Leases - Maturities of Lease Liabilities, Topic 842 (Details) $ in Millions	Sep. 30, 2019 USD ($)
Finance Leases
2020	$ 327
2021	391
2022	301
2023	169
2024	58
Thereafter	3
Total lease payments	1,249
Less: imputed interest	(73)
Total payments	1,176
Real Estate
Operating Leases
2020	221
2021	366
2022	283
2023	213
2024	163
Thereafter	297
Total lease payments	1,543
Less: imputed interest	(138)
Total payments	1,405
Equipment
Operating Leases
2020	73
2021	88
2022	37
2023	14
2024	9
Thereafter	14
Total lease payments	235
Less: imputed interest	(12)
Total payments	$ 223