Indemnifications (Details) - USD ($) $ in Millions	Apr. 30, 2019	Oct. 31, 2018
Tax Indemnification
Other Commitments [Line Items]
Net indemnification receivable - long-term	$ 299	$ 16
Net indemnification receivable - short-term	17	17
Net indemnification payable - long-term	9	9
Net indemnification payable - short-term	6	26
Cross-Indemnifications
Other Commitments [Line Items]
Receivable	94	104
Payable	$ 65	$ 83