EBP, Employer Contribution, Employee Minimum Years Of Service Requisite To Access Matching Contributions

No definition available.

Name:	fhn_EBPEmployerContributionEmployeeMinimumYearsOfServiceRequisiteToAccessMatchingContributions
Namespace Prefix:	fhn_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

EBP, Employer Contribution, Participant Contribution Matched, Percentage

+ References

No definition available.

+ Details

Name:	fhn_EBPEmployerContributionParticipantContributionMatchedPercentage
Namespace Prefix:	fhn_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

EBP, Employer Contribution Vesting Percentage

+ References

No definition available.

+ Details

Name:	fhn_EBPEmployerContributionVestingPercentage
Namespace Prefix:	fhn_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

EBP, Employer Contribution Vesting Service Period

+ References

No definition available.

+ Details

Name:	fhn_EBPEmployerContributionVestingServicePeriod
Namespace Prefix:	fhn_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

EBP, Maximum Loans Outstanding Per Participant, Two Different Loans, One General Purpose Loan

+ References

No definition available.

+ Details

Name:	fhn_EBPMaximumLoansOutstandingPerParticipantTwoDifferentLoansOneGeneralPurposeLoan
Namespace Prefix:	fhn_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

EBP, Maximum Loans Outstanding Per Participant, Two Different Loans, One Primary Residence Loan

+ References

No definition available.

+ Details

Name:	fhn_EBPMaximumLoansOutstandingPerParticipantTwoDifferentLoansOnePrimaryResidenceLoan
Namespace Prefix:	fhn_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

EBP, Maximum Loans Outstanding Per Participant, Two General Purpose Loans

+ References

No definition available.

+ Details

Name:	fhn_EBPMaximumLoansOutstandingPerParticipantTwoGeneralPurposeLoans
Namespace Prefix:	fhn_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

EBP, Maximum Loans Received Per Participant During Twelve-Month Period, One Other Loan

+ References

No definition available.

+ Details

Name:	fhn_EBPMaximumLoansReceivedPerParticipantDuringTwelveMonthPeriodOneOtherLoan
Namespace Prefix:	fhn_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

EBP, Maximum Loans Received Per Participant During Twelve-Month Period, One Primary Residence Loan

+ References

No definition available.

+ Details

Name:	fhn_EBPMaximumLoansReceivedPerParticipantDuringTwelveMonthPeriodOnePrimaryResidenceLoan
Namespace Prefix:	fhn_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

EBP, Minimum Age At End Of Most Recent 12-Month Period For Eligibility

+ References

No definition available.

+ Details

Name:	fhn_EBPMinimumAgeAtEndOfMostRecent12MonthPeriodForEligibility
Namespace Prefix:	fhn_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

EBP, Note Receivable From Participant, Account, Primary Residence, Borrowing Term

+ References

No definition available.

+ Details

Name:	fhn_EBPNoteReceivableFromParticipantAccountPrimaryResidenceBorrowingTerm
Namespace Prefix:	fhn_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

EBP, Note Receivable From Participant, General Loan, Borrowing Term

+ References

No definition available.

+ Details

Name:	fhn_EBPNoteReceivableFromParticipantGeneralLoanBorrowingTerm
Namespace Prefix:	fhn_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

EBP, Requisite Service Period

+ References

No definition available.

+ Details

Name:	fhn_EBPRequisiteServicePeriod
Namespace Prefix:	fhn_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

EBP, Requisite Service Period, Minimum Working Hours

+ References

No definition available.

+ Details

Name:	fhn_EBPRequisiteServicePeriodMinimumWorkingHours
Namespace Prefix:	fhn_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

EBP, Requisite Service Period, Number Of Consecutive 12-Month Periods

+ References

No definition available.

