| **Allowance for doubtful accounts**            | 6 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |
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| **Allowance for doubtful accounts [Abstract]** | Â                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
| Allowance for doubtful accounts                | Allowance for doubtful accountsPursuant to the adoption of new accounting guidance relating to disclosures about the allowance for losses and credit quality of finance receivables, we determined that we have two portfolio segments of finance receivables based on the type of financing inherent to each portfolio. The retail portfolio segment represents loans or leases to end-users for the purchase or lease of vehicles. The wholesale portfolio segment represents loans to dealers to finance their inventory. As the initial measurement attributes and the monitoring and assessment of credit risk or the performance of the receivables are consistent within each of our receivable portfolios, the Company determined that each portfolio consisted of one class of receivable.The activity related to our allowance for doubtful accounts for our retail portfolio, wholesale portfolio, and trade and other receivables is summarized as follows:  Three Months Ended April 30, 2011 RetailPortfolio WholesalePortfolio Trade andOtherReceivables Total(in millions)       Allowance for doubtful accounts, at beginning of period$54 $2 $38 $94Provision for doubtful accounts, net of recoveries1 — (3) (2)Charge-off of accounts(A)(15) — (1) (16)Allowance for doubtful accounts, at end of period$40 $2 $34 $76  Six Months Ended April 30, 2011 RetailPortfolio WholesalePortfolio Trade andOtherReceivables Total(in millions)       Allowance for doubtful accounts, at beginning of period$58 $2 $36 $96Provision for doubtful accounts, net of recoveries(1) — (1) (2)Charge-off of accounts(A)(17) — (1) (18)Allowance for doubtful accounts, at end of period$40 $2 $34 $76 Three Months  EndedApril 30, 2010 Six Months Ended April 30, 2010(in millions)   Allowance for doubtful accounts, at beginning of period$110 $104Provision for doubtful accounts, net of recoveries20 34Charge-off of accounts(A)(11) (19)Allowance for doubtful accounts, at end of period$119 $119_________________ (A)We repossess sold and leased vehicles on defaulted finance receivables and leases, and place them into Inventories. Losses recognized at the time of repossession and charged against the allowance for doubtful accounts were $12 million and $15 million for the three months and six months ended April 30, 2011, respectively, and $10 million and $18 million for the three months and six months ended April 30, 2010, respectively.Impaired finance receivables include accounts with specific loss reserves and certain accounts that are on non-accrual status. Most balances with specific loss reserves are also on a non-accrual status. In certain cases, we continue to collect payments on our impaired finance receivables.Information regarding impaired finance receivables is as follows:  As of April 30, 2011 RetailPortfolio WholesalePortfolio Total(in millions)     Impaired finance receivables with specific loss reserves$33 $— $33Impaired finance receivables without specific loss reserves1 — 1Specific loss reserves on impaired finance receivables15 — 15Finance receivables on non-accrual status18 — 18Average balance of impaired finance receivables39 — 39The Company uses the aging of our receivables as well as other inputs when assessing credit quality. The aging analysis for gross finance receivables is summarized as follows:  As of April 30, 2011 RetailPortfolio WholesalePortfolio Total(in millions)     Current$1,790 $1,237 $3,02730-90 days past due55 1 56Over 90 days past due16 1 17Total finance receivables$1,861 $1,239 $3,100 |

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| - Definition
Allowance for Doubtful Accounts [Abstract]
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| - Definition
Includes disclosure of allowances against amounts due to a company. Examples include allowance for doubtful trade accounts receivables, notes receivables, loans receivables.
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