Fair Values Of Assets And Liabilities Level 3 Rollforward (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013 Interest Rate Swap [Member]	Mar. 31, 2012 Interest Rate Swap [Member]	Dec. 31, 2011 Interest Rate Swap [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest Rate Swap Agreements - Assets	$ 7		$ 7
Interest Rate Swap Agreements - Liabilities	20		20
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	2		2
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings	(4)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	(2)	(2)	(2)	(2)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements	2	2	2	6
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net			(4)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	7		7
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases	(18)		(18)
Fair Value Hedge Assets					7	2	2
Fair Value Hedge Liabilities					$ (20)	$ (2)	$ (6)