Operating Leases - Supplemental Balance Sheet Information (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Jan. 01, 2019
Leases [Abstract]
Operating lease right-of-use assets	$ 2,426	$ 2,250	$ 2,000
Current maturities of operating leases	444	416
Long-term operating leases	1,991	1,848
Total lease liabilities	$ 2,435	$ 2,264
Weighted-average remaining lease term
Operating leases	7 years	7 years
Weighted-average discount rate
Operating leases	5.08%	5.15%