EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Basic earnings per common share:
Net income attributable to Huntington	$ 523	$ 527
Dividends on preferred shares	41	27
Net income applicable to common shares	482	500
Net income available to common shareholders, diluted	$ 482	$ 500
Average common shares issued and outstanding (in shares)	1,869,397	1,454,498
Basic earnings per common share (in usd per share)	$ 0.26	$ 0.34
Average dilutive potential common shares:
Stock options, restricted stock units and awards, and performance share units	24,087	20,340
Shares held in deferred compensation plans	7,163	7,041
Dilutive potential common shares (in shares)	31,250	27,381
Total diluted average common shares issued and outstanding (in shares)	1,900,647	1,481,879
Diluted earnings per common share (in usd per share)	$ 0.25	$ 0.34
Employee Stock Options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive awards (in shares)	1,175	3,486