3.26.1 html 819 484 1 true 187 0 false 6 false false R1.htm 0000001 - Document - COVER Sheet http://www.firsthorizon.com/role/COVER COVER Cover 1 false false R2.htm 9952151 - Statement - CONSOLIDATED BALANCE SHEETS Sheet http://www.firsthorizon.com/role/CONSOLIDATEDBALANCESHEETS CONSOLIDATED BALANCE SHEETS Statements 2 false false R3.htm 9952152 - Statement - CONSOLIDATED BALANCE SHEETS (Parenthetical) Sheet http://www.firsthorizon.com/role/CONSOLIDATEDBALANCESHEETSParenthetical CONSOLIDATED BALANCE SHEETS (Parenthetical) Statements 3 false false R4.htm 9952153 - Statement - CONSOLIDATED STATEMENTS OF INCOME Sheet http://www.firsthorizon.com/role/CONSOLIDATEDSTATEMENTSOFINCOME CONSOLIDATED STATEMENTS OF INCOME Statements 4 false false R5.htm 9952154 - Statement - CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME Sheet http://www.firsthorizon.com/role/CONSOLIDATEDSTATEMENTSOFCOMPREHENSIVEINCOME CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME Statements 5 false false R6.htm 9952155 - Statement - CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY Sheet http://www.firsthorizon.com/role/CONSOLIDATEDSTATEMENTSOFCHANGESINEQUITY CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY Statements 6 false false R7.htm 9952156 - Statement - CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (Parenthetical) Sheet http://www.firsthorizon.com/role/CONSOLIDATEDSTATEMENTSOFCHANGESINEQUITYParenthetical CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (Parenthetical) Statements 7 false false R8.htm 9952157 - Statement - CONSOLIDATED STATEMENTS OF CASH FLOWS Sheet http://www.firsthorizon.com/role/CONSOLIDATEDSTATEMENTSOFCASHFLOWS CONSOLIDATED STATEMENTS OF CASH FLOWS Statements 8 false false R9.htm 9952158 - Disclosure - Basis of Presentation and Accounting Policies Sheet http://www.firsthorizon.com/role/BasisofPresentationandAccountingPolicies Basis of Presentation and Accounting Policies Notes 9 false false R10.htm 9952159 - Disclosure - Investment Securities Sheet http://www.firsthorizon.com/role/InvestmentSecurities Investment Securities Notes 10 false false R11.htm 9952160 - Disclosure - Loans and Leases Sheet http://www.firsthorizon.com/role/LoansandLeases Loans and Leases Notes 11 false false R12.htm 9952161 - Disclosure - Allowance for Credit Losses Sheet http://www.firsthorizon.com/role/AllowanceforCreditLosses Allowance for Credit Losses Notes 12 false false R13.htm 9952162 - Disclosure - Mortgage Banking Activity Sheet http://www.firsthorizon.com/role/MortgageBankingActivity Mortgage Banking Activity Notes 13 false false R14.htm 9952163 - Disclosure - Goodwill and Other Intangible Assets Sheet http://www.firsthorizon.com/role/GoodwillandOtherIntangibleAssets Goodwill and Other Intangible Assets Notes 14 false false R15.htm 9952164 - Disclosure - Preferred Stock Sheet http://www.firsthorizon.com/role/PreferredStock Preferred Stock Notes 15 false false R16.htm 9952165 - Disclosure - Components of Other Comprehensive Income (Loss) Sheet http://www.firsthorizon.com/role/ComponentsofOtherComprehensiveIncomeLoss Components of Other Comprehensive Income (Loss) Notes 16 false false R17.htm 9952166 - Disclosure - Earnings Per Share Sheet http://www.firsthorizon.com/role/EarningsPerShare Earnings Per Share Notes 17 false false R18.htm 9952167 - Disclosure - Contingencies and Other Disclosures Sheet http://www.firsthorizon.com/role/ContingenciesandOtherDisclosures Contingencies and Other Disclosures Notes 18 false false R19.htm 9952168 - Disclosure - Retirement Plans Sheet http://www.firsthorizon.com/role/RetirementPlans Retirement Plans Notes 19 false false R20.htm 9952169 - Disclosure - Business Segment Information Sheet http://www.firsthorizon.com/role/BusinessSegmentInformation Business Segment Information Notes 20 false false R21.htm 9952170 - Disclosure - Variable Interest Entities Sheet http://www.firsthorizon.com/role/VariableInterestEntities Variable Interest Entities Notes 21 false false R22.htm 9952171 - Disclosure - Derivatives Sheet http://www.firsthorizon.com/role/Derivatives Derivatives Notes 22 false false R23.htm 9952172 - Disclosure - Master Netting and Similar Agreements ??? Repurchase, Reverse Repurchase, and Securities Borrowing Transactions Sheet http://www.firsthorizon.com/role/MasterNettingandSimilarAgreementsRepurchaseReverseRepurchaseandSecuritiesBorrowingTransactions Master Netting and Similar Agreements ??? Repurchase, Reverse Repurchase, and Securities Borrowing Transactions Notes 23 false false R24.htm 9952173 - Disclosure - Fair Value of Assets and Liabilities Sheet http://www.firsthorizon.com/role/FairValueofAssetsandLiabilities Fair Value of Assets and Liabilities Notes 24 false false R25.htm 9952174 - Disclosure - Subsequent Events Sheet http://www.firsthorizon.com/role/SubsequentEvents Subsequent Events Notes 25 false false R26.htm 995445 - Disclosure - Insider Trading Arrangements Sheet http://xbrl.sec.gov/ecd/role/InsiderTradingArrangements Insider Trading Arrangements Notes 26 false false R27.htm 9955511 - Disclosure - Basis of Presentation and Accounting Policies (Policies) Sheet http://www.firsthorizon.com/role/BasisofPresentationandAccountingPoliciesPolicies Basis of Presentation and Accounting Policies (Policies) Policies http://www.firsthorizon.com/role/BasisofPresentationandAccountingPolicies 27 false false R28.htm 9955512 - Disclosure - Basis of Presentation and Accounting Policies (Tables) Sheet http://www.firsthorizon.com/role/BasisofPresentationandAccountingPoliciesTables Basis of Presentation and Accounting Policies (Tables) Tables http://www.firsthorizon.com/role/BasisofPresentationandAccountingPolicies 28 false false R29.htm 9955513 - Disclosure - Investment Securities (Tables) Sheet http://www.firsthorizon.com/role/InvestmentSecuritiesTables Investment Securities (Tables) Tables http://www.firsthorizon.com/role/InvestmentSecurities 29 false false R30.htm 9955514 - Disclosure - Loans and Leases (Tables) Sheet http://www.firsthorizon.com/role/LoansandLeasesTables Loans and Leases (Tables) Tables http://www.firsthorizon.com/role/LoansandLeases 30 false false R31.htm 9955515 - Disclosure - Allowance for Credit Losses (Tables) Sheet http://www.firsthorizon.com/role/AllowanceforCreditLossesTables Allowance for Credit Losses (Tables) Tables http://www.firsthorizon.com/role/AllowanceforCreditLosses 31 false false R32.htm 9955516 - Disclosure - Mortgage Banking Activity (Tables) Sheet http://www.firsthorizon.com/role/MortgageBankingActivityTables Mortgage Banking Activity (Tables) Tables http://www.firsthorizon.com/role/MortgageBankingActivity 32 false false R33.htm 9955517 - Disclosure - Goodwill and Other Intangible Assets (Tables) Sheet http://www.firsthorizon.com/role/GoodwillandOtherIntangibleAssetsTables Goodwill and Other Intangible Assets (Tables) Tables http://www.firsthorizon.com/role/GoodwillandOtherIntangibleAssets 33 false false R34.htm 9955518 - Disclosure - Preferred Stock (Tables) Sheet http://www.firsthorizon.com/role/PreferredStockTables Preferred Stock (Tables) Tables http://www.firsthorizon.com/role/PreferredStock 34 false false R35.htm 9955519 - Disclosure - Components of Other Comprehensive Income (Loss) (Tables) Sheet http://www.firsthorizon.com/role/ComponentsofOtherComprehensiveIncomeLossTables Components of Other Comprehensive Income (Loss) (Tables) Tables http://www.firsthorizon.com/role/ComponentsofOtherComprehensiveIncomeLoss 35 false false R36.htm 9955520 - Disclosure - Earnings Per Share (Tables) Sheet http://www.firsthorizon.com/role/EarningsPerShareTables Earnings Per Share (Tables) Tables http://www.firsthorizon.com/role/EarningsPerShare 