REVENUE FROM CONTRACTS WITH CUSTOMERS - Disaggregation by Segment (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Disaggregation of Revenue [Line Items]
Wealth and asset management revenue	$ 502	$ 377	$ 974	$ 728
Noninterest income within the scope of other GAAP topics	283	94	493	237
Noninterest income	785	471	1,467	965
Payments and cash management revenue
Disaggregation of Revenue [Line Items]
Wealth and asset management revenue	193	150	370	290
Wealth and asset management revenue
Disaggregation of Revenue [Line Items]
Wealth and asset management revenue	134	102	254	203
Customer deposit and loan fees
Disaggregation of Revenue [Line Items]
Wealth and asset management revenue	77	62	147	116
Capital markets and advisory fees
Disaggregation of Revenue [Line Items]
Wealth and asset management revenue	72	41	146	71
Noninterest income	140	84	272	151
Leasing revenue
Disaggregation of Revenue [Line Items]
Wealth and asset management revenue	1	3	4	7
Noninterest income	21	19	42	39
Insurance income
Disaggregation of Revenue [Line Items]
Wealth and asset management revenue	21	19	42	39
Noninterest income	29	10	42	24
Other noninterest income
Disaggregation of Revenue [Line Items]
Wealth and asset management revenue	4	0	11	2
Operating Segments \| Consumer & Regional Banking
Disaggregation of Revenue [Line Items]
Wealth and asset management revenue	362	295	691	573
Noninterest income within the scope of other GAAP topics	95	44	153	93
Noninterest income	457	339	844	666
Operating Segments \| Consumer & Regional Banking \| Payments and cash management revenue
Disaggregation of Revenue [Line Items]
Wealth and asset management revenue	134	117	254	225
Operating Segments \| Consumer & Regional Banking \| Wealth and asset management revenue
Disaggregation of Revenue [Line Items]
Wealth and asset management revenue	128	98	242	193
Operating Segments \| Consumer & Regional Banking \| Customer deposit and loan fees
Disaggregation of Revenue [Line Items]
Wealth and asset management revenue	72	58	138	110
Operating Segments \| Consumer & Regional Banking \| Capital markets and advisory fees
Disaggregation of Revenue [Line Items]
Wealth and asset management revenue	7	2	14	6
Operating Segments \| Consumer & Regional Banking \| Leasing revenue
Disaggregation of Revenue [Line Items]
Wealth and asset management revenue	2	0	4	1
Operating Segments \| Consumer & Regional Banking \| Insurance income
Disaggregation of Revenue [Line Items]
Wealth and asset management revenue	17	19	35	36
Operating Segments \| Consumer & Regional Banking \| Other noninterest income
Disaggregation of Revenue [Line Items]
Wealth and asset management revenue	2	1	4	2
Operating Segments \| Commercial Banking
Disaggregation of Revenue [Line Items]
Wealth and asset management revenue	136	84	279	157
Noninterest income within the scope of other GAAP topics	139	93	248	182
Noninterest income	275	177	527	339
Operating Segments \| Commercial Banking \| Payments and cash management revenue
Disaggregation of Revenue [Line Items]
Wealth and asset management revenue	59	33	116	65
Operating Segments \| Commercial Banking \| Wealth and asset management revenue
Disaggregation of Revenue [Line Items]
Wealth and asset management revenue	6	4	12	10
Operating Segments \| Commercial Banking \| Customer deposit and loan fees
Disaggregation of Revenue [Line Items]
Wealth and asset management revenue	5	4	9	6
Operating Segments \| Commercial Banking \| Capital markets and advisory fees
Disaggregation of Revenue [Line Items]
Wealth and asset management revenue	65	39	132	65
Operating Segments \| Commercial Banking \| Leasing revenue
Disaggregation of Revenue [Line Items]
Wealth and asset management revenue	(1)	3	0	6
Operating Segments \| Commercial Banking \| Insurance income
Disaggregation of Revenue [Line Items]
Wealth and asset management revenue	3	0	6	3
Operating Segments \| Commercial Banking \| Other noninterest income
Disaggregation of Revenue [Line Items]
Wealth and asset management revenue	(1)	1	4	2
Treasury / Other
Disaggregation of Revenue [Line Items]
Wealth and asset management revenue	4	(2)	4	(2)
Noninterest income within the scope of other GAAP topics	49	(43)	92	(38)
Noninterest income	53	(45)	96	(40)
Treasury / Other \| Payments and cash management revenue
Disaggregation of Revenue [Line Items]
Wealth and asset management revenue	0	0	0	0
Treasury / Other \| Wealth and asset management revenue
Disaggregation of Revenue [Line Items]
Wealth and asset management revenue	0	0	0	0
Treasury / Other \| Customer deposit and loan fees
Disaggregation of Revenue [Line Items]
Wealth and asset management revenue	0	0	0	0
Treasury / Other \| Capital markets and advisory fees
Disaggregation of Revenue [Line Items]
Wealth and asset management revenue	0	0	0	0
Treasury / Other \| Leasing revenue
Disaggregation of Revenue [Line Items]
Wealth and asset management revenue	0	0	0	0
Treasury / Other \| Insurance income
Disaggregation of Revenue [Line Items]
Wealth and asset management revenue	1	0	1	0
Treasury / Other \| Other noninterest income
Disaggregation of Revenue [Line Items]
Wealth and asset management revenue	$ 3	$ (2)	$ 3	$ (2)

