Net Income Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended								6 Months Ended	12 Months Ended
	Jan. 29, 2017	Oct. 30, 2016	Jul. 31, 2016	May 01, 2016	Jan. 31, 2016	Oct. 25, 2015	Jul. 26, 2015	Apr. 26, 2015	Jul. 31, 2016	Jan. 29, 2017		Jan. 31, 2016		Jan. 25, 2015		Apr. 30, 2017	Dec. 12, 2016
Debt Instrument
Number of warrants terminated	63									63
Warrants outstanding		75															75
Total number of shares issued in Q4'17 and Q1'18 related to terminated Warrants	48									48
Number of shares issued in Q4'17 related to terminated Warrants	44									44
Stated interest rate - Convertible Notes	1.00%									1.00%
Conversion price - Convertible Notes	$ 20.0662									$ 20.0662
Warrant Strike Price										27.0122
Average stock price										$ 59.30
Numerator:
Net income	$ 655	$ 542	$ 261	$ 208	$ 207	$ 247	$ 26	$ 134	$ 469	$ 1,666		$ 614		$ 631
Denominator:
Denominator for basic net income per share, weighted average shares										541		543		552
Effect of dilutive securities:
Equity awards outstanding (in shares)										26		13		11
Incremental Common Shares Attributable to Dilutive Effect of Conversion of Debt Securities										44		13		0
Incremental Common Shares Attributable to Dilutive Effect of Call Options and Warrants										38		0		0
Denominator for diluted net income per share, weighted average shares (in shares)			634	599					620	649		569		563
Net income per share:
Basic net income per share	$ 1.18	$ 1.01	$ 0.49	$ 0.39	$ 0.38	$ 0.45	$ 0.05	$ 0.24	$ 0.88	$ 3.08	[1]	$ 1.13	[1]	$ 1.14	[1]
Diluted net income per share	$ 0.99	$ 0.83	$ 0.41	$ 0.35	$ 0.35	$ 0.44	$ 0.05	$ 0.24	$ 0.76	$ 2.57	[2]	$ 1.08	[2]	$ 1.12	[2]
Anti-dilutive common equivalent shares from stock options and RSUs (in shares)										8		10		12
Subsequent Event [Member]
Debt Instrument
Number of shares issued in Q1'18 related to terminated warrants																4

[1] Calculated as net income divided by basic weighted average shares.

[2] Calculated as net income divided by diluted weighted average shares.