Supplementary Financial Information - Accounts Receivables, net (Details) - USD ($) $ in Millions	12 Months Ended
	Oct. 31, 2020	Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2020	Oct. 31, 2019
Accounts Receivable, Net
Accounts receivable				$ 5,503	$ 6,142
Allowance for doubtful accounts	$ (111)	$ (111)	$ (101)	(122)	(111)
Accounts receivable, net				$ 5,381	$ 6,031
Allowance for Doubtful Accounts Receivable
Balance at beginning of period	111	129	101
Provision for doubtful accounts	62	60	57
Deductions, net of recoveries	(51)	(78)	(29)
Balance at end of period	$ 122	$ 111	$ 129