Fair Value Of Assets And Liabilities (Summary Of Book Value And Estimated Fair Value Of Financial Instruments) (Details) (USD $) In Thousands	Sep. 30, 2011		Dec. 31, 2010		Sep. 30, 2010
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans, net of unearned income and allowance for loan losses	$ 15,791,757		$ 16,117,773		$ 16,339,590
Trading Securities	1,227,197		769,750		1,214,595
Loans held for sale	217,320				279,642
Loans Receivable Held-for-sale, Net	386,147		375,289		414,259
Securities available for sale	3,327,846	[1]	3,031,930		2,611,460	[2]
Total deposits	15,698,255	[3]	15,208,231	[3]	14,975,920	[3]
Trading liabilities	471,120		361,920		414,666
Term borrowings	2,509,804		3,228,070		2,805,731
Book Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans, net of unearned income and allowance for loan losses	15,791,757				16,339,590
Short-term financial assets	1,077,937				868,876
Trading Securities	1,227,197				1,214,595
Loans Receivable Held-for-sale, Net	386,147				414,259
Securities available for sale	3,327,846				2,611,460
Derivative assets	384,759				359,535
Other assets	99,543				118,808
Nonearning assets	952,045				985,308
Defined maturity	1,721,882				2,058,138
Undefined maturity	13,976,373				12,917,782
Total deposits	15,698,255				14,975,920
Trading liabilities	471,120				414,666
Short-term financial liabilities	2,723,951				2,632,903
Term borrowings	2,509,806				2,805,732
Derivative liabilities	264,904				251,192
Other noninterest-bearing liabilities	554,302				422,395
Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans, net of unearned income and allowance for loan losses	15,083,851				15,570,548
Short-term financial assets	1,077,937				868,876
Trading Securities	1,227,197				1,214,595
Loans Receivable Held-for-sale, Net	386,147				414,259
Securities available for sale	3,327,846				2,611,460
Derivative assets	384,759				359,535
Other assets	99,543				118,808
Nonearning assets	952,045				985,308
Defined maturity	1,770,342				2,126,749
Undefined maturity	13,976,373				12,917,782
Total deposits	15,746,715				15,044,531
Trading liabilities	471,120				414,666
Short-term financial liabilities	2,723,951				2,632,903
Term borrowings	2,222,021				2,486,425
Derivative liabilities	264,904				251,192
Other noninterest-bearing liabilities	554,302				422,395
Loan commitments	1,419				1,134
Standby and other commitments	6,370				5,891
Contractual Amount [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loan commitments	7,417,606				7,737,043
Standby and other commitments	$ 373,335				$ 503,926

[1] 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.

[2] 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.

[3] Balances as of September 30, 2011, include $174.4 million of deposits that will be transferred in fourth quarter 2011 in connection with a divestiture. See Note 2 - Acquisitions and Divestitures.