Fair Value of Financial Instruments Fair Value of Financial Instruments (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
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	$ 0
Defined Benefit Plan, Transfers Between Measurement Levels	0	0	0	0
Long-term Debt, Fair Value	1,927,000,000		1,927,000,000		1,949,000,000
Long-term Debt	1,761,000,000		1,761,000,000		1,636,000,000
Cash Surrender Value, Fair Value Disclosure	$ 25,000,000		$ 25,000,000		$ 23,000,000