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v2.4.1.9

Loans and Leases (Composition of the Loans and Leases Outstanding By Credit Quality Indicator) (Details) (USD $) In Thousands, unless otherwise specified | Dec. 31, 2014 | Dec. 31, 2013 | Dec. 31, 2012
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Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans and leases, not acquired in a transfer accounted for as debt securities | $ 17,582,967fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities | $ 12,104,298fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities |
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net | 1,186,498us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet | 1,029,426us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet | 1,809,235us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet
Commercial |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans and leases, not acquired in a transfer accounted for as debt securities | 11,263,074fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 8,499,348fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember |
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net | 726,123us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 781,307us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember |
Commercial | Construction and land development |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans and leases, not acquired in a transfer accounted for as debt securities | 550,568fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 319,847fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember |
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net | 78,079us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 78,915us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember |
Commercial | Mortgage |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans and leases, not acquired in a transfer accounted for as debt securities | 7,552,948fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_MortgageReceivablesMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 6,362,490fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_MortgageReceivablesMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember |
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net | 577,518us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_MortgageReceivablesMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 642,891us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_MortgageReceivablesMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember |
Commercial | Other commercial real estate |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans and leases, not acquired in a transfer accounted for as debt securities | 244,875fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_CommercialRealEstateOtherReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 178,754fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_CommercialRealEstateOtherReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember |
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net | 40,193us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_CommercialRealEstateOtherReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 41,381us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_CommercialRealEstateOtherReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember |
Commercial | Commercial and industrial |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans and leases, not acquired in a transfer accounted for as debt securities | 1,988,934fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_CommercialAndIndustrialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 1,081,158fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_CommercialAndIndustrialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember |
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net | 27,254us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_CommercialAndIndustrialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 17,254us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_CommercialAndIndustrialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember |
Commercial | Lease financing |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans and leases, not acquired in a transfer accounted for as debt securities | 571,916fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_FinanceLeasesFinancingReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 381,763fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_FinanceLeasesFinancingReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember |
Commercial | Other |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans and leases, not acquired in a transfer accounted for as debt securities | 353,833fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_OtherLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 175,336fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_OtherLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember |
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net | 3,079us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_OtherLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 866us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_OtherLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember |
Commercial | Consumer and Other |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net | 3,079us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_ConsumerAndOtherMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 866us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_ConsumerAndOtherMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember |
Commercial | Pass |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans and leases, not acquired in a transfer accounted for as debt securities | 10,825,323fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember | 8,092,174fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember |
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net | 342,172us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember | 330,555us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember |
Commercial | Pass | Construction and land development |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans and leases, not acquired in a transfer accounted for as debt securities | 525,711fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember | 308,231fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember |
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net | 13,514us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember | 2,619us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember |
Commercial | Pass | Mortgage |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans and leases, not acquired in a transfer accounted for as debt securities | 7,284,714fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_MortgageReceivablesMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember | 6,094,505fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_MortgageReceivablesMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember |
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net | 300,187us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_MortgageReceivablesMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember | 296,824us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_MortgageReceivablesMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember |
Commercial | Pass | Other commercial real estate |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans and leases, not acquired in a transfer accounted for as debt securities | 242,053fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_CommercialRealEstateOtherReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember | 174,913fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_CommercialRealEstateOtherReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember |
