Commitments, Contingent Liabilities and Guarantees - Additional Information (Detail) (USD $) Share data in Millions, unless otherwise specified																											3 Months Ended				12 Months Ended							12 Months Ended
	Jun. 30, 2013		Mar. 31, 2013	Dec. 31, 2012		Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Jun. 30, 2013 Residential Mortgage	Mar. 31, 2013 Residential Mortgage	Dec. 31, 2012 Residential Mortgage	Jun. 30, 2012 Residential Mortgage	Mar. 31, 2012 Residential Mortgage	Dec. 31, 2011 Residential Mortgage	Jun. 30, 2013 Standby Letters of Credit	Dec. 31, 2012 Standby Letters of Credit	Jun. 30, 2013 Standby Letters of Credit Secured Debt	Dec. 31, 2012 Standby Letters of Credit Secured Debt	Jun. 30, 2013 Variable Rate Demand Note	Dec. 31, 2012 Variable Rate Demand Note	Jun. 30, 2013 Other Liabilities	Dec. 31, 2012 Other Liabilities	Jun. 30, 2013 Private Mortgage Reinsurance	Dec. 31, 2012 Private Mortgage Reinsurance	Jun. 30, 2013 Private Mortgage Reinsurance Lower Limit	Jun. 30, 2013 Private Mortgage Reinsurance Upper Limit	Sep. 30, 2012 Visa Litigation	Mar. 31, 2012 Visa Litigation	Jun. 30, 2011 Visa Litigation	Jun. 30, 2010 Visa Litigation	Dec. 31, 2011 Visa Litigation	Dec. 31, 2010 Visa Litigation	Dec. 31, 2009 Visa Litigation	Dec. 31, 2008 Visa Litigation	Jun. 30, 2013 Visa Litigation	Dec. 31, 2012 Visa Litigation	Dec. 31, 2007 Visa Litigation	Dec. 31, 2009 Visa	Dec. 31, 2008 Visa
Commitments and Contingencies Disclosure
Reserve for unfunded commitments															$ 2,000,000	$ 4,000,000					$ 166,000,000	$ 179,000,000
Percentage of the total standby letters of credit															98.00%	99.00%	48.00%	49.00%
Fifth Third Securities, Inc. (FTS) acted as the remarketing agent to issuers of VRDNs																			2,100,000,000	2,500,000,000
Letters of credit	4,043,000,000			4,281,000,000															302,000,000	345,000,000
Total Variable Rate Demand Notes	2,400,000,000			2,800,000,000
Letters of credit issued by the Bancorp related to variable rate demand notes	1,800,000,000			2,000,000,000
Total outstanding reinsurance coverage																							42,000,000	58,000,000
Approximate reserve related to exposures within the reinsurance portfolio																							15,000,000	18,000,000
Margin account balance held by the brokerage clearing agent	11,000,000			17,000,000
Fully and unconditionally guaranteed certain long-term borrowing obligations issued by wholly-owned issuing trust entities	812,000,000
Reinsurance coverage ranges of the total PMI coverage																									5.00%	10.00%
Increase Decrease In Maximum Exposure To Loss																															54,000,000
Outstanding balances on residential mortgage loans sold with representation and warranty provisions	510,000,000			661,000,000					117,000,000	112,000,000	110,000,000	57,000,000	55,000,000	55,000,000
Outstanding balances on residential mortgage loans sold with credit recourse									586,000,000		662,000,000
Delinquency Rates									4.70%		5.90%
Credit loss reserve	1,735,000,000	[1]	1,783,000,000	1,854,000,000	[1]	2,016,000,000	2,126,000,000	2,255,000,000	21,000,000		20,000,000
Recognized liability equal to the fair value of the indemnification obligation																																					3,000,000
Recorded share of litigation formally settled by Visa and for probable future litigation settlements																																	29,000,000	71,000,000	37,000,000	33,000,000	169,000,000
Visa IPO, shares of Visa's Class B common stock received																																							10.1
Received Class B common shares, carryover basis																																							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		400,000,000	500,000,000	1,565,000,000	800,000,000	700,000,000	3,000,000,000
Reduction of liability in cash to the swap counterparty																											6,000,000	75,000,000	19,000,000	20,000,000		35,000,000
Share of the Visa escrow account																																		169,000,000
Cash Proceeds Sale Of Stock																																						300,000,000
Maximum Reasonably Possible Loss Related To Mortgage Representation And Warranty Provisions In Excess Of Reserve									$ 78,000,000

[1] Includes $50 and $50 of commercial mortgage loans, $(13) and $(5) of ALLL, and $1 and $3 of other assets from consolidated VIEs that are included in their respective captions above at June 30, 2013 and December 31, 2012, respectively. See Note 8.