Loans and Leases - Additional Information (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable
Unamortized premiums and discounts, deferred loan fees and costs, and fair value adjustments	$ 125,000,000	$ 111,000,000
Unearned Income	680,000,000	700,000,000
Loans pledged at the FHLB	10,600,000,000	10,900,000,000
Loans pledged at the FRB	$ 34,100,000,000	$ 33,500,000,000

Describes the collateral pledged in support of Federal Home Loan Bank advances outstanding as of the Balance Sheet date.

No definition available.

+ Details

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Period Type:	instant

- Definition

Describes the collateral pledged in support of Federal Reserve Bank advances outstanding as of the Balance Sheet date.

+ References

No definition available.

+ Details

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Namespace Prefix:	fitb_
Data Type:	xbrli:monetaryItemType
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- Details

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Period Type:	duration

- Definition

Total carrying amount as of the balance sheet date of unearned revenue or income, not otherwise specified in the taxonomy, which is expected to be taken into income in future periods and obligations not separately disclosed in the balance sheet (other liabilities).

+ References

No definition available.

+ Details

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

- Definition

Amount of deferred fees paid by borrowers and unamortized costs incurred to originate loans and leases, unamortized loan commitments and loan syndication fees, and premiums over or discounts from face amounts of loans that are being amortized into income as an adjustment to yield. Excludes amounts for loans and leases covered under loss sharing agreements.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 20

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6378536&loc=d3e10092-111533

+ Details

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