Fair Value Of Assets And Liabilities (Schedule Of Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012	Dec. 31, 2011
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Loans held-for-sale	$ 232,684		$ 223,158
Total securities available-for-sale	2,992,725		3,098,492
Total MSR recognized by FHN	109,102	114,311	142,956	144,069
Total other assets	297,117		364,439
Total assets	5,029,374		5,067,086
Other short-term borrowings	10,984		15,073
Total other liabilities	199,999		234,188
Total liabilities	992,289		816,832
Fair Value Inputs Level1 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Loans held-for-sale	0		0
Total securities available-for-sale	14,996		13,794
Total MSR recognized by FHN	0		0
Total other assets	38,578		56,493
Total assets	53,574		70,287
Other short-term borrowings	0		0
Total other liabilities	16,580		10,538
Total liabilities	16,580		10,538
Fair Value Inputs Level2 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Loans held-for-sale	0		8,555
Total securities available-for-sale	2,968,653		3,065,925
Total MSR recognized by FHN	0		0
Total other assets	258,539		307,946
Total assets	4,608,479		4,603,081
Other short-term borrowings	0		0
Total other liabilities	181,369		220,690
Total liabilities	962,675		788,261
Fair Value Inputs Level3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	16,454
Loans held-for-sale	232,684		214,603
Total securities available-for-sale	9,076		18,773
Total MSR recognized by FHN	109,102		142,956
Total other assets	0		0
Total assets	367,321		393,718
Other short-term borrowings	10,984		15,073
Total other liabilities	2,050		2,960
Total liabilities	13,034		18,033
U S Treasury Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total securities available-for-sale	39,994		40,037
U S Treasury Securities [Member] | Fair Value Inputs Level1 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total securities available-for-sale	0		0
U S Treasury Securities [Member] | Fair Value Inputs Level2 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total securities available-for-sale	39,994		40,037
U S Treasury Securities [Member] | Fair Value Inputs Level3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total securities available-for-sale	0		0
Government Agency Issued Mortgage-Backed Securities ("MBS") [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total securities available-for-sale	1,065,551		1,427,029
Government Agency Issued Mortgage-Backed Securities ("MBS") [Member] | Fair Value Inputs Level1 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total securities available-for-sale	0		0
Government Agency Issued Mortgage-Backed Securities ("MBS") [Member] | Fair Value Inputs Level2 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total securities available-for-sale	1,065,551		1,427,029
Government Agency Issued Mortgage-Backed Securities ("MBS") [Member] | Fair Value Inputs Level3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total securities available-for-sale	0		0
Government Agency Issued Collateralized Mortgage Obligations ("CMO") [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total securities available-for-sale	1,849,353		1,572,836
Government Agency Issued Collateralized Mortgage Obligations ("CMO") [Member] | Fair Value Inputs Level1 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total securities available-for-sale	0		0
Government Agency Issued Collateralized Mortgage Obligations ("CMO") [Member] | Fair Value Inputs Level2 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total securities available-for-sale	1,849,353		1,572,836
Government Agency Issued Collateralized Mortgage Obligations ("CMO") [Member] | Fair Value Inputs Level3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total securities available-for-sale	0		0
Other U.S. Government Agencies [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total securities available-for-sale	3,276		14,547
Other U.S. Government Agencies [Member] | Fair Value Inputs Level1 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total securities available-for-sale	0		0
Other U.S. Government Agencies [Member] | Fair Value Inputs Level2 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total securities available-for-sale	0		9,453
Other U.S. Government Agencies [Member] | Fair Value Inputs Level3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total securities available-for-sale	3,276		5,094
States And Municipalities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total securities available-for-sale	15,255		18,070
States And Municipalities [Member] | Fair Value Inputs Level1 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total securities available-for-sale	0		0
States And Municipalities [Member] | Fair Value Inputs Level2 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total securities available-for-sale	13,755		16,570
States And Municipalities [Member] | Fair Value Inputs Level3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total securities available-for-sale	1,500		1,500
Corporate And Other Debt [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total securities available-for-sale			527
Corporate And Other Debt [Member] | Fair Value Inputs Level1 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total securities available-for-sale			527
Corporate And Other Debt [Member] | Fair Value Inputs Level2 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total securities available-for-sale			0
Corporate And Other Debt [Member] | Fair Value Inputs Level3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total securities available-for-sale			0
Venture Capital Investments [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total securities available-for-sale	4,300		12,179
