Benefit Plans (Schedule Of Components Of Net Periodic Benefit Cost (Income)) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Pension [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 18	$ 20	$ 35	$ 41
Interest cost	75	70	152	138
Expected return on plan assets	(143)	(146)	(288)	(292)
Amortization:
Net loss	38	55	80	112
Prior service cost (credit)	2	1	3	2
Curtailment	0	0	7	0
Net periodic benefit (income) cost	(10)	0	(11)	1
Postretirement [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	4	5	8	9
Interest cost	20	18	40	37
Expected return on plan assets	(3)	(4)	(7)	(9)
Amortization:
Net loss	3	8	6	17
Prior service cost (credit)	(7)	(11)	(14)	(21)
Curtailment	0	0	5	0
Net periodic benefit (income) cost	$ 17	$ 16	$ 38	$ 33