| **Accumulated Other Comprehensive Income/(Loss) (Tables)**               | 3 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |
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| **Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]** |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
| Schedule of Accumulated other comprehensive income/(loss)                | 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)Foreign currency translation Derivative financial instruments Total      Three Months Ended March 31, 2014     Balance at December 31, 2013$122 $(5) $117Other comprehensive income/(loss) before reclassifications5 (2) 3Amounts reclassified from accumulated other comprehensive income/(loss)— 1 1Other comprehensive income/(loss)5 (1) 4Balance at March 31, 2014$127 $(6) $121      Three Months Ended March 31, 2015     Balance at December 31, 2014$(359) $(5) $(364)Other comprehensive income/(loss) before reclassifications(401) 1 (400)Amounts reclassified from accumulated other comprehensive income/(loss)— 1 1Other comprehensive income/(loss)(401) 2 (399)Balance at March 31, 2015$(760) $(3) $(763)       |
| 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)  Three Months Ended March 31, Classification of income (expense) 2015 2014Foreign exchange contractsOther income (expense) $— $—Interest rate contractsInterest expense (1) (1)Reclassifications before tax  (1) (1)Tax (provision) benefit  — —Total reclassifications from Accumulated other comprehensive income/(loss)  $(1) $(1)                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |

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| - Definition
Tabular disclosure of information about items reclassified out of accumulated other comprehensive income (loss).
+ References
No definition available.
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| - Definition
Tabular disclosure of the components of accumulated other comprehensive income (loss).
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 14A -URI http://asc.fasb.org/extlink&oid=36458714&loc=SL7669686-108580
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