Equity Method Investment, Ownership Percentage Sold

No definition available.

Name:	fitb_EquityMethodInvestmentOwnershipPercentageSold
Namespace Prefix:	fitb_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Option to purchase additiona Non-voting units of Vantiv Holding, LLC

+ References

No definition available.

+ Details

Name:	fitb_IncrementalUnitPurchaseOption
Namespace Prefix:	fitb_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Valuation adjustments for loans held for sale and portfolio loans.

+ References

No definition available.

+ Details

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

- Definition

Nonrecurring losses included as charge-offs on loans transferred to OREO

+ References

No definition available.

+ Details

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

- Definition

Amount of operating branches management plans to sell or consolidate as a result of the Branch Consolidation and Sales Plan.

+ References

No definition available.

+ Details

Name:	fitb_OperatingBranchLocations
Namespace Prefix:	fitb_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of parcels of land management plans to sell as a result of the Branch Consolidation and Sales Plan. Represents parcels of undeveloped land that had been acquired for for future branch expansion.

+ References

No definition available.

+ Details

Name:	fitb_ParcelsOfUndevelopedLand
Namespace Prefix:	fitb_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Sensitivity Analysis of Decrease in Fair Value of Derivatives, Impact of 50 Basis Point Increase in the Interest Rate

+ References

No definition available.

+ Details

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

- Definition

Sensitivity Analysis of Decrease in Fair Value of Derivatives, Impact of 25 Basis Point Increase in the Interest Rate

+ References

No definition available.

+ Details

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

- Definition

Sensitivity Analysis of Increase in Fair Value of Derivatives, Impact of 50 Basis Point Decrease in the Interest Rate

+ References

No definition available.

+ Details

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

- Definition

Sensitivity Analysis of Increase in Fair Value of Derivatives, Impact of 10% Changes in the Assumed Loan Closing Rates

+ References

No definition available.

+ Details

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

- Definition

Sensitivity Analysis of Increase in Fair Value of Derivatives, Impact of 20% Changes in the Assumed Loan Closing Rates

+ References

No definition available.

+ Details

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

- Definition

Sensitivity Analysis of Increase in Fair Value of Derivatives, Impact of 25 Basis Point Decrease in the Interest Rate

+ References

No definition available.

+ Details

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

- Definition

Amount of addition (reduction) to the amount at which an asset could be incurred (settled) in a current transaction between willing parties.

+ References

No definition available.

+ Details

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

- Definition

Exercise price per share or per unit of warrants or rights outstanding.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.4-08.(i)(4))

-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

+ Details

Name:	us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Fair values as of the balance sheet date of the net amount of all assets and liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 45

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958

+ Details

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

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

- Definition

For each line item in the statement of financial position, the amounts of gains and losses from fair value changes included in earnings.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 30

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6957238&loc=d3e14172-108612

+ Details

Name:	us-gaap_FairValueOptionChangesInFairValueGainLoss1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

This item represents the estimated amount of gains or losses included in earnings during the period attributable to changes in instrument-specific credit risk arising from loans and other receivables held as assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 30

-Subparagraph (c)(1)

-URI http://asc.fasb.org/extlink&oid=6957238&loc=d3e14172-108612

+ Details

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

- Definition

The net gain (loss) resulting from a sale of loans, including adjustments to record loans classified as held-for-sale at the lower-of-cost-or-market and fair value adjustments to loan held for investment purposes.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 225

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-04.3(a))

-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 225

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-04.13(h))

-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

+ Details

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

- Definition

Fair value portion of loans held-for-sale including, but not limited to, mortgage loans and finance receivables.

+ References

No definition available.

+ Details

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

- Definition

The hypothetical financial impact of a 10 percent adverse change of the specified assumption on the fair value of transferor's interests in transferred financial assets (including any servicing assets or servicing liabilities) as of the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 860

-SubTopic 20

-Section 50

-Paragraph 4

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=13989330&loc=d3e107314-111719

+ Details

Name:	us-gaap_SensitivityAnalysisOfFairValueOfInterestsContinuedToBeHeldByTransferorServicingAssetsOrLiabilitiesImpactOf10PercentAdverseChangeInOtherAssumption
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The hypothetical financial impact of a 20 percent adverse change of the specified assumption on the fair value of transferor's interests in transferred financial assets (including any servicing assets or servicing liabilities) as of the balance sheet date.

