Marketable Securities (Tables)

12 Months Ended

Jan. 27, 2013

Notes to financial statements [Abstract]

Cash Equivalents and Marketable Securities

	January 27, 2013
	Amortized Cost		Unrealized Gain		Unrealized Loss			Estimated Fair Value
	(In thousands)
Debt securities of United States government agencies	$	867,087	$	1,199	$	(139	)	$	868,147
Corporate debt securities	1,255,297		3,175		(542		)	1,257,930
Mortgage backed securities issued by United States government-sponsored enterprises	183,034		6,194		(57		)	189,171
Money market funds	195,790		—		—			195,790
Debt securities issued by United States Treasury	785,228		1,102		(105		)	786,225
Total	$	3,286,436	$	11,670	$	(843	)	$	3,297,263
Classified as:
Cash equivalents								$	302,166
Marketable securities								2,995,097
Total								$	3,297,263

	January 29, 2012
	Amortized Cost		Unrealized Gain		Unrealized Loss			Estimated Fair Value
	(In thousands)
Debt securities of United States government agencies	$	769,300	$	1,605	$	(151	)	$	770,754
Corporate debt securities	1,114,439		3,268		(260		)	1,117,447
Mortgage backed securities issued by United States government-sponsored enterprises	156,668		4,964		(73		)	161,559
Money market funds	290,732		—		—			290,732
Debt securities issued by United States Treasury	533,616		2,161		(3		)	535,774
Total	$	2,864,755	$	11,998	$	(487	)	$	2,876,266
Classified as:
Cash equivalents								$	414,566
Marketable securities								2,461,700
Total								$	2,876,266

The following table provides the breakdown of the investments with unrealized losses at January 27, 2013:

	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	$	563,842	$	(35	)	$	694,088	$	(507	)	$	1,257,930	$	(542	)
Mortgage backed securities issued by United States government-sponsored enterprises	5,912		—			183,259		(57		)	189,171		(57		)
Debt securities of United States Treasury	278,383		(15		)	507,842		(90		)	786,225		(105		)
Debt securities issued by United States government agencies	355,378		(23		)	512,769		(116		)	868,147		(139		)
Total	$	1,203,515	$	(73	)	$	1,897,958	$	(770	)	$	3,101,473	$	(843	)

Schedule of Cash Equivalents and Marketable Securities Available for Sale

	January 27, 2013				January 29, 2012
	Amortized Cost		Estimated Fair Value		Amortized Cost		Estimated Fair Value
	(In thousands)
Less than one year	$	1,397,350	$	1,399,304	$	1,705,916	$	1,708,154
Due in 1 - 5 years	1,777,785		1,783,103		1,047,956		1,053,265
Mortgage-backed securities issued by government-sponsored enterprises not due at a single maturity date	111,301		114,856		110,883		114,847
Total	$	3,286,436	$	3,297,263	$	2,864,755	$	2,876,266