Variable Interest Entities - Additional Information (Detail) (USD $) In Millions, unless otherwise specified			12 Months Ended							12 Months Ended			12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2011 Variable Interest Entity, Primary Beneficiary Home Equity	Dec. 31, 2009 Variable Interest Entity, Primary Beneficiary Automobile Loan	Dec. 31, 2011 Variable Interest Entity, Primary Beneficiary Automobile Loan	Dec. 31, 2012 Variable Interest Entity, Primary Beneficiary Fifth Third Community Development Corporation Investments [Member]	Dec. 31, 2011 Variable Interest Entity, Primary Beneficiary Fifth Third Community Development Corporation Investments [Member]	Dec. 31, 2012 Variable Interest Entity, Not Primary Beneficiary Loans Receivable	Dec. 31, 2011 Variable Interest Entity, Not Primary Beneficiary Loans Receivable	Dec. 31, 2010 Variable Interest Entity, Not Primary Beneficiary Money Market Funds Upper Limit	Dec. 31, 2012 Variable Interest Entity, Not Primary Beneficiary Fifth Third Community Development Corporation Investments [Member]	Dec. 31, 2011 Variable Interest Entity, Not Primary Beneficiary Fifth Third Community Development Corporation Investments [Member]	Dec. 31, 2012 Variable Interest Entity, Not Primary Beneficiary Private Equity Funds	Dec. 31, 2011 Variable Interest Entity, Not Primary Beneficiary Private Equity Funds	Dec. 31, 2012 Variable Interest Entity, Not Primary Beneficiary Restructured Loans	Dec. 31, 2011 Variable Interest Entity, Not Primary Beneficiary Restructured Loans
Variable Interest Entity [Line Items]
Carry Value Of Loans Leases Or Lines Of Credit Securitized			$ 903	$ 2,700
Number of seperate transactions in which the Bancorp previously sold loans to an isolated trust and conduits					3
Maximum Exposure						18	10				1,442	1,243	310	327	2	12
Equity investments, fair value															0
Equity investments, carrying value	563	576
Unfunded commitment amounts								843	833				121	166		2
Capital Contribution To Private Equity Funds													61	48
Credit support										$ 1