Schedule of Changes in Goodwill by Segment (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
Jan. 31, 2014	Jan. 31, 2013
Goodwill [Line Items]
Beginning balance, Goodwill	$ 1,704	$ 1,309
Acquisitions		395
Corporate reorganization	0	0
Ending balance, Goodwill	1,704	1,704
HES
Goodwill [Line Items]
Beginning balance, Goodwill	985	600
Acquisitions		395
Corporate reorganization	(69)	(10)
Ending balance, Goodwill	916	985
NSS
Goodwill [Line Items]
Beginning balance, Goodwill	719	709
Acquisitions		0
Corporate reorganization	69	10
Ending balance, Goodwill	$ 788	$ 719

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=14024403&loc=d3e13816-109267

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

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-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13770-109266

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Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination.

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Amount of increase (decrease) from adjustments after acquisition date under purchase accounting of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (g)

-URI http://asc.fasb.org/extlink&oid=14024403&loc=d3e13816-109267

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 25

-Paragraph 16

-URI http://asc.fasb.org/extlink&oid=21917927&loc=d3e961-128460

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