XML 13 R54.htm IDEA: XBRL DOCUMENT v2.4.1.9
Allowance for Loan and Lease Losses (Troubled Debt Restructuring) (Details) (USD $)
In Thousands, unless otherwise specified
Mar. 31, 2015
Dec. 31, 2014
TDRs    
Financing Receivable, Modifications [Line Items]    
Accruing $ 131,466fcnca_FinancingReceivableRecordedInvestmentStillAccruing
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember		 $ 135,963fcnca_FinancingReceivableRecordedInvestmentStillAccruing
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember
Nonaccruing 25,525us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember		 15,516us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember
Financing Receivable, Modifications, Recorded Investment 156,991us-gaap_FinancingReceivableModificationsRecordedInvestment
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember		 151,479us-gaap_FinancingReceivableModificationsRecordedInvestment
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember
Non-PCI Loans    
Financing Receivable, Modifications [Line Items]    
Nonaccruing 66,046us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ fcnca_LoanDesignationAxis
= fcnca_NonPCILoansMember		 44,005us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ fcnca_LoanDesignationAxis
= fcnca_NonPCILoansMember
Non-PCI Loans | TDRs    
Financing Receivable, Modifications [Line Items]    
Accruing 86,884fcnca_FinancingReceivableRecordedInvestmentStillAccruing
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember
/ fcnca_LoanDesignationAxis
= fcnca_NonPCILoansMember		 91,316fcnca_FinancingReceivableRecordedInvestmentStillAccruing
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember
/ fcnca_LoanDesignationAxis
= fcnca_NonPCILoansMember
Nonaccruing 23,526us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember
/ fcnca_LoanDesignationAxis
= fcnca_NonPCILoansMember		 13,291us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember
/ fcnca_LoanDesignationAxis
= fcnca_NonPCILoansMember
Financing Receivable, Modifications, Recorded Investment 110,410us-gaap_FinancingReceivableModificationsRecordedInvestment
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember
/ fcnca_LoanDesignationAxis
= fcnca_NonPCILoansMember		 104,607us-gaap_FinancingReceivableModificationsRecordedInvestment
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember
/ fcnca_LoanDesignationAxis
= fcnca_NonPCILoansMember
PCI Loans | TDRs    
Financing Receivable, Modifications [Line Items]    
Accruing 44,582fcnca_FinancingReceivableRecordedInvestmentStillAccruing
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember
/ fcnca_LoanDesignationAxis
= fcnca_LoansAcquiredWithDeterioratedCreditQualityMember		 44,647fcnca_FinancingReceivableRecordedInvestmentStillAccruing
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember
/ fcnca_LoanDesignationAxis
= fcnca_LoansAcquiredWithDeterioratedCreditQualityMember
Nonaccruing 1,999us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember
/ fcnca_LoanDesignationAxis
= fcnca_LoansAcquiredWithDeterioratedCreditQualityMember		 2,225us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember
/ fcnca_LoanDesignationAxis
= fcnca_LoansAcquiredWithDeterioratedCreditQualityMember
Financing Receivable, Modifications, Recorded Investment 46,581us-gaap_FinancingReceivableModificationsRecordedInvestment
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember
/ fcnca_LoanDesignationAxis
= fcnca_LoansAcquiredWithDeterioratedCreditQualityMember		 46,872us-gaap_FinancingReceivableModificationsRecordedInvestment
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember
/ fcnca_LoanDesignationAxis
= fcnca_LoansAcquiredWithDeterioratedCreditQualityMember
Commercial | TDRs    
Financing Receivable, Modifications [Line Items]    
Accruing 104,848fcnca_FinancingReceivableRecordedInvestmentStillAccruing
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember		 107,305fcnca_FinancingReceivableRecordedInvestmentStillAccruing
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember
Nonaccruing 17,336us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember		 10,861us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember
Financing Receivable, Modifications, Recorded Investment 122,184us-gaap_FinancingReceivableModificationsRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember		 118,166us-gaap_FinancingReceivableModificationsRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember
Commercial | Construction and land development | TDRs    
Financing Receivable, Modifications [Line Items]    
Accruing 3,425fcnca_FinancingReceivableRecordedInvestmentStillAccruing
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember		 2,591fcnca_FinancingReceivableRecordedInvestmentStillAccruing
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember
Nonaccruing 490us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember		 446us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember
Financing Receivable, Modifications, Recorded Investment 3,915us-gaap_FinancingReceivableModificationsRecordedInvestment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember		 3,037us-gaap_FinancingReceivableModificationsRecordedInvestment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember
Commercial | Construction and land development | Non-PCI Loans    
Financing Receivable, Modifications [Line Items]    
Nonaccruing 1,497us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ fcnca_LoanDesignationAxis
= fcnca_NonPCILoansMember		 343us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ fcnca_LoanDesignationAxis
= fcnca_NonPCILoansMember
Commercial | Mortgage | TDRs    
Financing Receivable, Modifications [Line Items]    
Accruing 88,889fcnca_FinancingReceivableRecordedInvestmentStillAccruing
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_MortgageReceivablesMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember		 92,184fcnca_FinancingReceivableRecordedInvestmentStillAccruing
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_MortgageReceivablesMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember
