Long-term debt (Tables)

9 Months Ended

Oct. 25, 2015

Debt Instrument [Line Items]

Schedule of Long-term Debt Instruments [Table Text Block]

	October 25,			January 25,
	2015			2015
	(In millions)
Amount of the equity component	$	126		$	126
1.00% Convertible Senior Notes Due 2018	$	1,500		$	1,500
Unamortized debt discount (1)	(94		)	(116		)
Net carrying amount	$	1,406		$	1,384

(1) As of October 25, 2015, the unamortized debt discount will be amortized over a remaining period of 3.1 years.

The following table presents interest expense for the contractual interest and the accretion of debt discount and issuance costs:

	Three Months Ended				Nine Months Ended
	October 25,		October 26,		October 25,		October 26,
	2015		2014		2015		2014
	(In millions)
Contractual coupon interest expense	$	4	$	4	$	11	$	11
Amortization of debt discount and issuance costs	7		7		22		21
Total interest expense related to Notes	$	11	$	11	$	33	$	32