XML 104 R90.htm IDEA: XBRL DOCUMENT
v2.4.1.9

Employee Benefit Plans (Fair Value and Allocation Of Plan Assets) (Details) (USD $) In Thousands, unless otherwise specified | 12 Months Ended |
--- | --- | ---
Dec. 31, 2014 | Dec. 31, 2013 | Dec. 31, 2012
BancShares Plan |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 544,956us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember | 524,017us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember | $ 463,005us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember
Actual % of Plan Assets | 100.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember | 100.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember |
BancShares Plan | Fair Value |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 544,956us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_EstimateOfFairValueFairValueDisclosureMember | 524,017us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_EstimateOfFairValueFairValueDisclosureMember |
BancShares Plan | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1 Inputs) |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 393,578us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member | 380,540us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member |
BancShares Plan | Quoted Prices for Similar Assets and Liabilities (Level 2 Inputs) |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 151,378us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member | 143,477us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member |
BancShares Plan | Fair Value, Inputs, Level 3 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member |
BancShares Plan | Cash and Cash Equivalents |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Actual % of Plan Assets | 1.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_InvestmentTypeAxis = us-gaap_CashAndCashEquivalentsMember | 1.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_InvestmentTypeAxis = us-gaap_CashAndCashEquivalentsMember |
BancShares Plan | Cash and Cash Equivalents | Minimum |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Target Allocation | 0.00%us-gaap_DefinedBenefitPlanTargetPlanAssetAllocations / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_InvestmentTypeAxis = us-gaap_CashAndCashEquivalentsMember / us-gaap_RangeAxis = us-gaap_MinimumMember | 0.00%us-gaap_DefinedBenefitPlanTargetPlanAssetAllocations / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_InvestmentTypeAxis = us-gaap_CashAndCashEquivalentsMember / us-gaap_RangeAxis = us-gaap_MinimumMember |
BancShares Plan | Cash and Cash Equivalents | Maximum |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Target Allocation | 1.00%us-gaap_DefinedBenefitPlanTargetPlanAssetAllocations / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_InvestmentTypeAxis = us-gaap_CashAndCashEquivalentsMember / us-gaap_RangeAxis = us-gaap_MaximumMember | 1.00%us-gaap_DefinedBenefitPlanTargetPlanAssetAllocations / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_InvestmentTypeAxis = us-gaap_CashAndCashEquivalentsMember / us-gaap_RangeAxis = us-gaap_MaximumMember |
BancShares Plan | Cash and Cash Equivalents | Fair Value |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 3,854us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_EstimateOfFairValueFairValueDisclosureMember / us-gaap_InvestmentTypeAxis = us-gaap_CashAndCashEquivalentsMember | 2,517us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_EstimateOfFairValueFairValueDisclosureMember / us-gaap_InvestmentTypeAxis = us-gaap_CashAndCashEquivalentsMember |
BancShares Plan | Cash and Cash Equivalents | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1 Inputs) |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 3,854us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_InvestmentTypeAxis = us-gaap_CashAndCashEquivalentsMember | 2,517us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_InvestmentTypeAxis = us-gaap_CashAndCashEquivalentsMember |
BancShares Plan | Cash and Cash Equivalents | Quoted Prices for Similar Assets and Liabilities (Level 2 Inputs) |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_InvestmentTypeAxis = us-gaap_CashAndCashEquivalentsMember | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_InvestmentTypeAxis = us-gaap_CashAndCashEquivalentsMember |
BancShares Plan | Cash and Cash Equivalents | Fair Value, Inputs, Level 3 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_InvestmentTypeAxis = us-gaap_CashAndCashEquivalentsMember | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_InvestmentTypeAxis = us-gaap_CashAndCashEquivalentsMember |
BancShares Plan | Equity Securities |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Actual % of Plan Assets | 62.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember | 62.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember |
BancShares Plan | Equity Securities | Minimum |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Target Allocation | 55.00%us-gaap_DefinedBenefitPlanTargetPlanAssetAllocations / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember / us-gaap_RangeAxis = us-gaap_MinimumMember | 55.00%us-gaap_DefinedBenefitPlanTargetPlanAssetAllocations / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember / us-gaap_RangeAxis = us-gaap_MinimumMember |
BancShares Plan | Equity Securities | Maximum |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Target Allocation | 65.00%us-gaap_DefinedBenefitPlanTargetPlanAssetAllocations / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember / us-gaap_RangeAxis = us-gaap_MaximumMember | 65.00%us-gaap_DefinedBenefitPlanTargetPlanAssetAllocations / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember / us-gaap_RangeAxis = us-gaap_MaximumMember |