36 false false R37.htm 9955521 - Disclosure - Retirement Plans (Tables) Sheet http://www.firsthorizon.com/role/RetirementPlansTables Retirement Plans (Tables) Tables http://www.firsthorizon.com/role/RetirementPlans 37 false false R38.htm 9955522 - Disclosure - Business Segment Information (Tables) Sheet http://www.firsthorizon.com/role/BusinessSegmentInformationTables Business Segment Information (Tables) Tables http://www.firsthorizon.com/role/BusinessSegmentInformation 38 false false R39.htm 9955523 - Disclosure - Variable Interest Entities (Tables) Sheet http://www.firsthorizon.com/role/VariableInterestEntitiesTables Variable Interest Entities (Tables) Tables http://www.firsthorizon.com/role/VariableInterestEntities 39 false false R40.htm 9955524 - Disclosure - Derivatives (Tables) Sheet http://www.firsthorizon.com/role/DerivativesTables Derivatives (Tables) Tables http://www.firsthorizon.com/role/Derivatives 40 false false R41.htm 9955525 - Disclosure - Master Netting and Similar Agreements ??? Repurchase, Reverse Repurchase, and Securities Borrowing Transactions (Tables) Sheet http://www.firsthorizon.com/role/MasterNettingandSimilarAgreementsRepurchaseReverseRepurchaseandSecuritiesBorrowingTransactionsTables Master Netting and Similar Agreements ??? Repurchase, Reverse Repurchase, and Securities Borrowing Transactions (Tables) Tables http://www.firsthorizon.com/role/MasterNettingandSimilarAgreementsRepurchaseReverseRepurchaseandSecuritiesBorrowingTransactions 41 false false R42.htm 9955526 - Disclosure - Fair Value of Assets and Liabilities (Tables) Sheet http://www.firsthorizon.com/role/FairValueofAssetsandLiabilitiesTables Fair Value of Assets and Liabilities (Tables) Tables http://www.firsthorizon.com/role/FairValueofAssetsandLiabilities 42 false false R43.htm 9955527 - Disclosure - Investment Securities - Schedule of FHN's Investment Securities (Details) Sheet http://www.firsthorizon.com/role/InvestmentSecuritiesScheduleofFHNsInvestmentSecuritiesDetails Investment Securities - Schedule of FHN's Investment Securities (Details) Details 43 false false R44.htm 9955528 - Disclosure - Investment Securities - Schedule of Amortized Cost and Fair Value by Contractual Maturity (Details) Sheet http://www.firsthorizon.com/role/InvestmentSecuritiesScheduleofAmortizedCostandFairValuebyContractualMaturityDetails Investment Securities - Schedule of Amortized Cost and Fair Value by Contractual Maturity (Details) Details 44 false false R45.htm 9955529 - Disclosure - Investment Securities - Narrative (Details) Sheet http://www.firsthorizon.com/role/InvestmentSecuritiesNarrativeDetails Investment Securities - Narrative (Details) Details 45 false false R46.htm 9955530 - Disclosure - Investment Securities - Schedule of Investments within the Available for Sale Portfolio that had Unrealized Losses (Details) Sheet http://www.firsthorizon.com/role/InvestmentSecuritiesScheduleofInvestmentswithintheAvailableforSalePortfoliothathadUnrealizedLossesDetails Investment Securities - Schedule of Investments within the Available for Sale Portfolio that had Unrealized Losses (Details) Details 46 false false R47.htm 9955531 - Disclosure - Loans and Leases - Narrative (Details) Sheet http://www.firsthorizon.com/role/LoansandLeasesNarrativeDetails Loans and Leases - Narrative (Details) Details 47 false false R48.htm 9955532 - Disclosure - Loans and Leases - Schedule of Loans by Portfolio Segment (Details) Sheet http://www.firsthorizon.com/role/LoansandLeasesScheduleofLoansbyPortfolioSegmentDetails Loans and Leases - Schedule of Loans by Portfolio Segment (Details) Details 48 false false R49.htm 9955533 - Disclosure - Loans and Leases - Balances of Commercial Loan Portfolio Classes, Disaggregated by PD Grade and FICO Score - Current Year (Details) Sheet