Variable Interest Entities (Summary Of VIE Not Consolidated By FHN) (Details) (USD $)	Mar. 31, 2015		Dec. 31, 2014	Mar. 31, 2014
Variable Interest Entity [Line Items]
Loans, net of unearned income	$ 16,732,123,000	[1]	$ 16,230,166,000	$ 15,119,461,000
Term borrowings	1,573,215,000		1,880,105,000	1,507,048,000
Trading securities	1,532,463,000		1,194,391,000	1,194,749,000
Total MSR recognized by FHN	2,342,000			4,687,000
Custodial balances	5,060,897,000		5,195,656,000	4,534,245,000
Securities available for sale	3,672,331,000	[2]	3,556,613,000	3,571,179,000	[3]
Low Income Housing Partnerships [Member]
Variable Interest Entity [Line Items]
Maximum Loss Exposure	58,971,000	[4]		63,409,147	[5]
Maximum loss exposure, contractual funding commitments	3,600,000			6,500,000
Liability Recognized	3,608,761	[4],[6]		6,472,000	[5]
Low Income Housing Partnerships [Member] | Other Assets Member
Variable Interest Entity [Line Items]
Maximum loss exposure, current investments	55,400,000			56,900,000	[5]
New Market Tax Credit Llcs [Member]
Variable Interest Entity [Line Items]
Maximum Loss Exposure	21,360,000	[6],[7]		22,492,000	[8],[9]
Liability Recognized	0	[6],[7]		0	[8],[9]
New Market Tax Credit Llcs [Member] | Current Investment Funded By Borrowings [Member]
Variable Interest Entity [Line Items]
Maximum loss exposure, current investments	18,000,000			18,000,000
Small Issuer Trust Preferred Holdings [Member]
Variable Interest Entity [Line Items]
Maximum Loss Exposure	364,352,000	[10]		375,247,000	[11]
Liability Recognized	0	[10]		0	[11]
On Balance Sheet Trust Preferred Securitization [Member]
Variable Interest Entity [Line Items]
Maximum Loss Exposure	50,748,000	[12]		53,463,000	[13]
Liability Recognized	63,425,000	[12]		60,711,000	[13]
Loans, net of unearned income	112,500,000			112,500,000
Term borrowings	63,400,000			60,700,000
Trading securities	1,700,000			1,700,000
Proprietary Trust Preferred Issuances [Member]
Variable Interest Entity [Line Items]
Liability Recognized	206,186,000	[14]		206,186,000	[15]
Proprietary Agency Residential Mortgage Securitizations [Member]
Variable Interest Entity [Line Items]
Maximum Loss Exposure	25,786,000	[16]		54,559,000	[17]
Liability Recognized	0	[16]		0	[17]
Proprietary Agency Residential Mortgage Securitizations [Member] | Other Assets Member
Variable Interest Entity [Line Items]
Aggregate servicing advances	19,800,000			45,500,000
Holdings Of Agency Mortgage Backed Securities [Member]
Variable Interest Entity [Line Items]
Maximum Loss Exposure	4,338,653,000	[10],[18]
Liability Recognized	0	[10],[18]		0	[19]
Trading securities	859,700,000			537,300,000
Securities available for sale	3,500,000,000			3,300,000,000
Short Positions In Agency Mortgage Backed Securities [Member]
Variable Interest Entity [Line Items]
Liability Recognized				1,586,000	[15]
Commercial Loan Troubled Debt Restructurings [Member]
Variable Interest Entity [Line Items]
Maximum Loss Exposure	39,015,000	[20],[21]		58,736,000	[22],[23]
Maximum loss exposure, contractual funding commitments	4,200,000			1,500,000
Liability Recognized	0	[20],[21]		0
Loans, net of unearned income	34,800,000			57,200,000
Proprietary Residential Mortgage Securitizations [Member]
Variable Interest Entity [Line Items]
Trading securities	5,300,000			6,600,000
Total MSR recognized by FHN	700,000			2,400,000
Agency Residential Mortgage Securitizations [Member]
Variable Interest Entity [Line Items]
Total MSR recognized by FHN	$ 700,000			$ 2,400,000

[1] (b) March 31, 2015 includes $28.0 million of held-to-maturity consumer mortgage loans secured by residential real estate properties in process of foreclosure.

[2] Includes $3.2billion of securities pledged to secure public deposits, securities sold under agreements to repurchase, and for other purposes.

[3] Includes $3.3 billion of securities pledged to secure public deposits, securities sold under agreements to repurchase, and for other purposes.

[4] Maximum loss exposure represents $55.4 million of current investments and $3.6 million of accrued contractual funding commitments. Accrued funding commitments represent unconditional contractual obligations for future funding events, and are also recognized in Other Liabilities. FHN currently expects to be required to fund these accrued commitments by the end of 2016.

[5] Maximum loss exposure represents $56.9 million of current investments and $6.5 million of accrued contractual funding commitments. Accrued funding commitments represent unconditional contractual obligations for future funding events, and are also recognized in Other Liabilities. FHN currently expects to be required to fund these accrued commitments by the end of 2016.

[6] A liability is not recognized as investments are written down over the life of the related tax credit.

[7] Maximum loss exposure represents current investment balance. Of the initial investment, $18.0 million was funded through loans from community development enterprises.

[8] A liability is not recognized as investments are written down over the life of the related tax credit.

[9] Maximum loss exposure represents current investment balance. Of the initial investment, $18.0 million was funded through loans from community development enterprises.

[10] Maximum loss exposure represents the value of current investments. A liability is not recognized as FHN is solely a holder of the trusts’ securities.

[11] Maximum loss exposure represents the value of current investments. A liability is not recognized as FHN is solely a holder of the trusts’ securities.

[12] Includes $112.5 million classified as Loans, net of unearned income, and $1.7 million classified as Trading securities which are offset by $63.4 million classified as Term borrowings.

[13] Includes $112.5 million classified as Loans, net of unearned income, and $1.7 million classified as Trading securities which are offset by $60.7 million classified as Term borrowings.

[14] No exposure to loss due to the nature of FHN’s involvement.

[15] No exposure to loss due to the nature of FHN’s involvement.

[16] Includes $.7million classified as MSR related to proprietary and agency residential mortgage securitizations and $5.3 million classified as Trading securities related to proprietary residential mortgage securitizations. Aggregate servicing advances of $19.8 million are classified as Other assets.

[17] Includes $2.4million classified as MSR related to proprietary and agency residential mortgage securitizations and $6.6 million classified as Trading securities related to proprietary and agency residential mortgage securitizations. Aggregate servicing advances of $45.5 million are classified as Other assets.

[18] Includes $859.7 million classified as Trading securities and $3.5 billion classified as Securities available-for-sale.

[19] Includes $537.3 million classified as Trading securities and $3.3 billion classified as Securities available-for-sale.

[20] Maximum loss exposure represents $34.8 million of current receivables and $4.2 million of contractual funding commitments on loans related to commercial borrowers involved in a troubled debt restructuring.

[21] A liability is not recognized as the loans are the only variable interests held in the troubled commercial borrowers’ operations.

[22] Maximum loss exposure represents $57.2 million of current receivables and $1.5 million of contractual funding commitments on loans related to commercial borrowers involved in a troubled debt restructuring.

[23] A liability is not recognized as the loans are the only variable interests held in the troubled commercial borrowers’ operations.