| **Fair Value Measurements (Details 3) (Level 2, USD $)In Millions, unless otherwise specified** | Dec. 31, 2014                                                                                                           | Dec. 31, 2013                                                                                                          | Dec. 31, 2012                                                                                                           |
|-------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------|
| Level 2                                                                                         |                                                                                                                    |                                                                                                                   |                                                                                                                    |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis**             |                                                                                                                    |                                                                                                                   |                                                                                                                    |
| Fair value of impaired loans                                                                    | $ 248cfsc_FairValueOfImpairedLoans/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member | $ 88cfsc_FairValueOfImpairedLoans/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member | $ 122cfsc_FairValueOfImpairedLoans/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member |

| X                                                                                                                                                                                                                                               |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The fair value of impaired loans.
+ References
No definition available.
+ Details**Name:**cfsc_FairValueOfImpairedLoans**Namespace Prefix:**cfsc_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**instant |
| X                                                                                                                                                                                                                 |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |