Schedule of Acquisition Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
Jan. 31, 2014 acquisition	Jan. 31, 2013 acquisition
Business Combinations [Abstract]
Number of acquisitions	1us-gaap_NumberOfBusinessesAcquired	1us-gaap_NumberOfBusinessesAcquired
Cash consideration (paid and accrued)	$ 111	$ 505

The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Investing Activities

-URI http://asc.fasb.org/extlink&oid=6516133

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 13

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3213-108585

Name:	us-gaap_PaymentsToAcquireBusinessesGross
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration