Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest, Including FTE Adjustments

No definition available.

Name:	fitb_IncomeLossFromContinuingOperationsBeforeIncomeTaxesNoncontrollingInterestIncludingFTEAdjustments
Namespace Prefix:	fitb_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Interest Income (Expense), Operating, Including FTE Adjustments

+ References

No definition available.

+ Details

Name:	fitb_InterestIncomeExpenseOperatingIncludingFTEAdjustments
Namespace Prefix:	fitb_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Average amount outstanding of interest-earning and noninterest-earning assets.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name Regulation S-K (SK)
-Number 229
-Section 1402
-Paragraph a
-Publisher SEC

+ Details

Name:	us-gaap_AssetsAverageOutstanding
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

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.

+ References

No definition available.

+ Details

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

- Details

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

- Details

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

- Details

Name:	srt_StatementScenarioAxis=us-gaap_ScenarioAdjustmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Business Segments - Schedule of Movements Between Segments (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2025	Mar. 31, 2024	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Segment Reporting Information
Net interest income (FTE)	$ 1,442	$ 1,390
Income before income taxes (FTE)	658	664
Average assets	210,558	213,203
Operating Segments \| Consumer and Small Business Banking
Segment Reporting Information
Net interest income (FTE)	975	1,152
Income before income taxes (FTE)	522	685
Average assets	$ 54,406	$ 51,363
Operating Segments \| Consumer and Small Business Banking \| Scenario, Adjustment
Segment Reporting Information
Net interest income (FTE)			$ 103	$ 135	$ 74
Income before income taxes (FTE)			68	105	43
Average assets			$ 714	$ 686	$ 660