Capital Stock (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended			3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013	Mar. 31, 2014 Preferred Stock	Mar. 31, 2014 Common Stock	Apr. 01, 2014 Subsequent Event Preferred Stock
Class of Stock [Line Items]
Preferred Stock, Shares Issued				10,000,000
Preferred Stock, Dividend Rate, Percentage				5.875%
Preferred Stock, Liquidation Preference Per Share	$ 50		$ 50	$ 50.00
Preferred Stock, Dividend Payment Terms				Dividends were paid in cash on January 1, April 1, July 1 and October 1 of each year, commencing on July 1, 2011 and ending on April 1, 2014.
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	$ 7	$ 7		$ 7
Dividends Payable, Date Declared				Mar. 06, 2014	Apr. 14, 2014
Dividends Payable, Amount Per Share				$ 0.7344
Dividends Payable				7
Dividends Payable, Date to be Paid				Apr. 01, 2014	Jun. 02, 2014
Dividends Payable, Date of Record					May 01, 2014
Payments of Ordinary Dividends, Common Stock	12	0			12
Common Stock, Dividends, Per Share, Declared	$ 0.05	$ 0.00			$ 0.05
Dividends, Common Stock, Cash					14
Stock Repurchase Program, Authorized Amount					100
Share Repurchase Program Expiration Date					Sep. 20, 2016
Treasury Stock Acquired, Average Cost Per Share					$ 27.12
Treasury Stock, Shares, Acquired					850,000
Payments for Repurchase of Common Stock	$ 32	$ 0			$ 23