Derivatives (Narrative) (Details) (USD $)	1 Months Ended	3 Months Ended	9 Months Ended						9 Months Ended	3 Months Ended	9 Months Ended	12 Months Ended												3 Months Ended		9 Months Ended
	Sep. 30, 2011	Jun. 30, 2011	Sep. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Sep. 30, 2011 FHN [Member] Fixed Interest Rate Swaps To Hedge [Member] Long Term Debt Hedged With Fair Value Interest Rate Derivatives Using Shortcut Method [Member]	Sep. 30, 2010 FHN [Member] Fixed Interest Rate Swaps To Hedge [Member] Long Term Debt Hedged With Fair Value Interest Rate Derivatives Using Shortcut Method [Member]	Sep. 30, 2011 FHN [Member] Fixed Interest Rate Swaps To Hedge [Member] Long Term Debt Hedged With Fair Value Interest Rate Derivatives Using Long Haul Method [Member]	Sep. 30, 2011 FHN [Member] Visa Derivative [Member]	Sep. 30, 2011 FHN [Member] Visa Derivative [Member]	Dec. 31, 2010 FHN [Member] Visa Derivative [Member]	Dec. 31, 2010 FHN [Member] Visa Derivative [Member] Class B Shares [Member]	Sep. 30, 2011 FHN [Member] Additional Derivative Agreements [Member] Derivative Instruments With Adjustable Collateral Posting Thresholds [Member]	Sep. 30, 2010 FHN [Member] Additional Derivative Agreements [Member] Derivative Instruments With Adjustable Collateral Posting Thresholds [Member]	Sep. 30, 2011 FHN [Member] Visa Interest [Member]	Dec. 31, 2010 FHN [Member] Visa Interest [Member] Class B Shares [Member]	Sep. 30, 2011 Visa Interest [Member]	Sep. 30, 2011 FHN [Member] Derivative Instruments With Accelerated Termination Provisions [Member]	Sep. 30, 2010 FHN [Member] Derivative Instruments With Accelerated Termination Provisions [Member]	Sep. 30, 2011 FHN [Member] Subordinated Debentures Subject To Mandatory Redemption - Amounts Redeemed [Member]	Jun. 30, 2010 FHN [Member] Subordinated Debentures Subject To Mandatory Redemption - Amounts Redeemed [Member]	Sep. 30, 2010 Subordinated Debentures Subject To Mandatory Redemption - Amounts Redeemed [Member]	Sep. 30, 2011 FHN [Member]	Sep. 30, 2010 FHN [Member]	Sep. 30, 2011 FHN [Member]	Sep. 30, 2010 FHN [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Collateral cash receivables	$ 197,200,000		$ 197,200,000			$ 212,600,000
Collateral cash payables						130,000,000								126,800,000	130,000,000				126,800,000
Securities posted collateral														195,700,000	209,800,000				44,200,000	34,000,000
Net fair value of derivative liabilities with credit-risk related contingent accelerated termination provisions																			40,200,000	33,900,000
Net fair value of derivative assets with credit-risk related contingent accelerated termination provisions																			149,300,000
Net fair value of derivative assets with adjustable posting thresholds														152,000,000	146,700,000
Net fair value of derivative liabilities with adjustable posting thresholds														197,600,000	208,100,000
Total trading revenues																								92,600,000	106,900,000	247,000,000	304,000,000
Long-term debt							904,000,000	904,000,000	500,000,000
Net fair value of interest rate derivatives hedging long-term debt using the shortcut method							109,100,000	129,700,000
Noncallable senior debt maturing date									December 2015
Net fair value of interest rate derivatives hedging subordinated debt using long-haul method									26,400,000							2,200,000								11,100,000	20,200,000	11,100,000	20,200,000
Other long-term debt	2,509,804,000		2,509,804,000		3,228,070,000	2,805,731,000															200,000,000	200,000,000	200,000,000
Hedged held-to-maturity trust preferred loans principal balance																								196,300,000	211,600,000	196,300,000	211,600,000
Fixed rate conversion termination period, years																										5
Estimated conversion ratio			49.00%							49.00%	49.00%	51.00%
Additional amount deposited into escrow account				400,000,000
Cash payment to counterparty		700,000
Derivative liability related to sale of Visa shares																1,200,000	1,000,000
Foreign currency risk and interest rate risk associated with non-U.S dollar denominated loans	1,000,000		1,000,000
Number of Visa Class B shares sold	895,000
Number of Visa Class B shares sold	895,000												440,000
Derivative liability related to sale of Visa shares	$ 1,200,000		$ 1,200,000															$ 2,500,000