Intangible Assets - Schedule of Intangible Assets (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Finite-Lived Intangible Assets [Line Items]
Intangible assets, net	$ 267	$ 247
Mortgage servicing rights [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets, net	202	179
Purchased credit card relationships
Finite-Lived Intangible Assets [Line Items]
Intangible assets, net	58	60
Other
Finite-Lived Intangible Assets [Line Items]
Intangible assets, net	$ 7	$ 8