Net Income Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Oct. 25, 2015	Oct. 26, 2014	Oct. 25, 2015	Oct. 26, 2014
Numerator:
Net income	$ 246	$ 173	$ 406	$ 437
Denominator:
Denominator for basic net income per share, weighted average shares	542	548	544	555
Effect of dilutive securities:
Equity awards outstanding	13	10	13	11
Incremental Common Shares Attributable to Dilutive Effect of Conversion of Debt Securities	10	0	6	0
Denominator for diluted net income per share, weighted average shares	565	558	563	566
Net income per share:
Basic net income per share	$ 0.45	$ 0.32	$ 0.75	$ 0.79
Diluted net income per share	$ 0.44	$ 0.31	$ 0.72	$ 0.77
Antidilutive equity awards excluded from computation of earnings per share	9	11	13	16
Debt Instrument, Interest Rate, Stated Percentage	1.00%		1.00%
Debt Instrument, Convertible, Conversion Price	$ 20.1630		$ 20.1630
Warrant Strike Price	$ 27.1119