Leases - Supplemental Cash Flow Information (Details) $ in Millions	9 Months Ended
	Jul. 31, 2020 USD ($)
Leases [Abstract]
Cash paid for amount included in the measurement of lease liabilities	$ 175
Right-of-use assets obtained in exchange of lease liabilities	$ 151
Weighted-average remaining lease term in years	7 years
Weighted-average discount rate	2.80%