Employee Benefit Plans (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Pension Plans [Member]
Components of net periodic benefit cost:
Service cost	$ 28	$ 39	$ 56	$ 77
Interest cost	30	21	60	42
Expected return on plan assets	(51)	(48)	(101)	(96)
Amortization of:
Net actuarial (gain) loss	(1)	13	(3)	26
Prior service credit	(4)	(5)	(9)	(9)
Net periodic benefit cost	2	20	3	40
Other Postretirement Benefit Plans [Member]
Components of net periodic benefit cost:
Service cost	1	1	2	3
Interest cost	3	2	6	4
Expected return on plan assets	0	0	0	0
Amortization of:
Net actuarial (gain) loss	(2)	0	(3)	0
Prior service credit	(1)	(1)	(2)	(2)
Net periodic benefit cost	$ 1	$ 2	$ 3	$ 5