Leases - Maturities of Lease Liabilities (Details) $ in Millions	Jan. 31, 2020 USD ($)
Operating Leases
2020	$ 624
2021	662
2022	684
2023	588
2024	498
After 2024	2,606
Total lease payments	5,662
Less: interest	(1,218)
Present value of lease liabilities	4,444
Finance Leases
2020	104
2021	104
2022	107
2023	102
2024	94
After 2024	352
Total lease payments	863
Less: interest	(179)
Present value of lease liabilities	684
Operating and Finance Leases
2020	728
2021	766
2022	791
2023	690
2024	592
After 2024	2,958
Total lease payments	6,525
Less: interest	(1,397)
Present value of lease liabilities	5,128
Operating lease payments related to options to extend lease terms that are reasonably certain to be exercised	279
Minimum lease payments for operating leases signed but not yet commenced	265
Finance lease payments related to options to extend lease terms that are reasonably certain to be exercised	11
Minimum lease payments for finance leases signed but not yet commenced	45
Current operating lease liabilities	501
Current maturities of long-term debt	$ 72