Valuation and Qualifying Accounts (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Allowance for doubtful accounts and notes receivable deducted from assets to which it applies:
Balance at Beginning of Year	$ 20	$ 25	$ 24
Charged to Costs and Expenses	1	2	5
Charged to Other Accounts	0	0	0
Deductions	4	7	4
Balance at End of Year	$ 17	$ 20	$ 25