Changes in the Servicing Assets (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Servicing Assets at Fair Value [Line Items]
Carrying amount before valuation allowance as of the beginning of the period	$ 1,392fitb_MortgageServicingRights	$ 1,440fitb_MortgageServicingRights
Servicing rights that result from the transfer of residential mortgage or automobile loans	13	23
Amortization	(34)	(23)
Carrying amount before valuation allowance	1,371fitb_MortgageServicingRights	1,440fitb_MortgageServicingRights
Valuation allowance for servicing assets:
Beginning balance	(534)	(469)
(Provision for) recovery of MSR impairment	(48)	4
Ending balance	(582)	(465)
Carrying amount as of the end of the period	$ 789	$ 975

Carry amount of MSRs before valuation allowance.

No definition available.

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- Definition

Amount of additions from purchases, assumption or transfer to contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer.

+ References

+ Details

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- Definition

Amount of amortization of contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer.

+ References

+ Details

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- Definition

Fair value of contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 860

-SubTopic 50

-Section 50

-Paragraph 4

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=7882072&loc=d3e122739-111746

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=7516967&loc=d3e66267-113978

+ Details

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- Definition

Reflects the estimated amount of impairment as of the balance sheet date of recognized servicing assets that are being amortized in proportion to and over the period of estimated net servicing income or loss.

+ References

+ Details

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- Definition

New provisions recoveries or charged against this account which increase or reduce the net value of servicing assets.

+ References

+ Details

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