Benefit Plans (Schedule Of Components Of Net Periodic Benefit Cost (Income)) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Pension [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 17	$ 20	$ 52	$ 61
Interest cost	77	69	229	207
Expected return on plan assets	(143)	(146)	(431)	(438)
Amortization:
Net loss	39	56	119	168
Prior service cost (credit)	1	1	4	3
Curtailment	0	0	7	0
Net periodic benefit (income) cost	(9)	0	(20)	1
Postretirement [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	4	4	12	13
Interest cost	17	15	57	52
Expected return on plan assets	(4)	(5)	(11)	(14)
Amortization:
Net loss	(3)	(1)	3	16
Prior service cost (credit)	(8)	(10)	(22)	(31)
Curtailment	0	0	5	0
Net periodic benefit (income) cost	$ 6	$ 3	$ 44	$ 36