Leases (Lessee Liability Maturity) (Details) $ in Millions	Jan. 31, 2021 USD ($)
Operating Leases
2022	$ 2,189
2023	2,017
2024	1,861
2025	1,697
2026	1,527
Thereafter	11,658
Total undiscounted lease obligations	20,949
Less imputed interest	(6,574)
Operating lease, liability	14,375
Finance Leases
2022	717
2023	613
2024	551
2025	496
2026	449
Thereafter	4,746
Total undiscounted lease obligations	7,572
Less imputed interest	(3,234)
Finance lease, liability	$ 4,338