Income Taxes (Schedule of Income Tax Provision (Benefit)) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Current
US	$ 41	$ 24	$ 62
International	77	32	35
Total	118	56	97
Deferred
US	5	89	16
International	(75)	4	(1)
Total	(70)	93	15
Income tax provision (benefit)	$ 48	$ 149	$ 112