Supplementary Financial Information - Interest and other, net (Details) - USD ($) $ in Millions	12 Months Ended
	Oct. 31, 2020	Oct. 31, 2019	Oct. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Tax indemnifications	$ 1	$ (1,186)	$ (662)
Interest expense on borrowings	(239)	(242)	(312)
Non-operating retirement- related credits	240	85	233
Defined benefit plan settlement charges	(214)	0	0
Loss on extinguishment of debt	(40)	0	(126)
Other, net	21	(11)	49
Interest and other, net	$ (231)	(1,354)	(818)
Adjustment to indemnification receivable		764	$ 676
Adjustment to indemnification receivable from TMA		$ 417