Leases - Lease Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Leases [Abstract]
Operating and short-term lease cost	$ 535	$ 729
Finance lease cost:
Amortization of right-of-use assets	37	36
Interest on lease liability	16	12
Total finance lease cost	53	48
Total lease cost	$ 588	$ 777