Net Income Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended											12 Months Ended
	Jan. 27, 2019	[1]	Oct. 28, 2018	[1]	Jul. 29, 2018	Apr. 29, 2018	Jan. 28, 2018	[2]	Oct. 29, 2017	Jul. 30, 2017	Apr. 30, 2017	Jan. 27, 2019		Jan. 28, 2018		Jan. 29, 2017
Numerator:
Net income	$ 567		$ 1,230		$ 1,101	$ 1,244	$ 1,118		$ 838	$ 583	$ 507	$ 4,141		$ 3,047		$ 1,666
Denominator:
Basic weighted average shares (in shares)												608		599		541
Dilutive impact of outstanding securities:
Equity awards (in shares)												17		24		26
1.00% Convertible Senior Notes (in shares)												0		5		44
Warrants issued with the 1.00% Convertible Senior Notes (in shares)												0		4		38
Diluted weighted average shares (in shares)												625		632		649
Net income per share:
Basic (in USD per share)	$ 0.93		$ 2.02		$ 1.81	$ 2.05	$ 1.84		$ 1.39	$ 0.98	$ 0.86	$ 6.81	[3]	$ 5.09	[3]	$ 3.08	[3]
Diluted (in USD per share)	$ 0.92		$ 1.97		$ 1.76	$ 1.98	$ 1.78		$ 1.33	$ 0.92	$ 0.79	$ 6.63	[4]	$ 4.82	[4]	$ 2.57	[4]
Equity awards excluded from diluted net income per share because their effect would have been anti-dilutive (in shares)												5		4		8

[1] In the third and fourth quarters of fiscal year 2019, we recorded U.S. tax reform benefits of $138 million and $230 million, respectively, associated with the completion of our accounting for the enactment-date income tax effects of the TCJA. Refer to Note 13 of these Notes to the Consolidated Financial Statements for a discussion regarding the U.S. tax reform.

[2] In the fourth quarter of fiscal year 2018, we recorded a U.S. tax reform provisional net tax benefit of $133 million associated with the one-time transition tax on our historical foreign earnings and the adjustment of deferred tax balances to the lower corporate tax rate. Refer to Note 13 of these Notes to the Consolidated Financial Statements for a discussion regarding the U.S. tax reform.

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

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