Class settlement escrow deposit

No definition available.

Name:	fitb_ClassSettlementEscrow
Namespace Prefix:	fitb_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- Definition

Additional payment into escrow for plaintiffs not included in the class action suit

+ References

No definition available.

+ Details

Name:	fitb_NonClassActionEscrow
Namespace Prefix:	fitb_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of the funds paid into the class settlement escrow account have been returned to the control of the defendants through Class Exclusion Takedown Payments

+ References

No definition available.

+ Details

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

- Details

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

- Definition

Number of claims dismissed.

+ References

No definition available.

+ Details

Name:	us-gaap_LossContingencyClaimsDismissedNumber
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of plaintiffs that have filed claims pertaining to a loss contingency.

+ References

No definition available.

+ Details

Name:	us-gaap_LossContingencyNumberOfPlaintiffs
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The difference between the maximum amount of estimated loss and the amount recorded as of the balance sheet date.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 450

-SubTopic 20

-Section 05

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6395354&loc=d3e12631-108344

+ Details

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

- Details

Name:	us-gaap_LossContingenciesByNatureOfContingencyAxis=fitb_ExclusionClassSettlementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LossContingenciesByNatureOfContingencyAxis=fitb_FederalLawsuitsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LossContingenciesByNatureOfContingencyAxis=fitb_StateLawsuitsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Legal and Regulatory Proceedings - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended	3 Months Ended
	Dec. 31, 2008	Mar. 31, 2015	Dec. 31, 2012
Loss Contingencies
Number of alleging violations of ERISA that were dismissed	2
Percentage of funds returned to defendants		25.00%
Class Settlement Escrow			$ 46fitb_ClassSettlementEscrow
Non Class Action Escrow			4fitb_NonClassActionEscrow
Amount in excess of amounts reserved		61
Federal Lawsuits
Loss Contingencies
Number of merchants		460
State Lawsuits
Loss Contingencies
Number of merchants		1
Merchants requesting exclusion from class settlement
Loss Contingencies
Number of merchants		7,900