BancShares Plan | Equity Securities | Large capitalization | Fair Value |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 229,315us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_EstimateOfFairValueFairValueDisclosureMember / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_LargecapitalizationMember | 218,023us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_EstimateOfFairValueFairValueDisclosureMember / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_LargecapitalizationMember |
BancShares Plan | Equity Securities | Large capitalization | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1 Inputs) |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 229,315us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_LargecapitalizationMember | 218,023us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_LargecapitalizationMember |
BancShares Plan | Equity Securities | Large capitalization | Quoted Prices for Similar Assets and Liabilities (Level 2 Inputs) |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_LargecapitalizationMember | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_LargecapitalizationMember |
BancShares Plan | Equity Securities | Large capitalization | Fair Value, Inputs, Level 3 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_LargecapitalizationMember | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_LargecapitalizationMember |
BancShares Plan | Equity Securities | Middle capitalization | Fair Value |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 10,796us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_EstimateOfFairValueFairValueDisclosureMember / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_MiddlecapitalizationMember | 10,724us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_EstimateOfFairValueFairValueDisclosureMember / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_MiddlecapitalizationMember |
BancShares Plan | Equity Securities | Middle capitalization | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1 Inputs) |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 10,796us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_MiddlecapitalizationMember | 10,724us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_MiddlecapitalizationMember |
BancShares Plan | Equity Securities | Middle capitalization | Quoted Prices for Similar Assets and Liabilities (Level 2 Inputs) |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_MiddlecapitalizationMember | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_MiddlecapitalizationMember |
BancShares Plan | Equity Securities | Middle capitalization | Fair Value, Inputs, Level 3 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_MiddlecapitalizationMember | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_MiddlecapitalizationMember |
BancShares Plan | Equity Securities | Small capitalization | Fair Value |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 44,734us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_EstimateOfFairValueFairValueDisclosureMember / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_SmallcapitalizationMember | 43,928us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_EstimateOfFairValueFairValueDisclosureMember / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_SmallcapitalizationMember |
BancShares Plan | Equity Securities | Small capitalization | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1 Inputs) |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 44,734us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_SmallcapitalizationMember | 43,928us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_SmallcapitalizationMember |
BancShares Plan | Equity Securities | Small capitalization | Quoted Prices for Similar Assets and Liabilities (Level 2 Inputs) |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_SmallcapitalizationMember | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_SmallcapitalizationMember |
BancShares Plan | Equity Securities | Small capitalization | Fair Value, Inputs, Level 3 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_SmallcapitalizationMember | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_SmallcapitalizationMember |
BancShares Plan | Equity Securities | International equity (developed) | Fair Value |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 10,706us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_EstimateOfFairValueFairValueDisclosureMember / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_InternationalequitydevelopedMember | 10,535us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_EstimateOfFairValueFairValueDisclosureMember / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_InternationalequitydevelopedMember |
BancShares Plan | Equity Securities | International equity (developed) | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1 Inputs) |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 10,706us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_InternationalequitydevelopedMember | 10,535us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_InternationalequitydevelopedMember |
BancShares Plan | Equity Securities | International equity (developed) | Quoted Prices for Similar Assets and Liabilities (Level 2 Inputs) |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_InternationalequitydevelopedMember | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_InternationalequitydevelopedMember |
