Marketable Securities (Tables)

12 Months Ended

Jan. 25, 2015

Notes to financial statements [Abstract]

Cash Equivalents and Marketable Securities

	January 25, 2015
	Amortized Cost		Unrealized Gain		Unrealized Loss			Estimated Fair Value
	(In thousands)
Corporate debt securities	$	2,184,925	$	2,600	$	(1,214	)	$	2,186,311
Debt securities of United States government agencies	749,630		917		(227		)	750,320
Debt securities issued by United States Treasury	533,673		2,694		(3		)	536,364
Asset-backed securities	453,088		125		(329		)	452,884
Mortgage backed securities issued by United States government-sponsored enterprises	274,366		4,589		(850		)	278,105
Money market funds	132,495		—		—			132,495
Foreign government bonds	84,800		121		(5		)	84,916
Total	$	4,412,977	$	11,046	$	(2,628	)	$	4,421,395
Classified as:
Cash equivalents								$	294,710
Marketable securities								4,126,685
Total								$	4,421,395

	January 26, 2014
	Amortized Cost		Unrealized Gain		Unrealized Loss			Estimated Fair Value
	(In thousands)
Corporate debt securities	$	1,762,833	$	1,837	$	(945	)	$	1,763,725
Debt securities of United States government agencies	1,012,740		848		(261		)	1,013,327
Debt securities issued by United States Treasury	495,889		621		(57		)	496,453
Money market funds	307,865		—		—			307,865
Asset-backed securities	258,017		15		(315		)	257,717
Mortgage backed securities issued by United States government-sponsored enterprises	185,594		3,837		(725		)	188,706
Foreign government bonds	64,955		20		(120		)	64,855
Total	$	4,087,893	$	7,178	$	(2,423	)	$	4,092,648
Classified as:
Cash equivalents								$	572,425
Marketable securities								3,520,223
Total								$	4,092,648

The following table provides the breakdown of the investments that were in a continuous unrealized loss position at January 25, 2015:

	Less than 12 Months					12 Months or Greater					Total
	Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses
	(In thousands)
Corporate debt securities	$	709,392	$	(1,199	)	$	10,085	$	(15	)	$	719,477	$	(1,214	)
Mortgage backed securities issued by United States government-sponsored enterprises	81,245		(639		)	21,314		(211		)	102,559		(850		)
Debt securities of United States Treasury	10,026		(3		)	—		—			10,026		(3		)
Debt securities issued by United States government agencies	246,480		(227		)	—		—			246,480		(227		)
Asset-backed securities	306,066		(323		)	4,476		(6		)	310,542		(329		)
Foreign government bonds	11,008		(5		)	—		—			11,008		(5		)
Total	$	1,364,217	$	(2,396	)	$	35,875	$	(232	)	$	1,400,092	$	(2,628	)

Schedule of Cash Equivalents and Marketable Securities Available for Sale

	January 25, 2015				January 26, 2014
	Amortized Cost		Estimated Fair Value		Amortized Cost		Estimated Fair Value
	(In thousands)
Less than one year	$	1,570,233	$	1,570,622	$	1,883,132	$	1,883,753
Due in 1 - 5 years	2,719,852		2,725,945		2,114,289		2,117,387
Mortgage-backed securities issued by government-sponsored enterprises not due at a single maturity date	122,893		124,828		90,472		91,508
Total	$	4,412,978	$	4,421,395	$	4,087,893	$	4,092,648