CONSOLIDATED STATEMENTS OF EQUITY - USD ($) shares in Thousands, $ in Thousands	Total Stockholders' Equity	Common Stock	Additional Paid-In Capital	Cumulative Dividends In Excess Of Earnings	Accumulated Other Comprehensive Loss	Noncontrolling Interests	Total
Balance at Dec. 31, 2014	$ 10,735,297	$ 459,746	$ 11,431,987	$ (1,132,541)	$ (23,895)	$ 261,802	$ 10,997,099
Balance (in shares) at Dec. 31, 2014		459,746
Increase (Decrease) in Stockholders' Equity
Net income (loss)	(75,729)			(75,729)		5,974	(69,755)
Other comprehensive income	(8,220)				(8,220)		(8,220)
Issuance of common stock, net	68,141	$ 2,094	66,047			(2,448)	65,693
Issuance of common stock, net (in shares)		2,094
Conversion of DownREIT units (in shares)		70
Repurchase of common stock	(7,690)	$ (171)	(7,519)				(7,690)
Repurchase of common stock (in shares)		(171)
Exercise of stock options	27,425	$ 817	26,608				27,425
Exercise of stock options (in shares)		817
Amortization of deferred compensation	15,724		15,724				15,724
Common dividends	(521,898)			(521,898)			(521,898)
Distributions to noncontrolling interests	(263)		(263)			(8,143)	(8,406)
Issuance of noncontrolling interests						37,025	37,025
Balance at Jun. 30, 2015	10,232,787	$ 462,486	11,532,584	(1,730,168)	(32,115)	294,210	10,526,997
Balance (in shares) at Jun. 30, 2015		462,486
Balance at Dec. 31, 2015	9,343,643	$ 465,488	11,647,039	(2,738,414)	(30,470)	402,674	9,746,317
Balance (in shares) at Dec. 31, 2015		465,488
Increase (Decrease) in Stockholders' Equity
Net income (loss)	417,836			417,836		6,751	424,587
Other comprehensive income	(268)				(268)		(268)
Issuance of common stock, net	43,072	$ 1,715	41,357				43,072
Issuance of common stock, net (in shares)		1,715
Conversion of DownREIT units to common stock	5,022	$ 120	4,902			(5,022)
Conversion of DownREIT units (in shares)		120
Repurchase of common stock	(3,874)	$ (109)	(3,765)				(3,874)
Repurchase of common stock (in shares)		(109)
Exercise of stock options	2,852	$ 111	2,741				2,852
Exercise of stock options (in shares)		111
Amortization of deferred compensation	9,505		9,505				9,505
Common dividends	(537,061)			(537,061)			(537,061)
Distributions to noncontrolling interests	(36)		(36)			(12,437)	(12,473)
Issuance of noncontrolling interests						3,225	3,225
Deconsolidation of noncontrolling interests	439		(36)	475		67	506
Balance at Jun. 30, 2016	$ 9,281,130	$ 467,325	$ 11,701,707	$ (2,857,164)	$ (30,738)	$ 395,258	$ 9,676,388
Balance (in shares) at Jun. 30, 2016		467,325