Benefit Plans - Summary of the Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Net periodic pension cost:
Service cost	$ 140	$ 157	$ 279	$ 315
Interest cost	88	80	176	159
Estimated return on plan assets	(270)	(249)	(539)	(498)
Net amortization and other	9	9	17	17
Net periodic (benefit) cost	$ (33)	$ (3)	$ (67)	$ (7)