BancShares Plan | Equity Securities | International equity (developed) | Fair Value, Inputs, Level 3 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_InternationalequitydevelopedMember | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_InternationalequitydevelopedMember |
BancShares Plan | Equity Securities | International equity (emerging) | Fair Value |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 41,484us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_EstimateOfFairValueFairValueDisclosureMember / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_InternationalequityemergingMember | 40,643us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_EstimateOfFairValueFairValueDisclosureMember / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_InternationalequityemergingMember |
BancShares Plan | Equity Securities | International equity (emerging) | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1 Inputs) |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 41,484us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_InternationalequityemergingMember | 40,643us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_InternationalequityemergingMember |
BancShares Plan | Equity Securities | International equity (emerging) | Quoted Prices for Similar Assets and Liabilities (Level 2 Inputs) |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_InternationalequityemergingMember | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_InternationalequityemergingMember |
BancShares Plan | Equity Securities | International equity (emerging) | Fair Value, Inputs, Level 3 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_InternationalequityemergingMember | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_InternationalequityemergingMember |
BancShares Plan | Fixed Income Investments |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Actual % of Plan Assets | 28.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_InvestmentTypeAxis = us-gaap_FixedIncomeInvestmentsMember | 28.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_InvestmentTypeAxis = us-gaap_FixedIncomeInvestmentsMember |
BancShares Plan | Fixed Income Investments | Minimum |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Target Allocation | 25.00%us-gaap_DefinedBenefitPlanTargetPlanAssetAllocations / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_InvestmentTypeAxis = us-gaap_FixedIncomeInvestmentsMember / us-gaap_RangeAxis = us-gaap_MinimumMember | 25.00%us-gaap_DefinedBenefitPlanTargetPlanAssetAllocations / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_InvestmentTypeAxis = us-gaap_FixedIncomeInvestmentsMember / us-gaap_RangeAxis = us-gaap_MinimumMember |
BancShares Plan | Fixed Income Investments | Maximum |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Target Allocation | 40.00%us-gaap_DefinedBenefitPlanTargetPlanAssetAllocations / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_InvestmentTypeAxis = us-gaap_FixedIncomeInvestmentsMember / us-gaap_RangeAxis = us-gaap_MaximumMember | 40.00%us-gaap_DefinedBenefitPlanTargetPlanAssetAllocations / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_InvestmentTypeAxis = us-gaap_FixedIncomeInvestmentsMember / us-gaap_RangeAxis = us-gaap_MaximumMember |
BancShares Plan | Fixed Income Investments | Investment grade bonds | Fair Value |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 81,050us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_EstimateOfFairValueFairValueDisclosureMember / us-gaap_InvestmentTypeAxis = us-gaap_FixedIncomeInvestmentsMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_InvestmentgradebondsMember | 74,501us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_EstimateOfFairValueFairValueDisclosureMember / us-gaap_InvestmentTypeAxis = us-gaap_FixedIncomeInvestmentsMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_InvestmentgradebondsMember |
BancShares Plan | Fixed Income Investments | Investment grade bonds | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1 Inputs) |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_InvestmentTypeAxis = us-gaap_FixedIncomeInvestmentsMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_InvestmentgradebondsMember | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_InvestmentTypeAxis = us-gaap_FixedIncomeInvestmentsMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_InvestmentgradebondsMember |
BancShares Plan | Fixed Income Investments | Investment grade bonds | Quoted Prices for Similar Assets and Liabilities (Level 2 Inputs) |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 81,050us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_InvestmentTypeAxis = us-gaap_FixedIncomeInvestmentsMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_InvestmentgradebondsMember | 74,501us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_InvestmentTypeAxis = us-gaap_FixedIncomeInvestmentsMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_InvestmentgradebondsMember |
BancShares Plan | Fixed Income Investments | Investment grade bonds | Fair Value, Inputs, Level 3 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_InvestmentTypeAxis = us-gaap_FixedIncomeInvestmentsMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_InvestmentgradebondsMember | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_InvestmentTypeAxis = us-gaap_FixedIncomeInvestmentsMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_InvestmentgradebondsMember |
