Changes in Accumulated Other Comprehensive Income Balances (Details) - USD ($)		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015
Beginning Balance		$ (214,192,000)	$ (188,246,000)
Other comprehensive income before reclassifications, Net of tax		44,019,000	18,004,000
Amounts reclassifed from accumulated other comprehensive income, Net of tax		(268,000)	1,083,000
Other comprehensive income/(loss)	[1]	43,751,000	19,087,000
Ending Balance		(170,441,000)	(169,159,000)
Reclassification From Accumulated Other Comprehensive Income Current Period Tax		(200,000)	700,000
Unrealized Gain/(Loss) On Cash Flow Hedge [Member]
Beginning Balance		0	0
Other comprehensive income before reclassifications, Net of tax		3,839,000	0
Amounts reclassifed from accumulated other comprehensive income, Net of tax		(374,000)	0
Other comprehensive income/(loss)		3,465,000	0
Ending Balance		3,465,000	0
Other Comprehensive Income Loss Current Period Before Reclassification Adjustments, Tax		2,400,000	0
Reclassification From Accumulated Other Comprehensive Income Current Period Tax		(200,000)	0
OtherComprehensiveIncomeLossTax		2,200,000	0
Unrealized Gain Loss On Securities Available For Sale [Member]
Beginning Balance		3,394,000	18,581,000
Other comprehensive income before reclassifications, Net of tax		40,180,000	18,004,000
Amounts reclassifed from accumulated other comprehensive income, Net of tax		(1,020,000)	0
Other comprehensive income/(loss)		39,160,000	18,004,000
Ending Balance		42,554,000	36,585,000
Other Comprehensive Income Loss Current Period Before Reclassification Adjustments, Tax		25,000,000	11,300,000
Reclassification From Accumulated Other Comprehensive Income Current Period Tax		(600,000)	0
OtherComprehensiveIncomeLossTax		24,300,000	11,300,000
Pension And Other Postretirement Plans Costs [Member]
Beginning Balance		(217,586,000)	(206,827,000)
Other comprehensive income before reclassifications, Net of tax		0	0
Amounts reclassifed from accumulated other comprehensive income, Net of tax		1,126,000	1,083,000
Other comprehensive income/(loss)		1,126,000	1,083,000
Ending Balance		(216,460,000)	(205,744,000)
Other Comprehensive Income Loss Current Period Before Reclassification Adjustments, Tax		0	0
Reclassification From Accumulated Other Comprehensive Income Current Period Tax		700,000	700,000
OtherComprehensiveIncomeLossTax		$ 700,000	$ 700,000

[1] Due to the nature of the preferred stock issued by FHN and its subsidiaries, all components of Other comprehensive income/(loss) have been attributed solely to FHN as the controlling interest holder.