http://www.firsthorizon.com/role/LoansandLeasesBalancesofCommercialLoanPortfolioClassesDisaggregatedbyPDGradeandFICOScoreCurrentYearDetails Loans and Leases - Balances of Commercial Loan Portfolio Classes, Disaggregated by PD Grade and FICO Score - Current Year (Details) Details 49 false false R50.htm 9955534 - Disclosure - Loans and Leases - Balances of Commercial Loan Portfolio Classes, Disaggregated by PD Grade and FICO Score - Prior Year (Details) Sheet http://www.firsthorizon.com/role/LoansandLeasesBalancesofCommercialLoanPortfolioClassesDisaggregatedbyPDGradeandFICOScorePriorYearDetails Loans and Leases - Balances of Commercial Loan Portfolio Classes, Disaggregated by PD Grade and FICO Score - Prior Year (Details) Details 50 false false R51.htm 9955535 - Disclosure - Loans and Leases - Accruing and Non-Accruing Loans by Class (Details) Sheet http://www.firsthorizon.com/role/LoansandLeasesAccruingandNonAccruingLoansbyClassDetails Loans and Leases - Accruing and Non-Accruing Loans by Class (Details) Details 51 false false R52.htm 9955536 - Disclosure - Loans and Leases - Loan Modifications to Borrowers Experiencing Financial Difficulty (Details) Sheet http://www.firsthorizon.com/role/LoansandLeasesLoanModificationstoBorrowersExperiencingFinancialDifficultyDetails Loans and Leases - Loan Modifications to Borrowers Experiencing Financial Difficulty (Details) Details 52 false false R53.htm 9955537 - Disclosure - Loans and Leases - Performance of Loans that have been Modified in the Last 12 Months (Details) Sheet http://www.firsthorizon.com/role/LoansandLeasesPerformanceofLoansthathavebeenModifiedintheLast12MonthsDetails Loans and Leases - Performance of Loans that have been Modified in the Last 12 Months (Details) Details 53 false false R54.htm 9955538 - Disclosure - Allowance for Credit Losses - Narrative (Details) Sheet http://www.firsthorizon.com/role/AllowanceforCreditLossesNarrativeDetails Allowance for Credit Losses - Narrative (Details) Details 54 false false R55.htm 9955539 - Disclosure - Allowance for Credit Losses - Rollforward of Allowance for Credit Losses (Details) Sheet http://www.firsthorizon.com/role/AllowanceforCreditLossesRollforwardofAllowanceforCreditLossesDetails Allowance for Credit Losses - Rollforward of Allowance for Credit Losses (Details) Details 55 false false R56.htm 9955540 - Disclosure - Allowance for Credit Losses - Gross Charge-Offs by Year of Origination - Current Year (Details) Sheet http://www.firsthorizon.com/role/AllowanceforCreditLossesGrossChargeOffsbyYearofOriginationCurrentYearDetails Allowance for Credit Losses - Gross Charge-Offs by Year of Origination - Current Year (Details) Details 56 false false R57.htm 9955541 - Disclosure - Allowance for Credit Losses - Gross Charge-Offs by Year of Origination - Prior Year (Details) Sheet http://www.firsthorizon.com/role/AllowanceforCreditLossesGrossChargeOffsbyYearofOriginationPriorYearDetails Allowance for Credit Losses - Gross Charge-Offs by Year of Origination - Prior Year (Details) Details 57 false false R58.htm 9955542 - Disclosure - Mortgage Banking Activity - Narrative (Details) Sheet http://www.firsthorizon.com/role/MortgageBankingActivityNarrativeDetails Mortgage Banking Activity - Narrative (Details) Details 58 false false R59.htm 9955543 - Disclosure - Mortgage Banking Activity - Residential Mortgage Loans (Details) Sheet http://www.firsthorizon.com/role/MortgageBankingActivityResidentialMortgageLoansDetails Mortgage Banking Activity - Residential Mortgage Loans (Details) Details 59 false false R60.htm 9955544 - Disclosure - Mortgage Banking Activity - MSR Carrying Amount and Accumulated Amortization (Details) Sheet http://www.firsthorizon.com/role/MortgageBankingActivityMSRCarryingAmountandAccumulatedAmortizationDetails Mortgage Banking Activity - MSR Carrying Amount and Accumulated