|**Accumulated Other Comprehensive Income/(Loss) (Tables)**                 | 6 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        
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|**Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]**   |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       
|Schedule of Accumulated other comprehensive income/(loss)                  | Comprehensive income/(loss) and its components are presented in the Consolidated Statements of Comprehensive Income.  Changes in Accumulated other comprehensive income/(loss), net of tax, included in the Consolidated Statements of Changes in Stockholder's Equity, consisted of the following:(Millions of dollars)ForeigncurrencytranslationDerivativefinancialinstrumentsTotalBalance at June 30, 2012$61$(6)$55Three Months Ended June 30, 2013Balance at March 31, 2013$80$(7)$73Other comprehensive income/(loss) before reclassifications(63)2(61)Amounts reclassified from accumulated other comprehensive income/(loss)—11Other comprehensive income/(loss)(63)3(60)Balance at June 30, 2013$17$(4)$13Six Months Ended June 30, 2013Balance at December 31, 2012$184$(8)$176Other comprehensive income/(loss) before reclassifications(167)2(165)Amounts reclassified from accumulated other comprehensive income/(loss)—22Other comprehensive income/(loss)(167)4(163)Balance at June 30, 2013$17$(4)$13
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|(Millions of dollars)                                                      | Foreigncurrencytranslation                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            
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|Balance at June 30, 2012                                                   | $                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     
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|Three Months Ended June 30, 2013                                           |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       
|Balance at March 31, 2013                                                  | $                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     
|Other comprehensive income/(loss) before reclassifications                 | (63                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   
|Amounts reclassified from accumulated other comprehensive income/(loss)    | —                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     
|Other comprehensive income/(loss)                                          | (63                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   
|Balance at June 30, 2013                                                   | $                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     
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|Six Months Ended June 30, 2013                                             |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       
|Balance at December 31, 2012                                               | $                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     
|Other comprehensive income/(loss) before reclassifications                 | (167                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  
|Amounts reclassified from accumulated other comprehensive income/(loss)    | —                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     
|Other comprehensive income/(loss)                                          | (167                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  
|Balance at June 30, 2013                                                   | $                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     
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|Reclassifications out of Accumulated other comprehensive income/(loss)     | The effect of the reclassifications out of Accumulated other comprehensive income/(loss) on the Consolidated Statements of Profit was as follows:(Millions of dollars)Classification ofincome (expense)Three Months EndedJune 30, 2013Six Months EndedJune 30, 2013Foreign exchange contractsOther income (expense)$—$—Interest rate contractsInterest expense(2)(3)Reclassifications before tax(2)(3)Tax (provision) benefit11Total reclassifications from Accumulated other comprehensive income/(loss)$(1)$(2)                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     
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|(Millions of dollars)                                                      |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       
|                                                                           | Classification ofincome (expense)                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     
|Foreign exchange contracts                                                 | Other income (expense)                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
|Interest rate contracts                                                    | Interest expense                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      
|Reclassifications before tax                                               |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       
|Tax (provision) benefit                                                    |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       
|Total reclassifications from Accumulated other comprehensive income/(loss) |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       
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