Name:	fhn_ThresholdAmortizationPercentageOfMarketRelatedValueOfPlanAssets
Namespace Prefix:	fhn_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Percent of a plan's projected benefit obligation used to determine the threshold calculated under the minimum amortization method. Threshold is calculated as the greater of some percent of the plan's projected benefit obligation or some percent of the market-related value of plan assets at the beginning of the year.

No definition available.

Name:	fhn_ThresholdAmortizationPercentageOfProjectedBenefitObligation
Namespace Prefix:	fhn_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

Name:	us-gaap_DefinedBenefitPlanEstimatedFutureBenefitPaymentsAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Amount of benefits for defined benefit plan expected to be paid in five fiscal years after fifth fiscal year following latest fiscal year.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=108410482&loc=d3e1928-114920

Name:	us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Amount of benefits for defined benefit plan expected to be paid in next fiscal year following latest fiscal year.

Name:	us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Amount of benefits for defined benefit plan expected to be paid in fifth fiscal year following latest fiscal year.

Name:	us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Amount of benefits for defined benefit plan expected to be paid in fourth fiscal year following latest fiscal year.

Name:	us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Amount of benefits for defined benefit plan expected to be paid in third fiscal year following latest fiscal year.

Name:	us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Amount of benefits for defined benefit plan expected to be paid in second fiscal year following latest fiscal year.

Name:	us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

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.

No definition available.