Loan Modification Program, Loans Excluded From Modification Program

No definition available.

Name:	fitb_LoanModificationProgramLoansExcludedFromModificationProgram
Namespace Prefix:	fitb_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Modification Program Option, In-Process Modifications

+ References

No definition available.

+ Details

Name:	fitb_ModificationProgramOptionInProcessModifications
Namespace Prefix:	fitb_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Modification Program Option, Mortgage Interest Payment Deferral, Term

+ References

No definition available.

+ Details

Name:	fitb_ModificationProgramOptionMortgageInterestPaymentDeferralTerm
Namespace Prefix:	fitb_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Modification Program Option, Mortgage Term

+ References

No definition available.

+ Details

Name:	fitb_ModificationProgramOptionMortgageTerm
Namespace Prefix:	fitb_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Modification Program Option, Term Extension, Term

+ References

No definition available.

+ Details

Name:	fitb_ModificationProgramOptionTermExtensionTerm
Namespace Prefix:	fitb_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Modification Program Option, Trial Period

+ References

No definition available.

+ Details

Name:	fitb_ModificationProgramOptionTrialPeriod
Namespace Prefix:	fitb_
Data Type:	xbrli:durationItemType
Balance Type:	na
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

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479319/326-20-50-13

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-K (SK)
-Number 229
-Section 1405
-Paragraph c
-Publisher SEC

+ Details

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

- Definition

Amortized cost excluding accrued interest, of financing receivable modified during period for debtor experiencing financial difficulty.

+ References

+ Details

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

- Definition

Percentage of financing receivable modified during period for debtor experiencing financial difficulty to total financing receivables.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 42
-Subparagraph (a)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481962/310-10-50-42

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 12A
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481933/310-10-55-12A

+ Details

Name:	us-gaap_FinancingReceivableModificationToTotalFinancingReceivablesPercent
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of commitment to lend additional funds to debtor experiencing financial difficulty for which creditor has modified terms of financing receivable.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 36
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481962/310-10-50-36

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-SubTopic 40
-Topic 310
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481746/310-40-50-1

+ Details

Name:	us-gaap_LoansAndLeasesReceivableImpairedCommitmentToLend
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Recorded investment of consumer mortgage loan receivables secured by residential real estate properties for which formal foreclosure proceedings are in process.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 35
-SubTopic 10
-Topic 310
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481962/310-10-50-35

+ Details

Name:	us-gaap_MortgageLoansInProcessOfForeclosureAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ResidentialPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ConsumerPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_HomeEquityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Credit Quality and the Allowance for Loan and Lease Losses - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Financing Receivable, Allowance for Credit Losses
Mortgage loans in process of foreclosure amount	$ 108		$ 107
Financing receivable, excluding accrued interest, modified in period, amount	$ 207	$ 202
Loan modification program, percentage of modifications to total portfolio	0.18%	0.16%
Loan modification program, loans excluded from modification program	$ 8	$ 13
Unfunded commitment amounts	107		$ 130
Commercial
Financing Receivable, Allowance for Credit Losses
Financing receivable, excluding accrued interest, modified in period, amount	$ 170	$ 163
Loan modification program, percentage of modifications to total portfolio	0.24%	0.21%
Commercial \| Minimum
Financing Receivable, Allowance for Credit Losses
Term extension period	3 months
Commercial \| Maximum
Financing Receivable, Allowance for Credit Losses
Term extension period	12 months
Residential Mortgage
Financing Receivable, Allowance for Credit Losses
Financing receivable, excluding accrued interest, modified in period, amount	$ 26	$ 24
Loan modification program, percentage of modifications to total portfolio	0.15%	0.14%
Modification program option, mortgage term	480 months
Modification program option, in-process modifications	$ 1	$ 18
Residential Mortgage \| Minimum
Financing Receivable, Allowance for Credit Losses
Modification program option, trial period	3 months
Modification program option, mortgage interest payment deferral, term	6 months
Residential Mortgage \| Maximum
Financing Receivable, Allowance for Credit Losses
Modification program option, trial period	4 months
Modification program option, mortgage interest payment deferral, term	12 months
Consumer
Financing Receivable, Allowance for Credit Losses
Financing receivable, excluding accrued interest, modified in period, amount	$ 11	$ 15
Loan modification program, percentage of modifications to total portfolio	0.04%	0.05%
Consumer \| Home equity
Financing Receivable, Allowance for Credit Losses
Financing receivable, excluding accrued interest, modified in period, amount	$ 3	$ 4
Loan modification program, percentage of modifications to total portfolio	0.08%	0.10%
Modification program option, mortgage term	360 months