XML 88 R73.htm IDEA: XBRL DOCUMENT
v3.25.3

Variable Interest Entities - Schedule of the Impact of Qualifying LIHTC Investments (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2025 | Sep. 30, 2024 | Sep. 30, 2025 | Sep. 30, 2024
Low income housing tax credits |  |  |  |
Variable Interest Entity [Line Items] |  |  |  |
Amortization of qualifying investments | $ 20 | $ 18 | $ 55 | $ 48
Tax credits and Other tax benefits related to qualifying investments | (19) | (19) | (60) | (52)
Other tax benefits related to qualifying LIHTC investments |  |  |  |
Variable Interest Entity [Line Items] |  |  |  |
Tax credits and Other tax benefits related to qualifying investments | $ (2) | $ (3) | $ (7) | $ (9)

X
- Definition Amount, before amortization expense, of income tax credit and other tax benefit generated by investment under tax credit program elected to be accounted for using proportional amortization method. Includes, but is not limited to, investment under tax credit program not meeting condition for accounting under proportional amortization method. + References Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Topic 323 -SubTopic 740 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478156/323-740-50-2 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 740 -SubTopic 323 -Name Accounting Standards Codification -Section 50 -Paragraph 1A -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478156/740-323-50-1A + Details
Name: | us-gaap_AffordableHousingTaxCreditsAndOtherTaxBenefitsAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of amortization expense for investment that generates income tax credit and other income tax benefit under tax credit program accounted for using proportional amortization method. + References Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Topic 740 -SubTopic 323 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478156/740-323-50-2 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 740 -SubTopic 323 -Name Accounting Standards Codification -Section 50 -Paragraph 1A -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478156/740-323-50-1A + Details
Name: | us-gaap_AmortizationMethodQualifiedAffordableHousingProjectInvestmentsAmortization
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- 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/2003/role/disclosureRef -Topic 810 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481203/810-10-50-3 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 810 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 25 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481231/810-10-45-25 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 810 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (bb) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481203/810-10-50-3 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 810 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 25 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481231/810-10-45-25 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 860 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 1A -Subparagraph (b)(1)(i) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481420/860-30-50-1A Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Topic 860 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 1A -Subparagraph (b)(1)(ii) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481420/860-30-50-1A Reference 7: http://www.xbrl.org/2003/role/disclosureRef -Topic 860 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 1A -Subparagraph (b)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481420/860-30-50-1A + Details
Name: | us-gaap_VariableInterestEntityLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_InvestmentTypeAxis=fhn_LowIncomeHousingTaxCreditsMemberMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=fhn_OtherTaxBenefitsRelatedToQualifyingLihtcInvestmentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |