Capital Stock (Details) - USD ($)				12 Months Ended			27 Months Ended
	Mar. 01, 2016	Feb. 01, 2016	Jan. 15, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2015	Feb. 04, 2016	May. 27, 2014	Apr. 01, 2014	Sep. 18, 2013
Class of Stock [Line Items]
Preferred stock dividends paid				$ 0	$ 15,000,000	$ 29,000,000
Common stock dividends paid				$ 68,000,000	$ 60,000,000	$ 12,000,000
Cash dividends declared per common share (in dollars per share)				$ 0.25	$ 0.22	$ 0.05
Payments for repurchase of common stock				$ 180,000,000	$ 234,000,000	$ 4,000,000
Aggregate treasury stock shares repurchased							14,507,718
Aggregate treasury stock repurchased, average cost per share							$ 28.49
Aggregate payments for repurchase of common stock							$ 413,000,000
Preferred Stock
Class of Stock [Line Items]
Shares converted from preferred stock										27,573,735
Rate of conversion from preferred to common stock (in shares)										2.7574
Preferred stock dividends paid					15,000,000	29,000,000
Common Stock
Class of Stock [Line Items]
Common stock dividends paid				$ 68,000,000	$ 60,000,000	$ 12,000,000
Stock repurchase program, authorized amount									$ 450,000,000		$ 100,000,000
Treasury stock shares repurchased				5,571,909
Treasury stock repurchased, average cost per share				$ 32.32
Payments for repurchase of common stock				$ 180,000,000
Subsequent Event | Common Stock
Class of Stock [Line Items]
Dividends payable, date declared			Jan. 15, 2016
Cash dividends declared per common share (in dollars per share)			$ 0.07
Dividends declared on common stock			$ 19,000,000
Dividends payable, date of record		Feb. 01, 2016
Stock repurchase program, authorized amount								$ 1,100,000,000.0
Payments for Share Repurchases Related to Employee Stock Based Compensation | Common Stock
Class of Stock [Line Items]
Treasury stock shares repurchased				75,520
Scenario, Forecast | Common Stock
Class of Stock [Line Items]
Dividends payable, date to be paid	Mar. 01, 2016