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
	Jan. 31, 2020	Jan. 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	$ 13	$ (26)
Gain/(Loss) Recognized in Earnings on Derivative Instrument	0	(12)
Gain/(Loss) Recognized in Earnings on Derivative and Related Hedged Item	$ 0	$ 12