Basis of Presentation - Narrative (Details) - USD ($) $ in Millions	Apr. 30, 2020	Oct. 31, 2019
Retained Earnings Adjustments [Line Items]
Total lease liabilities	$ 1,141
Other non-current assets	$ 1,111
ASU 2016-02
Retained Earnings Adjustments [Line Items]
Total lease liabilities		$ 1,200
Other non-current assets		$ 1,200