Sales of Receivables and Servicing Rights - Servicing Rights and Residual Interests Economic Assumptions (Details)	3 Months Ended
Mar. 31, 2023	Mar. 31, 2022
Fixed-rate
Schedule of Servicing Assets at Amortized Value
Weighted- Average Life (in years)	6 years 8 months 12 days	7 years 3 months 18 days
Prepayment Speed (annual) (as a percent)	12.40%	8.10%
OAS (bps)	621	729
Adjustable-rate
Schedule of Servicing Assets at Amortized Value
Weighted- Average Life (in years)	3 years	2 years 9 months 18 days
Prepayment Speed (annual) (as a percent)	27.90%	27.70%
OAS (bps)	774	798

Option adjusted spread basis points.

No definition available.

Name:	fitb_OptionAdjustedSpreadBasisPoints
Namespace Prefix:	fitb_
Data Type:	xbrli:integerItemType
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/2003/role/disclosureRef
-Topic 860
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481326/860-20-50-4

+ Details

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

- Definition

Weighted average life of securitized assets regardless of when the transfer occurred, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 860
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (b)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481326/860-20-50-4

+ Details

Name:	us-gaap_AssumptionForFairValueOfAssetsOrLiabilitiesThatRelateToTransferorsContinuingInvolvementWeightedAverageLife1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Estimated rate of prepayment of principal on financial assets regardless of when the transfer occurred.

+ References

+ Details

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

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_FixedRateResidentialMortgageMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_AdjustableRateResidentialMortgageMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: