Benefit Plans (Schedule Of Components Of Net Periodic Benefit Cost (Income)) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Pension [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 18	$ 17	$ 55	$ 52
Interest cost	62	77	188	229
Expected return on plan assets	(125)	(143)	(376)	(431)
Amortization:
Net loss	55	39	108	119
Prior service cost (credit)	2	1	4	4
Curtailment	0	0	0	7
Net periodic benefit (income) cost	12	(9)	(21)	(20)
Postretirement [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	5	4	13	12
Interest cost	14	17	44	57
Expected return on plan assets	(4)	(4)	(11)	(11)
Amortization:
Net loss	0	(3)	7	3
Prior service cost (credit)	(7)	(8)	(22)	(22)
Curtailment	0	0	0	5
Net periodic benefit (income) cost	$ 8	$ 6	$ 31	$ 44