Leases (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Operating Leased Assets [Line Items]
Operating Leases, Rent Expense, Net	$ 90	$ 92	$ 102
Operating Leases, Future Minimum Payments Due, Current	73
Operating Leases, Future Minimum Payments, Due in Two Years	54
Operating Leases, Future Minimum Payments, Due in Three Years	35
Operating Leases, Future Minimum Payments, Due in Four Years	25
Operating Leases, Future Minimum Payments, Due in Five Years	22
Operating Leases, Future Minimum Payments, Due Thereafter	38
Operating Leases, Future Minimum Payments Due	$ 247