+ References

+ Details

Name:	us-gaap_SensitivityAnalysisOfFairValueOfInterestsContinuedToBeHeldByTransferorServicingAssetsOrLiabilitiesImpactOf20PercentAdverseChangeInOtherAssumption
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Value of loans held-for-sale transferred to loans held in the entity's portfolio in noncash transactions.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 50

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4313-108586

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 50

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4304-108586

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 50

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4332-108586

+ Details

Name:	us-gaap_TransferOfLoansHeldForSaleToPortfolioLoans1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Value of loans and leases held in the entity's portfolio transferred to loans and leases held-for-sale in noncash transactions.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 50

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4304-108586

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 50

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4332-108586

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 50

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4313-108586

+ Details

Name:	us-gaap_TransferOfPortfolioLoansAndLeasesToHeldForSale1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=fitb_DisposalGroupClassifiedAsHeldForSaleMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

Name:	us-gaap_FairValueByMeasurementFrequencyAxis=fitb_OtherRealEstateOwnedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByMeasurementFrequencyAxis=fitb_CommercialLoansHeldForSaleMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByMeasurementFrequencyAxis=fitb_NewCommercialLoansHeldForSaleMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByMeasurementFrequencyAxis=fitb_ResidentialMortgagelLoansHeldForSaleMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByMeasurementFrequencyAxis=fitb_AutomobilelLoansHeldForSaleMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Fair Value Measurements - Additional Information (Detail) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended			6 Months Ended		12 Months Ended
	Jun. 30, 2015 USD ($) $ / shares shares	Mar. 31, 2015 USD ($)	Jun. 30, 2014 USD ($)	Jun. 30, 2015 USD ($) $ / shares shares	Jun. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)	Jun. 30, 2009
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Portfolio loans to loans held for sale				$ 369	$ 96
Existing loans held for sale, further adjusted	$ 628			628		$ 561
Residential loans transferred to the Bancorp's portfolio				$ 139	13
Fair value changes included in earnings for instruments for which the fair value option was elected	$ 18
Incremental Unit Purchase Option \| shares	20			20
Vantiv Holding, LLC Warrant Exercise Price \| $ / shares	$ 15.98			$ 15.98
Percentage of Vantiv Holding, LLC sold to Advent for cash and warrants							51.00%
Disposal Group Classified As Held For Sale [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Operating Branch Locations	105			105
Parcels Of Undeveloped Land	31			31
Residential Mortgage Loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Residential loans transferred to the Bancorp's portfolio		$ 55
Fair value adjustment		$ 1
The fair value of loans				$ 2		$ 2
Interest Rate Lock Commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net fair value of the interest rate lock commitments	$ 13			13
Change in the fair value of the interest rate lock commitments, due to decrease in current interest rates of 25 bp	8			8
Change in the fair value of the interest rate lock commitments, due to decrease in current interest rates of 50 bp	15			15
Change in the fair value of the interest rate lock commitments, due to increase in current interest rates of 25 bp	8			8
Change in the fair value of the interest rate lock commitments, due to increase in current interest rates of 50 bp	17			17
Change in fair value of interest rate lock commitments, due to 10% adverse changes in the assumed loan closing rates	1			1
Change in fair value of interest rate lock commitments, due to 20% adverse changes in the assumed loan closing rates	3			3
Change in fair value of interest rate lock commitments, due to 10% favorable changes in the assumed loan closing rates	1			1
Change in fair value of interest rate lock commitments, due to 20% favorable changes in the assumed loan closing rates	3			3
Other Real Estate Owned
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net impact related to fair value adjustments	2		$ 3	5	13
Nonrecurring Losses Included As Charge-Offs	3		3	8	6
Commercial Loans Held For Sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net impact related to fair value adjustments			1	1	1
Gain Loss On Sales Of Loans Net				5	1
Commercial Loans HFS transferred from portfolio in the current quarter
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Portfolio loans to loans held for sale	26		$ 1	26	1
Net impact related to fair value adjustments	1			1	$ 1
Residential Mortgagel Loans Held For Sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Portfolio loans to loans held for sale	233
Net impact related to fair value adjustments	2			$ 2
Automobile Loans Held For Sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Portfolio loans to loans held for sale	$ 5