Goodwill and Other Intangible Assets - Gross Carrying Amount and Accumulated Amortization of Intangible Assets (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Goodwill [Line Items]
Gross Carrying Amount	$ 383	$ 207
Accumulated Amortization	212	190
Purchased Credit Card Relationship Intangible [Member]
Goodwill [Line Items]
Gross Carrying Amount	136
Accumulated Amortization	14
Core deposit intangibles [Member]
Goodwill [Line Items]
Gross Carrying Amount	105	65
Accumulated Amortization	56	48
Other intangible assets [Member]
Goodwill [Line Items]
Gross Carrying Amount	142	142
Accumulated Amortization	$ 142	$ 142