Assets and Liabilities Measured at Fair Value on a Recurring Basis (Parenthetical) (Detail) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Abstract]
Federal Home Loan Bank Stock	$ 248	$ 248
Federal Reserve Bank Stock	355	$ 352
DTCC Stock	$ 1

Represents an equity interest in Depository Trust Clearing Corporation. It does not have a readily determinable fair value because its ownership is restricted and it lacks a market (liquidity).

No definition available.

+ Details

Name:	fitb_DepositoryTrustClearingCorporationStock
Namespace Prefix:	fitb_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

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Data Type:	xbrli:stringItemType
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- Definition

Federal Home Loan Bank (FHLB) stock represents an equity interest in a FHLB. It does not have a readily determinable fair value because its ownership is restricted and it lacks a market (liquidity).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 325
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6478792&loc=d3e63345-112809

+ Details

Name:	us-gaap_FederalHomeLoanBankStock
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Federal Reserve Bank stock represents an equity interest in the Federal Reserve Bank. It does not have a readily determinable fair value because its ownership is restricted and it lacks a market (liquidity).

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant