Net Income Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jul. 26, 2015	Jul. 27, 2014	Jul. 26, 2015	Jul. 27, 2014
Numerator:
Net income	$ 26	$ 128	$ 160	$ 265
Denominator:
Denominator for basic net income per share, weighted average shares	541	558	545	559
Effect of dilutive securities:
Equity awards outstanding	11	13	13	12
Incremental Common Shares Attributable to Dilutive Effect of Conversion of Debt Securities	4	0	5	0
Denominator for diluted net income per share, weighted average shares	556	571	563	571
Net income per share:
Basic net income per share	$ 0.05	$ 0.23	$ 0.29	$ 0.47
Diluted net income per share	$ 0.05	$ 0.22	$ 0.28	$ 0.46
Antidilutive equity awards excluded from computation of earnings per share	1	4	4	8
Debt Instrument, Interest Rate, Stated Percentage	1.00%		1.00%
Debt Instrument, Convertible, Conversion Price	$ 20.16		$ 20.16
Warrant Strike Price	$ 27.13