Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2018	Oct. 31, 2018
Document Entity Information
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q3
Trading Symbol	FITB
Entity Registrant Name	FIFTH THIRD BANCORP
Entity Central Index Key	0000035527
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		655,615,619
Entity Current Reporting Status	Yes
Entity Small Business	false
EntityEmergingGrowthCompany	false