Marketable Securities (Tables)

3 Months Ended

Apr. 29, 2018

Schedule of Available-for-sale Securities [Line Items]

Cash Equivalents and Marketable Securities

	April 29, 2018
	Amortized Cost		Unrealized Gain		Unrealized Loss			Estimated Fair Value		Reported as
										Cash Equivalents		Marketable Securities
	(In millions)
Debt securities issued by the United States Treasury	$	2,741	$	—	$	(4	)	$	2,737	$	100	$	2,637
Corporate debt securities	1,803		—		(11		)	1,792		—		1,792
Debt securities of United States government agencies	1,734		—		(7		)	1,727		—		1,727
Money market funds	460		—		—			460		460		—
Asset-backed securities	230		—		(3		)	227		—		227
Mortgage-backed securities issued by United States government-sponsored enterprises	119		2		—			121		—		121
Foreign government bonds	31		—		—			31		—		31
Total	$	7,118	$	2	$	(25	)	$	7,095	$	560	$	6,535

	January 28, 2018
	Amortized Cost		Unrealized Gain		Unrealized Loss			Estimated Fair Value		Reported as
										Cash Equivalents		Marketable Securities
	(In millions)
Money market funds	$	3,789	$	—	$	—		$	3,789	$	3,789	$	—
Corporate debt securities	1,304		—		(9		)	1,295		—		1,295
Debt securities of United States government agencies	822		—		(7		)	815		—		815
Debt securities issued by the United States Treasury	577		—		(4		)	573		—		573
Asset-backed securities	254		—		(2		)	252		—		252
Mortgage-backed securities issued by United States government-sponsored enterprises	128		2		—			130		—		130
Foreign government bonds	42		—		(1		)	41		—		41
Total	$	6,916	$	2	$	(23	)	$	6,895	$	3,789	$	3,106

Schedule of Unrealized Loss on Investments

	Less than 12 Months					12 Months or Greater					Total
	Estimated Fair Value		Gross Unrealized Losses			Estimated Fair Value		Gross Unrealized Losses			Estimated Fair Value		Gross Unrealized Losses
	(In millions)
Debt securities issued by the United States Treasury	$	1,539	$	—		$	502	$	(4	)	$	2,041	$	(4	)
Debt securities issued by United States government agencies	1,039		(1		)	687		(6		)	1,726		(7		)
Corporate debt securities	253		(2		)	835		(9		)	1,088		(11		)
Asset-backed securities	56		(1		)	172		(2		)	228		(3		)
	$	2,887	$	(4	)	$	2,196	$	(21	)	$	5,083	$	(25	)

Investments Classified by Contractual Maturity Date

	April 29, 2018				January 28, 2018
	Amortized Cost		Estimated Fair Value		Amortized Cost		Estimated Fair Value
	(In millions)
Less than 1 year	$	5,490	$	5,481	$	5,381	$	5,375
Due in 1 - 5 years	1,593		1,578		1,500		1,485
Mortgage-backed securities issued by United States government-sponsored enterprises not due at a single maturity date	35		36		35		35
Total	$	7,118	$	7,095	$	6,916	$	6,895