Indemnifications (Details) - USD ($) $ in Millions	Apr. 30, 2018	Oct. 31, 2017
Tax Indemnification
Other Commitments [Line Items]
Receivable - long-term	$ 278	$ 1,430
Payables - short-term	172	36
Cross-Indemnifications
Other Commitments [Line Items]
Receivable	128	150
Payable	$ 89	$ 91