VIE (Variable Interest Entities - Additional Information) (Detail) - Variable Interest Entity, Not Primary Beneficiary - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Loans Provided to VIEs
Variable Interest Entity
Unfunded commitment amounts	$ 1,300		$ 1,300
Fifth Third Community Development Corporation Investments
Variable Interest Entity
Maximum Exposure	1,202		1,198
Total Assets	1,202		1,198
Fifth Third Community Development Corporation Investments \| Qualified Affordable Housing Tax Credits
Variable Interest Entity
Total Assets	1,100		1,100
Unfunded commitments in qualifying LIHTC investments	$ 384		374
Unfunded commitments in qualifying LIHTC investments expected funding date	2034
Private Equity Funds
Variable Interest Entity
Maximum Exposure	$ 165		73
Total Assets	86		41
Unfunded commitment amounts	79		$ 32
Capital Contribution To Private Equity Investments	1	$ 3
OTTI	$ 0	$ 4

Capital contributions to private equity funds.

No definition available.

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Balance Type:	debit
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- Definition

OTTI

+ References

No definition available.

+ Details

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Period Type:	duration

- Definition

Year in which contingent commitments to qualified affordable housing project investments are expected to be paid, in CCYY format.

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Reflects the unfunded portion of contractual agreements to lend funds to borrowers for loans whose terms have been modified by troubled debt restructuring.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 40
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=82895541&loc=d3e18794-111554

+ Details

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

- Definition

Amount of commitment or contingent commitments to qualified affordable housing project investments.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 740
-Section 50
-Paragraph 2
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=114775393&loc=SL49122993-202985

+ Details

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

- Definition

The reporting entity's maximum amount of exposure to loss as a result of its involvement with the Variable Interest Entity (VIE).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=108788376&loc=d3e5747-111685

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph b
-URI http://asc.fasb.org/extlink&oid=108788376&loc=d3e5728-111685

+ Details

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Balance Type:	credit
Period Type:	instant

- 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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Balance Type:	na
Period Type:	duration

- Definition

Carrying amount of the assets in the reporting entity's statement of financial position that relate to the reporting entity's variable interest in the Variable Interest Entity (VIE), where the reporting entity is not the VIE's primary beneficiary.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph a
-URI http://asc.fasb.org/extlink&oid=108788376&loc=d3e5728-111685

+ Details

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- Details

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- Details

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- Details

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Namespace Prefix:
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- Details

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