Investment Securities (Schedule Of FHN's Available For Sale Securities) (Details) (USD $)	Mar. 31, 2012		Dec. 31, 2011	Mar. 31, 2011
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, Amortized Cost	$ 3,186,822,000	[1]		$ 3,021,095,000	[2]
Securities available for sale, Gross Unrealized Gains	110,515,000	[1]		68,609,000	[2]
Securities available for sale, Gross Unrealized Losses	(734,000)	[1]		(4,226,000)	[2]
Securities available for sale, Fair Value	3,296,603,000	[1]	3,066,272,000	3,085,478,000	[2]
Pledged available for sale securities	2,800,000,000			2,800,000,000
FHN [Member]
Schedule of Available-for-sale Securities [Line Items]
Pledged available for sale securities	400,000,000			900,000,000
FRB [Member]
Schedule of Available-for-sale Securities [Line Items]
Restricted investments	66,100,000			66,200,000
U.S. Treasuries [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, Amortized Cost	40,011,000			60,126,000
Securities available for sale, Gross Unrealized Gains	26,000			196,000
Securities available for sale, Fair Value	40,037,000			60,322,000
Government Agency Issued Mortgage-Backed Securities ("MBS") [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, Amortized Cost	1,352,827,000			1,500,461,000
Securities available for sale, Gross Unrealized Gains	74,936,000			45,114,000
Securities available for sale, Gross Unrealized Losses	(734,000)			(3,346,000)
Securities available for sale, Fair Value	1,427,029,000			1,542,229,000
FHLB-Cincinnati Stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Restricted investments	125,500,000			125,500,000
Government Agency Issued Collateralized Mortgage Obligations ("CMO") [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, Amortized Cost	1,537,732,000			1,187,262,000
Securities available for sale, Gross Unrealized Gains	35,104,000			22,360,000
Securities available for sale, Gross Unrealized Losses				(870,000)
Securities available for sale, Fair Value	1,572,836,000			1,208,752,000
Other U.S. Government Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, Amortized Cost	14,121,000			20,218,000
Securities available for sale, Gross Unrealized Gains	426,000			907,000
Securities available for sale, Fair Value	14,547,000			21,125,000
States And Municipalities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, Amortized Cost	18,070,000			26,015,000
Securities available for sale, Fair Value	18,070,000			26,015,000
Equity [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, Amortized Cost	223,551,000	[3]		226,502,000	[4]
Securities available for sale, Gross Unrealized Gains	6,000	[3]
Securities available for sale, Gross Unrealized Losses				(10,000)	[4]
Securities available for sale, Fair Value	223,557,000	[3]		226,492,000	[4]
Other Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, Amortized Cost	510,000			511,000
Securities available for sale, Gross Unrealized Gains	17,000			32,000
Securities available for sale, Fair Value	$ 527,000			$ 543,000

[1] Includes $2.8 billion of securities pledged to secure public deposits, securities sold under agreements to repurchase, and for other purposes. Of this amount, $.4 billion was pledged as collateral for securities sold under repurchase agreements.

[2] Includes $2.8 billion of securities pledged to secure public deposits, securities sold under agreements to repurchase, and for other purposes. Of this amount, $.9 bilion was pledged as collateral for securities sold under repurchase agreements.

[3] Includes restricted investments in FHLB-Cincinnati stock of $125.5 million and FRB stock of $66.1 million. The remainder is money market, venture capital, and cost method investments.

[4] Includes restricted investments in FHLB-Cincinnati stock of $125.5 million and FRB stock of $66.2 million. The remainder is money market, venture capital, and cost method investments.