Business Segment Information (Amounts Of Consolidated Revenue, Expense, Tax And Assets) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011		Sep. 30, 2012 number		Sep. 30, 2011
Segment Reporting Information [Line Items]
Net interest income	$ 173,465		$ 176,340		$ 518,069		$ 521,955
Provision for loan losses	40,000		32,000		63,000		34,000
Noninterest income	163,538		220,887		524,886		604,816
Noninterest expense	263,169		322,708		1,112,340		980,960
Income/(loss) before income taxes	33,834		42,519		(132,385)		111,811
Provision/(benefit) for income taxes	5,260		8,367		(72,348)		16,362
Income/(loss) from continuing operations	28,574		34,152		(60,037)		95,449
Income/(loss) from discontinued operations, net of tax	108	[1]	4,828	[1]	160	[1]	9,369	[1]
Net income/(loss)	28,682		38,980		(59,877)		104,818
Average assets	25,089,754		24,778,116		25,101,544		24,622,862
Number of Operating Segments					4
Regional Banking [Member]
Segment Reporting Information [Line Items]
Net interest income	150,352		140,658		444,859		411,703
Provision for loan losses	4,286		(22,698)		1,688		(48,850)
Noninterest income	63,954		68,096		188,693		202,270
Noninterest expense	141,157		137,208		424,047		428,468
Income/(loss) before income taxes	68,863		94,244		207,817		234,355
Provision/(benefit) for income taxes	24,959		34,851		75,382		86,197
Net income/(loss)	43,904		59,393		132,435		148,158
Average assets	12,933,782		11,478,534		12,507,910		11,224,698
Capital Markets [Member]
Segment Reporting Information [Line Items]
Net interest income	4,759		5,552		16,056		16,564
Noninterest income	80,808		99,505		262,547		267,510
Noninterest expense	64,590		77,168		205,772		254,114
Income/(loss) before income taxes	20,977		27,889		72,831		29,960
Provision/(benefit) for income taxes	7,899		10,656		27,564		11,306
Net income/(loss)	13,078		17,233		45,267		18,654
Average assets	2,230,975		2,343,879		2,321,695		2,222,525
Corporate [Member]
Segment Reporting Information [Line Items]
Net interest income	(5,294)		(1,080)		(15,360)		(2,101)
Noninterest income	7,933		37,914		21,037		59,472
Noninterest expense	22,013		19,099		64,667		75,945
Income/(loss) before income taxes	(19,374)		17,735		(58,990)		(18,574)
Provision/(benefit) for income taxes	(13,496)		340		(38,988)		(29,578)
Net income/(loss)	(5,878)		17,395		(20,002)		11,004
Average assets	5,151,567		5,123,252		5,291,435		5,107,231
Non Strategic [Member]
Segment Reporting Information [Line Items]
Net interest income	23,648		31,210		72,514		95,789
Provision for loan losses	35,714		54,698		61,312		82,850
Noninterest income	10,843		15,372		52,609		75,564
Noninterest expense	35,409		89,233		417,854		222,433
Income/(loss) before income taxes	(36,632)		(97,349)		(354,043)		(133,930)
Provision/(benefit) for income taxes	(14,102)		(37,480)		(136,306)		(51,563)
Income/(loss) from continuing operations	(22,530)		(59,869)		(217,737)		(82,367)
Income/(loss) from discontinued operations, net of tax	108		4,828		160		9,369
Net income/(loss)	(22,422)		(55,041)		(217,577)		(72,998)
Average assets	$ 4,773,430		$ 5,832,451		$ 4,980,504		$ 6,068,408

[1] Due to the nature of the subsidiary preferred stock issued by First Horizon Preferred Funding, LLC, First Horizon Preferred Funding II, LLC, and FTBNA, all components of Income/(loss) from discontinued operations, net of tax have been attributed solely to FHN as the controlling interest holder.