Benefit Plans (Schedule Of Components Of Net Periodic Benefit Cost (Income)) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Pension [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 17	$ 18	$ 51	$ 55
Interest cost	46	62	139	188
Expected return on plan assets	(131)	(125)	(393)	(376)
Amortization:
Net loss	33	55	99	108
Prior service cost (credit)	1	2	3	4
Net periodic benefit (income) cost	(34)	12	(101)	(21)
Postretirement [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	5	5	15	13
Interest cost	8	14	29	44
Expected return on plan assets	(2)	(4)	(10)	(11)
Amortization:
Net loss	2	0	16	7
Prior service cost (credit)	(20)	(7)	(35)	(22)
Net periodic benefit (income) cost	$ (7)	$ 8	$ 15	$ 31