Quartely Summary (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Jan. 31, 2016	Oct. 25, 2015	Jul. 26, 2015	Apr. 26, 2015	Jan. 25, 2015	Oct. 26, 2014	Jul. 27, 2014	Apr. 27, 2014	Jan. 31, 2016	Jan. 25, 2015	Jan. 26, 2014
Selected Quarterly Financial Information [Abstract]
Revenue	$ 1,401	$ 1,305	$ 1,153	$ 1,151	$ 1,251	$ 1,225	$ 1,103	$ 1,103	$ 5,010	$ 4,682	$ 4,130
Cost of revenue	610	572	519	498	552	548	484	499	2,199	2,083	1,862
Gross profit	791	733	634	653	699	677	619	604	2,811	2,599	2,268
Net income	$ 207	$ 247	$ 26	$ 134	$ 193	$ 173	$ 128	$ 137	$ 614	$ 631	$ 440
Basic net income per share	$ 0.38	$ 0.45	$ 0.05	$ 0.24	$ 0.35	$ 0.32	$ 0.23	$ 0.24	$ 1.13	$ 1.14	$ 0.75
Diluted net income per share	$ 0.35	$ 0.44	$ 0.05	$ 0.24	$ 0.35	$ 0.31	$ 0.22	$ 0.24	$ 1.08	$ 1.12	$ 0.74