Summary of Significant Accounting Policies - Variable Interest Entities (Details) - USD ($) $ in Millions	Oct. 31, 2018	Oct. 31, 2017	Oct. 31, 2016	Oct. 31, 2015
Variable Interest Entity [Line Items]
Cash and cash equivalents	$ 1,320	$ 706	$ 804	$ 912
Variable Interest Entity Primary Beneficiary, Blue Diamond Parts [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	39	49
Cash and cash equivalents	4	10
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	4	13
Variable Interest Entity Primary Beneficiary Securitizations Treated As Borrowings [Member] | Financial Services Operations
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	1,000	900
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	852	754
Transaction Does Not Qualify for Sale Accounting [Member] | Financial Services Operations
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	370	278
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	$ 205	$ 194