SEGMENT REPORTING (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025 USD ($)	Sep. 30, 2024 USD ($)	Sep. 30, 2025 USD ($) business_unit	Sep. 30, 2024 USD ($)	Dec. 31, 2024 USD ($)
Segment Reporting Information [Line Items]
Number of reporting segments | business_unit			2
Net interest income (loss)	$ 1,506	$ 1,351	$ 4,399	$ 3,950
Provision for credit losses	122	106	340	313
Net interest income (loss) after provision (benefit) for credit losses	1,384	1,245	4,059	3,637
Noninterest income	628	523	1,593	1,481
Noninterest expense:
Direct personnel costs	757	684	2,150	1,986
Other noninterest expense, including corporate allocations	489	446	1,445	1,398
Total noninterest expense	1,246	1,130	3,595	3,384
Income (loss) before income taxes	766	638	2,057	1,734
Provision (benefit) for income taxes	133	116	351	308
Income attributable to non-controlling interest	4	5	14	16
Net income attributable to Huntington	629	517	1,692	1,410
Total Assets	210,228		210,228		$ 204,230
Total deposits	165,212		165,212		162,448
Operating Segments | Consumer & Regional Banking
Segment Reporting Information [Line Items]
Net interest income (loss)	1,061	1,050	3,018	3,013
Provision for credit losses	121	105	306	227
Net interest income (loss) after provision (benefit) for credit losses	940	945	2,712	2,786
Noninterest income	393	338	1,059	968
Noninterest expense:
Direct personnel costs	308	287	907	847
Other noninterest expense, including corporate allocations	541	512	1,601	1,517
Total noninterest expense	849	799	2,508	2,364
Income (loss) before income taxes	484	484	1,263	1,390
Provision (benefit) for income taxes	102	102	265	292
Income attributable to non-controlling interest	0	0	0	0
Net income attributable to Huntington	382	382	998	1,098
Total Assets	81,412		81,412		78,841
Total deposits	110,043		110,043		111,390
Operating Segments | Commercial Banking
Segment Reporting Information [Line Items]
Net interest income (loss)	538	529	1,564	1,579
Provision for credit losses	1	1	34	86
Net interest income (loss) after provision (benefit) for credit losses	537	528	1,530	1,493
Noninterest income	218	181	557	490
Noninterest expense:
Direct personnel costs	152	144	440	429
Other noninterest expense, including corporate allocations	167	145	499	454
Total noninterest expense	319	289	939	883
Income (loss) before income taxes	436	420	1,148	1,100
Provision (benefit) for income taxes	91	88	241	231
Income attributable to non-controlling interest	4	5	14	16
Net income attributable to Huntington	341	327	893	853
Total Assets	71,937		71,937		66,919
Total deposits	47,651		47,651		43,366
Treasury / Other
Segment Reporting Information [Line Items]
Net interest income (loss)	(93)	(228)	(183)	(642)
Provision for credit losses	0	0	0	0
Net interest income (loss) after provision (benefit) for credit losses	(93)	(228)	(183)	(642)
Noninterest income	17	4	(23)	23
Noninterest expense:
Direct personnel costs	297	253	803	710
Other noninterest expense, including corporate allocations	(219)	(211)	(655)	(573)
Total noninterest expense	78	42	148	137
Income (loss) before income taxes	(154)	(266)	(354)	(756)
Provision (benefit) for income taxes	(60)	(74)	(155)	(215)
Income attributable to non-controlling interest	0	0	0	0
Net income attributable to Huntington	(94)	$ (192)	(199)	$ (541)
Total Assets	56,879		56,879		58,470
Total deposits	$ 7,518		$ 7,518		$ 7,692