Assets and Liabilities Related to Non-consolidated VIEs and Maximum Exposure to Losses (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Variable Interest Entity [Line Items]
Total Assets	$ 116,967	$ 111,007	$ 113,380
Total Liabilities	103,716	96,927
Variable Interest Entity, Not Primary Beneficiary | Fifth Third Community Development Corporation Investments [Member]
Variable Interest Entity [Line Items]
Total Assets	1,243	1,241
Total Liabilities	269	286
Maximum Exposure	1,243	1,241
Variable Interest Entity, Not Primary Beneficiary | Private Equity Funds
Variable Interest Entity [Line Items]
Total Assets	161	129
Total Liabilities	3	3
Maximum Exposure	327	322
Variable Interest Entity, Not Primary Beneficiary | Money Market Funds
Variable Interest Entity [Line Items]
Total Assets	53	148
Maximum Exposure	62	158
Variable Interest Entity, Not Primary Beneficiary | Loans Receivable
Variable Interest Entity [Line Items]
Total Assets	1,370	1,175
Maximum Exposure	2,203	1,908
Variable Interest Entity, Not Primary Beneficiary | Restructured Loans [Member]
Variable Interest Entity [Line Items]
Total Assets	10	12
Maximum Exposure	$ 12	$ 13