Allowance for Doubtful Accounts - Narrative (Details) $ in Millions	12 Months Ended
	Oct. 31, 2018 USD ($) segments class	Oct. 31, 2017 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Portfolio Segments for Finance Receivables | segments	2
Classes Of Receivables In Each Portfolio | class	1
Retail Portfolio [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impaired Financing Receivable, Average Recorded Investment | $	$ 19	$ 18