Summary of Significant Accounting Policies - Organization and Description of the Business and Variable Interest Entities (Details) $ in Millions	6 Months Ended
	Apr. 30, 2021 USD ($) segment	Oct. 31, 2020 USD ($)
Variable Interest Entity [Line Items]
Number of segments | segment	4
Assets	$ 7,084	$ 6,637
Liabilities	10,724	10,459
Cash and cash equivalents	1,233	1,843
Financial Services
Variable Interest Entity [Line Items]
Assets	2,493	2,191
Variable Interest Entity Primary Beneficiary, Blue Diamond Parts
Variable Interest Entity [Line Items]
Assets	29	37
Liabilities	2	3
Cash and cash equivalents	3	4
Variable Interest Entity Primary Beneficiary Securitizations Treated As Borrowings | Financial Services
Variable Interest Entity [Line Items]
Assets	996	661
Liabilities	885	610
Transaction Does Not Qualify for Sale Accounting | Financial Services
Variable Interest Entity [Line Items]
Assets	377	397
Liabilities	$ 253	$ 288