Intangible Assets - Schedule of Intangible Assets (Detail) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Finite-Lived Intangible Assets [Line Items]
Total intangible assets	$ 234	$ 295
Mortgage servicing rights [Member]
Finite-Lived Intangible Assets [Line Items]
Total intangible assets	184	237
Purchased credit card relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Total intangible assets	49	54
Favorable lease agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Total intangible assets	1	4
Residential Mortgage [Member] | Mortgage servicing rights [Member]
Finite-Lived Intangible Assets [Line Items]
Total intangible assets	182	227
Commercial [Member] | Mortgage servicing rights [Member]
Finite-Lived Intangible Assets [Line Items]
Total intangible assets	$ 2	$ 10