BancShares Plan | Fixed Income Investments | Intermediate bonds | Fair Value |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 53,806us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_EstimateOfFairValueFairValueDisclosureMember / us-gaap_InvestmentTypeAxis = us-gaap_FixedIncomeInvestmentsMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_IntermediatebondsMember | 48,746us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_EstimateOfFairValueFairValueDisclosureMember / us-gaap_InvestmentTypeAxis = us-gaap_FixedIncomeInvestmentsMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_IntermediatebondsMember |
BancShares Plan | Fixed Income Investments | Intermediate bonds | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1 Inputs) |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_InvestmentTypeAxis = us-gaap_FixedIncomeInvestmentsMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_IntermediatebondsMember | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_InvestmentTypeAxis = us-gaap_FixedIncomeInvestmentsMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_IntermediatebondsMember |
BancShares Plan | Fixed Income Investments | Intermediate bonds | Quoted Prices for Similar Assets and Liabilities (Level 2 Inputs) |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 53,806us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_InvestmentTypeAxis = us-gaap_FixedIncomeInvestmentsMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_IntermediatebondsMember | 48,746us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_InvestmentTypeAxis = us-gaap_FixedIncomeInvestmentsMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_IntermediatebondsMember |
BancShares Plan | Fixed Income Investments | Intermediate bonds | Fair Value, Inputs, Level 3 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_InvestmentTypeAxis = us-gaap_FixedIncomeInvestmentsMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_IntermediatebondsMember | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_InvestmentTypeAxis = us-gaap_FixedIncomeInvestmentsMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_IntermediatebondsMember |
BancShares Plan | Fixed Income Investments | High-yield corporate bonds | Fair Value |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 6,592us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_EstimateOfFairValueFairValueDisclosureMember / us-gaap_InvestmentTypeAxis = us-gaap_FixedIncomeInvestmentsMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_HighyieldcorporatebondsMember | 10,111us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_EstimateOfFairValueFairValueDisclosureMember / us-gaap_InvestmentTypeAxis = us-gaap_FixedIncomeInvestmentsMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_HighyieldcorporatebondsMember |
BancShares Plan | Fixed Income Investments | High-yield corporate bonds | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1 Inputs) |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_InvestmentTypeAxis = us-gaap_FixedIncomeInvestmentsMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_HighyieldcorporatebondsMember | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_InvestmentTypeAxis = us-gaap_FixedIncomeInvestmentsMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_HighyieldcorporatebondsMember |
BancShares Plan | Fixed Income Investments | High-yield corporate bonds | Quoted Prices for Similar Assets and Liabilities (Level 2 Inputs) |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 6,592us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_InvestmentTypeAxis = us-gaap_FixedIncomeInvestmentsMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_HighyieldcorporatebondsMember | 10,111us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_InvestmentTypeAxis = us-gaap_FixedIncomeInvestmentsMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_HighyieldcorporatebondsMember |
BancShares Plan | Fixed Income Investments | High-yield corporate bonds | Fair Value, Inputs, Level 3 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_InvestmentTypeAxis = us-gaap_FixedIncomeInvestmentsMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_HighyieldcorporatebondsMember | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_InvestmentTypeAxis = us-gaap_FixedIncomeInvestmentsMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_HighyieldcorporatebondsMember |
BancShares Plan | Fixed Income Investments | U. S. Treasury | Fair Value |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 2,550us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_EstimateOfFairValueFairValueDisclosureMember / us-gaap_InvestmentTypeAxis = us-gaap_FixedIncomeInvestmentsMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_USTreasurySecuritiesMember | 4,395us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_EstimateOfFairValueFairValueDisclosureMember / us-gaap_InvestmentTypeAxis = us-gaap_FixedIncomeInvestmentsMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_USTreasurySecuritiesMember |
BancShares Plan | Fixed Income Investments | U. S. Treasury | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1 Inputs) |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 2,550us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_InvestmentTypeAxis = us-gaap_FixedIncomeInvestmentsMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_USTreasurySecuritiesMember | 4,395us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_InvestmentTypeAxis = us-gaap_FixedIncomeInvestmentsMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_USTreasurySecuritiesMember |
BancShares Plan | Fixed Income Investments | U. S. Treasury | Quoted Prices for Similar Assets and Liabilities (Level 2 Inputs) |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_InvestmentTypeAxis = us-gaap_FixedIncomeInvestmentsMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_USTreasurySecuritiesMember | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_InvestmentTypeAxis = us-gaap_FixedIncomeInvestmentsMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_USTreasurySecuritiesMember |
BancShares Plan | Fixed Income Investments | U. S. Treasury | Fair Value, Inputs, Level 3 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_InvestmentTypeAxis = us-gaap_FixedIncomeInvestmentsMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_USTreasurySecuritiesMember | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_InvestmentTypeAxis = us-gaap_FixedIncomeInvestmentsMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_USTreasurySecuritiesMember |
BancShares Plan | Fixed Income Investments | International emerging bond | Fair Value |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 9,930us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_EstimateOfFairValueFairValueDisclosureMember / us-gaap_InvestmentTypeAxis = us-gaap_FixedIncomeInvestmentsMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_InternationalemergingbondMember | 10,119us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_EstimateOfFairValueFairValueDisclosureMember / us-gaap_InvestmentTypeAxis = us-gaap_FixedIncomeInvestmentsMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_InternationalemergingbondMember |
BancShares Plan | Fixed Income Investments | International emerging bond | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1 Inputs) |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_InvestmentTypeAxis = us-gaap_FixedIncomeInvestmentsMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_InternationalemergingbondMember | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_InvestmentTypeAxis = us-gaap_FixedIncomeInvestmentsMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_InternationalemergingbondMember |
BancShares Plan | Fixed Income Investments | International emerging bond | Quoted Prices for Similar Assets and Liabilities (Level 2 Inputs) |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 9,930us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_InvestmentTypeAxis = us-gaap_FixedIncomeInvestmentsMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_InternationalemergingbondMember | 10,119us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_InvestmentTypeAxis = us-gaap_FixedIncomeInvestmentsMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_InternationalemergingbondMember |
BancShares Plan | Fixed Income Investments | International emerging bond | Fair Value, Inputs, Level 3 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_InvestmentTypeAxis = us-gaap_FixedIncomeInvestmentsMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_InternationalemergingbondMember | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_InvestmentTypeAxis = us-gaap_FixedIncomeInvestmentsMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = fcnca_InternationalemergingbondMember |
BancShares Plan | Alternative investments |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Actual % of Plan Assets | 9.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_InvestmentTypeAxis = fcnca_AlternativeinvestmentsMember | 9.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_InvestmentTypeAxis = fcnca_AlternativeinvestmentsMember |
BancShares Plan | Alternative investments | Minimum |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Target Allocation | 0.00%us-gaap_DefinedBenefitPlanTargetPlanAssetAllocations / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_InvestmentTypeAxis = fcnca_AlternativeinvestmentsMember / us-gaap_RangeAxis = us-gaap_MinimumMember | 0.00%us-gaap_DefinedBenefitPlanTargetPlanAssetAllocations / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_InvestmentTypeAxis = fcnca_AlternativeinvestmentsMember / us-gaap_RangeAxis = us-gaap_MinimumMember |
BancShares Plan | Alternative investments | Maximum |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Target Allocation | 10.00%us-gaap_DefinedBenefitPlanTargetPlanAssetAllocations / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_InvestmentTypeAxis = fcnca_AlternativeinvestmentsMember / us-gaap_RangeAxis = us-gaap_MaximumMember | 8.00%us-gaap_DefinedBenefitPlanTargetPlanAssetAllocations / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_InvestmentTypeAxis = fcnca_AlternativeinvestmentsMember / us-gaap_RangeAxis = us-gaap_MaximumMember |
BancShares Plan | Alternative investments | Commodities Investment | Fair Value |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 17,671us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / fcnca_AlternativeinvestmentsAxis = us-gaap_CommoditiesInvestmentMember / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_EstimateOfFairValueFairValueDisclosureMember / us-gaap_InvestmentTypeAxis = fcnca_AlternativeinvestmentsMember | 19,014us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / fcnca_AlternativeinvestmentsAxis = us-gaap_CommoditiesInvestmentMember / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_EstimateOfFairValueFairValueDisclosureMember / us-gaap_InvestmentTypeAxis = fcnca_AlternativeinvestmentsMember |
