Assets and Liabilities Related to Non-consolidated VIEs and Maximum Exposure to Losses (Detail) (USD $) In Millions, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011	Jun. 30, 2011
Variable Interest Entity [Line Items]
Total Assets	$ 117,543	$ 116,967	$ 110,805
Total Liabilities	103,719	103,716	98,204
Variable Interest Entity, Not Primary Beneficiary | Fifth Third Community Development Corporation Investments [Member]
Variable Interest Entity [Line Items]
Total Assets	1,306	1,243	1,282
Total Liabilities	300	269	282
Maximum Exposure	1,306	1,243	1,282
Variable Interest Entity, Not Primary Beneficiary | Private Equity Funds
Variable Interest Entity [Line Items]
Total Assets	173	161	114
Total Liabilities		3	2
Maximum Exposure	321	327	298
Variable Interest Entity, Not Primary Beneficiary | Money Market Funds
Variable Interest Entity [Line Items]
Total Assets	59	53	59
Maximum Exposure	65	62	66
Variable Interest Entity, Not Primary Beneficiary | Loans Receivable
Variable Interest Entity [Line Items]
Total Assets	1,625	1,370	1,236
Maximum Exposure	2,675	2,203	2,010
Variable Interest Entity, Not Primary Beneficiary | Restructured Loans [Member]
Variable Interest Entity [Line Items]
Total Assets	8	10	12
Maximum Exposure	$ 9	$ 12	$ 14