Intangible Assets (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 72	$ 167
Accumulated Amortization	(58)	(152)
Net Carrying Amount	14us-gaap_FiniteLivedIntangibleAssetsNet	15us-gaap_FiniteLivedIntangibleAssetsNet
Core Deposits
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	34	122
Accumulated Amortization	(24)	(112)
Net Carrying Amount	10	10
Other Intangible Assets
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	38	45
Accumulated Amortization	(34)	(40)
Net Carrying Amount	$ 4	$ 5

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=26713463&loc=d3e16323-109275

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- Definition

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

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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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