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net | 11,033us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_CommercialRealEstateOtherReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember | 22,225us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_CommercialRealEstateOtherReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember |
Commercial | Pass | Commercial and industrial |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans and leases, not acquired in a transfer accounted for as debt securities | 1,859,415fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_CommercialAndIndustrialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember | 964,840fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_CommercialAndIndustrialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember |
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net | 16,637us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_CommercialAndIndustrialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember | 8,021us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_CommercialAndIndustrialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember |
Commercial | Pass | Lease financing |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans and leases, not acquired in a transfer accounted for as debt securities | 564,319fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_FinanceLeasesFinancingReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember | 375,371fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_FinanceLeasesFinancingReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember |
Commercial | Pass | Other |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans and leases, not acquired in a transfer accounted for as debt securities | 349,111fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_OtherLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember | 174,314fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_OtherLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember |
Commercial | Pass | Consumer and Other |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net | 801us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_ConsumerAndOtherMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember | 866us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_ConsumerAndOtherMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember |
Commercial | Special Mention |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans and leases, not acquired in a transfer accounted for as debt securities | 182,453fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SpecialMentionMember | 147,325fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SpecialMentionMember |
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net | 125,195us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SpecialMentionMember | 146,841us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SpecialMentionMember |
Commercial | Special Mention | Construction and land development |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans and leases, not acquired in a transfer accounted for as debt securities | 20,025fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SpecialMentionMember | 8,620fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SpecialMentionMember |
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net | 6,063us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SpecialMentionMember | 15,530us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SpecialMentionMember |
Commercial | Special Mention | Mortgage |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans and leases, not acquired in a transfer accounted for as debt securities | 129,247fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_MortgageReceivablesMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SpecialMentionMember | 119,515fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_MortgageReceivablesMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SpecialMentionMember |
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net | 98,724us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_MortgageReceivablesMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SpecialMentionMember | 125,295us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_MortgageReceivablesMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SpecialMentionMember |
Commercial | Special Mention | Other commercial real estate |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans and leases, not acquired in a transfer accounted for as debt securities | 909fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_CommercialRealEstateOtherReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SpecialMentionMember | 1,362fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_CommercialRealEstateOtherReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SpecialMentionMember |
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net | 16,271us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_CommercialRealEstateOtherReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SpecialMentionMember | 3,431us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_CommercialRealEstateOtherReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SpecialMentionMember |
Commercial | Special Mention | Commercial and industrial |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans and leases, not acquired in a transfer accounted for as debt securities | 27,683fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_CommercialAndIndustrialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SpecialMentionMember | 14,686fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_CommercialAndIndustrialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SpecialMentionMember |
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net | 4,137us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_CommercialAndIndustrialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SpecialMentionMember | 2,585us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_CommercialAndIndustrialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SpecialMentionMember |
Commercial | Special Mention | Lease financing |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans and leases, not acquired in a transfer accounted for as debt securities | 3,205fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_FinanceLeasesFinancingReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SpecialMentionMember | 2,160fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_FinanceLeasesFinancingReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SpecialMentionMember |
Commercial | Special Mention | Other |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans and leases, not acquired in a transfer accounted for as debt securities | 1,384fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_OtherLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SpecialMentionMember | 982fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_OtherLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SpecialMentionMember |
Commercial | Special Mention | Consumer and Other |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net | 0us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_ConsumerAndOtherMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SpecialMentionMember | 0us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_ConsumerAndOtherMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SpecialMentionMember |
Commercial | Substandard |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans and leases, not acquired in a transfer accounted for as debt securities | 157,333fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember | 156,956fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember |
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net | 247,138us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember | 244,122us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember |
Commercial | Substandard | Construction and land development |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans and leases, not acquired in a transfer accounted for as debt securities | 4,720fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember | 2,944fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember |
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net | 53,739us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember | 52,228us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember |
Commercial | Substandard | Mortgage |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans and leases, not acquired in a transfer accounted for as debt securities | 134,677fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_MortgageReceivablesMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember | 141,913fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_MortgageReceivablesMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember |
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net | 171,920us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_MortgageReceivablesMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember | 179,657us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_MortgageReceivablesMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember |
Commercial | Substandard | Other commercial real estate |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans and leases, not acquired in a transfer accounted for as debt securities | 1,765fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_CommercialRealEstateOtherReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember | 2,216fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_CommercialRealEstateOtherReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember |
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net | 12,889us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_CommercialRealEstateOtherReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember | 7,012us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_CommercialRealEstateOtherReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember |
Commercial | Substandard | Commercial and industrial |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans and leases, not acquired in a transfer accounted for as debt securities | 8,878fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_CommercialAndIndustrialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember | 6,352fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_CommercialAndIndustrialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember |
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net | 6,312us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_CommercialAndIndustrialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember | 5,225us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_CommercialAndIndustrialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember |
Commercial | Substandard | Lease financing |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans and leases, not acquired in a transfer accounted for as debt securities | 3,955fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_FinanceLeasesFinancingReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember | 3,491fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_FinanceLeasesFinancingReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember |
Commercial | Substandard | Other |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans and leases, not acquired in a transfer accounted for as debt securities | 3,338fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_OtherLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember | 40fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_OtherLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember |
Commercial | Substandard | Consumer and Other |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net | 2,278us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_ConsumerAndOtherMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember | 0us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_ConsumerAndOtherMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember |
Commercial | Doubtful |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans and leases, not acquired in a transfer accounted for as debt securities | 2,895fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_DoubtfulMember | 6,022fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_DoubtfulMember |
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net | 9,241us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_DoubtfulMember | 57,877us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_DoubtfulMember |
Commercial | Doubtful | Construction and land development |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans and leases, not acquired in a transfer accounted for as debt securities | 0fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_DoubtfulMember | 52fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_DoubtfulMember |
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net | 2,809us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_DoubtfulMember | 7,436us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_DoubtfulMember |
Commercial | Doubtful | Mortgage |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans and leases, not acquired in a transfer accounted for as debt securities | 2,366fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_MortgageReceivablesMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_DoubtfulMember | 5,159fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_MortgageReceivablesMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_DoubtfulMember |
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net | 6,302us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_MortgageReceivablesMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_DoubtfulMember | 40,471us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_MortgageReceivablesMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_DoubtfulMember |
Commercial | Doubtful | Other commercial real estate |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans and leases, not acquired in a transfer accounted for as debt securities | 0fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_CommercialRealEstateOtherReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_DoubtfulMember | 75fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_CommercialRealEstateOtherReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_DoubtfulMember |
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net | 0us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_CommercialRealEstateOtherReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_DoubtfulMember | 8,713us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_CommercialRealEstateOtherReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_DoubtfulMember |
Commercial | Doubtful | Commercial and industrial |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans and leases, not acquired in a transfer accounted for as debt securities | 164fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_CommercialAndIndustrialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_DoubtfulMember | 144fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_CommercialAndIndustrialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_DoubtfulMember |
