The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(i)-(ii)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Weighted average remaining contractual term for equity-based awards excluding options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (e)(1)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsOutstandingWeightedAverageRemainingContractualTerms
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
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

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

- Details

Name:	us-gaap_AwardTypeAxis=us-gaap_RestrictedStockUnitsRSUMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	fitb_GrantPriceRangeAxis=fitb_Range1015Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	fitb_GrantPriceRangeAxis=fitb_Range1520Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	fitb_GrantPriceRangeAxis=fitb_Range2025Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	fitb_GrantPriceRangeAxis=fitb_Range2530Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Stock-Based Compensation (Unvested RSUs by Grant-Date Fair Value) (Detail) - Restricted Stock Units - shares shares in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award
Number of Shares/Units Outstanding at Year End	5,086	371	0
Weighted-Average Remaining Contractual Life (in years)	1 year 8 months 12 days
$10.01-$15.00
Share-based Compensation Arrangement by Share-based Payment Award
Number of Shares/Units Outstanding at Year End	638
Weighted-Average Remaining Contractual Life (in years)	1 year 1 month 6 days
$15.01-$20.00
Share-based Compensation Arrangement by Share-based Payment Award
Number of Shares/Units Outstanding at Year End	4,265
Weighted-Average Remaining Contractual Life (in years)	1 year 9 months 18 days
$20.01-$25.00
Share-based Compensation Arrangement by Share-based Payment Award
Number of Shares/Units Outstanding at Year End	159
Weighted-Average Remaining Contractual Life (in years)	2 years
$25.01-$30.00
Share-based Compensation Arrangement by Share-based Payment Award
Number of Shares/Units Outstanding at Year End	24
Weighted-Average Remaining Contractual Life (in years)	2 years 1 month 6 days