Employee Benefit Plans And Other Postretirement Benefits (Schedule Of Pension Plans With PBO And ABO In Excess Of Fair value Of Plan Assets) (Details) (Pension Plan Assets [Member], USD $) In Billions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012 benefit_plan
Pension Plan Assets [Member]
Defined Benefit Plan, Plans with Benefit Obligations in Excess of Plan Assets [Abstract]
PBO	$ 1.8
Fair value of plan assets	1.5
Number of plans	1
Defined Benefit Plan, Pension Plans with Accumulated Benefit Obligations in Excess of Plan Assets [Abstract]
ABO	1.7
Fair value of plan assets	$ 1.5
Number of plans	1