Summary of the Credit Risk Profile of the Bancorp's Residential Mortgage and Consumer Portfolio Segments by Class (Parenthetical) (Detail) (Residential Mortgage, USD $) In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Residential Mortgage
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Portfolio loans and leases at fair value	$ 109	$ 92