Accounting for Leases as a Lessee - Future Minimum Lease Commitments (Details) $ in Millions	Apr. 30, 2020 USD ($)
Operating Leases
Remainder of fiscal 2020	$ 116
2021	194
2022	175
2023	158
2024	135
Thereafter	444
Total future lease payments	1,222
Less: imputed interest	(108)
Total lease liabilities	1,114
Finance Leases
Remainder of 2020	3
2021	6
2022	6
2023	7
2024	7
Thereafter	41
Total future lease payments	70
Less: imputed interest	(11)
Total lease liability balance	$ 59