Amortization (Details) Details 60 false false R61.htm 9955545 - Disclosure - Goodwill and Other Intangible Assets - Schedule of Goodwill by Reportable Segment (Details) Sheet http://www.firsthorizon.com/role/GoodwillandOtherIntangibleAssetsScheduleofGoodwillbyReportableSegmentDetails Goodwill and Other Intangible Assets - Schedule of Goodwill by Reportable Segment (Details) Details 61 false false R62.htm 9955546 - Disclosure - Goodwill and Other Intangible Assets - Schedule of Intangible Assets and Accumulated Amortization Included in the Consolidated Statements of Condition (Details) Sheet http://www.firsthorizon.com/role/GoodwillandOtherIntangibleAssetsScheduleofIntangibleAssetsandAccumulatedAmortizationIncludedintheConsolidatedStatementsofConditionDetails Goodwill and Other Intangible Assets - Schedule of Intangible Assets and Accumulated Amortization Included in the Consolidated Statements of Condition (Details) Details 62 false false R63.htm 9955547 - Disclosure - Preferred Stock - Non-Cumulative Perpetual Preferred Stock (Details) Sheet http://www.firsthorizon.com/role/PreferredStockNonCumulativePerpetualPreferredStockDetails Preferred Stock - Non-Cumulative Perpetual Preferred Stock (Details) Details 63 false false R64.htm 9955548 - Disclosure - Preferred Stock - Narrative (Details) Sheet http://www.firsthorizon.com/role/PreferredStockNarrativeDetails Preferred Stock - Narrative (Details) Details 64 false false R65.htm 9955549 - Disclosure - Components of Other Comprehensive Income (Loss) - Schedule of Changes in AOCI (Details) Sheet http://www.firsthorizon.com/role/ComponentsofOtherComprehensiveIncomeLossScheduleofChangesinAOCIDetails Components of Other Comprehensive Income (Loss) - Schedule of Changes in AOCI (Details) Details http://www.firsthorizon.com/role/ComponentsofOtherComprehensiveIncomeLossTables 65 false false R66.htm 9955550 - Disclosure - Components of Other Comprehensive Income (Loss) - Schedule of Reclassification from AOCI (Details) Sheet http://www.firsthorizon.com/role/ComponentsofOtherComprehensiveIncomeLossScheduleofReclassificationfromAOCIDetails Components of Other Comprehensive Income (Loss) - Schedule of Reclassification from AOCI (Details) Details http://www.firsthorizon.com/role/ComponentsofOtherComprehensiveIncomeLossTables 66 false false R67.htm 9955551 - Disclosure - Earnings Per Share - Schedule of Reconciliation of Net Income to Net Income Available to Common Shareholders (Details) Sheet http://www.firsthorizon.com/role/EarningsPerShareScheduleofReconciliationofNetIncometoNetIncomeAvailabletoCommonShareholdersDetails Earnings Per Share - Schedule of Reconciliation of Net Income to Net Income Available to Common Shareholders (Details) Details 67 false false R68.htm 9955552 - Disclosure - Earnings Per Share - Schedule of Anti-Dilutive Options and Awards (Details) Sheet http://www.firsthorizon.com/role/EarningsPerShareScheduleofAntiDilutiveOptionsandAwardsDetails Earnings Per Share - Schedule of Anti-Dilutive Options and Awards (Details) Details 68 false false R69.htm 9955553 - Disclosure - Contingencies and Other Disclosures (Details) Sheet http://www.firsthorizon.com/role/ContingenciesandOtherDisclosuresDetails Contingencies and Other Disclosures (Details) Details http://www.firsthorizon.com/role/ContingenciesandOtherDisclosures 69 false false R70.htm 9955554 - Disclosure - Retirement Plans - Narrative (Details) Sheet http://www.firsthorizon.com/role/RetirementPlansNarrativeDetails Retirement Plans - Narrative (Details) Details 70 false false R71.htm 9955555 - Disclosure - Retirement Plans - Schedule of Components of Net Periodic Benefit Cost (Details) Sheet http://www.firsthorizon.com/role/RetirementPlansScheduleofComponentsofNetPeriodicBenefitCostDetails Retirement Plans - Schedule of Components of Net Periodic Benefit Cost (Details) Details 71 false false R72.htm 9955556 - Disclosure - Business Segment Information - Narrative (Details) Sheet http://www.firsthorizon.com/role/BusinessSegmentInformationNarrativeDetails Business Segment Information - Narrative (Details) Details 72 false false R73.htm 9955557 - Disclosure - Business Segment Information - Amounts of Consolidated Revenue, Expense, Tax and Assets by Segment (Details) Sheet http://www.firsthorizon.com/role/BusinessSegmentInformationAmountsofConsolidatedRevenueExpenseTaxandAssetsbySegmentDetails Business Segment Information - Amounts of Consolidated Revenue, Expense, Tax and Assets by Segment (Details) Details 73 false false R74.htm 9955558 - Disclosure - Business Segment Information - Noninterest Income (Details) Sheet http://www.firsthorizon.com/role/BusinessSegmentInformationNoninterestIncomeDetails Business Segment Information - Noninterest Income (Details) Details 74 false false R75.htm 9955559 - Disclosure - Business Segment Information - Noninterest Expense (Details) Sheet http://www.firsthorizon.com/role/BusinessSegmentInformationNoninterestExpenseDetails Business Segment Information - Noninterest Expense (Details) Details 75 false false R76.htm 9955560 - Disclosure - Variable Interest Entities - Schedule of VIEs Consolidated by FHN (Details) Sheet http://www.firsthorizon.com/role/VariableInterestEntitiesScheduleofVIEsConsolidatedbyFHNDetails Variable Interest Entities - Schedule of VIEs Consolidated by FHN (Details) Details 76 false false R77.htm 9955561 - Disclosure - Variable Interest Entities - Schedule of the Impact of Qualifying LIHTC Investments (Details) Sheet http://www.firsthorizon.com/role/VariableInterestEntitiesScheduleoftheImpactofQualifyingLIHTCInvestmentsDetails Variable Interest Entities - Schedule of the Impact of Qualifying LIHTC Investments (Details) Details 77 false false R78.htm 9955562 - Disclosure - Variable Interest Entities - Schedule of VIEs Not Consolidated by FHN (Details) Sheet http://www.firsthorizon.com/role/VariableInterestEntitiesScheduleofVIEsNotConsolidatedbyFHNDetails Variable Interest Entities - Schedule of VIEs Not Consolidated by FHN (Details) Details 78 false false R79.htm 9955563 - Disclosure - Derivatives - Narrative (Details) Sheet http://www.firsthorizon.com/role/DerivativesNarrativeDetails Derivatives - Narrative (Details) Details 79 false false R80.htm 9955564 - Disclosure - Derivatives - Derivatives Associated with Fixed Income Trading Activities (Details) Sheet http://www.firsthorizon.com/role/DerivativesDerivativesAssociatedwithFixedIncomeTradingActivitiesDetails Derivatives - Derivatives Associated with Fixed Income Trading Activities (Details) Details 80 false false R81.htm 9955565 - Disclosure - Derivatives - Derivatives Associated with Interest Rate Risk Management Activities (Details) Sheet http://www.firsthorizon.com/role/DerivativesDerivativesAssociatedwithInterestRateRiskManagementActivitiesDetails Derivatives - Derivatives Associated with Interest Rate Risk Management Activities (Details) Details 81 false false R82.htm 9955566 - Disclosure - Derivatives - Gains/(Losses) on Derivatives Associated with Interest Rate Risk Management Activities (Details) Sheet http://www.firsthorizon.com/role/DerivativesGainsLossesonDerivativesAssociatedwithInterestRateRiskManagementActivitiesDetails Derivatives - Gains/(Losses) on Derivatives Associated with Interest Rate Risk Management Activities (Details) Details 82 false false R83.htm 9955567 - Disclosure - Derivatives - Derivatives Associated with Cash Flow Hedges and Mortgage Banking Hedges (Details) Sheet http://www.firsthorizon.com/role/DerivativesDerivativesAssociatedwithCashFlowHedgesandMortgageBankingHedgesDetails Derivatives - Derivatives Associated with Cash Flow Hedges and Mortgage Banking Hedges (Details) Details 