Supplementary Financial Information - Interest and Other, Net (Details) - USD ($) $ in Millions			3 Months Ended		6 Months Ended
	Apr. 30, 2020	Oct. 31, 2019	Apr. 30, 2020	Apr. 30, 2019	Apr. 30, 2020	Apr. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Tax indemnifications	$ 63	$ 57	$ 1	$ 5	$ 1	$ 15
Interest expense on borrowings			(64)	(61)	(122)	(125)
Other, net			63	11	134	39
Interest and other, net			$ 0	$ (45)	$ 13	$ (71)