Employee Benefit Plans - Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 31	$ 51
Interest cost	55	47
Expected return on plan assets	(63)	(78)
Amortization of unrecognized (gain) loss	2	30
Amortization of prior service credit	0	0
Other	0	1
Total	25	51
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	2
Interest cost	10	7
Expected return on plan assets	0	0
Amortization of unrecognized (gain) loss	(9)	(3)
Amortization of prior service credit	(28)	(28)
Other	0	0
Total	$ (26)	$ (22)