BancShares Plan | Alternative investments | Commodities Investment | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1 Inputs) |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 17,671us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / fcnca_AlternativeinvestmentsAxis = us-gaap_CommoditiesInvestmentMember / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_InvestmentTypeAxis = fcnca_AlternativeinvestmentsMember | 19,014us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / fcnca_AlternativeinvestmentsAxis = us-gaap_CommoditiesInvestmentMember / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_InvestmentTypeAxis = fcnca_AlternativeinvestmentsMember |
BancShares Plan | Alternative investments | Commodities Investment | Quoted Prices for Similar Assets and Liabilities (Level 2 Inputs) |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / fcnca_AlternativeinvestmentsAxis = us-gaap_CommoditiesInvestmentMember / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_InvestmentTypeAxis = fcnca_AlternativeinvestmentsMember | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / fcnca_AlternativeinvestmentsAxis = us-gaap_CommoditiesInvestmentMember / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_InvestmentTypeAxis = fcnca_AlternativeinvestmentsMember |
BancShares Plan | Alternative investments | Commodities Investment | Fair Value, Inputs, Level 3 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / fcnca_AlternativeinvestmentsAxis = us-gaap_CommoditiesInvestmentMember / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_InvestmentTypeAxis = fcnca_AlternativeinvestmentsMember | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / fcnca_AlternativeinvestmentsAxis = us-gaap_CommoditiesInvestmentMember / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_InvestmentTypeAxis = fcnca_AlternativeinvestmentsMember |
BancShares Plan | Alternative investments | Hedge Funds | Fair Value |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 32,468us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / fcnca_AlternativeinvestmentsAxis = us-gaap_HedgeFundsMember / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_EstimateOfFairValueFairValueDisclosureMember / us-gaap_InvestmentTypeAxis = fcnca_AlternativeinvestmentsMember | 30,761us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / fcnca_AlternativeinvestmentsAxis = us-gaap_HedgeFundsMember / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_EstimateOfFairValueFairValueDisclosureMember / us-gaap_InvestmentTypeAxis = fcnca_AlternativeinvestmentsMember |
BancShares Plan | Alternative investments | Hedge Funds | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1 Inputs) |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 32,468us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / fcnca_AlternativeinvestmentsAxis = us-gaap_HedgeFundsMember / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_InvestmentTypeAxis = fcnca_AlternativeinvestmentsMember | 30,761us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / fcnca_AlternativeinvestmentsAxis = us-gaap_HedgeFundsMember / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_InvestmentTypeAxis = fcnca_AlternativeinvestmentsMember |
BancShares Plan | Alternative investments | Hedge Funds | Quoted Prices for Similar Assets and Liabilities (Level 2 Inputs) |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets |  |  |
BancShares Plan | Alternative investments | Hedge Funds | Fair Value, Inputs, Level 3 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / fcnca_AlternativeinvestmentsAxis = us-gaap_HedgeFundsMember / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_InvestmentTypeAxis = fcnca_AlternativeinvestmentsMember | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / fcnca_AlternativeinvestmentsAxis = us-gaap_HedgeFundsMember / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancSharesPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_InvestmentTypeAxis = fcnca_AlternativeinvestmentsMember |
Bancorporation Plan |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 155,618us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancorporationPlanMember | 150,374us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancorporationPlanMember |
Bancorporation Plan | Fair Value |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 155,618us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancorporationPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_EstimateOfFairValueFairValueDisclosureMember |  |
Bancorporation Plan | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1 Inputs) |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 143,938us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancorporationPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member |  |
Bancorporation Plan | Quoted Prices for Similar Assets and Liabilities (Level 2 Inputs) |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 11,680us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancorporationPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member |  |
Bancorporation Plan | Fair Value, Inputs, Level 3 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancorporationPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member |  |
Bancorporation Plan | Cash and Cash Equivalents |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Target Allocation | 35.00%us-gaap_DefinedBenefitPlanTargetPlanAssetAllocations / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancorporationPlanMember / us-gaap_InvestmentTypeAxis = us-gaap_CashAndCashEquivalentsMember |  |
Actual % of Plan Assets | 8.40%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancorporationPlanMember / us-gaap_InvestmentTypeAxis = us-gaap_CashAndCashEquivalentsMember |  |
