Distribution Reinvestment and Share Purchase Plan	12 Months Ended
Dec. 31, 2012
Distribution Reinvestment and Share Purchase Plan [Abstract]
Distribution Reinvestment and Share Purchase Plan	Distribution Reinvestment and Share Purchase Plan On December 16, 2008, the Company filed with the SEC a Form S-3 Registration Statement to register 5,000,000 Common Shares pursuant to a Distribution Reinvestment and Share Purchase Plan (the "DRIP Plan"). The registration statement was automatically declared effective the same day and was to expire at the earlier of the date on which all 5,000,000 shares had been issued or December 16, 2011. On November 18, 2011, the Company filed with the SEC a Form S-3 Registration Statement to register 4,850,000 Common Shares under the DRIP Plan, which included the remaining shares available for issuance under the 2008 registration, which terminated as of such date. The registration statement was automatically declared effective the same day and expires at the earlier of the date on which all 4,850,000 shares have been issued or November 18, 2014. The Company has 4,833,763 Common Shares available for issuance under the DRIP Plan at December 31, 2012. The DRIP Plan provides holders of record and beneficial owners of Common Shares and Preferred Shares with a simple and convenient method of investing cash distributions in additional Common Shares (which is referred to herein as the “Dividend Reinvestment – DRIP Plan”). Common Shares may also be purchased on a monthly basis with optional cash payments made by participants in the DRIP Plan and interested new investors, not currently shareholders of EQR, at the market price of the Common Shares less a discount ranging between 0% and 5%, as determined in accordance with the DRIP Plan (which is referred to herein as the “Share Purchase – DRIP Plan”). Common Shares purchased under the DRIP Plan may, at the option of EQR, be directly issued by EQR or purchased by EQR's transfer agent in the open market using participants’ funds. The net proceeds from any Common Share issuances are contributed to ERPOP in exchange for OP Units.

Distribution Reinvestment and Share Purchase Plan

On December 16, 2008, the Company filed with the SEC a Form S-3 Registration Statement to register 5,000,000 Common Shares pursuant to a Distribution Reinvestment and Share Purchase Plan (the "DRIP Plan"). The registration statement was automatically declared effective the same day and was to expire at the earlier of the date on which all 5,000,000 shares had been issued or December 16, 2011. On November 18, 2011, the Company filed with the SEC a Form S-3 Registration Statement to register 4,850,000 Common Shares under the DRIP Plan, which included the remaining shares available for issuance under the 2008 registration, which terminated as of such date. The registration statement was automatically declared effective the same day and expires at the earlier of the date on which all 4,850,000 shares have been issued or November 18, 2014. The Company has 4,833,763 Common Shares available for issuance under the DRIP Plan at December 31, 2012.

The DRIP Plan provides holders of record and beneficial owners of Common Shares and Preferred Shares with a simple and convenient method of investing cash distributions in additional Common Shares (which is referred to herein as the “Dividend Reinvestment – DRIP Plan”). Common Shares may also be purchased on a monthly basis with optional cash payments made by participants in the DRIP Plan and interested new investors, not currently shareholders of EQR, at the market price of the Common Shares less a discount ranging between 0% and 5%, as determined in accordance with the DRIP Plan (which is referred to herein as the “Share Purchase – DRIP Plan”). Common Shares purchased under the DRIP Plan may, at the option of EQR, be directly issued by EQR or purchased by EQR's transfer agent in the open market using participants’ funds. The net proceeds from any Common Share issuances are contributed to ERPOP in exchange for OP Units.