Business Segment Information (Amounts Of Consolidated Revenue, Expense, Tax And Assets) (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Segment Reporting Information [Line Items]
Net interest income		$ 200,701	$ 176,264	$ 390,409	$ 348,338
Provision/(provision credit) for loan losses		(2,000)	4,000	(3,000)	7,000
Noninterest income		127,673	145,514	244,612	279,819
Noninterest expense		217,917	226,822	440,122	453,749
Income/(loss) before income taxes		112,457	90,956	197,899	167,408
Provision/(benefit) for income taxes	[1]	17,253	30,016	44,307	54,255
Net income/(loss)		95,204	60,940	153,592	113,153
Average assets		28,876,350	26,828,548	28,841,422	26,723,621
Regional Banking
Segment Reporting Information [Line Items]
Net interest income		201,997	178,318	395,386	350,627
Provision/(provision credit) for loan losses		260	10,883	3,358	25,651
Noninterest income		64,737	61,275	123,713	120,551
Noninterest expense		152,659	164,524	300,723	309,920
Income/(loss) before income taxes		113,815	64,186	215,018	135,607
Provision/(benefit) for income taxes		41,136	22,333	77,724	47,709
Net income/(loss)		72,679	41,853	137,294	87,898
Average assets		18,431,757	16,575,643	18,194,854	16,260,417
Fixed Income
Segment Reporting Information [Line Items]
Net interest income		4,979	3,146	6,130	5,813
Noninterest income		55,205	78,083	106,027	145,205
Noninterest expense		54,001	62,802	102,686	121,427
Income/(loss) before income taxes		6,183	18,427	9,471	29,591
Provision/(benefit) for income taxes		1,946	6,785	2,970	10,677
Net income/(loss)		4,237	11,642	6,501	18,914
Average assets		2,696,430	2,470,724	2,288,336	2,370,201
Corporate Segment
Segment Reporting Information [Line Items]
Net interest income		(14,995)	(15,847)	(29,095)	(30,208)
Noninterest income		6,218	4,909	11,694	10,632
Noninterest expense		24,563	15,930	41,443	29,391
Income/(loss) before income taxes		(33,340)	(26,868)	(58,844)	(48,967)
Provision/(benefit) for income taxes	[1]	(35,711)	(12,744)	(48,769)	(23,959)
Net income/(loss)		2,371	(14,124)	(10,075)	(25,008)
Average assets		6,226,743	5,833,303	6,789,751	6,097,764
Non Strategic
Segment Reporting Information [Line Items]
Net interest income		8,720	10,647	17,988	22,106
Provision/(provision credit) for loan losses		(2,260)	(6,883)	(6,358)	(18,651)
Noninterest income		1,513	1,247	3,178	3,431
Noninterest expense		(13,306)	(16,434)	(4,730)	(6,989)
Income/(loss) before income taxes		25,799	35,211	32,254	51,177
Provision/(benefit) for income taxes		9,882	13,642	12,382	19,828
Net income/(loss)		15,917	21,569	19,872	31,349
Average assets		$ 1,521,420	$ 1,948,878	$ 1,568,481	$ 1,995,239

[1] Provision/(benefit) for income taxes for consolidated results and the Corporate segment for the three and six months ended June 30, 2017, relative to the prior year periods, was affected by a decline in the effective tax rate in 2017 primarily related to the reversal of the valuation allowance for the deferred tax asset related to its 2012 federal capital loss carryforward based on capital gain transactions initiated in second quarter 2017. See Note 15 – Income Taxes in the Notes to Consolidated Financial Statements on FHN’s Form 10-K for the year ended December 31, 2016, for additional information.