Schedule of Purchase Price Allocations Related to Acquisitions (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
Jan. 31, 2014	Jan. 31, 2013
Business Acquisition [Line Items]
Tax deductible goodwill	$ 0	$ 0
Non-tax deductible goodwill	0	395
Weighted average lives of finite-lived intangibles (years)	12 years	4 years
Customer Relationships
Business Acquisition [Line Items]
Identifiable intangible assets (finite-lived)	0	62
Weighted average lives of finite-lived intangibles (years)	0 years	5 years
Other
Business Acquisition [Line Items]
Identifiable intangible assets (finite-lived)	$ 3	$ 10
Weighted average lives of finite-lived intangibles (years)	12 years	1 year

Business Acquisition Purchase Price Allocation Goodwill Expected Non Tax Deductible Amount

No definition available.

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- Definition

Weighted average amortization period of finite-lived intangible assets acquired either individually or as part of a group of assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

-Paragraph 1

-Subparagraph (a)(3)

-URI http://asc.fasb.org/extlink&oid=26713463&loc=d3e16265-109275

+ Details

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- Details

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- Definition

The amount of goodwill arising from a business combination that is expected to be deductible for tax purposes.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 30

-Section 50

-Paragraph 1

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

+ Details

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- Definition

Amount of increase in assets, excluding financial assets, lacking physical substance with a definite life, resulting from a business combination.

+ References

No definition available.

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