Leases - Schedule of Future Minimum Operating and Finance Lease Maturities (Details) - USD ($) $ in Millions	Dec. 31, 2019	Jan. 01, 2019
Operating Leases
2020	$ 2,754
2021	2,583
2022	2,311
2023	1,908
2024	1,615
Thereafter	3,797
Total lease payments	14,968
Less imputed interest	2,142
Total	12,826	$ 11,364
Finance Leases
2020	1,013
2021	733
2022	414
2023	101
2024	71
Thereafter	115
Total lease payments	2,447
Less imputed interest	144
Total	$ 2,303	$ 2,016