Commitments, Contingent Liabilities and Guarantees - Additional Information (Detail) (USD $) Share data in Millions, unless otherwise specified	12 Months Ended						3 Months Ended		12 Months Ended
	Dec. 31, 2013		Mar. 31, 2014		Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2014 Residential Mortgage	Mar. 31, 2013 Residential Mortgage	Dec. 31, 2013 Residential Mortgage	Dec. 31, 2012 Residential Mortgage	Mar. 31, 2014 Secured Debt	Mar. 31, 2014 Standby Letters of Credit	Dec. 31, 2013 Standby Letters of Credit	Mar. 31, 2014 Standby Letters of Credit Secured Debt	Dec. 31, 2013 Standby Letters of Credit Secured Debt	Mar. 31, 2014 Variable Rate Demand Note	Dec. 31, 2013 Variable Rate Demand Note	Mar. 31, 2014 Other Liabilities	Dec. 31, 2013 Other Liabilities	Mar. 31, 2014 Other Liabilities Residential Mortgage	Dec. 31, 2013 Other Liabilities Residential Mortgage	Mar. 31, 2014 Private Mortgage Reinsurance	Dec. 31, 2013 Private Mortgage Reinsurance	Mar. 31, 2014 Private Mortgage Reinsurance Lower Limit	Mar. 31, 2014 Private Mortgage Reinsurance Upper Limit	Mar. 31, 2014 Visa Litigation	Dec. 31, 2013 Visa Litigation	Dec. 31, 2009 Visa Litigation	Sep. 30, 2012 Visa	Mar. 31, 2012 Visa	Jun. 30, 2011 Visa	Dec. 31, 2010 Visa	Jun. 30, 2010 Visa	Dec. 31, 2009 Visa
Commitments and Contingencies Disclosure
Reserve for unfunded commitments												$ 2,000,000	$ 2,000,000					$ 153,000,000	$ 162,000,000
Percentage of the total standby letters of credit												98.00%	97.00%	48.00%	48.00%
Fifth Third Securities, Inc. (FTS) acted as the remarketing agent to issuers of VRDNs																1,700,000,000	1,800,000,000
Letters of credit	4,129,000,000		4,194,000,000													277,000,000	300,000,000
Total Variable Rate Demand Notes	2,100,000,000		2,000,000,000
Letters of credit issued by the Bancorp related to variable rate demand notes	1,500,000,000		1,400,000,000
Total outstanding reinsurance coverage																						33,000,000	37,000,000
Approximate reserve related to exposures within the reinsurance portfolio																						7,000,000	10,000,000
Margin account balance held by the brokerage clearing agent	12,000,000		16,000,000
Fully and unconditionally guaranteed certain long-term borrowing obligations issued by wholly-owned issuing trust entities											62,000,000
Repurchase Claim Settlement	25,000,000
Amount in excess of amounts reserved			117,000,000				50,000,000
Reinsurance coverage ranges of the total PMI coverage																								5.00%	10.00%
Outstanding balances on residential mortgage loans sold with representation and warranty provisions							38,000,000	112,000,000	44,000,000	110,000,000										38,000,000	44,000,000
Outstanding balances on residential mortgage loans sold with credit recourse							563,000,000		579,000,000
Delinquency Rates							3.60%		4.40%
Credit loss reserve	1,582,000,000	[1]	1,483,000,000	[1]	1,783,000,000	1,854,000,000	15,000,000		16,000,000
Recorded share of litigation formally settled by Visa and for probable future litigation settlements																										43,000,000	48,000,000
Visa IPO, shares of Visa's Class B common stock received																																		10.1
Received Class B common shares, carryover basis																																		0
Visa deposited into the litigation escrow account																												3,000,000,000	150,000,000	1,565,000,000	400,000,000	800,000,000	500,000,000
Repurchase Demand Request								67,000,000
Outstanding Repurchase Demand Inventory							$ 21,000,000		$ 46,000,000

[1] Includes $102 and $49 of cash and due from banks, $7 and $0 of other short-term investments, $48 and $48 of commercial mortgage loans, $2,031 and $1,010 of automobile loans, $(18) and $(15) of ALLL, $23 and $13 of other assets, $3 and $1 of other liabilities, and $2,119 and $1,048 of long-term debt from consolidated VIEs that are included in their respective captions above at March 31, 2014 and December 31, 2013, respectively. See Note 8.