Variable Interest Entities - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended						3 Months Ended			3 Months Ended		9 Months Ended
	Mar. 31, 2013	Sep. 30, 2013 Variable Interest Entity, Primary Beneficiary Automobile Loan	Sep. 30, 2013 Variable Interest Entity, Primary Beneficiary Fifth Third Community Development Corporation Investments	Dec. 31, 2012 Variable Interest Entity, Primary Beneficiary Fifth Third Community Development Corporation Investments	Sep. 30, 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	Sep. 30, 2013 Variable Interest Entity, Not Primary Beneficiary Fifth Third Community Development Corporation Investments	Dec. 31, 2012 Variable Interest Entity, Not Primary Beneficiary Fifth Third Community Development Corporation Investments	Sep. 30, 2013 Variable Interest Entity, Not Primary Beneficiary Private Equity Funds	Sep. 30, 2012 Variable Interest Entity, Not Primary Beneficiary Private Equity Funds	Sep. 30, 2013 Variable Interest Entity, Not Primary Beneficiary Private Equity Funds	Sep. 30, 2012 Variable Interest Entity, Not Primary Beneficiary Private Equity Funds	Dec. 31, 2012 Variable Interest Entity, Not Primary Beneficiary Private Equity Funds	Sep. 30, 2013 Variable Interest Entity, Not Primary Beneficiary Restructured Loans	Dec. 31, 2012 Variable Interest Entity, Not Primary Beneficiary Restructured Loans
Variable Interest Entity
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			20	18				1,420	1,442	303		303		310	1	2
Unfunded commitment amounts					1,900	843				96		96		121
Capital Contribution To Private Equity Funds										$ 11	$ 11	$ 25	$ 35