Leases Lessee, Operating Lease, Liability, Maturity (Details) $ in Millions	Oct. 31, 2019 USD ($)
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
Remainder of 2020	$ 580
2021	2,462
2022	2,242
2023	2,019
2024	1,829
Thereafter	16,430
Total undiscounted lease obligations	25,562
Less imputed interest	(8,081)
Net lease obligations	17,481
Finance Lease, Liability, Payment, Due [Abstract]
Remainder of 2020	173
2021	755
2022	702
2023	579
2024	498
Thereafter	5,688
Total undiscounted lease obligations	8,395
Less imputed interest	(3,859)
Net lease obligations	$ 4,536