CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Class of Stock [Line Items]
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	1,000,000,000	1,000,000,000
Common stock, shares issued	426,307,336	399,508,751
Common stock, shares outstanding	423,497,310	396,698,725
Treasury stock, shares	2,810,026	2,810,026
Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares authorized	20,000,000	20,000,000
Series A Preferred Stock
Class of Stock [Line Items]
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares issued	6,000,000	6,000,000
Preferred stock, shares outstanding	6,000,000	6,000,000
Preferred stock, aggregate liquidation value	$ 600,000,000	$ 600,000,000
Preferred stock, dividend rate (percent)	5.25%	5.25%
Series B Preferred Stock
Class of Stock [Line Items]
Preferred stock, par value (in dollars per share)	$ 0.01
Preferred stock, shares issued	1,375,000
Preferred stock, shares outstanding	1,375,000
Preferred stock, aggregate liquidation value	$ 13,750,000
Preferred stock, dividend rate (percent)	5.50%