Marketable Securities (Tables)

9 Months Ended

Oct. 26, 2014

Notes to financial statements [Abstract]

Cash Equivalents and Marketable Securities

	October 26, 2014
	Amortized Cost		Unrealized Gain		Unrealized Loss			Estimated Fair Value
	(In thousands)
Corporate debt securities	$	1,954,162	$	3,418	$	(520	)	$	1,957,060
Debt securities of United States government agencies	585,391		787		(53		)	586,125
Debt securities issued by United States Treasury	575,188		2,891		(66		)	578,013
Asset-backed securities	437,791		159		(199		)	437,751
Mortgage-backed securities issued by United States government-sponsored enterprises	273,812		4,590		(718		)	277,684
Foreign government bonds	85,259		135		(16		)	85,378
Money market funds	72,881		—		—			72,881
Total	$	3,984,484	$	11,980	$	(1,572	)	$	3,994,892
Classified as:
Cash equivalents								$	148,778
Marketable securities								3,846,114
Total								$	3,994,892

	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

Schedule of Unrealized Loss on Investments [Table Text Block]

	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	$	698,851	$	(83	)	$	1,258,209	$	(437	)	$	1,957,060	$	(520	)
Debt securities of United States government agencies	278,703		(8		)	307,422		(45		)	586,125		(53		)
Debt securities issued by United States Treasury	71,564		(66		)	506,449		—			578,013		(66		)
Asset-backed securities	224,100		(27		)	213,651		(173		)	437,751		(200		)
Mortgage-backed securities issued by United States government-sponsored enterprises	—		—			277,684		(717		)	277,684		(717		)
Foreign government bonds	33,606		—			51,772		(16		)	85,378		(16		)
Total	$	1,306,824	$	(184	)	$	2,615,187	$	(1,388	)	$	3,922,011	$	(1,572	)

Schedule of Cash Equivalents and Marketable Securities Available for Sale

	October 26, 2014				January 26, 2014
	Amortized Cost		Estimated Fair Value		Amortized Cost		Estimated Fair Value
	(In thousands)
Less than 1 year	$	1,378,709	$	1,379,705	$	1,883,132	$	1,883,753
Due in 1 - 5 years	2,490,537		2,497,644		2,114,289		2,117,387
Mortgage-backed securities issued by government-sponsored enterprises not due at a single maturity date	115,238		117,543		90,472		91,508
Total	$	3,984,484	$	3,994,892	$	4,087,893	$	4,092,648