Summary of Significant Accounting Policies - Variable Interest Entities (Details) - USD ($) $ in Millions	Jul. 31, 2017	Oct. 31, 2016	Jul. 31, 2016	Oct. 31, 2015
Variable Interest Entity [Line Items]
Cash and cash equivalents	$ 911	$ 804	$ 547	$ 912
Variable Interest Entity Primary Beneficiary, Blue Diamond Parts [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	35	51
Cash and cash equivalents	3	6
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	13	16
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	901	865
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	773	722
Transaction Does Not Qualify for Sale Accounting [Member] | Financial Services Operations
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	242	249
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	$ 156	$ 136