Nonaccruing 11,326us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_MortgageReceivablesMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember		 8,937us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_MortgageReceivablesMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember
Financing Receivable, Modifications, Recorded Investment 100,215us-gaap_FinancingReceivableModificationsRecordedInvestment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_MortgageReceivablesMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember		 101,121us-gaap_FinancingReceivableModificationsRecordedInvestment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_MortgageReceivablesMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember
Commercial | Mortgage | Non-PCI Loans    
Financing Receivable, Modifications [Line Items]    
Nonaccruing 26,058us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_MortgageReceivablesMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ fcnca_LoanDesignationAxis
= fcnca_NonPCILoansMember		 24,720us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_MortgageReceivablesMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ fcnca_LoanDesignationAxis
= fcnca_NonPCILoansMember
Commercial | Other commercial real estate | TDRs    
Financing Receivable, Modifications [Line Items]    
Accruing 2,123fcnca_FinancingReceivableRecordedInvestmentStillAccruing
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialRealEstateOtherReceivableMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember		 2,374fcnca_FinancingReceivableRecordedInvestmentStillAccruing
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialRealEstateOtherReceivableMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember
Nonaccruing 423us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialRealEstateOtherReceivableMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember		 449us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialRealEstateOtherReceivableMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember
Financing Receivable, Modifications, Recorded Investment 2,546us-gaap_FinancingReceivableModificationsRecordedInvestment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialRealEstateOtherReceivableMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember		 2,823us-gaap_FinancingReceivableModificationsRecordedInvestment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialRealEstateOtherReceivableMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember
Commercial | Other commercial real estate | Non-PCI Loans    
Financing Receivable, Modifications [Line Items]    
Nonaccruing 650us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialRealEstateOtherReceivableMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ fcnca_LoanDesignationAxis
= fcnca_NonPCILoansMember		 619us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialRealEstateOtherReceivableMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ fcnca_LoanDesignationAxis
= fcnca_NonPCILoansMember
Commercial | Commercial and industrial | TDRs    
Financing Receivable, Modifications [Line Items]    
Accruing 9,248fcnca_FinancingReceivableRecordedInvestmentStillAccruing
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= fcnca_CommercialAndIndustrialMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember		 9,864fcnca_FinancingReceivableRecordedInvestmentStillAccruing
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= fcnca_CommercialAndIndustrialMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember
Nonaccruing 4,768us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= fcnca_CommercialAndIndustrialMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember		 664us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= fcnca_CommercialAndIndustrialMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember
Financing Receivable, Modifications, Recorded Investment 14,016us-gaap_FinancingReceivableModificationsRecordedInvestment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= fcnca_CommercialAndIndustrialMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember		 10,528us-gaap_FinancingReceivableModificationsRecordedInvestment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= fcnca_CommercialAndIndustrialMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember
Commercial | Commercial and industrial | Non-PCI Loans    
Financing Receivable, Modifications [Line Items]    
Nonaccruing 5,691us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= fcnca_CommercialAndIndustrialMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ fcnca_LoanDesignationAxis
= fcnca_NonPCILoansMember		 1,741us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= fcnca_CommercialAndIndustrialMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ fcnca_LoanDesignationAxis
= fcnca_NonPCILoansMember
Commercial | Lease financing | TDRs    
Financing Receivable, Modifications [Line Items]    
Accruing 1,163fcnca_FinancingReceivableRecordedInvestmentStillAccruing
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_FinanceLeasesFinancingReceivableMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember		 258fcnca_FinancingReceivableRecordedInvestmentStillAccruing
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_FinanceLeasesFinancingReceivableMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember
Nonaccruing 329us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_FinanceLeasesFinancingReceivableMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember		 365us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_FinanceLeasesFinancingReceivableMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember
Financing Receivable, Modifications, Recorded Investment 1,492us-gaap_FinancingReceivableModificationsRecordedInvestment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_FinanceLeasesFinancingReceivableMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember		 623us-gaap_FinancingReceivableModificationsRecordedInvestment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_FinanceLeasesFinancingReceivableMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember
