Restructuring - Restructuring Reserve Roll Forward (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Restructuring Reserve [Roll Forward]
Beginning balance	$ 3	$ 5
Charges	9	8	24
Payments and other adjustments	(12)	(10)
Ending balance	0	3	5
Employee Termination Benefits
Restructuring Reserve [Roll Forward]
Beginning balance	3	4
Charges	9	6
Payments and other adjustments	(12)	(7)
Ending balance	0	3
Other Restructuring Costs
Restructuring Reserve [Roll Forward]
Beginning balance	0	1
Charges	0	2
Payments and other adjustments	0	(3)
Ending balance	$ 0	$ 0