Consolidated Statements of Changes in Equity (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024		Dec. 31, 2023	Dec. 31, 2022
Equity, Class of Treasury Stock [Line Items]
Accounting Standards Update [Extensible List]			Accounting Standards Update 2023-02	Accounting Standards Update 2022-02 [Member]
Common stock - cash dividends declared per share (in dollars per share)	$ 0.60		$ 0.60	$ 0.60
Common stock repurchased under share repurchase program	$ 626	[1]	$ 10	$ 12
Preferred Stock
Equity, Class of Treasury Stock [Line Items]
Preferred stock issuance, net of offering cost (in shares)				4,936
Preferred stock issuance, net of offering cost (in dollars per share)				$ 100,000
2024 General Purchase Program
Equity, Class of Treasury Stock [Line Items]
Common stock repurchased under share repurchase program	$ 604

[1] 2024 includes $604 million repurchased under FHN's general purchase programs.