Capital Stock (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Apr. 01, 2014	May 27, 2014	Sep. 18, 2013
Class of Stock [Line Items]
Payments of Ordinary Dividends, Preferred Stock and Preference Stock	$ 0	$ 7
Payments of Ordinary Dividends, Common Stock	16	12
Common Stock, Dividends, Per Share, Declared	$ 0.06	$ 0.05
Payments for Repurchase of Common Stock	1	32
Preferred Stock
Class of Stock [Line Items]
Convertible Preferred Stock, Aggregate Shares Issued upon Conversion			27,573,735
Convertible Preferred Stock, Shares Issued upon Conversion			2.7574
Common Stock
Class of Stock [Line Items]
Dividends Payable, Date Declared	Apr. 13, 2015
Dividends Payable, Date of Record	May 01, 2015
Dividends Payable, Date to be Paid	Jun. 01, 2015
Payments of Ordinary Dividends, Common Stock	16
Common Stock, Dividends, Per Share, Declared	$ 0.06
Dividends, Common Stock, Cash	16
Stock Repurchase Program, Authorized Amount				450	100
Share Repurchase Program Expiration Date	Dec. 31, 2016
Common Stock | Payments for Share Repurchases Related to Employee Stock Based Compensation [Member]
Class of Stock [Line Items]
Treasury Stock, Shares, Acquired	39,351
Payments for Repurchase of Common Stock	$ 1
Treasury Stock Acquired, Average Cost Per Share	$ 27.07