Document and Entity Information (USD $)	12 Months Ended
	Dec. 31, 2011	Jun. 30, 2011
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2011
Document Fiscal Year Focus	2011
Document Fiscal Period Focus	FY
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	919,818,137
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	No
Entity Public Float		$ 11,727,681,247