+ Details

Name:	fhn_EBPRequisiteServicePeriodNumberOfConsecutive12MonthPeriods
Namespace Prefix:	fhn_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 962
-SubTopic 205
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478416/962-205-50-1

+ Details

Name:	us-gaap-ebp_EmployeeBenefitPlanDescriptionOfPlanLineItems
Namespace Prefix:	us-gaap-ebp_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of employer matching contribution on eligible participant contribution to employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

+ References

+ Details

Name:	us-gaap-ebp_EmployeeBenefitPlanEmployerContributionMatchingPercentage
Namespace Prefix:	us-gaap-ebp_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of plan asset, in forfeited nonvested account, no longer allocated to participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

+ References

+ Details

Name:	us-gaap-ebp_EmployeeBenefitPlanForfeitedNonvestedAccount
Namespace Prefix:	us-gaap-ebp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of decrease in forfeited nonvested account of employee stock purchase, saving, or similar plan (employee benefit plan (EBP)) from administrative expense.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 962
-SubTopic 205
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (j)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478416/962-205-50-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 962
-SubTopic 205
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6A-04(5)(c))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477804/962-205-S99-1

+ Details

Name:	us-gaap-ebp_EmployeeBenefitPlanForfeitedNonvestedAccountDecreaseForAdministrativeExpense
Namespace Prefix:	us-gaap-ebp_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of decrease in forfeited nonvested account of employee stock purchase, saving, or similar plan (employee benefit plan (EBP)) from employer contribution.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 962
-SubTopic 325
-Name Accounting Standards Codification
-Section 55
-Paragraph 17
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478873/962-325-55-17

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 962
-SubTopic 205
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (j)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478416/962-205-50-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 962
-SubTopic 205
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6A-04(5)(c))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477804/962-205-S99-1

+ Details

Name:	us-gaap-ebp_EmployeeBenefitPlanForfeitedNonvestedAccountDecreaseForEmployerContribution
Namespace Prefix:	us-gaap-ebp_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of maximum account balance that participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)) can borrow.

+ References

+ Details

Name:	us-gaap-ebp_EmployeeBenefitPlanNoteReceivableFromParticipantAccountMaximumBorrowingAmount
Namespace Prefix:	us-gaap-ebp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Percentage of maximum account balance that participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)) can borrow to total participant account balance.

+ References

+ Details

Name:	us-gaap-ebp_EmployeeBenefitPlanNoteReceivableFromParticipantAccountMaximumBorrowingToTotalAccountPercentage
Namespace Prefix:	us-gaap-ebp_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of minimum account balance that participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)) can borrow.

+ References

+ Details

Name:	us-gaap-ebp_EmployeeBenefitPlanNoteReceivableFromParticipantAccountMinimumBorrowingAmount
Namespace Prefix:	us-gaap-ebp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Percentage of eligible compensation contributed for participant automatically enrolled in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

+ References

+ Details

Name:	us-gaap-ebp_EmployeeBenefitPlanParticipantContributionAutomaticDeferralRate
Namespace Prefix:	us-gaap-ebp_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of maximum pretax annual compensation that participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)), is permitted to contribute to total pretax annual compensation.

+ References

+ Details

Name:	us-gaap-ebp_EmployeeBenefitPlanParticipantContributionPretaxMaximumAnnualCompensationToTotalCompensationPercentage
Namespace Prefix:	us-gaap-ebp_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Interest rate on participant loan in schedule of asset held for investment of employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name Employee Retirement Income Security Act of 1974
-Number 2520
-Section 103
-Subsection 10
-Paragraph b
-Subparagraph (1)(i)(D)
-Publisher DOL-EBSA

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 962
-SubTopic 205
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6A-05(a)(Schedule I))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477804/962-205-S99-1

