Bank Premises and Equipment - Additional Information (Detail) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2015 USD ($)	Jun. 30, 2014 USD ($)	Jun. 30, 2014 USD ($)
Bank Premises And Equipment [Line Items]
Bank premises impairment	$ 98	$ 18	$ 18
Disposal Group Classified As Held For Sale [Member]
Bank Premises And Equipment [Line Items]
Operating Branch Locations	105
Parcels Of Undeveloped Land	31

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

No definition available.

+ Details

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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

The aggregate amount of write-downs for impairments recognized during the period for long-lived assets held for abandonment, exchange or sale.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 360

-SubTopic 10

-Section 45

-Paragraph 15

-URI http://asc.fasb.org/extlink&oid=8077374&loc=d3e2611-110228

Reference 2: 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

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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

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- Details

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Namespace Prefix:
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