Benefit Plans (Schedule Of Components Of Net Periodic Benefit Cost (Income)) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Pension [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 19	$ 17
Interest cost	63	77
Expected return on plan assets	(126)	(145)
Amortization:
Net loss	27	42
Prior service cost (credit)	1	1
Curtailment	0	7
Net periodic benefit (income) cost	(16)	(1)
Postretirement [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	4	4
Interest cost	15	20
Expected return on plan assets	(3)	(4)
Amortization:
Net loss	3	3
Prior service cost (credit)	(7)	(7)
Curtailment	0	5
Net periodic benefit (income) cost	$ 12	$ 21