+ Details

Name:	us-gaap-ebp_EmployeeBenefitPlanParticipantLoanInterestRate
Namespace Prefix:	us-gaap-ebp_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	dei_LegalEntityAxis=fhn_EBP002Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	fhn_EBPEmployerContributionTypeAxis=fhn_CompanyMatchingContributionsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	fhn_EBPEmployerContributionTypeAxis=fhn_CompanySavingsContributionsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	fhn_EBPEmployerContributionTypeAxis=fhn_EmployerNonElectiveContributionsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap-ebp_EmployeeBenefitPlanContributionParticipatingEmployerAxis=fhn_PartTimeEmployeesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap-ebp_EmployeeBenefitPlanContributionParticipatingEmployerAxis=fhn_LongTermPartTimeEmployeesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	fhn_EBPParticipantContributionTypeAxis=fhn_PreTaxAndRothContributionsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	fhn_EBPParticipantContributionTypeAxis=fhn_NonRothAfterTaxContributionsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

Plan Description (Details) - EBP 002	12 Months Ended
Plan Description (Details) - EBP 002	Dec. 31, 2025 USD ($) yr loan h	Jan. 01, 2025 yr	Dec. 31, 2024 USD ($) yr
EBP, Description of Plan [Line Items]
Participant contribution, automatic, deferral rate	3.00%
Employer contribution, matching percentage	100.00%
Employer contribution vesting percentage	100.00%
Forfeited nonvested account \| $	$ 97,052		$ 390,812
Forfeited nonvested account, decrease from administrative expense \| $	0
Forfeited nonvested account, decrease from employer contribution \| $	931,569
Note receivable from participant, account, minimum borrowing, amount \| $	1,000
Note receivable from participant, account, maximum borrowing, amount \| $	$ 50,000
Note receivable from participant, account, maximum borrowing, to total account, percentage	50.00%
Maximum loans outstanding per participant, two general purpose loans \| loan	2
Maximum loans outstanding per participant, two different loans, one general purpose loan \| loan	1
Maximum loans outstanding per participant, two different loans, one primary residence loan \| loan	1
Maximum loans received per participant during twelve-month period, one primary residence loan \| loan	1
Maximum loans received per participant during twelve-month period, one other loan \| loan	1
Company Matching Contributions
EBP, Description of Plan [Line Items]
Employer contribution, employee minimum years of service requisite to access matching contributions	1 year
Employer contribution vesting service period	3 years
Company Savings Contributions
EBP, Description of Plan [Line Items]
Employer contribution vesting percentage	100.00%
Employer Non-Elective Contributions
EBP, Description of Plan [Line Items]
Employer contribution vesting service period	2 years
Employer contribution vesting percentage	100.00%
Part Time Employees
EBP, Description of Plan [Line Items]
Requisite service period	12 months
Requisite service period, minimum working hours \| h	1,000
Long Term Part Time Employees
EBP, Description of Plan [Line Items]
Requisite service period, minimum working hours \| h	500
EBP, Requisite Service Period, Number Of Consecutive 12-Month Periods \| yr		2	3
EBP, Minimum Age At End Of Most Recent 12-Month Period For Eligibility \| yr	21
Maximum
EBP, Description of Plan [Line Items]
Maximum participant contribution	60.00%
Employer contribution, annual fixed rate contribution, percentage	6.00%
Note receivable from participant, general loan, borrowing term	60 months
Note receivable from participant, account, primary residence, borrowing term	120 months
Participant loan interest rate	8.50%
Maximum \| Pre-Tax and Roth Contributions
EBP, Description of Plan [Line Items]
Maximum participant contribution	50.00%
Maximum \| Non-Roth After Tax Contributions
EBP, Description of Plan [Line Items]
Maximum participant contribution	10.00%
Minimum
EBP, Description of Plan [Line Items]
Maximum participant contribution	1.00%
Employer contribution, annual fixed rate contribution, percentage	1.00%
Note receivable from participant, general loan, borrowing term	12 months
Note receivable from participant, account, primary residence, borrowing term	12 months
Participant loan interest rate	3.25%
Minimum \| Pre-Tax and Roth Contributions
EBP, Description of Plan [Line Items]
Maximum participant contribution	1.00%
Minimum \| Non-Roth After Tax Contributions
EBP, Description of Plan [Line Items]
Maximum participant contribution	1.00%