CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	50,000,000	50,000,000
Preferred stock, shares issued	4,475,000	3,375,000
Preferred stock, shares outstanding	4,475,000	3,375,000
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	1,000,000,000	1,000,000,000
Common stock, shares issued	653,736,607	648,317,395
Common stock, shares outstanding	480,218,547	527,259,920
Treasury stock, common, shares	173,518,060	121,057,475