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net | 130us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_CommercialAndIndustrialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_DoubtfulMember | 1,257us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_CommercialAndIndustrialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_DoubtfulMember |
Commercial | Doubtful | Lease financing |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans and leases, not acquired in a transfer accounted for as debt securities | 365fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_FinanceLeasesFinancingReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_DoubtfulMember | 592fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_FinanceLeasesFinancingReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_DoubtfulMember |
Commercial | Doubtful | Other |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans and leases, not acquired in a transfer accounted for as debt securities | 0fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_OtherLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_DoubtfulMember | 0fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_OtherLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_DoubtfulMember |
Commercial | Doubtful | Consumer and Other |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net | 0us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_ConsumerAndOtherMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_DoubtfulMember | 0us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_ConsumerAndOtherMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_DoubtfulMember |
Commercial | Ungraded |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans and leases, not acquired in a transfer accounted for as debt securities | 95,070fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = fcnca_UngradedMember | 96,871fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = fcnca_UngradedMember |
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net | 2,377us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = fcnca_UngradedMember | 1,912us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = fcnca_UngradedMember |
Commercial | Ungraded | Construction and land development |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans and leases, not acquired in a transfer accounted for as debt securities | 112fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = fcnca_UngradedMember | 0fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = fcnca_UngradedMember |
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net | 1,954us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = fcnca_UngradedMember | 1,102us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = fcnca_UngradedMember |
Commercial | Ungraded | Mortgage |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans and leases, not acquired in a transfer accounted for as debt securities | 1,944fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_MortgageReceivablesMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = fcnca_UngradedMember | 1,398fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_MortgageReceivablesMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = fcnca_UngradedMember |
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net | 385us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_MortgageReceivablesMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = fcnca_UngradedMember | 644us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_MortgageReceivablesMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = fcnca_UngradedMember |
Commercial | Ungraded | Other commercial real estate |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans and leases, not acquired in a transfer accounted for as debt securities | 148fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_CommercialRealEstateOtherReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = fcnca_UngradedMember | 188fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_CommercialRealEstateOtherReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = fcnca_UngradedMember |
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net | 0us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_CommercialRealEstateOtherReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = fcnca_UngradedMember | 0us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_CommercialRealEstateOtherReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = fcnca_UngradedMember |
Commercial | Ungraded | Commercial and industrial |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans and leases, not acquired in a transfer accounted for as debt securities | 92,794fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_CommercialAndIndustrialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = fcnca_UngradedMember | 95,136fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_CommercialAndIndustrialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = fcnca_UngradedMember |
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net | 38us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_CommercialAndIndustrialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = fcnca_UngradedMember | 166us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_CommercialAndIndustrialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = fcnca_UngradedMember |
Commercial | Ungraded | Lease financing |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans and leases, not acquired in a transfer accounted for as debt securities | 72fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_FinanceLeasesFinancingReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = fcnca_UngradedMember | 149fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_FinanceLeasesFinancingReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = fcnca_UngradedMember |
Commercial | Ungraded | Other |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans and leases, not acquired in a transfer accounted for as debt securities | 0fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_OtherLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = fcnca_UngradedMember | 0fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_OtherLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = fcnca_UngradedMember |
Commercial | Ungraded | Consumer and Other |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net | 0us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_ConsumerAndOtherMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = fcnca_UngradedMember | 0us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_ConsumerAndOtherMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = fcnca_UngradedMember |
Noncommercial |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans and leases, not acquired in a transfer accounted for as debt securities | 6,319,893fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember | 3,604,950fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember |
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net | 460,375us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember | 248,119us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember |
Noncommercial | Mortgage |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans and leases, not acquired in a transfer accounted for as debt securities | 2,520,542fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_MortgageReceivablesMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember | 982,421fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_MortgageReceivablesMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember |
