| **Employee Separation Charges (Details) - USD ($) $ in Millions** | 12 Months Ended |
|-------------------------------------------------------------------|-----------------|
||
| **Restructuring and Related Activities [Abstract]**               |            |   |
| Separation charges                                                | $ 0             | $ 15 |
| **Employee Separation Charges**                                   |            |   |
| Liability balance at beginning of year                            | 10              | 0 |
| Increase in liability (separation charges)                        | 0               | 15 |
| Reduction in liability (payments)                                 | (10)            | (5) |
| Liability balance at end of year                                  | $ 0             | $ 10 |

| X                                                                                                                                                                                                                                                                                           |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
As of the balance sheet date, the liability for employee separation charges.
+ References
No definition available.
+ Details**Name:**cfsc_AccruedSeparationCharges**Namespace Prefix:**cfsc_**Data Type:**xbrli:monetaryItemType**Balance Type:**credit**Period Type:**instant |
| X                                                                                                                                                                                                                                                                                                               |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Benefit payments made during the period in connection with employee separation programs.
+ References
No definition available.
+ Details**Name:**cfsc_BenefitPaymentsSeparationCharges**Namespace Prefix:**cfsc_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**duration |
| X                                                                                                                                                                                                        |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - References
No definition available.
+ Details**Name:**cfsc_EmployeeSeparationChargesRollForward**Namespace Prefix:**cfsc_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                   |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - References
No definition available.
+ Details**Name:**us-gaap_RestructuringAndRelatedActivitiesAbstract**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |
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|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of expenses for special or contractual termination benefits provided to current employees involuntarily terminated under a benefit arrangement associated exit or disposal activities pursuant to an authorized plan. Excludes expenses related to one-time termination benefits, a discontinued operation or an asset retirement obligation.
+ References
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