| **Fair Value Measurements (Tables)**                                     | 3 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
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| **Fair Value Disclosures [Abstract]**                                    |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |
| Assets and liabilities measured at fair value                            | Assets and liabilities measured on a recurring basis at fair value included in our Consolidated Statements of Financial Position are summarized below:(Millions of dollars)        March 31, 2015 Level 1 Level 2 Level 3 Total Assets/Liabilities,at Fair ValueAssets       Derivative financial instruments, net$— $88 $— $88Total Assets$— $88 $— $88Liabilities       Guarantees$— $— $1 $1Total Liabilities$— $— $1 $1         December 31, 2014 Level 1 Level 2 Level 3 Total Assets/Liabilities,at Fair ValueAssets         Derivative financial instruments, net$— $78 $— $78Total Assets$— $78 $— $78Liabilities       Guarantees$— $— $1 $1Total Liabilities$— $— $1 $1                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
| Roll-forwards of liabilities measured at fair value using Level 3 inputs | Below are roll-forwards of liabilities measured at fair value using Level 3 inputs for the three months ended March 31, 2015 and 2014.  These instruments were valued using pricing models that, in management’s judgment, reflect the assumptions of a marketplace participant.(Millions of dollars)GuaranteesBalance as of December 31, 2014$1Issuance of guarantees—Expiration of guarantees—Balance as of March 31, 2015$1  (Millions of dollars)GuaranteesBalance as of December 31, 2013$1Issuance of guarantees—Expiration of guarantees—Balance as of March 31, 2014$1                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |
| Fair values of financial instruments                                     | Please refer to the table below for the fair values of our financial instruments.(Millions of dollars)March 31, 2015 December 31, 2014     CarryingAmount FairValue CarryingAmount FairValue Fair ValueLevels ReferenceCash and cash equivalents$1,147 $1,147 $857 $857 1  Foreign currency contracts:           In a receivable position$8 $8 $5 $5 2 Note 5In a payable position$(18) $(18) $(15) $(15) 2 Note 5Cross currency contracts           In a receivable position$27 $27 $17 $17 2 Note 5Finance receivables, net (excluding finance leases(1))$20,918 $20,688 $21,434 $21,093 3 Note 4Restricted cash and cash equivalents(2)$16 $16 $11 $11 1  Short-term borrowings$(5,259) $(5,259) $(4,699) $(4,699) 1  Long-term debt$(23,500) $(24,107) $(24,574) $(25,103) 2  Interest rate swaps:           In a net receivable position$77 $77 $79 $79 2 Note 5In a net payable position$(6) $(6) $(8) $(8) 2 Note 5Guarantees$(1) $(1) $(1) $(1) 3 Note 7            (1)As of March 31, 2015 and December 31, 2014, represents finance leases with a net carrying value of $7.10 billion and $7.64 billion, respectively.(2) Included in Other assets in the Consolidated Statements of Financial Position. |

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| - Definition
Tabular disclosure of the fair value of financial instruments, including financial assets and financial liabilities, and the measurements of those instruments, assets, and liabilities.
+ References
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| - Definition
Tabular disclosure of the fair value measurement of liabilities using significant unobservable inputs (Level 3), a reconciliation of the beginning and ending balances, separately presenting changes attributable to the following: (1) total gains or losses for the period (realized and unrealized), segregating those gains or losses included in earnings (or changes in net assets), and gains or losses recognized in other comprehensive income (loss) and a description of where those gains or losses included in earnings (or changes in net assets) are reported in the statement of income (or activities); (2) purchases, sales, issues, and settlements (each type disclosed separately); and (3) transfers in and transfers out of Level 3 (for example, transfers due to changes in the observability of significant inputs) by class of liability.
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| - Definition
Tabular disclosure of assets and liabilities, including [financial] instruments measured at fair value that are classified in stockholders' equity, if any, that are measured at fair value on a recurring basis. The disclosures contemplated herein include the fair value measurements at the reporting date by the level within the fair value hierarchy in which the fair value measurements in their entirety fall, segregating fair value measurements using quoted prices in active markets for identical assets (Level 1), significant other observable inputs (Level 2), and significant unobservable inputs (Level 3).
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