XML 88 R61.htm IDEA: XBRL DOCUMENT
v3.22.0.1

Significant Accounting Policies - Narrative (Details) | 12 Months Ended
--- | ---
Dec. 31, 2021 USD ($)
Change in Accounting Estimate [Line Items] |
Performance obligation, description of timing | one year or less
Past due threshold period for nonaccrual status | 90 days
Past due threshold period for nonaccrual status, consumer real estate loans | 30 days
TD Merger Agreement |
Change in Accounting Estimate [Line Items] |
Merger and integration expense | $ 0
Deposit Bases |
Change in Accounting Estimate [Line Items] |
Intangible assets, amortization period | 10 years
Minimum | Furniture and Fixtures |
Change in Accounting Estimate [Line Items] |
Useful life of premises and equipment | 3 years
Minimum | Building |
Change in Accounting Estimate [Line Items] |
Useful life of premises and equipment | 7 years
Maximum | Furniture and Fixtures |
Change in Accounting Estimate [Line Items] |
Useful life of premises and equipment | 15 years
Maximum | Building |
Change in Accounting Estimate [Line Items] |
Useful life of premises and equipment | 45 years
Non-Accruing |
Change in Accounting Estimate [Line Items] |
Accounts receivable, net | $ 12,000,000

X
- Definition Financing Receivable, Past Due Threshold Period For Nonaccrual Status + References No definition available. + Details
Name: | fhn_FinancingReceivablePastDueThresholdPeriodForNonaccrualStatus
Namespace Prefix: | fhn_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Financing Receivable, Past Due Threshold Period For Nonaccrual Status, Consumer Real Estate Loans + References No definition available. + Details
Name: | fhn_FinancingReceivablePastDueThresholdPeriodForNonaccrualStatusConsumerRealEstateLoans
Namespace Prefix: | fhn_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount, after allowance for credit loss, of right to consideration from customer for product sold and service rendered in normal course of business. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 954 -SubTopic 310 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=123366838&loc=d3e3073-115593 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(3)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(5)) -URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910 + Details
Name: | us-gaap_AccountsReceivableNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Costs incurred to effect a business combination which have been expensed during the period. Such costs could include business integration costs, systems integration and conversion costs, and severance and other employee-related costs. + References No definition available. + Details
Name: | us-gaap_BusinessCombinationIntegrationRelatedCosts
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 No definition available. + Details
Name: | us-gaap_ChangeInAccountingEstimateLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Useful life of finite-lived intangible assets, 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_FiniteLivedIntangibleAssetUsefulLife
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment. + References No definition available. + Details
Name: | us-gaap_PropertyPlantAndEquipmentUsefulLife
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Description of timing for satisfying performance obligation in contract with customer. Includes, but is not limited to, as services are rendered, and upon shipment, delivery or completion of service. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 606 -SubTopic 10 -Section 50 -Paragraph 12 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130554-203045 + Details
Name: | us-gaap_RevenuePerformanceObligationDescriptionOfTiming
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_BusinessAcquisitionAxis=fhn_TDMergerAgreementMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=fhn_DepositBasesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_FurnitureAndFixturesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_BuildingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | fhn_LoansAccruingAndNonAccruingInformationByClassAxis=fhn_NonAccruingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |