Variable Interest Entities (Summary Of VIE Not Consolidated By FHN) (Details) (USD $)	Sep. 30, 2011		Dec. 31, 2010	Sep. 30, 2010		Dec. 31, 2009
Variable Interest Entity [Line Items]
Loans, net of unearned income	$ 16,241,402,000	[1],[2]	$ 16,782,572,000	$ 17,059,489,000	[1],[2]
Term borrowings	2,509,804,000		3,228,070,000	2,805,731,000
Trading securities	1,227,197,000		769,750,000	1,214,595,000
Total MSR recognized by FHN	150,803,000		207,319,000	191,943,000		302,611,000
Custodial balances	4,412,375,000		4,376,285,000	4,393,107,000
Securities available for sale, Fair Value	3,327,846,000	[3]	3,031,930,000	2,611,460,000	[4]
Low Income Housing Partnerships [Member]
Variable Interest Entity [Line Items]
Maximum loss exposure, contractual funding commitments	1,500,000			1,300,000
Low Income Housing Partnerships [Member] | Other Assets [Member]
Variable Interest Entity [Line Items]
Maximum Loss Exposure	76,607,000	[5],[6]		94,702,000	[5],[7]
Maximum loss exposure, current investments	75,100,000			93,400,000
Small Issuer Trust Preferred Holdings [Member] | Loans, Net Of Unearned Income [Member]
Variable Interest Entity [Line Items]
Maximum Loss Exposure	457,156,000	[8]		465,350,000	[8]
On-Balance Sheet Trust Preferred Securitization [Member]
Variable Interest Entity [Line Items]
Maximum Loss Exposure	62,253,000			63,186,000
Liability Recognized	51,908,000			50,988,000
Loans, net of unearned income	112,500,000			112,500,000
Term borrowings	51,900,000			51,000,000
Trading securities	1,700,000			1,700,000
Proprietary Trust Preferred Issuances [Member] | Term Borrowings [Member]
Variable Interest Entity [Line Items]
Liability Recognized	206,186,000	[9]		309,000,000	[9]
Proprietary & Agency Residential Mortgage Securitizations [Member]
Variable Interest Entity [Line Items]
Maximum Loss Exposure	476,329,000			330,053,000
Custodial balances				112,900,000
Proprietary & Agency Residential Mortgage Securitizations [Member] | Other Assets [Member]
Variable Interest Entity [Line Items]
Aggregate servicing advances	317,100,000			239,900,000
Holdings of Agency Mortgage-Backed Securities [Member]
Variable Interest Entity [Line Items]
Maximum Loss Exposure	3,588,871,000	[8]		2,773,925,000	[8]
Trading securities	563,700,000			612,300,000
Securities available for sale, Fair Value	3,000,000,000			2,200,000,000
Short Positions in Agency Mortgage-Backed Securities [Member] | Trading Liabilities [Member]
Variable Interest Entity [Line Items]
Liability Recognized	1,617,000	[9]		11,357,000	[9]
Commercial Loan Troubled Debt Restructurings [Member]
Variable Interest Entity [Line Items]
Maximum Loss Exposure	98,400,000
Maximum loss exposure, contractual funding commitments	600,000			4,600,000
Commercial Loan Troubled Debt Restructurings [Member] | Current Receivables [Member]
Variable Interest Entity [Line Items]
Maximum Loss Exposure				123,100,000
Commercial Loan Troubled Debt Restructurings [Member] | Loans, Net Of Unearned Income [Member]
Variable Interest Entity [Line Items]
Maximum Loss Exposure	98,977,000	[10],[11]		127,699,000	[10],[12]
Managed Discretionary Trusts [Member]
Variable Interest Entity [Line Items]
Maximum Loss Exposure		[9]
Liability Recognized		[9]
Proprietary Residential Mortgage Securitizations [Member]
Variable Interest Entity [Line Items]
Trading securities	12,200,000			16,100,000
Total MSR recognized by FHN	80,900,000			99,200,000
Agency Residential Mortgage Securitizations [Member]
Variable Interest Entity [Line Items]
Trading securities	15,500,000			20,800,000
Total MSR recognized by FHN	$ 50,600,000			$ 67,000,000

[1] Q3 2011 and Q3 2010 include $26.9 million and $41.9 million of reserves, respectively, and $623.3 million and $735.8 million of balances in restricted consumer real estate loans, respectively.

[2] Q3 2011 and Q3 2010 include $5.5 million and $5.9 million of reserves, respectively, and $42.4 million and $60.7 million of balances in restricted permanent mortgage loans, respectively.

[3] Includes $3.0 billion of securities pledged to secure public deposits, securities sold under agreements to repurchase, and for other purposes. As of September 30, 2011, FHN had pledged $1.1 billion of the $3.0 billion pledged available for sale securities as collateral for securities sold under repurchase agreements.

[4] Includes $2.3 billion of securities pledged to secure public deposits, securities sold under agreements to repurchase, and for other purposes. As of September 30, 2010, FHN had pledged $1.1 billion of the $2.3 billion pledged available for sale securities as collateral for securities sold under repurchase agreements.

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

[6] Maximum loss exposure represents $75.1 million of current investments and $1.5 million of contractual funding commitments. Only the current investment amount is included in Other assets.

[7] Maximum loss exposure represents $93.4 million of current investments and $1.3 million of contractual funding commitments. Only the current investment amount is included in Other Assets.

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

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

[11] Maximum loss exposure represents $98.4 million of current receivables and $.6 million of contractual funding commitments on loans related to commercial borrowers involved in a troubled debt restructuring.

[12] Maximum loss exposure represents $123.1 million of current receivables and $4.6 million of contractual funding commitments on loans related to commercial borrowers involved in a troubled debt restructuring.