Commitments, Contingent Liabilities and Guarantees - Additional Information (Detail) (USD $) Share data in Millions, unless otherwise specified																	3 Months Ended					3 Months Ended						12 Months Ended				12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2012 Residential Mortgage [Member]	Dec. 31, 2011 Residential Mortgage [Member]	Dec. 31, 2012 Standby Letters of Credit	Dec. 31, 2011 Standby Letters of Credit	Dec. 31, 2012 Standby Letters of Credit Secured Debt	Dec. 31, 2011 Standby Letters of Credit Secured Debt	Dec. 31, 2012 Variable Rate Demand Note [Member]	Dec. 31, 2011 Variable Rate Demand Note [Member]	Dec. 31, 2012 Other Liabilities Commitments to Extend Credit [Member]	Dec. 31, 2011 Other Liabilities Commitments to Extend Credit [Member]	Dec. 31, 2012 Private Mortgage Reinsurance	Jun. 30, 2011 Private Mortgage Reinsurance	Dec. 31, 2011 Private Mortgage Reinsurance	Dec. 31, 2012 Private Mortgage Reinsurance Minimum [Member]	Dec. 31, 2012 Private Mortgage Reinsurance Upper Limit	Sep. 30, 2012 Visa Litigation	Mar. 31, 2012 Visa Litigation	Dec. 31, 2011 Visa Litigation	Jun. 30, 2011 Visa Litigation	Dec. 31, 2010 Visa Litigation	Jun. 30, 2010 Visa Litigation	Dec. 31, 2009 Visa Litigation	Dec. 31, 2012 Visa Litigation	Dec. 31, 2008 Visa Litigation	Dec. 31, 2007 Visa Litigation	Dec. 31, 2009 Visa	Dec. 31, 2008 Visa
Commitments and Contingencies Disclosure [Line Items]
Reserve for unfunded commitments									$ 4,000,000	$ 5,000,000					$ 179,000,000	$ 181,000,000
Percentage of the total standby letters of credit									99.00%	98.00%	49.00%	54.00%
Fifth Third Securities, Inc. (FTS) acted as the remarketing agent to issuers of VRDNs													2,500,000,000	2,900,000,000
Letters of credit	4,281,000,000		4,744,000,000										345,000,000	440,000,000
Total outstanding reinsurance coverage																	58,000,000		77,000,000
Approximate reserve related to exposures within the reinsurance portfolio																	18,000,000		27,000,000
Margin account balance held by the brokerage clearing agent	17,000,000		14,000,000
Fully and unconditionally guaranteed certain long-term borrowing obligations issued by wholly-owned issuing trust entities	800,000,000		2,200,000,000
Reinsurance coverage ranges of the total PMI coverage																				5.00%	10.00%
Collateral Release Amount																		5,000,000
Increase (decrease) to the Bancorp's reserve liability																	2,000,000	11,000,000						54,000,000
Increase Decrease In Maximum Exposure To Loss																	3,000,000	27,000,000
Outstanding balances on residential mortgage loans sold with representation and warranty provisions							110,000,000	55,000,000
Outstanding balances on residential mortgage loans sold with credit recourse							662,000,000	772,000,000
Delinquency Rates							5.90%	6.70%
Credit loss reserve	1,854,000,000	[1]	2,255,000,000	[1]	3,004,000,000	3,749,000,000	20,000,000	17,000,000
Recognized liability equal to the fair value of the indemnification obligation																								49,000,000							3,000,000
Recorded share of litigation formally settled by Visa and for probable future litigation settlements																								78,000,000				29,000,000	33,000,000	71,000,000	169,000,000
Visa IPO, shares of Visa's Class B common stock received																																	10.1
Received Class B common shares, carryover basis																														3,000,000,000			0
Sale of the Class B shares, recognition of the derivative liability and reversal of the net litigation reserve liability resulted in a pre-tax benefit																												288,000,000
Sale of the Class B shares, recognition of the derivative liability and reversal of the net litigation reserve liability resulted in an after-tax benefit																												187,000,000
Free-standing derivative liability initial fair value with reversal of net Visa litigation reserve																												55,000,000
Visa deposited into the litigation escrow account																						150,000,000		1,565,000,000	400,000,000	800,000,000	500,000,000	700,000,000
Reduction of liability in cash to the swap counterparty																						6,000,000	75,000,000		19,000,000	35,000,000	20,000,000
Cash Proceeds Sale Of Stock																																300,000,000
Maximum Reasonably Possible Loss Related To Mortgage Representation And Warranty Provisions In Excess Of Reserve	$ 83,000,000

[1] At December 31, 2012 and 2011, includes $0 and $30 of cash, $0 and $7 of other short-term investments, $50 and $50 of commercial mortgage loans, $0 and $223 of home equity loans, $0 and $259 of automobile loans, ($5) and ($10) of ALLL, $3 and $4 of other assets, $0 and $4 of other liabilities, $0 and $191 of long-term debt from consolidated VIEs that are included in their respective captions. See Note 10.