Benefit Plans (Schedule Of Components Of Net Periodic Benefit Cost (Income)) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Pension [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 18	$ 18	$ 37	$ 35
Interest cost	63	75	126	152
Expected return on plan assets	(125)	(143)	(251)	(288)
Amortization:
Net loss	26	38	53	80
Prior service cost (credit)	1	2	2	3
Curtailment	0	0	0	7
Net periodic benefit (income) cost	(17)	(10)	(33)	(11)
Postretirement [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	4	4	8	8
Interest cost	15	20	30	40
Expected return on plan assets	(4)	(3)	(7)	(7)
Amortization:
Net loss	4	3	7	6
Prior service cost (credit)	(8)	(7)	(15)	(14)
Curtailment	0	0	0	5
Net periodic benefit (income) cost	$ 11	$ 17	$ 23	$ 38