Employee Benefit Plans (Schedule Of Estimated Benefits Expected To Be Paid) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Pension Plans Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
2016	$ 695
2017	739
2018	780
2019	818
2020	854
Thereafter in the succeeding five years	4,728
Employer contribution	334	$ 332
Expected employer contribution next year	327
Other Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
2016	89
2017	95
2018	101
2019	107
2020	113
Thereafter in the succeeding five years	593
Employer contribution	61	$ 57
Expected employer contribution next year	61
Federal Subsidy [Member]
Defined Benefit Plan Disclosure [Line Items]
2016	(6)
2017	(7)
2018	(7)
2019	(8)
2020	(8)
Thereafter in the succeeding five years	$ (17)