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	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2011	Dec. 31, 2010
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Loans held-for-sale	$ 224,635		$ 217,320
Total securities available-for-sale	2,926,153		3,129,587
Total MSR recognized by FHN	120,537	144,069	150,803	207,319
Total other assets	357,326		409,173
Total assets	4,833,017		5,134,079
Other short-term borrowings	11,585		15,814
Total other liabilities	225,084		264,904
Total liabilities	753,639		751,838
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	13,794		13,788
Total MSR recognized by FHN	0		0
Total other assets	38,163		61,845
Total assets	51,957		75,633
Other short-term borrowings	0		0
Total other liabilities	12,424		18,377
Total liabilities	12,424		18,377
Fair Value Inputs Level2 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Loans held-for-sale	10,996		10,468
Total securities available-for-sale	2,897,657		3,094,754
Total MSR recognized by FHN	0		0
Total other assets	319,163		347,328
Total assets	4,418,438		4,660,573
Other short-term borrowings	0		0
Total other liabilities	210,320		242,871
Total liabilities	727,290		713,991
Fair Value Inputs Level3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Loans held-for-sale	213,639		206,852
Total securities available-for-sale	14,702		21,045
Total MSR recognized by FHN	120,537		150,803
Total other assets	0		0
Total assets	362,622		397,873
Other short-term borrowings	11,585		15,814
Total other liabilities	2,340		3,656
Total liabilities	13,925		19,470
U S Treasury Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total securities available-for-sale	54,996		40,189
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	54,996		40,189
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	1,271,450		1,514,960
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	1,271,450		1,514,960
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	1,554,741		1,510,175
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	1,554,741		1,510,175
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	4,202		17,931
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		11,565
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	4,202		6,366
States And Municipalities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total securities available-for-sale	17,970		19,365
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	16,470		17,865
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	517		528
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	517		528
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		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		0
Venture Capital Investments [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total securities available-for-sale	9,000		13,179
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	9,000		13,179
Equity Mutual Funds And Other [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total securities available-for-sale	13,277		13,260
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	13,277		13,260
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
Deferred Compensation Assets [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	23,301		24,414
Deferred Compensation Assets [Member] | Fair Value Inputs Level1 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	23,301		24,414
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	14,862		37,431
Total other liabilities	12,424		18,377
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	14,862		37,431
Total other liabilities	12,424		18,377
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	319,163		347,266
Total other liabilities	210,320		242,871
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	319,163		347,266
Total other liabilities	210,320		242,871
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 assets			62
Total other liabilities	2,340		3,656
Derivatives Other [Member] | Fair Value Inputs Level1 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets			0
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 assets			62
Total other liabilities	0		0
Derivatives Other [Member] | Fair Value Inputs Level3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets			0
Total other liabilities	2,340		3,656
Capital Markets [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	1,185,165		1,199,443
Total trading liabilities - capital markets	516,970		471,120
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	1,185,160		1,199,438
Total trading liabilities - capital markets	516,970		471,120
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	124,722		102,054
Total trading liabilities - capital markets	350,434		281,174
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	124,722		102,054
Total trading liabilities - capital markets	350,434		281,174
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	564,425		374,691
Total trading liabilities - capital markets	5,125		13
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		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	564,425		374,691
Total trading liabilities - capital markets	5,125		13
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		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	72,340		189,044
Total trading liabilities - capital markets	8,096		1,604
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		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	72,340		189,044
Total trading liabilities - capital markets	8,096		1,604
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		0
Capital Markets [Member] | Other U.S. Government Agencies [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	82,736		193,021
Total trading liabilities - capital markets	4,439		1,649
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	82,736		193,021
Total trading liabilities - capital markets	4,439		1,649
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	31,817		28,229
Total trading liabilities - capital markets	1,109		1,379
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		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	31,817		28,229
Total trading liabilities - capital markets	1,109		1,379
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		0
Capital Markets [Member] | Corporate And Other Debt [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	308,314		312,404
Total trading liabilities - capital markets	146,750		185,301
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	308,309		312,399
Total trading liabilities - capital markets	146,750		185,301
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	811
Total trading liabilities - capital markets	1,017
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
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	811
Total trading liabilities - capital markets	1,017
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
Total trading liabilities - capital markets	0
Mortgage Banking [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	19,201		27,753
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	5,462		8,585
Mortgage Banking [Member] | Fair Value Inputs Level3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	13,739		19,168
Mortgage Banking [Member] | Principal Only Strip [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	5,462		8,585
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	5,462		8,585
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	0		0
Mortgage Banking [Member] | Interest Only Strip [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	13,739		19,168
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	$ 13,739		$ 19,168