Credit Quality Additional Information (Detail) - USD ($) $ in Millions	Jun. 30, 2015	Jun. 30, 2014
Troubled Debt Restructuring
Line of credit commitments for modified troubled debt restructurings	$ 65	$ 63
Letter of credit commitments for modified troubled debt restructurings	26	$ 26
Mortgage Loans In Process Of Foreclosure Amount	$ 331

Recorded Investment of consumer mortgage loan receivables secured by residential real estate properties for which formal foreclosure proceedings are in process.

No definition available.

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