Derivatives And Risk Management (Summary Of Before Tax Effect Of Fair Value Hedges Not Designated For Hedge Accounting) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Basis Swaps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) on Derivatives, Net of Settlement	$ (3)	$ (5)	$ (16)	$ 2
Derivative Instruments, Gain (Loss) on Derivatives, Settled	9	2		3
Fixed Price Call Options [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) on Derivatives, Net of Settlement	11	8	(11)	(27)
Fixed Price Swaps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) on Derivatives, Net of Settlement	45	8	24	96
Derivative Instruments, Gain (Loss) on Derivatives, Settled	15		(21)
Interest Rate Swaps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) on Derivatives, Net of Settlement	1	(1)	(4)	1
Derivative Instruments, Gain (Loss) on Derivatives, Settled			$ (1)