Business Segment Information (Amounts Of Consolidated Revenue, Expense, Tax And Assets) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012		Mar. 31, 2011
Segment Reporting Information [Line Items]
Net interest income	$ 171,929		$ 172,755
Provision for loan losses	8,000		1,000
Noninterest income	202,441		196,335
Noninterest expense	321,994		313,796
Income/(loss) before income taxes	44,376		54,294
Provision/(benefit) for income taxes	10,570		12,162
Income/(loss) from continuing operations	33,806		42,132
Income/(loss) from discontinued operations, net of tax	(435)	[1]	871	[1]
Net income/(loss)	33,371		43,003
Average assets	25,200,373		24,570,170
Regional Banking [Member]
Segment Reporting Information [Line Items]
Net interest income	146,554		134,771
Provision for loan losses	(7,426)		(12,404)
Noninterest income	59,901		66,319
Noninterest expense	139,359		147,794
Income/(loss) before income taxes	74,522		65,700
Provision/(benefit) for income taxes	27,199		24,051
Net income/(loss)	47,323		41,649
Average assets	12,182,128		11,032,101
Capital Markets [Member]
Segment Reporting Information [Line Items]
Net interest income	5,684		5,503
Noninterest income	106,775		90,080
Noninterest expense	80,302		73,563
Income/(loss) before income taxes	32,157		22,020
Provision/(benefit) for income taxes	12,240		8,406
Net income/(loss)	19,917		13,614
Average assets	2,350,821		2,061,282
Corporate [Member]
Segment Reporting Information [Line Items]
Net interest income	(4,727)		(332)
Noninterest income	9,266		12,708
Noninterest expense	22,521		20,665
Income/(loss) before income taxes	(17,982)		(8,289)
Provision/(benefit) for income taxes	(11,805)		(10,617)
Net income/(loss)	(6,177)		2,328
Average assets	5,429,068		5,109,272
Non-Strategic [Member]
Segment Reporting Information [Line Items]
Net interest income	24,418		32,813
Provision for loan losses	15,426		13,404
Noninterest income	26,499		27,228
Noninterest expense	79,812		71,774
Income/(loss) before income taxes	(44,321)		(25,137)
Provision/(benefit) for income taxes	(17,064)		(9,678)
Income/(loss) from continuing operations	(27,257)		(15,459)
Income/(loss) from discontinued operations, net of tax	(435)		871
Net income/(loss)	(27,692)		(14,588)
Average assets	$ 5,238,356		$ 6,367,515

[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.