Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Income from continuing operations	$ 3,731,988	$ 190,069
Allocation to Noncontrolling Interests – Operating Partnership, net	(143,315)	(7,053)
Net (income) attributable to Noncontrolling Interests – Partially Owned Properties	(764)	(643)
Preferred distributions	(773)	(891)
Premium on redemption of Preferred Shares	0	(2,789)
Income from continuing operations available to Common Shares, net of Noncontrolling Interests	3,587,136	178,693
Discontinued operations, net of Noncontrolling Interests	(151)	149
Numerator for net income per share – basic	3,586,985	178,842
Income from continuing operations available to Common Shares	3,730,451	185,746
Discontinued operations, net	(157)	155
Numerator for net income per share – diluted	$ 3,730,294	$ 185,901
Denominator for net income per share – basic	364,592	363,098
Effect of dilutive securities - OP Units	13,697	13,598
Effect of dilutive securities - Long-term compensation shares/units	3,954	3,631
Denominator for net income per share – diluted	382,243	380,327
Net income available to Common Shares	$ 9.84	$ 0.49
Income from continuing operations available to Common Shares	9.84	0.49
Net income per share - basic - Discontinued operations, net of Noncontrolling Interests	0.00	0.00
Income from continuing operations available to Common Shares	9.76	0.49
Net income per share - diluted - discontinued operations, net	$ 0.00	$ 0.00
ERPOP [Member]
Income from continuing operations	$ 3,731,988	$ 190,069
Net (income) attributable to Noncontrolling Interests – Partially Owned Properties	(764)	(643)
Allocation to Preference Units	(773)	(891)
Premium on redemption of Preferred Shares	0	(2,789)
Discontinued operations, net	$ (157)	$ 155
Effect of dilutive securities - Long-term compensation shares/units	3,954	3,631
Denominator for net income per share – diluted	382,243	380,327
Net income available to Common Shares	$ 9.84	$ 0.49
Income from continuing operations available to Common Shares	9.84	0.49
Income from continuing operations available to Common Shares	$ 9.76	$ 0.49
Income from continuing operations available to Units	$ 3,730,451	$ 185,746
Numerator for net income per Unit – basic and diluted	$ 3,730,294	$ 185,901
Denominator for net income per Unit – basic	378,289	376,696
Net income per Unit - basic - Discontinued operations, net	$ 0.00	$ 0.00
Net income per Unit - diluted - Discontinued operations, net	$ 0.00	$ 0.00