Financial Instruments - Schedule of Pre-Tax Effect of Derivative Instruments and Related Hedged Items in a Fair Value Hedging Relationship (Details) - Interest rate contracts - Interest and other, net - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jul. 31, 2020	Jul. 31, 2019	Jul. 31, 2020	Jul. 31, 2019
Derivative Instruments, Gain (Loss)
Total amounts of income/ (expense) line items presented in the statement of financial performance in which the effects of fair value hedges are recorded	$ (28)	$ (831)	$ (15)	$ (902)
Gain/(Loss) Recognized in Earnings on Derivative Instrument	1	8	11	24
Gain/(Loss) Recognized in Earnings on Derivative and Related Hedged Item	$ (1)	$ (8)	$ (11)	$ (24)