| **Finance Receivables - Narrative (Details) $ in Millions**            | Apr. 30, 2018 USD ($) segments | Jan. 31, 2018 segments | Oct. 31, 2017 USD ($) |
|------------------------------------------------------------------------|--------------------------------|------------------------|-----------------------|
| **Schedule of Securitization [Line Items]**                            |                           |                   |                  |
| Loans and Leases Receivable, Net Amount                                | $ 1,900                        |                   | $ 1,800               |
| Number of Portfolio Segments for Finance Receivables | segments        | 2                              | 2                      |                  |
| Trac Funding Facility [Member]                                         |                           |                   |                  |
| **Schedule of Securitization [Line Items]**                            |                           |                   |                  |
| Finance Receivables Retail Accounts Collateral For Borrowed Securities | $ 805                          |                   | 797                   |
| Cash Collateral for Borrowed Securities                                | 238                            |                   | 163                   |
| Financial Services Operations                                          |                           |                   |                  |
| **Schedule of Securitization [Line Items]**                            |                           |                   |                  |
| Assets Net Of Intercompany Balances                                    | $ 2,300                        |                   | $ 2,200               |

| X                                                                                                                                                                                                                                                      |
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Assets Net Of Intercompany Balances
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| - Definition
Finance Receivables Retail Accounts Collateral For Borrowed Securities
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Number of Portfolio Segments for Finance Receivables
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|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Carrying amount as of the balance sheet date of cash collateral held for borrowed securities, for which the cash is restricted as to withdrawal or usage.
+ References
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|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount after allowance and deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements and loans held for sale.
+ References
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| - Definition
Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.
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No definition available.
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