Income Taxes (Schedule Of Computation Of Income Tax Expense Differed From The Amounts Computed By Applying Of Statutory Federal Income Tax Rate To Income/(Loss) Before Income Taxes)(Details) (USD $)	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Federal income tax rate	35.00%	35.00%	35.00%
Tax computed at statutory rate	$ 108,343,000	$ 2,923,000	$ (35,597,000)
Increase/(decrease) resulting from:
State income taxes	8,424,000	(2,556,000)	(4,234,000)
Bank owned life insurance ("BOLI")	(6,671,000)	(6,646,000)	(7,428,000)
401(k) - employee stock ownership plan ("ESOP")	(659,000)	(568,000)	(155,000)
Tax-exempt interest	(5,798,000)	(5,094,000)	(4,469,000)
Non-deductible expenses	829,000	963,000	1,175,000
Tax credits	(11,392,000)	(13,340,000)	(18,125,000)
Subsidiary liquidations	0fhn_SubsidaryLiquidation	0fhn_SubsidaryLiquidation	(6,733,000)fhn_SubsidaryLiquidation
Change in valuation allowance - DTA	(13,168,000)	(4,427,000)	0
Other changes in unrecognized tax benefits	(1,570,000)	(5,106,000)	(8,981,000)
Other	163,000	1,682,000	(715,000)
Total income tax expense/(benefit)	$ 78,501,000us-gaap_IncomeTaxExpenseBenefit	$ (32,169,000)us-gaap_IncomeTaxExpenseBenefit	$ (85,262,000)us-gaap_IncomeTaxExpenseBenefit

Income Taxes (Schedule Of Computation Of Income Tax Expense Differed From The Amounts Computed By Applying Of Statutory Federal Income Tax Rate To Income/(Loss) Before Income Taxes)(Details) (USD $)

12 Months Ended

Dec. 31, 2014

Dec. 31, 2013

Dec. 31, 2012

Income Tax Disclosure [Abstract]

Federal income tax rate

35.00%us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate

Tax computed at statutory rate

$ 108,343,000us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate

$ 2,923,000us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate

$ (35,597,000)us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate

Increase/(decrease) resulting from:

State income taxes

8,424,000us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes

(2,556,000)us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes

(4,234,000)us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes

Bank owned life insurance ("BOLI")

(6,671,000)fhn_IncomeTaxReconciliationNontaxableIncome

(6,646,000)fhn_IncomeTaxReconciliationNontaxableIncome

(7,428,000)fhn_IncomeTaxReconciliationNontaxableIncome

401(k) - employee stock ownership plan ("ESOP")

(659,000)us-gaap_IncomeTaxRateReconciliationDeductionsEmployeeStockOwnershipPlanDividends

(568,000)us-gaap_IncomeTaxRateReconciliationDeductionsEmployeeStockOwnershipPlanDividends

(155,000)us-gaap_IncomeTaxRateReconciliationDeductionsEmployeeStockOwnershipPlanDividends

Tax-exempt interest

(5,798,000)us-gaap_IncomeTaxReconciliationTaxExemptIncome

(5,094,000)us-gaap_IncomeTaxReconciliationTaxExemptIncome

(4,469,000)us-gaap_IncomeTaxReconciliationTaxExemptIncome

Non-deductible expenses

829,000us-gaap_IncomeTaxReconciliationNondeductibleExpense

963,000us-gaap_IncomeTaxReconciliationNondeductibleExpense

1,175,000us-gaap_IncomeTaxReconciliationNondeductibleExpense

Tax credits

(11,392,000)us-gaap_IncomeTaxReconciliationTaxCredits

(13,340,000)us-gaap_IncomeTaxReconciliationTaxCredits

(18,125,000)us-gaap_IncomeTaxReconciliationTaxCredits

Subsidiary liquidations

0fhn_SubsidaryLiquidation

(6,733,000)fhn_SubsidaryLiquidation

Change in valuation allowance - DTA

(13,168,000)us-gaap_IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance

(4,427,000)us-gaap_IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance

0us-gaap_IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance

Other changes in unrecognized tax benefits

(1,570,000)fhn_IncomeTaxRateReconciliationOtherChangesInUnrecognizedTaxBenefits

(5,106,000)fhn_IncomeTaxRateReconciliationOtherChangesInUnrecognizedTaxBenefits

(8,981,000)fhn_IncomeTaxRateReconciliationOtherChangesInUnrecognizedTaxBenefits

Other

163,000us-gaap_IncomeTaxReconciliationOtherAdjustments

1,682,000us-gaap_IncomeTaxReconciliationOtherAdjustments

(715,000)us-gaap_IncomeTaxReconciliationOtherAdjustments

Total income tax expense/(benefit)

$ 78,501,000us-gaap_IncomeTaxExpenseBenefit

$ (32,169,000)us-gaap_IncomeTaxExpenseBenefit

$ (85,262,000)us-gaap_IncomeTaxExpenseBenefit

- Definition

Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to ither changes in unrecognized tax benefits.

+ References

No definition available.

+ Details

Name:	fhn_IncomeTaxRateReconciliationOtherChangesInUnrecognizedTaxBenefits
Namespace Prefix:	fhn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Income tax reconciliation nontaxable income.

+ References

No definition available.

+ Details

Name:	fhn_IncomeTaxReconciliationNontaxableIncome
Namespace Prefix:	fhn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	fhn_Increasedecreaseresultingfromabstract
Namespace Prefix:	fhn_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Loss from liquidation of subsidary corporation

+ References

No definition available.

+ Details

Name:	fhn_SubsidaryLiquidation
Namespace Prefix:	fhn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 12

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32687-109319

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SAB TOPIC 6.I)

-URI http://asc.fasb.org/extlink&oid=34349781&loc=d3e330036-122817

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 13

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32698-109319

+ Details

Name:	us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

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

- Definition

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.4-08.(h))

-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 08

-Paragraph h

-Article 4

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Income Tax Expense (or Benefit)

-URI http://asc.fasb.org/extlink&oid=6515339

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 9

-Subparagraph (a),(b)

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32639-109319

+ Details

Name:	us-gaap_IncomeTaxExpenseBenefit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

+ References

+ Details

Name:	us-gaap_IncomeTaxRateReconciliationDeductionsEmployeeStockOwnershipPlanDividends
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 12

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32687-109319

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 13

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32698-109319

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 45

-Paragraph 20

-URI http://asc.fasb.org/extlink&oid=37586315&loc=d3e32123-109318

+ Details

Name:	us-gaap_IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The amount of income tax expense or benefit for the period computed by applying the domestic federal statutory tax rates to pretax income from continuing operations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 12

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32687-109319

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 13

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32698-109319

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 08

-Paragraph h

-Subparagraph 2

-Article 4

+ Details

Name:	us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

+ References

+ Details

Name:	us-gaap_IncomeTaxReconciliationNondeductibleExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

+ References

+ Details

Name:	us-gaap_IncomeTaxReconciliationOtherAdjustments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 12

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32687-109319

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 13

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32698-109319

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 08

-Paragraph h

-Subparagraph 1

-Article 4

+ Details

Name:	us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

+ References

+ Details

Name:	us-gaap_IncomeTaxReconciliationTaxCredits
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

+ References

+ Details

Name:	us-gaap_IncomeTaxReconciliationTaxExemptIncome
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration