Derivatives and Hedging (Details 2) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Other current assets | Derivatives designated as hedging instruments
Aggregate carrying amount of derivatives
Interest rate swaps, fair value hedges	$ 5	$ 4
Other assets | Derivatives designated as hedging instruments
Aggregate carrying amount of derivatives
Interest rate swaps, fair value hedges	31	17
Other long-term liabilities | Derivatives designated as hedging instruments
Aggregate carrying amount of derivatives
Interest rate swaps, cash flow hedges	16	13
Cross-currency swaps, cash flow hedges	7
Other long-term liabilities | Nondesignated
Aggregate carrying amount of derivatives
Interest rate swaps not designated as hedging instruments	$ 15