XML 125 R98.htm IDEA: XBRL DOCUMENT
v3.22.0.1

Short-Term Borrowings - Narrative (Details) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2021 USD ($)
Short-term Debt [Line Items] |
Federal home loan bank, advances, maturity period | 90 days
Trading liabilities maturity period (less than) | 90 days
Other short-term borrowings maturity period (or less) | 1 year
Fixed Income Securities |
Short-term Debt [Line Items] |
Securities pledged to secure other short term borrowings | $ 33

X
- Definition Other Short-Term Borrowings, Maturity Period + References No definition available. + Details
Name: | fhn_OtherShortTermBorrowingsMaturityPeriod
Namespace Prefix: | fhn_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Trading Securities, Maturity Period + References No definition available. + Details
Name: | fhn_TradingSecuritiesMaturityPeriod
Namespace Prefix: | fhn_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of restricted investment in debt security measured at fair value with change in fair value recognized in net income (trading). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 860 -SubTopic 30 -Section 50 -Paragraph 1A -Subparagraph (b)(1)(i) -URI http://asc.fasb.org/extlink&oid=109249958&loc=SL6224234-111729 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 954 -SubTopic 210 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=120413209&loc=SL6242269-115581 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 954 -SubTopic 210 -Section 45 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=120413173&loc=SL6242262-115580 + Details
Name: | us-gaap_DebtSecuritiesTradingRestricted
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Maturity period on variable rate advances made and reported by Federal Home Loan Bank (FHLBank), in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
Name: | us-gaap_FederalHomeLoanBankAdvancesMaturityPeriodVariableRate
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
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 No definition available. + Details
Name: | us-gaap_ShortTermDebtLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_FixedIncomeSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |