Financial Instruments - Schedule of Pre-Tax Effect of Derivative Instruments and Related Hedged Items in a Fair Value Hedging Relationship (Details) - Interest and other, net - Interest rate contracts - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Oct. 31, 2021	Oct. 31, 2021	Oct. 31, 2020	Oct. 31, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Total amounts of income/(expense) line items in the statement of financial performance in which the effects of fair value hedges are recorded		$ 2,209	$ (231)	$ (1,354)
Gain/(loss) recognized in earnings on derivative instruments	$ (17)		6	27
Gain/(loss) recognized in earnings on hedged item		$ 17	$ (6)	$ (27)