Quartely Summary (Details) - USD ($) $ / shares in Units, $ 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
Selected Quarterly Financial Information [Abstract]
Revenue	$ 2,911	$ 2,636	$ 1,937	$ 2,173	$ 2,004	$ 1,428	$ 1,305	$ 2,230	$ 9,714		$ 6,910		$ 5,010
Cost of revenue	1,110	1,067	787	870	821	602	554	928	3,892		2,847		2,199
Gross profit	1,801	1,569	1,150	1,303	1,183	826	751	1,302	5,822		4,063		2,811
Net income	$ 1,118	$ 838	$ 507	$ 655	$ 542	$ 261	$ 208	$ 583	$ 3,047		$ 1,666		$ 614
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]
Tax Cuts and Jobs Act of 2017, Income Tax Benefit									$ (133)	[3]	$ 0		$ 0

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

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

[3] We recognized a provisional tax benefit of $133 million, which was included as a component of income tax expense.