Intangible Assets - Schedule of Intangible Assets (Detail) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Finite-Lived Intangible Assets [Line Items]
Intangible assets, net	$ 299	$ 247
Mortgage servicing rights [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets, net	237	179
Purchased credit card relationships
Finite-Lived Intangible Assets [Line Items]
Intangible assets, net	57	60
Favorable lease argeement
Finite-Lived Intangible Assets [Line Items]
Intangible assets, net	$ 5	$ 8