Fair Value of Financial Instruments Fair Value of Financial Instruments (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Dec. 31, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3			$ 0
Defined Benefit Plan, Transfers Between Measurement Levels	1,000,000	0	0
Long-term Debt, Fair Value	2,059,000,000		2,059,000,000	2,091,000,000
Long-term Debt	1,736,000,000		1,736,000,000	1,735,000,000
Cash Surrender Value, Fair Value Disclosure	$ 23,000,000		$ 23,000,000	$ 23,000,000