Acquisitions Schedule of Purchase Price Allocations Related to Acquisitions (Detail) $ in Millions	12 Months Ended
Jan. 31, 2014 USD ($)
Business Acquisition [Line Items]
Weighted average lives of finite-lived intangibles (years)	12 years
Customer Relationships
Business Acquisition [Line Items]
Identifiable intangible assets (finite-lived)	$ 0
Other
Business Acquisition [Line Items]
Identifiable intangible assets (finite-lived)	$ 3
Weighted average lives of finite-lived intangibles (years)	12 years

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.

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

Name:	us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration