Employee Benefit Plans (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Pension Plans [Member]
Components of net periodic benefit cost:
Service cost	$ 38	$ 40
Interest cost	21	18
Expected return on plan assets	(48)	(48)
Amortization of:
Net actuarial loss	13	20
Prior service credit	(4)	(4)
Net periodic benefit cost	20	26
Other Postretirement Benefit Plans [Member]
Components of net periodic benefit cost:
Service cost	2	2
Interest cost	2	2
Expected return on plan assets	0	0
Amortization of:
Net actuarial loss	0	0
Prior service credit	(1)	(2)
Net periodic benefit cost	$ 3	$ 2