Variable Interest Entities - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Variable Interest Entity
Carry Value Of Loans Leases Or Lines Of Credit Securitized	$ 509
Variable Interest Entity, Primary Beneficiary | Fifth Third Community Development Corporation Investments
Variable Interest Entity
Maximum Exposure	19		18
Variable Interest Entity, Not Primary Beneficiary | Loans Receivable
Variable Interest Entity
Unfunded commitment amounts	1,500		843
Variable Interest Entity, Not Primary Beneficiary | Automobile Loan
Variable Interest Entity
Carry Value Of Loans Leases Or Lines Of Credit Securitized	509
Number of seperate transactions in which the Bancorp previously sold loans to an isolated trust and conduits	1
Variable Interest Entity, Not Primary Beneficiary | Fifth Third Community Development Corporation Investments
Variable Interest Entity
Maximum Exposure	1,389		1,442
Variable Interest Entity, Not Primary Beneficiary | Private Equity Funds
Variable Interest Entity
Maximum Exposure	305		310
Unfunded commitment amounts	114		121
Capital Contribution To Private Equity Funds	3	11
Variable Interest Entity, Not Primary Beneficiary | Restructured Loans
Variable Interest Entity
Maximum Exposure	$ 2		$ 2