Indemnifications (Details) - USD ($) $ in Millions	Jul. 31, 2018	Oct. 31, 2017
Tax Indemnification
Other Commitments [Line Items]
Receivable - long-term	$ 111	$ 1,430
Payables - short-term	2	36
Cross-Indemnifications
Other Commitments [Line Items]
Receivable	116	150
Payable	$ 89	$ 91