Intangible Assets (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Finite-Lived Intangible Assets
Gross Carrying Amount	$ 3,129	$ 3,049
Accumulated Amortization	(1,720)	(1,664)
Valuation Allowance	(612)	(661)
Net Carrying Amount	797	724
Mortgage Servicing Rights
Finite-Lived Intangible Assets
Gross Carrying Amount	2,898	2,825
Accumulated Amortization	(1,520)	(1,467)
Valuation Allowance	(612)	(661)
Net Carrying Amount	766	697
Automobile Servicing Rights
Finite-Lived Intangible Assets
Gross Carrying Amount	6
Net Carrying Amount	6
Core Deposits
Finite-Lived Intangible Assets
Gross Carrying Amount	180	180
Accumulated Amortization	(162)	(160)
Net Carrying Amount	18	20
Other Intangible Assets
Finite-Lived Intangible Assets
Gross Carrying Amount	45	44
Accumulated Amortization	(38)	(37)
Net Carrying Amount	$ 7	$ 7

Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

-Paragraph 2

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=7658586&loc=d3e16323-109275

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 142

-Paragraph 45

-Subparagraph a(1)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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- Definition

Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

+ References

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- Definition

Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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- Definition

Total of allowances and reserves, the valuation and qualifying accounts that are either netted against the cost of an asset (in order to value it at its carrying value) or that reflect a liability established to represent expected future costs.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 09

-Article 12

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=6881521&loc=d3e24092-122690

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