Debt (Details) $ / shares in Units, $ in Thousands, shares in Millions	3 Months Ended				9 Months Ended
	Jan. 28, 2018 USD ($)	Oct. 29, 2017 USD ($) $ / shares shares		Oct. 30, 2016 USD ($)	Oct. 29, 2017 USD ($) $ / shares shares		Oct. 30, 2016 USD ($)	Jul. 28, 2017 $ / shares	Jan. 29, 2017 USD ($)
Debt Instrument
Stated interest rate, Convertible Notes		1.00%			1.00%
Repayment of Convertible Notes		$ 62,000
Convertible Notes - Face Amount		$ 24,000			$ 24,000				$ 827,000
Shares issued - Convertible Notes | shares		3
Loss on early debt conversions		$ 1,000			19,000		$ 15,000
Closing stock price | $ / shares								$ 201.86
If-converted value in excess of principal - Convertible Notes		$ 217,000
Conversion ratio - Convertible Notes		49.8977
Principal amount of Convertible Notes		$ 1			$ 1
Conversion price - Convertible Notes | $ / shares		$ 20.0410			$ 20.0410
Extinguishment of Debt, to date		$ 1,480,000			$ 1,480,000
Initial debt component - Convertible Notes		1,350,000
Initial carrying amount of equity component		126,000			$ 126,000
Purchaser's discount of Convertible Notes		23,000
Initial unamortized debt discount at issuance		$ 148,000
Effective interest rate - Convertible Notes		3.15%			3.15%
Unamortized debt discount - Convertible Notes		$ (1,000)	[1]		$ (1,000)	[1]			(31,000)
Convertible Notes, net carrying amount		23,000			$ 23,000				796,000
Remaining discount amortization period					1 year 1 month 2 days
Coupon interest expense, Convertible Notes		0		$ 3,000	$ 0		10,000
Amortization of Debt Issuance Costs and Discounts		0		5,000	2,000		20,000
Total interest expense related to Convertible Notes		$ 0		$ 8,000	$ 2,000		$ 30,000
Shares received from Note Hedges | shares		3			3
Proceeds from issuance of debt		$ 1,980,000
Unamortized discount and issuance costs		(15,000)			$ (15,000)				(17,000)
Long-term debt, net carrying amount		1,985,000			1,985,000				1,983,000
2021 Notes [Member]
Debt Instrument
Long-term Debt, Gross		$ 1,000,000			$ 1,000,000				1,000,000
Long-term Debt, Stated interest rate		2.20%			2.20%
Expected remaining term - Long-term debt		3 years 10 months 18 days
Effective interest rate - Long-term debt		2.38%
2026 Notes [Member]
Debt Instrument
Long-term Debt, Gross		$ 1,000,000			$ 1,000,000				$ 1,000,000
Long-term Debt, Stated interest rate		3.20%			3.20%
Expected remaining term - Long-term debt		8 years 10 months 19 days
Effective interest rate - Long-term debt		3.31%
Subsequent Event [Member]
Debt Instrument
Subsequent repayment of Convertible debt	$ 8,000

[1] As of October 29, 2017, the remaining period over which the unamortized debt discount will be amortized is 1.1 years.