Basis of Presentation - Narrative (Details) - USD ($) $ in Millions	Jul. 31, 2020	Oct. 31, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total lease liabilities	$ 1,161
Other non-current assets	$ 1,099	$ 0
ASU 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total lease liabilities		1,200
Other non-current assets		$ 1,200