Summary of Significant Accounting Policies - Variable Interest Entities (Details) - USD ($) $ in Millions	Jul. 31, 2019	Oct. 31, 2018
Variable Interest Entity [Line Items]
Cash and cash equivalents	$ 1,160	$ 1,320
Variable Interest Entity Primary Beneficiary, Blue Diamond Parts [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	28	39
Cash and cash equivalents	3	4
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	3	4
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	1,100	994
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	956	852
Transaction Does Not Qualify for Sale Accounting [Member] \| Financial Services Operations
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	465	370
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	$ 253	$ 205

Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 4
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
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The carrying amount of the consolidated Variable Interest Entity's assets included in the reporting entity's statement of financial position.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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The carrying amount of the consolidated Variable Interest Entity's liabilities included in the reporting entity's statement of financial position.

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