Loan Sales and Securitizations (Schedule of Principal Amount of Delinquent Loans, and Net Credit Losses) (Details) (USD $)	3 Months Ended				9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011		Sep. 30, 2012		Sep. 30, 2011
Financing Receivable, Allowance for Credit Losses [Line Items]
Principal amount of loans securitized and sold	$ 6,300,000,000		$ 8,700,000,000		$ 6,300,000,000		$ 8,700,000,000
Residential Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Principal Amount of Residential Real Estate Loans	15,889,548,000	[1],[2],[3]	19,007,433,000	[1],[2],[3]	15,889,548,000	[1],[2],[3]	19,007,433,000	[1],[2],[3]
Net Credit Losses	136,583,000	[2]	159,488,000	[2]	365,467,000	[2]	415,486,000	[2]
Principal Amount90 Days Or More Past Due Or Nonaccrual [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Principal Amount of Residential Real Estate Loans	700,000,000		800,000,000		700,000,000		800,000,000
Principal Amount90 Days Or More Past Due Or Nonaccrual [Member] | Government National Mortgage Association Certificates And Obligations G N M A [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Principal Amount of Residential Real Estate Loans	$ 35,400,000		$ 39,600,000		$ 35,400,000		$ 39,600,000

[1] On September 30, 2012 and 2011, includes $.7 billion and $.8 billion, respectively, where the principal amount is 90 days or more past due or nonaccrual. Included in these amounts are $35.4 million and $39.6 million of GNMA guaranteed mortgages on September 30, 2012 and 2011, respectively.

[2] No delinquency or net credit loss data is provided for the loans transferred to FNMA or FHLMC because these agencies retain credit risk. See Note 9 - Contingencies and Other Disclosures for discussion related to repurchase obligations for loans transferred to GSEs or private investors.

[3] Amounts represent real estate residential loans in FHN’s portfolio, held-for-sale, and loans that have been transferred in proprietary securitizations and whole loan sales in which FHN has a retained interest other than servicing rights. Also includes $6.3 billion and $8.7 billion of loans transferred to GSEs with any type of retained interest on September 30, 2012 and 2011, respectively.