83 false false R84.htm 9955568 - Disclosure - Derivatives - Gains/(Losses) on Derivatives Associated with Cash Flow Hedges and Mortgage Banking Hedges (Details) Sheet http://www.firsthorizon.com/role/DerivativesGainsLossesonDerivativesAssociatedwithCashFlowHedgesandMortgageBankingHedgesDetails Derivatives - Gains/(Losses) on Derivatives Associated with Cash Flow Hedges and Mortgage Banking Hedges (Details) Details 84 false false R85.htm 9955569 - Disclosure - Derivatives - Derivative Assets and Collateral Received (Details) Sheet http://www.firsthorizon.com/role/DerivativesDerivativeAssetsandCollateralReceivedDetails Derivatives - Derivative Assets and Collateral Received (Details) Details 85 false false R86.htm 9955570 - Disclosure - Derivatives - Derivative Liabilities and Collateral Pledged (Details) Sheet http://www.firsthorizon.com/role/DerivativesDerivativeLiabilitiesandCollateralPledgedDetails Derivatives - Derivative Liabilities and Collateral Pledged (Details) Details 86 false false R87.htm 9955571 - Disclosure - Master Netting and Similar Agreements ??? Repurchase, Reverse Repurchase, and Securities Borrowing Transactions - Securities Purchased under Agreements to Resell and Collateral Pledged by Counterparties (Details) Sheet http://www.firsthorizon.com/role/MasterNettingandSimilarAgreementsRepurchaseReverseRepurchaseandSecuritiesBorrowingTransactionsSecuritiesPurchasedunderAgreementstoResellandCollateralPledgedbyCounterpartiesDetails Master Netting and Similar Agreements ??? Repurchase, Reverse Repurchase, and Securities Borrowing Transactions - Securities Purchased under Agreements to Resell and Collateral Pledged by Counterparties (Details) Details 87 false false R88.htm 9955572 - Disclosure - Master Netting and Similar Agreements ??? Repurchase, Reverse Repurchase, and Securities Borrowing Transactions - Securities Sold under Agreements to Repurchase and Collateral Pledged by Company (Details) Sheet http://www.firsthorizon.com/role/MasterNettingandSimilarAgreementsRepurchaseReverseRepurchaseandSecuritiesBorrowingTransactionsSecuritiesSoldunderAgreementstoRepurchaseandCollateralPledgedbyCompanyDetails Master Netting and Similar Agreements ??? Repurchase, Reverse Repurchase, and Securities Borrowing Transactions - Securities Sold under Agreements to Repurchase and Collateral Pledged by Company (Details) Details 88 false false R89.htm 9955573 - Disclosure - Master Netting and Similar Agreements ??? Repurchase, Reverse Repurchase, and Securities Borrowing Transactions - Schedule of the Remaining Contractual Maturity by Collateral Type of Securities Sold under Agreements to Repurchase (Details) Sheet http://www.firsthorizon.com/role/MasterNettingandSimilarAgreementsRepurchaseReverseRepurchaseandSecuritiesBorrowingTransactionsScheduleoftheRemainingContractualMaturitybyCollateralTypeofSecuritiesSoldunderAgreementstoRepurchaseDetails Master Netting and Similar Agreements ??? Repurchase, Reverse Repurchase, and Securities Borrowing Transactions - Schedule of the Remaining Contractual Maturity by Collateral Type of Securities Sold under Agreements to Repurchase (Details) Details 89 false false R90.htm 9955574 - Disclosure - Fair Value of Assets and Liabilities - Schedule of Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) Sheet http://www.firsthorizon.com/role/FairValueofAssetsandLiabilitiesScheduleofAssetsandLiabilitiesMeasuredatFairValueonaRecurringBasisDetails Fair Value of Assets and Liabilities - Schedule of Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) Details 90 false false R91.htm 9955575 - Disclosure - Fair Value of Assets and Liabilities - Schedule of Changes in Level 3 Assets and Liabilities Measured at Fair Value (Details) Sheet http://www.firsthorizon.com/role/FairValueofAssetsandLiabilitiesScheduleofChangesinLevel3AssetsandLiabilitiesMeasuredatFairValueDetails Fair Value of Assets and Liabilities - Schedule of Changes in Level 3 Assets and Liabilities Measured at Fair Value (Details) Details 91 false false R92.htm 9955576 - Disclosure - Fair Value of Assets and Liabilities - Narrative (Details) Sheet http://www.firsthorizon.com/role/FairValueofAssetsandLiabilitiesNarrativeDetails Fair Value of Assets and Liabilities - Narrative (Details) Details 92 false false R93.htm 9955577 - Disclosure - Fair Value of Assets and Liabilities - Nonrecurring Fair Value Measurements (Details) Sheet http://www.firsthorizon.com/role/FairValueofAssetsandLiabilitiesNonrecurringFairValueMeasurementsDetails Fair Value of Assets and Liabilities - Nonrecurring Fair Value Measurements (Details) Details 93 false false R94.htm 9955578 - Disclosure - Fair Value of Assets and Liabilities - Gains/(losses) on Nonrecurring Fair Value Measurements (Details) Sheet http://www.firsthorizon.com/role/FairValueofAssetsandLiabilitiesGainslossesonNonrecurringFairValueMeasurementsDetails Fair Value of Assets and Liabilities - Gains/(losses) on Nonrecurring Fair Value Measurements (Details) Details 94 false false R95.htm 9955579 - Disclosure - Fair Value of Assets and Liabilities - Schedule of Unobservable Inputs Utilized in Determining the Fair Value of Level 3 Recurring and Non-Recurring Measurements (Details) Sheet http://www.firsthorizon.com/role/FairValueofAssetsandLiabilitiesScheduleofUnobservableInputsUtilizedinDeterminingtheFairValueofLevel3RecurringandNonRecurringMeasurementsDetails Fair Value of Assets and Liabilities - Schedule of Unobservable Inputs Utilized in Determining the Fair Value of Level 3 Recurring and Non-Recurring Measurements (Details) Details 95 false false R96.htm 9955580 - Disclosure - Fair Value of Assets and Liabilities - Schedule of Differences between the Fair Value Carrying Amount of Mortgages Held-for-sale and Aggregate Unpaid Principal Amount (Details) Sheet http://www.firsthorizon.com/role/FairValueofAssetsandLiabilitiesScheduleofDifferencesbetweentheFairValueCarryingAmountofMortgagesHeldforsaleandAggregateUnpaidPrincipalAmountDetails Fair Value of Assets and Liabilities - Schedule of Differences between the Fair Value Carrying Amount of Mortgages Held-for-sale and Aggregate Unpaid Principal Amount (Details) Details 96 false false R97.htm 9955581 - Disclosure - Fair Value of Assets and Liabilities - Changes in Fair Value of Assets and Liabilities which Fair Value Option Included in Current Period Earnings (Details) Sheet http://www.firsthorizon.com/role/FairValueofAssetsandLiabilitiesChangesinFairValueofAssetsandLiabilitieswhichFairValueOptionIncludedinCurrentPeriodEarningsDetails Fair Value of Assets and Liabilities - Changes in Fair Value of Assets and Liabilities which Fair Value Option Included in Current Period Earnings (Details) Details 97 false false R98.htm 9955582 - Disclosure - Fair Value of Assets and Liabilities - Schedule of Book Value and Estimated Fair Value of Financial Instruments (Details) Sheet http://www.firsthorizon.com/role/FairValueofAssetsandLiabilitiesScheduleofBookValueandEstimatedFairValueofFinancialInstrumentsDetails Fair Value of Assets and Liabilities - Schedule of Book Value and Estimated Fair Value of Financial Instruments (Details) Details 98 false false R99.htm 9955583 - Disclosure - Subsequent Events (Details) Sheet http://www.firsthorizon.com/role/SubsequentEventsDetails Subsequent Events (Details) Details http://www.firsthorizon.com/role/SubsequentEvents 99 false false All Reports Book All Reports fhn-20260331.htm fhn-20260331.xsd fhn-20260331_cal.xml fhn-20260331_def.xml fhn-20260331_lab.xml fhn-20260331_pre.xml fhn-20260331_g1.jpg fhn-20260331_g2.jpg http://fasb.org/us-gaap/2025 http://xbrl.sec.gov/dei/2025 http://xbrl.sec.gov/ecd/2025 true true