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net | 382,340us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_MortgageReceivablesMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember | 213,851us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_MortgageReceivablesMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember |
Noncommercial | Revolving mortgage |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans and leases, not acquired in a transfer accounted for as debt securities | 2,561,800fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_HomeEquityMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember | 2,113,285fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_HomeEquityMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember |
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net | 74,109us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_HomeEquityMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember | 30,834us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_HomeEquityMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember |
Noncommercial | Construction and land development |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans and leases, not acquired in a transfer accounted for as debt securities | 120,097fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_ConstructionAndLandDevelopmentNoncommercialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember | 122,792fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_ConstructionAndLandDevelopmentNoncommercialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember |
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net | 912us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_ConstructionAndLandDevelopmentNoncommercialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember | 2,583us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_ConstructionAndLandDevelopmentNoncommercialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember |
Noncommercial | Consumer |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans and leases, not acquired in a transfer accounted for as debt securities | 1,117,454fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_ConsumerLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember | 386,452fcnca_Loansandleasesnotacquiredinatransferaccountedforasdebtsecurities / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_ConsumerLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember |
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net | 3,014us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_ConsumerLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember | 851us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_ConsumerLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember |
Non-PCI Loans [Member] | Noncommercial |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Current | 398,225us-gaap_FinancingReceivableRecordedInvestmentCurrent / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember / fcnca_LoanDesignationAxis = fcnca_PurchasedcreditimpairedMember | 192,179us-gaap_FinancingReceivableRecordedInvestmentCurrent / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember / fcnca_LoanDesignationAxis = fcnca_PurchasedcreditimpairedMember |
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net | 460,375us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember / fcnca_LoanDesignationAxis = fcnca_PurchasedcreditimpairedMember | 248,119us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember / fcnca_LoanDesignationAxis = fcnca_PurchasedcreditimpairedMember |
30-59 Days Past Due | 12,984us-gaap_FinancingReceivableRecordedInvestment30To59DaysPastDue / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember / fcnca_LoanDesignationAxis = fcnca_PurchasedcreditimpairedMember | 17,402us-gaap_FinancingReceivableRecordedInvestment30To59DaysPastDue / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember / fcnca_LoanDesignationAxis = fcnca_PurchasedcreditimpairedMember |
60-89 Days Past Due | 10,443us-gaap_FinancingReceivableRecordedInvestment60To89DaysPastDue / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember / fcnca_LoanDesignationAxis = fcnca_PurchasedcreditimpairedMember | 6,544us-gaap_FinancingReceivableRecordedInvestment60To89DaysPastDue / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember / fcnca_LoanDesignationAxis = fcnca_PurchasedcreditimpairedMember |
90 Days or Greater | 38,723us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember / fcnca_LoanDesignationAxis = fcnca_PurchasedcreditimpairedMember | 31,994us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember / fcnca_LoanDesignationAxis = fcnca_PurchasedcreditimpairedMember |
Non-PCI Loans [Member] | Noncommercial | Mortgage |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Current | 326,589us-gaap_FinancingReceivableRecordedInvestmentCurrent / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_MortgageReceivablesMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember / fcnca_LoanDesignationAxis = fcnca_PurchasedcreditimpairedMember | 162,771us-gaap_FinancingReceivableRecordedInvestmentCurrent / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_MortgageReceivablesMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember / fcnca_LoanDesignationAxis = fcnca_PurchasedcreditimpairedMember |
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net | 382,340us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_MortgageReceivablesMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember / fcnca_LoanDesignationAxis = fcnca_PurchasedcreditimpairedMember | 213,851us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_MortgageReceivablesMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember / fcnca_LoanDesignationAxis = fcnca_PurchasedcreditimpairedMember |
30-59 Days Past Due | 11,432us-gaap_FinancingReceivableRecordedInvestment30To59DaysPastDue / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_MortgageReceivablesMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember / fcnca_LoanDesignationAxis = fcnca_PurchasedcreditimpairedMember | 15,261us-gaap_FinancingReceivableRecordedInvestment30To59DaysPastDue / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_MortgageReceivablesMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember / fcnca_LoanDesignationAxis = fcnca_PurchasedcreditimpairedMember |
60-89 Days Past Due | 10,073us-gaap_FinancingReceivableRecordedInvestment60To89DaysPastDue / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_MortgageReceivablesMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember / fcnca_LoanDesignationAxis = fcnca_PurchasedcreditimpairedMember | 6,544us-gaap_FinancingReceivableRecordedInvestment60To89DaysPastDue / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_MortgageReceivablesMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember / fcnca_LoanDesignationAxis = fcnca_PurchasedcreditimpairedMember |
90 Days or Greater | 34,246us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_MortgageReceivablesMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember / fcnca_LoanDesignationAxis = fcnca_PurchasedcreditimpairedMember | 29,275us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_MortgageReceivablesMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember / fcnca_LoanDesignationAxis = fcnca_PurchasedcreditimpairedMember |
Non-PCI Loans [Member] | Noncommercial | Revolving mortgage |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Current | 68,548us-gaap_FinancingReceivableRecordedInvestmentCurrent / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_HomeEquityMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember / fcnca_LoanDesignationAxis = fcnca_PurchasedcreditimpairedMember | 26,642us-gaap_FinancingReceivableRecordedInvestmentCurrent / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_HomeEquityMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember / fcnca_LoanDesignationAxis = fcnca_PurchasedcreditimpairedMember |
