Employee Benefit Plans (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Pension Plans [Member]
Components of net periodic benefit cost:
Service cost	$ 28	$ 37	$ 84	$ 114
Interest cost	30	22	90	64
Expected return on plan assets	(50)	(48)	(151)	(144)
Amortization of:
Net actuarial (gain) loss	(2)	14	(5)	40
Prior service credit	(5)	(5)	(14)	(14)
Settlement loss	0	12	0	12
Net periodic benefit cost	1	32	4	72
Other Postretirement Benefit Plans [Member]
Components of net periodic benefit cost:
Service cost	1	1	3	4
Interest cost	3	2	9	6
Expected return on plan assets	0	0	0	0
Amortization of:
Net actuarial (gain) loss	(1)	0	(4)	0
Prior service credit	(1)	(1)	(3)	(3)
Settlement loss	0	0	0	0
Net periodic benefit cost	$ 2	$ 2	$ 5	$ 7