity controlled by EQR’s Chairman of the Board of Trustees. The lease terminates on January 31, 2022. Amounts incurred for such office space for the years ended December 31, 2011, 2010 and 2009, respectively, were approximately $2.2 million, $2.7 million and $3.0 million. The Company believes these amounts equal market rates for such rental space.

The entire disclosure for related party transactions, including the nature of the relationship(s), a description of the transactions, the amount of the transactions, the effects of any change in the method of establishing the terms of the transaction from the previous period, stated interest rate, expiration date, terms and manner of settlement per the agreement with the related party, and amounts due to or from related parties. If the entity and one or more other entities are under common ownership or management control and this control affects the operating results or financial position, disclosure includes the nature of the control relationship even if there are no transactions between the entities. Disclosure may also include the aggregate amount of current and deferred tax expense for each statement of earnings presented where the entity is a member of a group that files a consolidated tax return, the amount of any tax related balances due to or from affiliates as of the date of each statement of financial position presented, the principal provisions of the method by which the consolidated amount of current and deferred tax expense is allocated to the members of the group and the nature and effect of any changes in that method. Examples of related party transactions include transactions between (a) a parent company and its subsidiary; (b) subsidiaries of a common parent; (c) and entity and its principal owners; and (d) affiliates.

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