Intangible Assets (Detail) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Finite-Lived Intangible Assets
Gross Carrying Amount	$ 3,241	$ 3,049
Accumulated Amortization	(1,790)	(1,664)
Valuation Allowance	(511)	(661)
Net Carrying Amount	940	724
Mortgage Servicing Rights
Finite-Lived Intangible Assets
Gross Carrying Amount	3,036	2,825
Accumulated Amortization	(1,610)	(1,467)
Valuation Allowance	(511)	(661)
Net Carrying Amount	915	697
Automobile Servicing Rights
Finite-Lived Intangible Assets
Gross Carrying Amount	6
Accumulated Amortization	(2)
Net Carrying Amount	4
Core Deposits
Finite-Lived Intangible Assets
Gross Carrying Amount	154	180
Accumulated Amortization	(139)	(160)
Net Carrying Amount	15	20
Other Intangible Assets
Finite-Lived Intangible Assets
Gross Carrying Amount	45	44
Accumulated Amortization	(39)	(37)
Net Carrying Amount	$ 6	$ 7