Significant Accounting Policies (Details 6) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Significant Accounting Policies
Interest expense	$ (230,974)	$ (254,930)	$ (463,147)	$ (509,164)
Other Income	139,607	37,944	188,191	84,932
Net income attributable to noncontrolling interests	(80,748)	(70,047)	(143,248)	(128,667)
NET INCOME ATTRIBUTABLE TO COMMON STOCKHOLDERS	$ 472,944	$ 406,587	835,118	748,235
Accumulated Net Gain (Loss) from Derivatives Including Portion Attributable to Noncontrolling Interest | Amount reclassified from accumulated other comprehensive income (loss)
Significant Accounting Policies
Interest expense			(5,278)	(5,274)
Accumulated Net Gain (Loss) from Derivatives Attributable to Noncontrolling Interest | Amount reclassified from accumulated other comprehensive income (loss)
Significant Accounting Policies
Net income attributable to noncontrolling interests			757	768
Accumulated derivative losses, net | Amount reclassified from accumulated other comprehensive income (loss)
Significant Accounting Policies
NET INCOME ATTRIBUTABLE TO COMMON STOCKHOLDERS			(4,521)	$ (4,506)
Accumulated Net Investment Gain (Loss) Including Portion Attributable to Noncontrolling Interest | Amount reclassified from accumulated other comprehensive income (loss)
Significant Accounting Policies
Other Income			80,187
Accumulated Net Investment Gain (Loss) Attributable to Noncontrolling Interest | Amount reclassified from accumulated other comprehensive income (loss)
Significant Accounting Policies
Net income attributable to noncontrolling interests			(11,502)
Net gains (losses) on marketable securities | Amount reclassified from accumulated other comprehensive income (loss)
Significant Accounting Policies
NET INCOME ATTRIBUTABLE TO COMMON STOCKHOLDERS			$ 68,685