Income Taxes (Details 4) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
	Sep. 30, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Progression of the liability for uncertain tax positions, excluding interest and penalties
Balance at January 1		$ 18	$ 59	$ 52
Reductions for tax positions of prior years	(10)	0	(46)	0
Additions for tax positions of current year		1	5	7
Balance at December 31		$ 19	$ 18	$ 59