Assets and Liabilities Related to Non-consolidated VIEs and Maximum Exposure to Losses (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012
Variable Interest Entity
Total Assets	$ 121,382	$ 121,894	$ 116,747
Total Liabilities	107,462	108,130
Variable Interest Entity, Not Primary Beneficiary | Fifth Third Community Development Corporation Investments
Variable Interest Entity
Total Assets	1,389	1,442
Total Liabilities	399	394
Maximum Exposure	1,389	1,442
Variable Interest Entity, Not Primary Beneficiary | Private Equity Funds
Variable Interest Entity
Total Assets	191	189
Maximum Exposure	305	310
Variable Interest Entity, Not Primary Beneficiary | Loans Receivable
Variable Interest Entity
Total Assets	1,671	1,622
Maximum Exposure	3,141	2,465
Variable Interest Entity, Not Primary Beneficiary | Automobile Loan Securitizations
Variable Interest Entity
Total Assets	6
Maximum Exposure	6
Variable Interest Entity, Not Primary Beneficiary | Restructured Loans
Variable Interest Entity
Total Assets	2	2
Maximum Exposure	$ 2	$ 2