| **Employee Separation Charges (Tables)**            | 9 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                           |
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| **Restructuring and Related Activities [Abstract]** |                                                                                                                                                                                                                                                                                                                                                                                                                     |
| Summary of separation activity                      | The following table summarizes the 2015 and 2016 separation activity:(Millions of dollars) Liability balance at December 31, 2014$—Increase in liability (separation charges)15Reduction in liability (payments)(5)Liability balance at December 31, 2015$10Increase in liability (separation charges)—Reduction in liability (payments)(10)Liability balance at September 30, 2016$—   |

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| - Definition
Represents separation costs and benefit payments made to employees subject to the separation programs.
+ References
No definition available.
+ Details**Name:**cfsc_EmployeeSeparationChargesAndBenefitsDisclosureTextBlock**Namespace Prefix:**cfsc_**Data Type:**nonnum:textBlockItemType**Balance Type:**na**Period Type:**duration |
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| - References
No definition available.
+ Details**Name:**us-gaap_RestructuringAndRelatedActivitiesAbstract**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |