Earnings Per Share (Narrative) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Income from continuing operations attributable to FHN	$ 25,699	$ 31,277	$ (68,600)	$ 86,886
Effect of dilutive securities	1,678,000	1,519,000		2,447,000
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock options, weighted average exercise price	$ 21.27	$ 24.34	$ 21.94	$ 25.91
Shares excluded from computation of earnings per share	10,000,000	10,700,000	10,400,000	10,100,000
Other Equity Awards [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares excluded from computation of earnings per share		1,100,000	3,500,000	300,000