Variable Interest Entities - Additional Information (Detail) (USD $)										12 Months Ended									3 Months Ended		9 Months Ended
	Sep. 30, 2011		Dec. 31, 2010		Sep. 30, 2010		Sep. 30, 2011 Variable Interest Entity, Primary Beneficiary	Dec. 31, 2010 Variable Interest Entity, Primary Beneficiary	Sep. 30, 2010 Variable Interest Entity, Primary Beneficiary	Dec. 31, 2010 Variable Interest Entity, Primary Beneficiary Home Equity	Dec. 31, 2008 Variable Interest Entity, Primary Beneficiary Automobile Loan	Sep. 30, 2011 Variable Interest Entity, Primary Beneficiary Automobile Loan	Dec. 31, 2010 Variable Interest Entity, Primary Beneficiary Automobile Loan	Sep. 30, 2010 Variable Interest Entity, Primary Beneficiary Automobile Loan	Sep. 30, 2011 Variable Interest Entity, Primary Beneficiary Fifth Third Community Development Corporation Investments [Member]	Sep. 30, 2011 Fifth Third Community Development Corporation Investments [Member] Variable Interest Entity, Not Primary Beneficiary	Dec. 31, 2010 Fifth Third Community Development Corporation Investments [Member] Variable Interest Entity, Not Primary Beneficiary	Sep. 30, 2010 Fifth Third Community Development Corporation Investments [Member] Variable Interest Entity, Not Primary Beneficiary	Sep. 30, 2011 Variable Interest Entity, Not Primary Beneficiary Private Equity Funds	Sep. 30, 2010 Variable Interest Entity, Not Primary Beneficiary Private Equity Funds	Sep. 30, 2011 Variable Interest Entity, Not Primary Beneficiary Private Equity Funds	Sep. 30, 2010 Variable Interest Entity, Not Primary Beneficiary Private Equity Funds	Dec. 31, 2010 Variable Interest Entity, Not Primary Beneficiary Private Equity Funds	Sep. 30, 2011 Variable Interest Entity, Not Primary Beneficiary Restructured Loans	Dec. 31, 2010 Variable Interest Entity, Not Primary Beneficiary Restructured Loans	Sep. 30, 2010 Variable Interest Entity, Not Primary Beneficiary Restructured Loans	Dec. 31, 2010 Variable Interest Entity, Not Primary Beneficiary Money Market Funds Upper Limit	Sep. 30, 2011 Variable Interest Entity, Not Primary Beneficiary Loans Receivable	Dec. 31, 2010 Variable Interest Entity, Not Primary Beneficiary Loans Receivable	Sep. 30, 2010 Variable Interest Entity, Not Primary Beneficiary Loans Receivable
Variable Interest Entity [Line Items]
Carry Value Of Loans Leases Or Lines Of Credit Securitized										$ 903,000,000,000	$ 2,700,000,000
Number of seperate transactions in which the Bancorp previously sold loans to an isolated trust and conduits													3
Maximum Exposure															8,000,000	1,270,000,000	1,241,000,000	1,140,000,000	295,000,000	293,000,000	295,000,000	293,000,000	322,000,000	13,000,000	13,000,000	27,000,000
Equity investments, fair value																								0
Unfunded commitment amounts																			178,000,000	176,000,000	178,000,000	176,000,000	193,000,000	2,000,000	1,000,000	1,000,000		781,000,000	733,000,000	549,000,000
Capital Contribution To Private Equity Funds																			14,000,000	3,000,000	29,000,000	22,000,000
Credit support	$ 2,028,000,000	[1]	$ 1,515,000,000	[1]	$ 3,271,000,000	[1]	$ 7,000,000	$ 7,000,000	$ 7,000,000			$ 7,000,000	$ 7,000,000	$ 7,000,000													$ 1,000,000

[1] Includes $35, $52, and $56 of cash, $7, $7 and $7 of other short-term investments, $29, $29 and $29 of commercial mortgage loans, $228, $241 and $248 of home equity loans, $334, $648 and $771 of automobile loans, ($10), ($14) and ($15) of ALLL, $3, $7 and $7 of other assets, $5, $12 and $17 of other liabilities and $270, $692 and $834 of long-term debt from consolidated VIEs that are included in their respective captions above at September 30, 2011, December 31, 2010 and September 30, 2010, respectively. See Note 9.