Fair Value of Financial Instruments (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Net realized losses	$ 1,000,000	$ 1,000,000
Long-term Debt, Fair Value	2,074,000,000	1,949,000,000
Long-term Debt	1,916,000,000	1,636,000,000
Defined Benefit Plan, Transfers Between Measurement Levels	0	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	$ 0	$ 0