XML 167 R148.htm IDEA: XBRL DOCUMENT v3.25.4

SEGMENT INFORMATION - Narrative (Details)	12 Months Ended
	Dec. 31, 2025
Segment Reporting, Asset Reconciling Item [Line Items]
Number Of Reportable Segments, Not Disclosed Flag	true
Operating Lease Equipment | Minimum
Segment Reporting, Asset Reconciling Item [Line Items]
Useful Life (years)	3 years
Operating Lease Equipment | Maximum
Segment Reporting, Asset Reconciling Item [Line Items]
Useful Life (years)	10 years
Rail Equipment | Minimum
Segment Reporting, Asset Reconciling Item [Line Items]
Useful Life (years)	40 years
Rail Equipment | Maximum
Segment Reporting, Asset Reconciling Item [Line Items]
Useful Life (years)	50 years

X

- Definition

Number Of Reportable Segments, Not Disclosed Flag

+ References

No definition available.

+ Details

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Namespace Prefix:	fcnca_
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Balance Type:	na
Period Type:	duration

X

- Definition

Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
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Balance Type:
Period Type:

X

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
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Balance Type:
Period Type:

X

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=fcnca_RailEquipmentMember
Namespace Prefix:
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Balance Type:
Period Type: