Goodwill and Intangible Assets (Goodwill Rollforward) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended			9 Months Ended
	Oct. 31, 2014	Aug. 01, 2014	Nov. 01, 2013	Oct. 31, 2014	Nov. 01, 2013
Goodwill [Roll Forward]
Beginning balance				$ 1,693
Goodwill impairment charges	0	(486)	0	(486)	0
Ending balance	1,207			1,207
NSS
Goodwill [Roll Forward]
Beginning balance				788
Goodwill impairment charges				0
Ending balance	788			788
HES
Goodwill [Roll Forward]
Beginning balance				905
Goodwill impairment charges				(486)
Ending balance	$ 419			$ 419