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479806/606-10-50-7

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479806/606-10-50-5

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 91
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479777/606-10-55-91

Reference 4: http://www.xbrl.org/2003/role/exampleRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 91
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479777/606-10-55-91

Reference 5: http://www.xbrl.org/2003/role/exampleRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 91
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479777/606-10-55-91

Reference 6: http://www.xbrl.org/2003/role/exampleRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 91
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479777/606-10-55-91

Reference 7: http://www.xbrl.org/2003/role/exampleRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 91
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479777/606-10-55-91

Reference 8: http://www.xbrl.org/2003/role/exampleRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 91
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479777/606-10-55-91

Reference 9: http://www.xbrl.org/2003/role/exampleRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 91
-Subparagraph (g)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479777/606-10-55-91

+ Details

Name:	us-gaap_DisaggregationOfRevenueLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The total amount of noninterest income which may be derived from: (1) fees and commissions; (2) premiums earned; (3) insurance policy charges; (4) the sale or disposal of assets; and (5) other sources not otherwise specified.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 220
-SubTopic 40
-Name Accounting Standards Codification
-Section 55
-Paragraph 21
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147476153/220-40-55-21

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 942
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(13))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478524/942-220-S99-1

+ Details

Name:	us-gaap_NoninterestIncome
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 40
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-40

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 42
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-42

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 41
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-41

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (ee)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-32

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 30
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-30

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 22
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-22

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 22
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-22

Reference 8: http://www.xbrl.org/2003/role/exampleRef
-Topic 220
-SubTopic 40
-Name Accounting Standards Codification
-Section 55
-Paragraph 4
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147476153/220-40-55-4

Reference 9: http://www.xbrl.org/2003/role/exampleRef
-Topic 220
-SubTopic 40
-Name Accounting Standards Codification
-Section 55
-Paragraph 14
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147476153/220-40-55-14

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479806/606-10-50-7

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 270
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (i)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482964/270-10-50-1

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 924
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 11.L)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479941/924-10-S99-1

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479806/606-10-50-5

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479806/606-10-50-4

+ Details

Name:	us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of revenue that is not accounted for under Topic 606.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(1))
-SubTopic 10
-Topic 220
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483621/220-10-S99-2

+ Details

Name:	us-gaap_RevenueNotFromContractWithCustomer
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	srt_ProductOrServiceAxis=hban_CardsAndPaymentProcessingRevenueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ProductOrServiceAxis=hban_TrustAndInvestmentManagementServicesRevenueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ProductOrServiceAxis=hban_ServiceChargesRevenueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ProductOrServiceAxis=hban_CapitalMarketFeesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ProductOrServiceAxis=hban_LeasingRevenueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ProductOrServiceAxis=hban_InsuranceRevenueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ProductOrServiceAxis=hban_OtherRevenueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ConsolidationItemsAxis=us-gaap_OperatingSegmentsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=hban_ConsumerAndBusinessBankingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=hban_CommercialBankingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ConsolidationItemsAxis=us-gaap_CorporateNonSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: