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		6 Months Ended
	Apr. 30, 2021	Apr. 30, 2020	Apr. 30, 2021	Apr. 30, 2020
Derivative Instruments, Gain (Loss)
Total amounts of income/(expense) line items in the statement of financial performance in which the effects of fair value hedges are recorded	$ (26)	$ 0	$ (51)	$ 13
Gain/(loss) recognized in earnings on derivative instruments	(7)	10	(10)	10
Gain/(loss) recognized in earnings on hedged item	$ 7	$ (10)	$ 10	$ (10)