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net | 74,109us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_HomeEquityMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember / fcnca_LoanDesignationAxis = fcnca_PurchasedcreditimpairedMember | 30,834us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_HomeEquityMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember / fcnca_LoanDesignationAxis = fcnca_PurchasedcreditimpairedMember |
30-59 Days Past Due | 1,405us-gaap_FinancingReceivableRecordedInvestment30To59DaysPastDue / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_HomeEquityMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember / fcnca_LoanDesignationAxis = fcnca_PurchasedcreditimpairedMember | 2,138us-gaap_FinancingReceivableRecordedInvestment30To59DaysPastDue / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_HomeEquityMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember / fcnca_LoanDesignationAxis = fcnca_PurchasedcreditimpairedMember |
60-89 Days Past Due | 345us-gaap_FinancingReceivableRecordedInvestment60To89DaysPastDue / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_HomeEquityMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember / fcnca_LoanDesignationAxis = fcnca_PurchasedcreditimpairedMember | 0us-gaap_FinancingReceivableRecordedInvestment60To89DaysPastDue / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_HomeEquityMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember / fcnca_LoanDesignationAxis = fcnca_PurchasedcreditimpairedMember |
90 Days or Greater | 3,811us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_HomeEquityMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember / fcnca_LoanDesignationAxis = fcnca_PurchasedcreditimpairedMember | 2,054us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_HomeEquityMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember / fcnca_LoanDesignationAxis = fcnca_PurchasedcreditimpairedMember |
Non-PCI Loans [Member] | Noncommercial | Construction and land development |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Current | 506us-gaap_FinancingReceivableRecordedInvestmentCurrent / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_ConstructionAndLandDevelopmentNoncommercialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember / fcnca_LoanDesignationAxis = fcnca_PurchasedcreditimpairedMember | 1,925us-gaap_FinancingReceivableRecordedInvestmentCurrent / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_ConstructionAndLandDevelopmentNoncommercialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember / fcnca_LoanDesignationAxis = fcnca_PurchasedcreditimpairedMember |
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net | 912us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_ConstructionAndLandDevelopmentNoncommercialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember / fcnca_LoanDesignationAxis = fcnca_PurchasedcreditimpairedMember | 2,583us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_ConstructionAndLandDevelopmentNoncommercialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember / fcnca_LoanDesignationAxis = fcnca_PurchasedcreditimpairedMember |
30-59 Days Past Due | 0us-gaap_FinancingReceivableRecordedInvestment30To59DaysPastDue / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_ConstructionAndLandDevelopmentNoncommercialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember / fcnca_LoanDesignationAxis = fcnca_PurchasedcreditimpairedMember | 0us-gaap_FinancingReceivableRecordedInvestment30To59DaysPastDue / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_ConstructionAndLandDevelopmentNoncommercialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember / fcnca_LoanDesignationAxis = fcnca_PurchasedcreditimpairedMember |
60-89 Days Past Due | 0us-gaap_FinancingReceivableRecordedInvestment60To89DaysPastDue / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_ConstructionAndLandDevelopmentNoncommercialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember / fcnca_LoanDesignationAxis = fcnca_PurchasedcreditimpairedMember | 0us-gaap_FinancingReceivableRecordedInvestment60To89DaysPastDue / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_ConstructionAndLandDevelopmentNoncommercialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember / fcnca_LoanDesignationAxis = fcnca_PurchasedcreditimpairedMember |
90 Days or Greater | 406us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_ConstructionAndLandDevelopmentNoncommercialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember / fcnca_LoanDesignationAxis = fcnca_PurchasedcreditimpairedMember | 658us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = fcnca_ConstructionAndLandDevelopmentNoncommercialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember / fcnca_LoanDesignationAxis = fcnca_PurchasedcreditimpairedMember |
Non-PCI Loans [Member] | Noncommercial | Consumer |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Current | 2,582us-gaap_FinancingReceivableRecordedInvestmentCurrent / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_ConsumerLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember / fcnca_LoanDesignationAxis = fcnca_PurchasedcreditimpairedMember | 841us-gaap_FinancingReceivableRecordedInvestmentCurrent / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_ConsumerLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember / fcnca_LoanDesignationAxis = fcnca_PurchasedcreditimpairedMember |
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net | 3,014us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_ConsumerLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember / fcnca_LoanDesignationAxis = fcnca_PurchasedcreditimpairedMember | 851us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesCarryingAmountNet / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_ConsumerLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember / fcnca_LoanDesignationAxis = fcnca_PurchasedcreditimpairedMember |
30-59 Days Past Due | 147us-gaap_FinancingReceivableRecordedInvestment30To59DaysPastDue / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_ConsumerLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember / fcnca_LoanDesignationAxis = fcnca_PurchasedcreditimpairedMember | 3us-gaap_FinancingReceivableRecordedInvestment30To59DaysPastDue / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_ConsumerLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember / fcnca_LoanDesignationAxis = fcnca_PurchasedcreditimpairedMember |
60-89 Days Past Due | 25us-gaap_FinancingReceivableRecordedInvestment60To89DaysPastDue / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_ConsumerLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember / fcnca_LoanDesignationAxis = fcnca_PurchasedcreditimpairedMember | 0us-gaap_FinancingReceivableRecordedInvestment60To89DaysPastDue / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_ConsumerLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember / fcnca_LoanDesignationAxis = fcnca_PurchasedcreditimpairedMember |
90 Days or Greater | $ 260us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_ConsumerLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember / fcnca_LoanDesignationAxis = fcnca_PurchasedcreditimpairedMember | $ 7us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_ConsumerLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fcnca_NoncommercialSegmentMember / fcnca_LoanDesignationAxis = fcnca_PurchasedcreditimpairedMember |

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