Derivatives (Derivatives associated with legacy Mortgage Servicing Activities) (Details) (USD $) In Thousands, unless otherwise specified					3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended
	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2011	Dec. 31, 2010	Sep. 30, 2012 Forwards And Futures [Member] Retained Interest [Member] Hedging Instruments [Member]	Sep. 30, 2011 Forwards And Futures [Member] Retained Interest [Member] Hedging Instruments [Member]	Sep. 30, 2012 Forwards And Futures [Member] Retained Interest [Member] Hedging Instruments [Member]	Sep. 30, 2011 Forwards And Futures [Member] Retained Interest [Member] Hedging Instruments [Member]	Sep. 30, 2012 Interest Rate Swaps And Swaptions [Member] Retained Interest [Member] Hedging Instruments [Member]	Sep. 30, 2011 Interest Rate Swaps And Swaptions [Member] Retained Interest [Member] Hedging Instruments [Member]	Sep. 30, 2012 Interest Rate Swaps And Swaptions [Member] Retained Interest [Member] Hedging Instruments [Member]	Sep. 30, 2011 Interest Rate Swaps And Swaptions [Member] Retained Interest [Member] Hedging Instruments [Member]	Sep. 30, 2012 Mortgage Servicing Rights [Member] Retained Interest [Member] Hedged Items [Member]	Sep. 30, 2011 Mortgage Servicing Rights [Member] Retained Interest [Member] Hedged Items [Member]	Sep. 30, 2012 Mortgage Servicing Rights [Member] Retained Interest [Member] Hedged Items [Member]	Sep. 30, 2011 Mortgage Servicing Rights [Member] Retained Interest [Member] Hedged Items [Member]	Sep. 30, 2012 Other Retained Interests [Member] Retained Interest [Member] Hedged Items [Member]	Sep. 30, 2011 Other Retained Interests [Member] Retained Interest [Member] Hedged Items [Member]	Sep. 30, 2012 Other Retained Interests [Member] Retained Interest [Member] Hedged Items [Member]	Sep. 30, 2011 Other Retained Interests [Member] Retained Interest [Member] Hedged Items [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Notional									$ 1,837,600	$ 2,543,000	$ 1,837,600	$ 2,543,000
Notional, Forwards and Futures					20,000	3,145,000	20,000	3,145,000
Assets									6,693	9,619	6,693	9,619
Assets, Forwards and Futures					542	28,553	542	28,553
Liabilities									4,282	29,381	4,282	29,381
Liabilities, Forwards and Futures					0	6,286	0	6,286
Gains/(Losses)									4,580	7,881	5,498	30,105
Gains/(Losses), Forwards and Futures					207	22,586	9,839	28,934
Total MSR recognized by FHN	120,537	144,069	150,803	207,319									117,522	147,240	117,522	147,240
Fair value of retained interests	1,204,366	988,217	1,227,197														19,201	27,754	19,201	27,754
Gains/(Losses)													$ (1,279)	$ (22,452)	$ (379)	$ (25,776)	$ 978	$ (983)	$ 425	$ 1,658