Business Segment Information (Amounts Of Consolidated Revenue, Expense, Tax And Assets) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2012		Jun. 30, 2011		Jun. 30, 2012		Jun. 30, 2011
Segment Reporting Information [Line Items]
Net interest income	$ 172,675		$ 172,860		$ 344,604		$ 345,615
Provision for loan losses	15,000		1,000		23,000		2,000
Noninterest income	158,907		187,593		361,348		383,929
Noninterest expense	527,177		344,455		849,171		658,252
Income/(loss) before income taxes	(210,595)		14,998		(166,219)		69,292
Provision/(benefit) for income taxes	(88,178)		(4,167)		(77,608)		7,995
Income/(loss) from continuing operations	(122,417)		19,165		(88,611)		61,297
Income/(loss) from discontinued operations, net of tax	487	[1]	3,671	[1]	52	[1]	4,541	[1]
Net income/(loss)	(121,930)		22,836		(88,559)		65,838
Average assets	25,014,635		24,518,015		25,107,504		24,543,948
Regional Banking [Member]
Segment Reporting Information [Line Items]
Net interest income	147,204		135,583		293,277		269,942
Provision for loan losses	4,828		(13,748)		(2,598)		(26,152)
Noninterest income	64,838		67,853		124,739		134,174
Noninterest expense	142,428		143,346		281,787		291,140
Income/(loss) before income taxes	64,786		73,838		138,827		139,128
Provision/(benefit) for income taxes	23,362		27,075		50,375		50,968
Net income/(loss)	41,424		46,763		88,452		88,160
Average assets	12,354,917		11,113,268		12,292,457		11,095,675
Capital Markets [Member]
Segment Reporting Information [Line Items]
Net interest income	5,613		5,509		11,297		11,012
Noninterest income	74,964		77,925		181,739		168,005
Noninterest expense	60,886		103,383		141,188		176,946
Income/(loss) before income taxes	19,691		(19,949)		51,848		2,071
Provision/(benefit) for income taxes	7,421		(7,756)		19,661		650
Net income/(loss)	12,270		(12,193)		32,187		1,421
Average assets	2,384,449		2,259,309		2,367,635		2,160,843
Corporate [Member]
Segment Reporting Information [Line Items]
Net interest income	(4,110)		412		(8,837)		81
Noninterest income	3,838		8,850		13,104		21,558
Noninterest expense	19,374		36,287		41,895		56,959
Income/(loss) before income taxes	(19,646)		(27,025)		(37,628)		(35,320)
Provision/(benefit) for income taxes	(12,922)		(18,917)		(24,727)		(29,537)
Net income/(loss)	(6,724)		(8,108)		(12,901)		(5,783)
Average assets	5,295,278		5,089,016		5,362,173		5,099,088
Non-Strategic [Member]
Segment Reporting Information [Line Items]
Net interest income	23,968		31,356		48,867		64,580
Provision for loan losses	10,172		14,748		25,598		28,152
Noninterest income	15,267		32,965		41,766		60,192
Noninterest expense	304,489		61,439		384,301		133,207
Income/(loss) before income taxes	(275,426)		(11,866)		(319,266)		(36,587)
Provision/(benefit) for income taxes	(106,039)		(4,569)		(122,917)		(14,086)
Income/(loss) from continuing operations	(169,387)		(7,297)		(196,349)		(22,501)
Income/(loss) from discontinued operations, net of tax	487		3,671		52		4,541
Net income/(loss)	(168,900)		(3,626)		(196,297)		(17,960)
Average assets	$ 4,979,991		$ 6,056,422		$ 5,085,239		$ 6,188,342

[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 Other comprehensive income/(loss) have been attributed solely to FHN as the controlling interest holder.