Supplementary Financial Information - Accounts Receivables (Details) - USD ($) $ in Millions	12 Months Ended
	Oct. 31, 2017	Oct. 31, 2016	Oct. 31, 2015	Oct. 31, 2017	Oct. 31, 2016
Accounts Receivable, Net
Accounts receivable				$ 4,515	$ 4,221
Allowance for doubtful accounts	$ (107)	$ (80)	$ (106)	(101)	(107)
Accounts receivable, net				$ 4,414	$ 4,114
Allowance for Doubtful Accounts Receivable
Balance at beginning of year	107	80	106
Provision for doubtful accounts	30	65	19
Deductions, net of recoveries	(36)	(38)	(45)
Balance at end of year	$ 101	$ 107	$ 80