Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income (loss) from continuing operations	$ 907,621	$ 657,101	$ (168,174)
Income (Loss) Attributable to Noncontrolling Interest	(34,226)	(24,771)	6,834
Net (income) loss attributable to Noncontrolling Interests – Partially Owned Properties	(3,657)	(2,544)	538
Preferred distributions	(3,357)	(4,145)	(4,145)
Preferred Stock Redemption Premium	(3,486)	0	0
Income (loss) from continuing operations available to Common Shares, net of Noncontrolling Interests	862,895	625,641	(164,947)
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	382	1,522	1,991,415
Numerator for net income per share – basic	863,277	627,163	1,826,468
Income From Continuing Operations Available To Common Shares	897,121	650,412
Discontinued operations, net	397	1,582	2,073,527
Net Income (Loss) Available to Common Stockholders, Diluted	$ 897,518	$ 651,994	$ 1,826,468
Weighted average Common Shares outstanding	363,498	361,181	354,305
Dilutive Op Units	13,576	13,718
Dilutive Securities Options	3,546	2,836
Weighted average Common Shares outstanding	380,620	377,735	354,305
Earnings Per Share, Basic	$ 2.37	$ 1.74	$ 5.16
Earnings Per Share, Diluted	2.36	1.73	5.16
Income (loss) from continuing operations available to Common Shares	2.37	1.73	(0.47)
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic Share	0.00	0.01	5.63
Income (loss) from continuing operations available to Common Shares	2.36	1.72	(0.47)
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Diluted Share	$ 0.00	$ 0.01	$ 5.63
ERPOP [Member]
Income (loss) from continuing operations	$ 907,621	$ 657,101	$ (168,174)
Net (income) loss attributable to Noncontrolling Interests – Partially Owned Properties	(3,657)	(2,544)	538
Preferred Stock Redemption Premium	(3,486)	0	0
Discontinued operations, net	$ 397	$ 1,582	$ 2,073,527
Dilutive Securities Options	3,546	2,836
Weighted average Common Shares outstanding	380,620	377,735	368,038
Earnings Per Share, Basic	$ 2.37	$ 1.74	$ 5.16
Earnings Per Share, Diluted	2.36	1.73	5.16
Income (loss) from continuing operations available to Common Shares	2.37	1.73	(0.47)
Income (loss) from continuing operations available to Common Shares	$ 2.36	$ 1.72	$ (0.47)
Allocation to Preference Units	$ (3,357)	$ (4,145)	$ (4,145)
Income Loss From Continuing Operations Available To Units	897,121	650,412	(171,781)
Numerator for net income per Unit – basic and diluted (1)	$ 897,518	$ 651,994	$ 1,901,746
Weighted Average Limited Partnership and General Partnership Units Outstanding, Basic	377,074	374,899	368,038
Income (Loss) from Discontinued Operations, Net of Tax, Per Outstanding Limited Partnership and General Partnership Unit, Basic	$ 0.00	$ 0.01	$ 5.63
Income Loss From Discontinued Operations Net Of Tax Per Outstanding Limited Partnership And General Partnership net Diluted	$ 0.00	$ 0.01	$ 5.63