Investment Securities (Schedule Of FHN's Investment Securities) (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2017		Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, Amortized Cost	$ 3,969,748	[1]	$ 3,971,435	[2]
Securities available for sale, Gross Unrealized Gains	18,655	[1]	19,869	[2]
Securities available for sale, Gross Unrealized Losses	(49,125)	[1]	(47,805)	[2]
Securities available for sale, Fair Value	3,939,278	[1]	3,943,499	[2]
Pledged available for sale securities	3,500,000		3,300,000
Schedule Of Held To Maturity Securities [Line Items]
Securities held to maturity, Amortized cost	14,354		14,347
Securities held to maturity, Gross Unrealized Gains	449		426
Securities held to maturity, Gross Unrealized Losses	0		0
Securities held to maturity, Fair Value	14,803		14,773
FRB [Member]
Schedule of Available-for-sale Securities [Line Items]
Restricted investments	68,600		68,600
FHLB-Cincinnati Stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Restricted investments	87,900		87,900
U.S. treasuries
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, Amortized Cost	100		100
Securities available for sale, Gross Unrealized Gains	0		0
Securities available for sale, Gross Unrealized Losses	0		0
Securities available for sale, Fair Value	100		100
Government Agency Issued Mortgage-Backed Securities ("MBS")
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, Amortized Cost	2,171,843		2,217,593
Securities available for sale, Gross Unrealized Gains	13,675		14,960
Securities available for sale, Gross Unrealized Losses	(25,596)		(23,866)
Securities available for sale, Fair Value	2,159,922		2,208,687
Government Agency Issued Collateralized Mortgage Obligations ("CMO")
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, Amortized Cost	1,610,857		1,566,986
Securities available for sale, Gross Unrealized Gains	4,980		4,909
Securities available for sale, Gross Unrealized Losses	(23,526)		(23,937)
Securities available for sale, Fair Value	1,592,311		1,547,958
Equity and other
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, Amortized Cost	186,948	[3]	186,756	[4]
Securities available for sale, Gross Unrealized Gains	0	[3]	0	[4]
Securities available for sale, Gross Unrealized Losses	(3)	[3]	(2)	[4]
Securities available for sale, Fair Value	186,945	[3]	186,754	[4]
Schedule Of Held To Maturity Securities [Line Items]
Securities held to maturity, Amortized cost	0
Securities held to maturity, Fair Value	0
States And Municipalities
Schedule Of Held To Maturity Securities [Line Items]
Securities held to maturity, Amortized cost	4,354		4,347
Securities held to maturity, Gross Unrealized Gains	386		393
Securities held to maturity, Gross Unrealized Losses	0		0
Securities held to maturity, Fair Value	4,740		4,740
Corporate Bonds
Schedule Of Held To Maturity Securities [Line Items]
Securities held to maturity, Amortized cost	10,000		10,000
Securities held to maturity, Gross Unrealized Gains	63		33
Securities held to maturity, Gross Unrealized Losses	0		0
Securities held to maturity, Fair Value	$ 10,063		$ 10,033

[1] Includes $ 3 . 5 billion of securities pledged to secure public deposits, securities sold under agreements to repurchase, and for other purposes.

[2] Includes $ 3.3 billion of securities pledged to secure public deposits, securities sold under agreements to repu rchase, and for other purposes .

[3] Includes restricted investments in FHLB-Cincinnati stock of $ 87 . 9 million and FRB stock of $ 68.6 million . The remainder is money market, mutual funds, and cost method investments.

[4] Includes restricted investments in FHLB-Cincinnati stock of $ 87.9 million and FRB stock of $ 68.6 million. The remainder is money market , mutual funds, and cost method investments.