Net Income Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended							6 Months Ended	12 Months Ended
	Jan. 28, 2018	Oct. 29, 2017	Apr. 30, 2017	Jan. 29, 2017	Oct. 30, 2016	Jul. 31, 2016	May 01, 2016	Jul. 30, 2017	Jan. 28, 2018		Jan. 29, 2017		Jan. 31, 2016
Numerator:
Net income	$ 1,118	$ 838	$ 507	$ 655	$ 542	$ 261	$ 208	$ 583	$ 3,047		$ 1,666		$ 614
Denominator:
Basic weighted average shares									599		541		543
Effect of dilutive securities:
Equity awards									24		26		13
1.00% Convertible Senior Notes									5		44		13
Warrants issued with the 1.00% Convertible Senior Notes									4		38		0
Weighted average shares used in diluted per share computation									632		649		569
Net income per share:
Basic net income per share	$ 1.84	$ 1.39	$ 0.86	$ 1.18	$ 1.01	$ 0.49	$ 0.39	$ 0.98	$ 5.09	[1]	$ 3.08	[1]	$ 1.13	[1]
Diluted net income per share	$ 1.78	$ 1.33	$ 0.79	$ 0.99	$ 0.83	$ 0.41	$ 0.35	$ 0.92	$ 4.82	[2]	$ 2.57	[2]	$ 1.08	[2]
Equity awards excluded from diluted net income per share because their effect would have been anti-dilutive									4		8		10
Stated interest rate - Convertible Notes	1.00%								1.00%
Conversion price - Convertible Notes	$ 20.0350								$ 20.0350
Average stock price									$ 158.35

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

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