Variable Interest Entities (Summary Of VIE Not Consolidated By FHN) (Details) (USD $)	Sep. 30, 2013		Dec. 31, 2012	Sep. 30, 2012		Dec. 31, 2011
Variable Interest Entity [Line Items]
Loans, net of unearned income	$ 15,408,556,000		$ 16,708,582,000	$ 16,523,783,000
Term borrowings	1,771,288,000		2,226,482,000	2,263,238,000
Trading securities	1,343,134,000		1,262,720,000	1,204,366,000
Total MSR recognized by FHN	116,686,000		114,311,000	120,537,000		144,069,000
Custodial balances	4,434,746,000		4,602,472,000	4,569,113,000
Securities available for sale	3,186,943,000	[1]	3,061,808,000	3,123,629,000	[2]
Low Income Housing Partnerships [Member]
Variable Interest Entity [Line Items]
Maximum Loss Exposure	53,123,000	[3],[4]		57,030,000	[3],[5]
Maximum loss exposure, contractual funding commitments	7,000,000			500,000
Liability Recognized	0	[3],[4]		0	[3],[5]
Low Income Housing Partnerships [Member] | Other Assets Member
Variable Interest Entity [Line Items]
Maximum loss exposure, current investments	46,100,000			56,500,000
New Market Tax Credit Llcs [Member]
Variable Interest Entity [Line Items]
Maximum Loss Exposure	23,014,000	[3],[6]		20,312,000	[3],[7]
Liability Recognized	0	[3],[6]		0	[3],[7]
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			15,300,000
Small Issuer Trust Preferred Holdings [Member]
Variable Interest Entity [Line Items]
Maximum Loss Exposure	402,307,000	[8]		446,045,000	[8]
Liability Recognized	0	[8]		0	[8]
On Balance Sheet Trust Preferred Securitization [Member]
Variable Interest Entity [Line Items]
Maximum Loss Exposure	54,314,000	[9]		60,662,000	[10]
Liability Recognized	59,860,000	[9]		53,511,000	[10]
Loans, net of unearned income	112,500,000			112,500,000
Term borrowings	59,900,000			53,700,000
Trading securities	1,700,000			1,700,000
Proprietary Trust Preferred Issuances [Member]
Variable Interest Entity [Line Items]
Liability Recognized	206,186,000	[11]		206,186,000	[11]
Proprietary Agency Residential Mortgage Securitizations [Member]
Variable Interest Entity [Line Items]
Maximum Loss Exposure	409,429,000	[12]		425,741,000	[13]
Liability Recognized	0	[12]		0	[13]
Proprietary Agency Residential Mortgage Securitizations [Member] | Other Assets Member
Variable Interest Entity [Line Items]
Aggregate servicing advances	289,100,000			300,600,000
On Balance Sheet Consumer Loan Securitizations [Member]
Variable Interest Entity [Line Items]
Maximum Loss Exposure	21,084,000	[14]		6,654,000	[15]
Liability Recognized	235,874,000	[14]		302,633,000	[15]
Loans, net of unearned income	257,000,000			309,300,000
Term borrowings	235,900,000			302,600,000
Holdings Of Agency Mortgage Backed Securities [Member]
Variable Interest Entity [Line Items]
Maximum Loss Exposure	3,398,870,000	[16],[8]		3,462,956,000	[17],[8]
Liability Recognized	0	[16],[8]		0	[17],[8]
Trading securities	498,300,000			636,800,000
Securities available for sale	2,900,000,000			2,800,000,000
Short Positions In Agency Mortgage Backed Securities [Member]
Variable Interest Entity [Line Items]
Liability Recognized	1,545,000	[11]		13,221,000	[11]
Commercial Loan Troubled Debt Restructurings [Member]
Variable Interest Entity [Line Items]
Maximum Loss Exposure	73,127,000	[18],[19]		95,681,000	[18],[20]
Maximum loss exposure, contractual funding commitments	2,900,000			1,400,000
Liability Recognized	0	[18],[19]		0	[18],[20]
Loans, net of unearned income	70,200,000			94,300,000
Managed Discretionary Trusts [Member]
Variable Interest Entity [Line Items]
Maximum Loss Exposure	0	[11]		0	[11]
Liability Recognized	0	[11]		0	[11]
Proprietary Residential Mortgage Securitizations [Member]
Variable Interest Entity [Line Items]
Trading securities	7,300,000			8,400,000
Total MSR recognized by FHN	72,900,000			71,500,000
Agency Residential Mortgage Securitizations [Member]
Variable Interest Entity [Line Items]
Trading securities	8,400,000			10,800,000
Total MSR recognized by FHN	$ 31,800,000			$ 34,400,000

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

[2] Includes $2.8 billion of securities pledged to secure public deposits, securities sold under agreements to repurchase, and for other purposes.

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

[4] 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 Other assets.

[5] Maximum loss exposure represents $56.5 million of current investments and $.5 million of contractual funding commitments. Only the current investment amount is included in Other assets.

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

[7] Maximum loss exposure represents current investment balance. Of the initial investment $15.3 million was funded through loans from community development enterprises.

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

[9] 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.

[10] Includes $112.5 million classified as Loans, net of unearned income, and $1.7 million classified as Trading securities which are offset by $53.7 million classified as Term borrowings.

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

[12] 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.

[13] Includes $71.5 million and $34.4 million classified as MSR and $8.4 million and $10.8 million classified as Trading securities related to proprietary and agency residential mortgage securitizations, respectively. Aggregate servicing advances of $300.6 million are classified as Other assets.

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

[15] Includes $309.3 million as Loans, net of unearned income which are offset by $302.6 million classified as Term borrowings.

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

[17] Includes $636.8 million classified as Trading securities and $2.8 billion classified as Securities available-for-sale.

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

[19] 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.

[20] Maximum loss exposure represents $94.3 million of current receivables and $1.4 million of contractual funding commitments on loans related to commercial borrowers involved in a troubled debt restructuring.