EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Basic earnings per common share:
Net income attributable to Huntington	$ 629	$ 517	$ 1,692	$ 1,410
Dividends on preferred shares	27	36	81	107
Net income available to common shareholders	602	481	1,611	1,303
Net income available to common shareholders, diluted	$ 602	$ 481	$ 1,611	$ 1,303
Average common shares issued and outstanding (in shares)	1,459,129	1,452,682	1,456,979	1,450,794
Basic earnings per common share (in usd per share)	$ 0.41	$ 0.33	$ 1.11	$ 0.90
Average dilutive potential common shares:
Stock options, restricted stock units, and performance share units	18,491	17,061	18,662	16,622
Shares held in deferred compensation plans	6,967	7,239	7,036	7,443
Dilutive potential common shares (in shares)	25,458	24,300	25,698	24,065
Total diluted average common shares issued and outstanding (in shares)	1,484,587	1,476,982	1,482,677	1,474,859
Diluted earnings per common share (in usd per share)	$ 0.41	$ 0.33	$ 1.09	$ 0.88
Employee Stock Options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive awards (in shares)	230	4,253	1,693	7,002