Venture Capital Investments [Member] | Fair Value Inputs Level1 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total securities available-for-sale	0		0
Venture Capital Investments [Member] | Fair Value Inputs Level2 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total securities available-for-sale	0		0
Venture Capital Investments [Member] | Fair Value Inputs Level3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total securities available-for-sale	4,300		12,179
Equity Mutual Funds And Other [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total securities available-for-sale	14,996		13,267
Equity Mutual Funds And Other [Member] | Fair Value Inputs Level1 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total securities available-for-sale	14,996		13,267
Equity Mutual Funds And Other [Member] | Fair Value Inputs Level2 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total securities available-for-sale	0		0
Equity Mutual Funds And Other [Member] | Fair Value Inputs Level3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total securities available-for-sale	0		0
Interest Only Strip [Member] | Fair Value Inputs Level3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities			17,381
Deferred Compensation Assets [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	22,785		24,102
Deferred Compensation Assets [Member] | Fair Value Inputs Level1 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	22,785		24,102
Deferred Compensation Assets [Member] | Fair Value Inputs Level2 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	0		0
Deferred Compensation Assets [Member] | Fair Value Inputs Level3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	0		0
Derivatives Forwards And Futures [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	15,793		32,391
Total other liabilities	16,580		10,538
Derivatives Forwards And Futures [Member] | Fair Value Inputs Level1 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	15,793		32,391
Total other liabilities	16,580		10,538
Derivatives Forwards And Futures [Member] | Fair Value Inputs Level2 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	0		0
Total other liabilities	0		0
Derivatives Forwards And Futures [Member] | Fair Value Inputs Level3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	0		0
Total other liabilities	0		0
Derivatives, Interest Rate Contracts [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	258,539		307,946
Total other liabilities	181,364		220,686
Derivatives, Interest Rate Contracts [Member] | Fair Value Inputs Level1 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	0		0
Total other liabilities	0		0
Derivatives, Interest Rate Contracts [Member] | Fair Value Inputs Level2 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	258,539		307,946
Total other liabilities	181,364		220,686
Derivatives, Interest Rate Contracts [Member] | Fair Value Inputs Level3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	0		0
Total other liabilities	0		0
Derivatives Other [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other liabilities	2,055		2,964
Derivatives Other [Member] | Fair Value Inputs Level1 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other liabilities	0		0
Derivatives Other [Member] | Fair Value Inputs Level2 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other liabilities	5		4
Derivatives Other [Member] | Fair Value Inputs Level3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other liabilities	2,050		2,960
Capital Markets [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	1,381,292		1,213,431
Total trading liabilities - capital markets	781,306		567,571
Capital Markets [Member] | Fair Value Inputs Level1 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	0		0
Total trading liabilities - capital markets	0		0
Capital Markets [Member] | Fair Value Inputs Level2 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	1,381,287		1,213,426
Total trading liabilities - capital markets	781,306		567,571
Capital Markets [Member] | Fair Value Inputs Level3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	5		5
Total trading liabilities - capital markets	0		0
Capital Markets [Member] | U S Treasury Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	99,618		106,317
Total trading liabilities - capital markets	434,119		445,381
Capital Markets [Member] | U S Treasury Securities [Member] | Fair Value Inputs Level1 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	0		0
Total trading liabilities - capital markets	0		0
Capital Markets [Member] | U S Treasury Securities [Member] | Fair Value Inputs Level2 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	99,618		106,317
Total trading liabilities - capital markets	434,119		445,381
Capital Markets [Member] | U S Treasury Securities [Member] | Fair Value Inputs Level3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	0		0
Total trading liabilities - capital markets	0		0
Capital Markets [Member] | Government Agency Issued Mortgage-Backed Securities ("MBS") [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	385,351		435,924
Total trading liabilities - capital markets	26,121
Capital Markets [Member] | Government Agency Issued Mortgage-Backed Securities ("MBS") [Member] | Fair Value Inputs Level1 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	0		0
Total trading liabilities - capital markets	0
Capital Markets [Member] | Government Agency Issued Mortgage-Backed Securities ("MBS") [Member] | Fair Value Inputs Level2 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	385,351		435,924
Total trading liabilities - capital markets	26,121
Capital Markets [Member] | Government Agency Issued Mortgage-Backed Securities ("MBS") [Member] | Fair Value Inputs Level3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	0		0
