Financial Instruments - Offsetting Assets and Liabilities (Details) $ in Millions	Apr. 30, 2020 USD ($) business_days	Oct. 31, 2019 USD ($) business_days
Derivative assets
Gross Amount Recognized	$ 896	$ 468
Gross Amount Offset	0	0
Net Amount Presented	896	468
Gross Amounts Not Offset
Derivatives	83	123
Financial Collateral	809	263
Net Amount	4	82
Derivative liabilities
Gross Amount Recognized	91	147
Gross Amount Offset	0	0
Net Amount Presented	91	147
Gross Amounts Not Offset
Derivatives	83	123
Financial Collateral	3	19
Net Amount	$ 5	$ 5
Business days prior to respective reporting date | business_days	2	2
Cash collateral	$ 3
Counterparty collateral		$ 19