Bancorporation Plan | Cash and Cash Equivalents | Fair Value |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 13,077us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancorporationPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_EstimateOfFairValueFairValueDisclosureMember / us-gaap_InvestmentTypeAxis = us-gaap_CashAndCashEquivalentsMember |  |
Bancorporation Plan | Cash and Cash Equivalents | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1 Inputs) |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 13,077us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancorporationPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_InvestmentTypeAxis = us-gaap_CashAndCashEquivalentsMember |  |
Bancorporation Plan | Cash and Cash Equivalents | Quoted Prices for Similar Assets and Liabilities (Level 2 Inputs) |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancorporationPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_InvestmentTypeAxis = us-gaap_CashAndCashEquivalentsMember |  |
Bancorporation Plan | Cash and Cash Equivalents | Fair Value, Inputs, Level 3 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancorporationPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_InvestmentTypeAxis = us-gaap_CashAndCashEquivalentsMember |  |
Bancorporation Plan | Equity Securities |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Target Allocation | 60.00%us-gaap_DefinedBenefitPlanTargetPlanAssetAllocations / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancorporationPlanMember / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember |  |
Actual % of Plan Assets | 68.97%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancorporationPlanMember / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember |  |
Bancorporation Plan | Equity Securities | Maximum |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Target Allocation | 70.00%us-gaap_DefinedBenefitPlanTargetPlanAssetAllocations / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancorporationPlanMember / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember / us-gaap_RangeAxis = us-gaap_MaximumMember |  |
Bancorporation Plan | Equity Securities | Fair Value |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 107,333us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancorporationPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_EstimateOfFairValueFairValueDisclosureMember / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember |  |
Bancorporation Plan | Equity Securities | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1 Inputs) |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 107,333us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancorporationPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember |  |
Bancorporation Plan | Equity Securities | Quoted Prices for Similar Assets and Liabilities (Level 2 Inputs) |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancorporationPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember |  |
Bancorporation Plan | Equity Securities | Fair Value, Inputs, Level 3 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancorporationPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_InvestmentTypeAxis = us-gaap_EquitySecuritiesMember |  |
Bancorporation Plan | Debt Securities |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Actual % of Plan Assets | 22.62%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancorporationPlanMember / us-gaap_InvestmentTypeAxis = us-gaap_DebtSecuritiesMember |  |
Bancorporation Plan | Debt Securities | Fair Value |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 35,208us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancorporationPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_EstimateOfFairValueFairValueDisclosureMember / us-gaap_InvestmentTypeAxis = us-gaap_DebtSecuritiesMember |  |
Bancorporation Plan | Debt Securities | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1 Inputs) |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 23,528us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancorporationPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_InvestmentTypeAxis = us-gaap_DebtSecuritiesMember |  |
Bancorporation Plan | Debt Securities | Quoted Prices for Similar Assets and Liabilities (Level 2 Inputs) |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 11,680us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancorporationPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_InvestmentTypeAxis = us-gaap_DebtSecuritiesMember |  |
Bancorporation Plan | Debt Securities | Fair Value, Inputs, Level 3 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = fcnca_BancorporationPlanMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_InvestmentTypeAxis = us-gaap_DebtSecuritiesMember |  |

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- Definition Assets, usually stocks, bonds, and other investments, that have been segregated and restricted (usually in a trust) to provide benefits, at their fair value as of the measurement date. Plan assets include amounts contributed by the employer (and by employees for a contributory plan) and amounts earned from investing the contributions, less benefits paid. If a plan has liabilities other than for benefits, those non-benefit obligations may be considered as reductions of plan assets. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=35743120&loc=d3e1928-114920 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 30 -Section 35 -Paragraph 50 -URI http://asc.fasb.org/extlink&oid=29635418&loc=d3e12355-114930 + Details
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