Total trading liabilities - capital markets	0
Capital Markets [Member] | Government Agency Issued Collateralized Mortgage Obligations ("CMO") [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	283,932		190,244
Total trading liabilities - capital markets	24,986
Capital Markets [Member] | Government Agency Issued Collateralized Mortgage Obligations ("CMO") [Member] | Fair Value Inputs Level1 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	0		0
Total trading liabilities - capital markets	0
Capital Markets [Member] | Government Agency Issued Collateralized Mortgage Obligations ("CMO") [Member] | Fair Value Inputs Level2 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	283,932		190,244
Total trading liabilities - capital markets	24,986
Capital Markets [Member] | Government Agency Issued Collateralized Mortgage Obligations ("CMO") [Member] | Fair Value Inputs Level3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	0		0
Total trading liabilities - capital markets	0
Capital Markets [Member] | Other U.S. Government Agencies [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	195,051		183,718
Total trading liabilities - capital markets	50,547		1,822
Capital Markets [Member] | Other U.S. Government Agencies [Member] | Fair Value Inputs Level1 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	0		0
Total trading liabilities - capital markets	0		0
Capital Markets [Member] | Other U.S. Government Agencies [Member] | Fair Value Inputs Level2 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	195,051		183,718
Total trading liabilities - capital markets	50,547		1,822
Capital Markets [Member] | Other U.S. Government Agencies [Member] | Fair Value Inputs Level3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	0		0
Total trading liabilities - capital markets	0		0
Capital Markets [Member] | States And Municipalities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	21,141		33,481
Total trading liabilities - capital markets			181
Capital Markets [Member] | States And Municipalities [Member] | Fair Value Inputs Level1 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	0		0
Total trading liabilities - capital markets			0
Capital Markets [Member] | States And Municipalities [Member] | Fair Value Inputs Level2 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	21,141		33,481
Total trading liabilities - capital markets			181
Capital Markets [Member] | States And Municipalities [Member] | Fair Value Inputs Level3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	0		0
Total trading liabilities - capital markets			0
Capital Markets [Member] | Corporate And Other Debt [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	396,191		263,303
Total trading liabilities - capital markets	245,533		120,088
Capital Markets [Member] | Corporate And Other Debt [Member] | Fair Value Inputs Level1 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	0		0
Total trading liabilities - capital markets	0		0
Capital Markets [Member] | Corporate And Other Debt [Member] | Fair Value Inputs Level2 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	396,186		263,298
Total trading liabilities - capital markets	245,533		120,088
Capital Markets [Member] | Corporate And Other Debt [Member] | Fair Value Inputs Level3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	5		5
Total trading liabilities - capital markets	0		0
Capital Markets [Member] | Equity Mutual Funds And Other [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	8		444
Total trading liabilities - capital markets			99
Capital Markets [Member] | Equity Mutual Funds And Other [Member] | Fair Value Inputs Level1 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	0		0
Total trading liabilities - capital markets			0
Capital Markets [Member] | Equity Mutual Funds And Other [Member] | Fair Value Inputs Level2 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	8		444
Total trading liabilities - capital markets			99
Capital Markets [Member] | Equity Mutual Funds And Other [Member] | Fair Value Inputs Level3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	0		0
Total trading liabilities - capital markets			0
Mortgage Banking [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	16,454		24,610
Mortgage Banking [Member] | Fair Value Inputs Level1 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	0		0
Mortgage Banking [Member] | Fair Value Inputs Level2 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	0		7,229
Mortgage Banking [Member] | Fair Value Inputs Level3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	16,454		17,381
Mortgage Banking [Member] | Principal Only Strip [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	5,293		7,229
Mortgage Banking [Member] | Principal Only Strip [Member] | Fair Value Inputs Level1 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	0		0
Mortgage Banking [Member] | Principal Only Strip [Member] | Fair Value Inputs Level2 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	0		7,229
Mortgage Banking [Member] | Principal Only Strip [Member] | Fair Value Inputs Level3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	5,293		0
Mortgage Banking [Member] | Interest Only Strip [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	11,161		17,381
Mortgage Banking [Member] | Interest Only Strip [Member] | Fair Value Inputs Level1 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	0		0
Mortgage Banking [Member] | Interest Only Strip [Member] | Fair Value Inputs Level2 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	0		0
Mortgage Banking [Member] | Interest Only Strip [Member] | Fair Value Inputs Level3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	$ 11,161		$ 17,381