Accounting for Leases as a Lessee - Additional Lease Information (Details) $ in Millions	6 Months Ended
	Apr. 30, 2020 USD ($)
Leases [Abstract]
Operating Leases, Weighted-average remaining lease term (in years)	7 years 4 months 24 days
Operating Leases, Weighted-average discount rate	2.70%
Finance Leases, Weighted-average remaining lease term (in years)	10 years
Finance Leases, Weighted-average discount rate	3.50%
Cash outflows from operating leases	$ 118
ROU assets obtained in exchange for new operating lease liabilities	$ 203