Equity, Capital and Other Interests (Tables)

3 Months Ended

Mar. 31, 2012

Common shares and units rollforward

	2012
Common Shares
Common Shares outstanding at January 1,	297,508,185
Common Shares Issued:
Conversion of OP Units	31,361
Issuance of Common Shares	2,078,310
Exercise of share options	690,340
Employee Share Purchase Plan (ESPP)	85,837
Restricted share grants, net	128,136
Common Shares outstanding at March 31,	300,522,169
Units
Units outstanding at January 1,	13,492,543
LTIP Units, net	70,235
Conversion of OP Units to Common Shares	(31,361	)
Units outstanding at March 31,	13,531,417
Total Common Shares and Units outstanding at March 31,	314,053,586
Units Ownership Interest in Operating Partnership	4.3	%

Redeemable Noncontrolling Interest [Table Text Block]

	2012
Balance at January 1,	$	416,404
Change in market value	37,603
Change in carrying value	3,217
Balance at March 31,	$	457,224

Schedule Of Preferred Stock [Table Text Block]

				Amounts in thousands
	Redemption Date (1)	Annual Dividend per Share (2)		March 31, 2012		December 31, 2011
Preferred Shares of beneficial interest, $0.01 par value;   100,000,000 shares authorized:
8.29% Series K Cumulative Redeemable Preferred; liquidation   value $50 per share; 1,000,000 shares issued and outstanding   at March 31, 2012 and December 31, 2011	12/10/26		$4.145	$	50,000	$	50,000
6.48% Series N Cumulative Redeemable Preferred; liquidation   value $250 per share; 600,000 shares issued and outstanding   at March 31, 2012 and December 31, 2011 (3)	06/19/08		$16.20	150,000		150,000
				$	200,000	$	200,000

(1) On or after the redemption date, redeemable preferred shares (Series K and N) may be redeemed for cash at the option of the Company, in whole or in part, at a redemption price equal to the liquidation price per share, plus accrued and unpaid distributions, if any.

(2) Dividends on all series of Preferred Shares are payable quarterly at various pay dates. The dividend listed for Series N is a Preferred Share rate and the equivalent Depositary Share annual dividend is $1.62 per share.

(3) The Series N Preferred Shares have a corresponding depositary share that consists of ten times the number of shares and one-tenth the liquidation value and dividend per share.

Limited Partner [Member]

Common shares and units rollforward

	2012
General and Limited Partner Units
General and Limited Partner Units outstanding at January 1,	311,000,728
Issued to General Partner:
Issuance of OP Units	2,078,310
Exercise of EQR share options	690,340
EQR’s Employee Share Purchase Plan (ESPP)	85,837
EQR's restricted share grants, net	128,136
Issued to Limited Partners:
LTIP Units, net	70,235
General and Limited Partner Units outstanding at March 31,	314,053,586
Limited Partner Units
Limited Partner Units outstanding at January 1,	13,492,543
Limited Partner LTIP Units, net	70,235
Conversion of Limited Partner OP Units to EQR Common Shares	(31,361	)
Limited Partner Units outstanding at March 31,	13,531,417
Limited Partner Units Ownership Interest in Operating Partnership	4.3	%

Redeemable Noncontrolling Interest [Table Text Block]

	2012
Balance at January 1,	$	416,404
Change in market value	37,603
Change in carrying value	3,217
Balance at March 31,	$	457,224

Schedule Of Preferred Stock [Table Text Block]

				Amounts in thousands
	Redemption Date (1)	Annual Dividend per Unit (2)		March 31, 2012		December 31, 2011
Preference Units:
8.29% Series K Cumulative Redeemable Preference Units;   liquidation value $50 per unit; 1,000,000 units issued and   outstanding at March 31, 2012 and December 31, 2011	12/10/26		$4.145	$	50,000	$	50,000
6.48% Series N Cumulative Redeemable Preference Units;   liquidation value $250 per unit; 600,000 units issued and   outstanding at March 31, 2012 and December 31, 2011 (3)	06/19/08		$16.20	150,000		150,000
				$	200,000	$	200,000

(1) On or after the redemption date, redeemable preference units (Series K and N) may be redeemed for cash at the option of the Operating Partnership, in whole or in part, at a redemption price equal to the liquidation price per unit, plus accrued and unpaid distributions, if any, in conjunction with concurrent redemption of the corresponding Company Preferred Shares.

(2) Dividends on all series of Preference Units are payable quarterly at various pay dates. The dividend listed for Series N is a Preference Unit rate and the equivalent depositary unit annual dividend is $1.62 per unit.

(3) The Series N Preference Units have a corresponding depositary unit that consists of ten times the number of units and one-tenth the liquidation value and dividend per unit.