Guarantees (Details) - USD ($) $ in Millions	12 Months Ended
	Jan. 29, 2017		Jan. 31, 2016		Jan. 25, 2015
Notes to financial statements [Abstract]
SHIELD warranty charge			$ 26
Estimated product warranty liabilities
Balance at beginning of period	$ 11	[1]	8		$ 8
Additions	2		27		5
Deductions	(5)		(24)		(5)
Balance at end of period	$ 8	[1]	$ 11	[1]	$ 8

[1] Please refer to Note 10 of these Notes to the Consolidated Financial Statements for a discussion regarding warranties.