Goodwill and Other Intangible Assets - Components of Goodwill and Other Intangible Assets (Detail) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Finite-Lived Intangible Assets [Line Items]
Goodwill, Gross Carrying Value	$ 13,906	$ 13,904
Goodwill, Net Carrying Value	13,906	13,904
Amortized intangible assets, Gross Carrying Value	4,225	4,367
Amortized intangible assets, Accumulated Amortization	(2,250)	(1,796)
Amortized intangible assets, Net Carrying Value	1,975	2,571
Purchased Credit Card Relationship Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Amortized intangible assets, Gross Carrying Value	2,125	2,242
Amortized intangible assets, Accumulated Amortization	(682)	(378)
Amortized intangible assets, Net Carrying Value	1,443	1,864
Core Deposit Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Amortized intangible assets, Gross Carrying Value	1,771	1,771
Amortized intangible assets, Accumulated Amortization	(1,402)	(1,275)
Amortized intangible assets, Net Carrying Value	369	496
Other [Member]
Finite-Lived Intangible Assets [Line Items]
Amortized intangible assets, Gross Carrying Value	329	354
Amortized intangible assets, Accumulated Amortization	(166)	(143)
Amortized intangible assets, Net Carrying Value	$ 163	$ 211