Capital Stock (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended			0 Months Ended	9 Months Ended		0 Months Ended		3 Months Ended	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013	Apr. 01, 2014 Preferred Stock	Sep. 30, 2014 Preferred Stock	Apr. 01, 2014 Preferred Stock	May 27, 2014 Common Stock	Sep. 18, 2013 Common Stock	Sep. 30, 2014 Common Stock	Sep. 30, 2014 Common Stock
Class of Stock [Line Items]
Preferred Stock, Liquidation Preference Per Share	$ 50		$ 50		$ 50
Convertible Preferred Stock, Conversion Date						Apr. 01, 2014
Convertible Preferred Stock, Aggregate Shares Issued upon Conversion								27,573,735
Convertible Preferred Stock, Shares Issued upon Conversion								2.7574
Payments of Ordinary Dividends, Preferred Stock and Preference Stock			$ 15	$ 22			$ 15
Dividends Payable, Date Declared												Oct. 06, 2014
Dividends Payable, Date of Record												Oct. 31, 2014
Dividends Payable, Date to be Paid												Dec. 01, 2014
Payments of Ordinary Dividends, Common Stock			43	0								43
Common Stock, Dividends, Per Share, Declared	$ 0.06	$ 0.05	$ 0.16	$ 0.05								$ 0.06
Dividends, Common Stock, Cash												16
Stock Repurchase Program, Authorized Amount									450	100
Share Repurchase Program Expiration Date												Dec. 31, 2016
Treasury Stock, Shares, Acquired											1,200,000	3,200,000
Payments for Repurchase of Common Stock			97	1							30	83
Treasury Stock Acquired, Average Cost Per Share											$ 24.75	$ 26.03
Share Repurchases Related To Employee Stock Based Compensation Awards											114,580	536,829
Payments for Share Repurchases Related To Employee Stock Based Compensation Awards											$ 3	$ 14
Payments Per Share for Share Repurchases Related To Employee Stock Based Compensation Award											$ 26.20	$ 26.69