Variable Interest Entities (Summary Of VIE Not Consolidated By FHN) (Details) (USD $)	Sep. 30, 2014		Dec. 31, 2013	Sep. 30, 2013		Dec. 31, 2012
Variable Interest Entity [Line Items]
Loans, net of unearned income	$ 15,812,017,000		$ 15,389,074,000	$ 15,408,556,000
Term borrowings	1,491,138,000		1,739,859,000	1,771,288,000
Trading securities	1,338,022,000		801,718,000	1,343,134,000
Total MSR recognized by FHN	2,880,000		72,793,000	116,686,000		114,311,000
Custodial balances	4,603,826,000		4,637,839,000	4,434,746,000
Securities available-for-sale	3,534,671,000	[1]	3,398,457,000	3,186,943,000	[2]
Low Income Housing Partnerships [Member]
Variable Interest Entity [Line Items]
Maximum Loss Exposure	49,317,000	[3],[4]		53,123,000	[5],[6]
Maximum loss exposure, contractual funding commitments	5,900,000			7,000,000
Liability Recognized	0	[3],[4]		0	[5],[6]
Low Income Housing Partnerships [Member] | Other Assets Member
Variable Interest Entity [Line Items]
Maximum loss exposure, current investments	43,500,000			46,100,000
New Market Tax Credit Llcs [Member]
Variable Interest Entity [Line Items]
Maximum Loss Exposure	21,929,000	[4],[7]		23,014,000	[5],[8]
Liability Recognized	0	[4],[7]		0	[5],[8]
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	364,912,000	[9]		402,307,000	[9]
Liability Recognized	0	[9]		0	[9]
On Balance Sheet Trust Preferred Securitization [Member]
Variable Interest Entity [Line Items]
Maximum Loss Exposure	52,320,000	[10]		54,314,000	[11]
Liability Recognized	61,853,000	[10]		59,860,000	[11]
Loans, net of unearned income	112,500,000			112,500,000
Term borrowings	61,900,000			59,900,000
Trading securities	1,700,000			1,700,000
Proprietary Trust Preferred Issuances [Member]
Variable Interest Entity [Line Items]
Liability Recognized	206,186,000	[12]		206,186,000	[13]
Proprietary Agency Residential Mortgage Securitizations [Member]
Variable Interest Entity [Line Items]
Maximum Loss Exposure	26,973,000	[14]		409,429,000	[15]
Liability Recognized	0	[14]		0	[15]
Proprietary Agency Residential Mortgage Securitizations [Member] | Other Assets Member
Variable Interest Entity [Line Items]
Aggregate servicing advances	19,900,000			289,100,000
On Balance Sheet Consumer Loan Securitizations [Member]
Variable Interest Entity [Line Items]
Maximum Loss Exposure				21,084,000	[16]
Liability Recognized				235,874,000	[16]
Loans, net of unearned income				257,000,000
Term borrowings				235,900,000
Holdings Of Agency Mortgage Backed Securities [Member]
Variable Interest Entity [Line Items]
Maximum Loss Exposure	3,843,125,000	[17],[9]		3,398,870,000	[18],[9]
Liability Recognized	0	[17],[9]		0	[18],[9]
Trading securities	502,600,000			498,300,000
Securities available-for-sale	3,300,000,000			2,900,000,000
Short Positions In Agency Mortgage Backed Securities [Member]
Variable Interest Entity [Line Items]
Liability Recognized				1,545,000	[13]
Commercial Loan Troubled Debt Restructurings [Member]
Variable Interest Entity [Line Items]
Maximum Loss Exposure	55,539,000	[19],[20]		73,127,000	[21],[22]
Maximum loss exposure, contractual funding commitments	3,100,000			2,900,000
Liability Recognized	0	[19],[20]		0	[21],[22]
Loans, net of unearned income	52,400,000			70,200,000
Managed Discretionary Trusts [Member]
Variable Interest Entity [Line Items]
Maximum Loss Exposure	0	[12]		0	[13]
Liability Recognized	0	[12]		0	[13]
Proprietary Residential Mortgage Securitizations [Member]
Variable Interest Entity [Line Items]
Trading securities	6,100,000			7,300,000
Total MSR recognized by FHN	700,000			72,900,000
Agency Residential Mortgage Securitizations [Member]
Variable Interest Entity [Line Items]
Trading securities				8,400,000
Total MSR recognized by FHN	$ 200,000			$ 31,800,000

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

[2] Includes $2.9 billion of securities pledged to secure public deposits, securities sold under agreements to repurchase, and for other purposes.

[3] Maximum loss exposure represents $43.5 million of current investments and $5.9 million of contractual funding commitments. Only the current investment amount is included in Other assets.

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

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

[6] Maximum loss exposure represents $46.1 million of current investments and $7.0 million of contractual funding commitments. Only the current investment amount is included in Otherassets.

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

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

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

[10] Includes $112.5 million classified as Loans, net of unearned income, and $1.7 million classified as Trading securities which are offset by $61.9 million classified as Term borrowings.

[11] Includes $112.5 million classified as Loans, net of unearned income, and $1.7 million classified as Trading securities which are offset by $59.9 million classified as Term borrowings.

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

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

[14] Includes $.7 million and $.2 million classified as MSR related to proprietary and agency residential mortgage securitizations, respectively, and $6.1 million classified as Trading securities related to proprietary residential mortgage securitizations. Aggregate servicing advances of $19.9 million are classified as Other assets.

[15] Includes $72.9 million and $31.8 million classified as MSR and $7.3 million and $8.4 million classified as Trading securities related to proprietary and agency residential mortgage securitizations, respectively. Aggregate servicing advances of $289.1 million are classified as Other assets.

[16] Includes $257.0 million classified as Loans, net of unearned income which are offset by $235.9 million classified as Term borrowings.

[17] Includes $502.6 million classified as Trading securities and $3.3 billion classified as Securities available-for-sale.

[18] Includes $498.3 million classified as Trading securities and $2.9 billion classified as Securities available-for-sale.

[19] Maximum loss exposure represents $52.4 million of current receivables and $3.1 million of contractual funding commitments on loans related to commercial borrowers involved in a troubled debt restructuring.

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

[21] Maximum loss exposure represents $70.2 million of current receivables and $2.9 million of contractual funding commitments on loans related to commercial borrowers involved in a troubled debt restructuring.

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