Summary of Average Impaired Loans and Leases and Interest Income by Class (Parenthetical) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended				12 Months Ended
	Mar. 31, 2015		Mar. 31, 2014		Dec. 31, 2014
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	$ 2,208		$ 3,202
Commercial Portfolio Segment | Variable Interest Entity, Primary Beneficiary
Financing Receivable, Impaired [Line Items]
Number of Contracts					5
Commercial Portfolio Segment | Commercial Mortgage Loans, Owner-occupied
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	112	[1]	162	[1]
Commercial Portfolio Segment | Commercial Mortgage Loans, Owner-occupied | Variable Interest Entity, Primary Beneficiary
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	$ 28		$ 28
Number of Contracts	5		5

[1] Excludes five restructured nonaccrual loans associated with a consolidated VIE in which the Bancorp has no continuing credit risk due to the risk being assumed by a third party, with an average recorded investment of $28 at March 31, 2015 and March 31, 2014 and an immaterial amount of interest income recognized for the three months ended March 31, 2015 and March 31, 2014.