Commercial | Lease financing | Non-PCI Loans    
Financing Receivable, Modifications [Line Items]    
Nonaccruing 346us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_FinanceLeasesFinancingReceivableMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ fcnca_LoanDesignationAxis
= fcnca_NonPCILoansMember		 374us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_FinanceLeasesFinancingReceivableMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ fcnca_LoanDesignationAxis
= fcnca_NonPCILoansMember
Commercial | Other | TDRs    
Financing Receivable, Modifications [Line Items]    
Accruing 0fcnca_FinancingReceivableRecordedInvestmentStillAccruing
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= fcnca_OtherLoansMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember		 34fcnca_FinancingReceivableRecordedInvestmentStillAccruing
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= fcnca_OtherLoansMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember
Nonaccruing 0us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= fcnca_OtherLoansMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember		 0us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= fcnca_OtherLoansMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember
Financing Receivable, Modifications, Recorded Investment 0us-gaap_FinancingReceivableModificationsRecordedInvestment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= fcnca_OtherLoansMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember		 34us-gaap_FinancingReceivableModificationsRecordedInvestment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= fcnca_OtherLoansMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember
Noncommerical | TDRs    
Financing Receivable, Modifications [Line Items]    
Accruing 26,618fcnca_FinancingReceivableRecordedInvestmentStillAccruing
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fcnca_NoncommercialSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember		 28,658fcnca_FinancingReceivableRecordedInvestmentStillAccruing
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fcnca_NoncommercialSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember
Nonaccruing 8,189us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fcnca_NoncommercialSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember		 4,655us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fcnca_NoncommercialSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember
Financing Receivable, Modifications, Recorded Investment 34,807us-gaap_FinancingReceivableModificationsRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fcnca_NoncommercialSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember		 33,313us-gaap_FinancingReceivableModificationsRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fcnca_NoncommercialSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember
Noncommerical | Mortgage | TDRs    
Financing Receivable, Modifications [Line Items]    
Accruing 23,060fcnca_FinancingReceivableRecordedInvestmentStillAccruing
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_MortgageReceivablesMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fcnca_NoncommercialSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember		 22,597fcnca_FinancingReceivableRecordedInvestmentStillAccruing
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_MortgageReceivablesMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fcnca_NoncommercialSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember
Nonaccruing 5,097us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_MortgageReceivablesMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fcnca_NoncommercialSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember		 4,655us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_MortgageReceivablesMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fcnca_NoncommercialSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember
Financing Receivable, Modifications, Recorded Investment 28,157us-gaap_FinancingReceivableModificationsRecordedInvestment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_MortgageReceivablesMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fcnca_NoncommercialSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember		 27,252us-gaap_FinancingReceivableModificationsRecordedInvestment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_MortgageReceivablesMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fcnca_NoncommercialSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember
Noncommerical | Mortgage | Non-PCI Loans    
Financing Receivable, Modifications [Line Items]    
Nonaccruing 19,238us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_MortgageReceivablesMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fcnca_NoncommercialSegmentMember
/ fcnca_LoanDesignationAxis
= fcnca_NonPCILoansMember		 14,242us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_MortgageReceivablesMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fcnca_NoncommercialSegmentMember
/ fcnca_LoanDesignationAxis
= fcnca_NonPCILoansMember
Noncommerical | Other | Non-PCI Loans    
Financing Receivable, Modifications [Line Items]    
Nonaccruing 2,052us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= fcnca_OtherLoansMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fcnca_NoncommercialSegmentMember
/ fcnca_LoanDesignationAxis
= fcnca_NonPCILoansMember		 1,966us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= fcnca_OtherLoansMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fcnca_NoncommercialSegmentMember
/ fcnca_LoanDesignationAxis
= fcnca_NonPCILoansMember
Noncommerical | Construction and land development | TDRs    
Financing Receivable, Modifications [Line Items]    
Accruing 733fcnca_FinancingReceivableRecordedInvestmentStillAccruing
