Variable Interest Entities - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended			12 Months Ended						3 Months Ended			12 Months Ended
	Mar. 31, 2013	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013 Variable Interest Entity, Primary Beneficiary Automobile Loan	Mar. 31, 2013 Variable Interest Entity, Primary Beneficiary Automobile Loan	Dec. 31, 2013 Variable Interest Entity, Primary Beneficiary Fifth Third Community Development Corporation Investments [Member]	Dec. 31, 2012 Variable Interest Entity, Primary Beneficiary Fifth Third Community Development Corporation Investments [Member]	Dec. 31, 2013 Variable Interest Entity, Not Primary Beneficiary Loans Receivable	Dec. 31, 2012 Variable Interest Entity, Not Primary Beneficiary Loans Receivable	Mar. 31, 2013 Variable Interest Entity, Not Primary Beneficiary Automobile Loan	Dec. 31, 2013 Variable Interest Entity, Not Primary Beneficiary Fifth Third Community Development Corporation Investments [Member]	Dec. 31, 2012 Variable Interest Entity, Not Primary Beneficiary Fifth Third Community Development Corporation Investments [Member]	Dec. 31, 2013 Variable Interest Entity, Not Primary Beneficiary Private Equity Funds	Dec. 31, 2012 Variable Interest Entity, Not Primary Beneficiary Private Equity Funds	Dec. 31, 2013 Variable Interest Entity, Not Primary Beneficiary Restructured Loans	Dec. 31, 2012 Variable Interest Entity, Not Primary Beneficiary Restructured Loans
Variable Interest Entity [Line Items]
Carry Value Of Loans Leases Or Lines Of Credit Securitized	$ 509			$ 1,300						$ 509
Number of seperate transactions in which the Bancorp previously sold loans to an isolated trust and conduits					1
Maximum Exposure						21	18				1,436	1,442	294	310	1	2
Equity investments, carrying value		423	563
Unfunded commitment amounts								962	843				90	121
Capital Contribution To Private Equity Funds													$ 31	$ 61