Debt (Details) $ / shares in Units, shares in Millions	12 Months Ended
	Jan. 28, 2018 USD ($) $ / shares shares		Jan. 29, 2017 USD ($) shares	Jan. 31, 2016 USD ($)
Debt Instrument
Proceeds from Issuance of Long-term Debt	$ 1,980,000,000
Unamortized discount and issuance costs	(15,000,000)		$ (17,000,000)
Long-term debt	1,985,000,000		1,983,000,000
Convertible Notes - Initial face value	$ 1,500,000,000
Stated interest rate - Convertible Notes	1.00%
Terms of conversion feature - Convertible Notes	during any fiscal quarter, if the last reported sale price of the common stock for at least 20 trading days during a period of 30 consecutive trading days ending on the last trading day of the immediately preceding fiscal quarter is greater than or equal to 130% of the conversion price on each applicable trading day, the Convertible Notes become convertible at the holders' option.
Repayment of Convertible Notes	$ 812,000,000
Extinguishment of Debt, to date	$ 1,480,000,000
Convertible debt conversion, shares | shares	33
Loss on early debt conversions	$ 19,000,000		21,000,000	$ 0
Closing stock price | $ / shares	$ 243.33
If-converted value in excess of principal - Convertible Notes	$ 174,000,000
Conversion ratio - Convertible Notes	49.9127
Principal amount of Convertible Notes	$ 1,000
Conversion price - Convertible Notes | $ / shares	$ 20.0350
Initial debt component - Convertible Notes	$ 1,350,000,000
Initial carrying amount of equity component	126,000,000
Purchaser's discount of Convertible Notes	23,000,000
Initial unamortized debt discount at issuance	$ 148,000,000
Effective interest rate - Convertible Notes	3.15%
Convertible Notes - Face Amount	$ 15,000,000		827,000,000
Unamortized debt discount - Convertible Notes	0	[1]	(31,000,000)
Convertible Notes	15,000,000		796,000,000
Contractual coupon interest expense	0		9,000,000	15,000,000
Amortization of debt discount	2,000,000		24,000,000	29,000,000
Total interest expense related to Convertible Notes	$ 2,000,000		$ 33,000,000	$ 44,000,000
Note Hedges Strike Price | $ / shares	$ 20.0350
Exercise of convertible note hedges, shares | shares	56
Number of warrants terminated | shares	12		63
Number of shares issued related to terminated Warrants | shares	10		48
Additional borrowing capacity from Revolving Credit Facility	$ 425,000,000
Revolving Credit Facility [Member]
Debt Instrument
Revoling credit facility, Current borrowing capacity	575,000,000
Commercial Paper [Member]
Debt Instrument
Revoling credit facility, Current borrowing capacity	$ 575,000,000
2021 Notes [Member]
Debt Instrument
Long-term Debt, Stated interest rate	2.20%
Expected remaining term - Long-term debt	3 years 7 months 18 days
Effective interest rate - Long-term debt	2.38%
Long-term Debt, Gross	$ 1,000,000,000		$ 1,000,000,000
2026 Notes [Member]
Debt Instrument
Long-term Debt, Stated interest rate	3.20%
Expected remaining term - Long-term debt	8 years 7 months 19 days
Effective interest rate - Long-term debt	3.31%
Long-term Debt, Gross	$ 1,000,000,000		$ 1,000,000,000

[1] As of January 28, 2018, the balance of unamortized debt discount was not significant and will be fully amortized in fiscal year 2019.