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= fcnca_ConstructionAndLandDevelopmentNoncommercialMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fcnca_NoncommercialSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember		 1,391fcnca_FinancingReceivableRecordedInvestmentStillAccruing
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= fcnca_ConstructionAndLandDevelopmentNoncommercialMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fcnca_NoncommercialSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember
Nonaccruing 0us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= fcnca_ConstructionAndLandDevelopmentNoncommercialMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fcnca_NoncommercialSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember		 0us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= fcnca_ConstructionAndLandDevelopmentNoncommercialMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fcnca_NoncommercialSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember
Financing Receivable, Modifications, Recorded Investment 733us-gaap_FinancingReceivableModificationsRecordedInvestment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= fcnca_ConstructionAndLandDevelopmentNoncommercialMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fcnca_NoncommercialSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember		 1,391us-gaap_FinancingReceivableModificationsRecordedInvestment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= fcnca_ConstructionAndLandDevelopmentNoncommercialMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fcnca_NoncommercialSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember
Noncommerical | Construction and land development | Non-PCI Loans    
Financing Receivable, Modifications [Line Items]    
Nonaccruing 0us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= fcnca_ConstructionAndLandDevelopmentNoncommercialMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fcnca_NoncommercialSegmentMember
/ fcnca_LoanDesignationAxis
= fcnca_NonPCILoansMember		 0us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= fcnca_ConstructionAndLandDevelopmentNoncommercialMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fcnca_NoncommercialSegmentMember
/ fcnca_LoanDesignationAxis
= fcnca_NonPCILoansMember
Noncommerical | Revolving mortgage | TDRs    
Financing Receivable, Modifications [Line Items]    
Accruing 1,871fcnca_FinancingReceivableRecordedInvestmentStillAccruing
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_HomeEquityMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fcnca_NoncommercialSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember		 3,675fcnca_FinancingReceivableRecordedInvestmentStillAccruing
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_HomeEquityMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fcnca_NoncommercialSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember
Nonaccruing 1,112us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_HomeEquityMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fcnca_NoncommercialSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember		 0us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_HomeEquityMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fcnca_NoncommercialSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember
Financing Receivable, Modifications, Recorded Investment 2,983us-gaap_FinancingReceivableModificationsRecordedInvestment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_HomeEquityMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fcnca_NoncommercialSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember		 3,675us-gaap_FinancingReceivableModificationsRecordedInvestment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_HomeEquityMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fcnca_NoncommercialSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember
Noncommerical | Revolving mortgage | Non-PCI Loans    
Financing Receivable, Modifications [Line Items]    
Nonaccruing 9,837us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_HomeEquityMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fcnca_NoncommercialSegmentMember
/ fcnca_LoanDesignationAxis
= fcnca_NonPCILoansMember		 0us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_HomeEquityMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fcnca_NoncommercialSegmentMember
/ fcnca_LoanDesignationAxis
= fcnca_NonPCILoansMember
Noncommerical | Consumer and Other | TDRs    
Financing Receivable, Modifications [Line Items]    
Accruing 954fcnca_FinancingReceivableRecordedInvestmentStillAccruing
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= fcnca_ConsumerAndOtherMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fcnca_NoncommercialSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember		 995fcnca_FinancingReceivableRecordedInvestmentStillAccruing
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= fcnca_ConsumerAndOtherMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fcnca_NoncommercialSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember
Nonaccruing 1,980us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= fcnca_ConsumerAndOtherMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fcnca_NoncommercialSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember		 0us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= fcnca_ConsumerAndOtherMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fcnca_NoncommercialSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember
Financing Receivable, Modifications, Recorded Investment $ 2,934us-gaap_FinancingReceivableModificationsRecordedInvestment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= fcnca_ConsumerAndOtherMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fcnca_NoncommercialSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember		 $ 995us-gaap_FinancingReceivableModificationsRecordedInvestment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= fcnca_ConsumerAndOtherMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fcnca_NoncommercialSegmentMember
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= fcnca_TroubledDebtRestructuringMember