Benefit Plans (Schedule of Components of Net Periodic Pension Cost) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Pension [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 68	$ 74	$ 70
Interest cost	184	251	306
Expected return on plan assets	(522)	(502)	(576)
Amortization:
Net loss	131	134	159
Prior service cost (credit)	5	5	6
Settlement and curtailment	0	10	27
Net periodic benefit cost (income)	(134)	(28)	(8)
Postretirement Benefit Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	20	16	16
Interest cost	38	59	76
Expected return on plan assets	(14)	(14)	(15)
Amortization:
Net loss	22	10	5
Prior service cost (credit)	(46)	(30)	(30)
Settlement and curtailment	0	0	5
Net periodic benefit cost (income)	$ 20	$ 41	$ 57