Assets and Liabilities Related to Non-consolidated VIEs and Maximum Exposure to Losses (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Variable Interest Entity [Line Items]
Total Assets	$ 138,706	$ 130,443	$ 121,894
Total Liabilities	123,041	115,817
Variable Interest Entity, Not Primary Beneficiary | Fifth Third Community Development Corporation Investments [Member]
Variable Interest Entity [Line Items]
Total Assets	1,432	1,436
Total Liabilities	364	407
Maximum Exposure	1,432	1,436
Variable Interest Entity, Not Primary Beneficiary | Private Equity Funds [Member]
Variable Interest Entity [Line Items]
Total Assets	189	204
Maximum Exposure	267	294
Variable Interest Entity, Not Primary Beneficiary | Loans Receivable
Variable Interest Entity [Line Items]
Total Assets	1,900	1,830
Maximum Exposure	2,759	2,792
Variable Interest Entity, Not Primary Beneficiary | Automobile Loan Securitizations
Variable Interest Entity [Line Items]
Total Assets	2	4
Maximum Exposure	2	4
Variable Interest Entity, Not Primary Beneficiary | Restructured Loans
Variable Interest Entity [Line Items]
Total Assets		1
Maximum Exposure		$ 1