Financial Instruments (Details 1) (USD $) In Thousands	Oct. 01, 2011	Apr. 02, 2011
Fair values and gross unrealized losses of the investments
Available-for-Sale Securities, Less Than 12 Months, Fair Value	$ 324,412	$ 435,492
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	(2,120)	(1,627)
Available-for-Sale Securities, 12 Months or Greater, Fair Value	33,585	36,980
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses	(3,892)	(3,317)
Available-for-Sale Securities, Fair Value, Total	357,997	472,472
Available-for-Sale Securities, Gross Unrealized Losses, Total	(6,012)	(4,944)
Commercial Paper [Member]
Fair values and gross unrealized losses of the investments
Available-for-Sale Securities, Less Than 12 Months, Fair Value		44,982
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses		(1)
Available-for-Sale Securities, 12 Months or Greater, Fair Value		0
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses		0
Available-for-Sale Securities, Fair Value, Total		44,982
Available-for-Sale Securities, Gross Unrealized Losses, Total		(1)
Corporate Bonds [Member]
Fair values and gross unrealized losses of the investments
Available-for-Sale Securities, Less Than 12 Months, Fair Value	29,634	6,129
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	(570)	(4)
Available-for-Sale Securities, 12 Months or Greater, Fair Value	0	0
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses	0	0
Available-for-Sale Securities, Fair Value, Total	29,634	6,129
Available-for-Sale Securities, Gross Unrealized Losses, Total	(570)	(4)
Auction Rate Securities [Member]
Fair values and gross unrealized losses of the investments
Available-for-Sale Securities, Less Than 12 Months, Fair Value	0	0
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	0	0
Available-for-Sale Securities, 12 Months or Greater, Fair Value	29,048	34,950
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses	(3,852)	(3,300)
Available-for-Sale Securities, Fair Value, Total	29,048	34,950
Available-for-Sale Securities, Gross Unrealized Losses, Total	(3,852)	(3,300)
Municipal Bonds [Member]
Fair values and gross unrealized losses of the investments
Available-for-Sale Securities, Less Than 12 Months, Fair Value	4,607	4,992
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	(9)	(42)
Available-for-Sale Securities, 12 Months or Greater, Fair Value	486	936
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses	(6)	(10)
Available-for-Sale Securities, Fair Value, Total	5,093	5,928
Available-for-Sale Securities, Gross Unrealized Losses, Total	(15)	(52)
U.S. Government and Agency Securities [Member]
Fair values and gross unrealized losses of the investments
Available-for-Sale Securities, Less Than 12 Months, Fair Value	93,586	108,464
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	(45)	(207)
Available-for-Sale Securities, 12 Months or Greater, Fair Value	0	0
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses	0	0
Available-for-Sale Securities, Fair Value, Total	93,586	108,464
Available-for-Sale Securities, Gross Unrealized Losses, Total	(45)	(207)
Foreign Government and Agency Securities [Member]
Fair values and gross unrealized losses of the investments
Available-for-Sale Securities, Less Than 12 Months, Fair Value	24,974	67,061
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	(8)	(16)
Available-for-Sale Securities, 12 Months or Greater, Fair Value	0	0
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses	0	0
Available-for-Sale Securities, Fair Value, Total	24,974	67,061
Available-for-Sale Securities, Gross Unrealized Losses, Total	(8)	(16)
Floating Rate Notes [Member]
Fair values and gross unrealized losses of the investments
Available-for-Sale Securities, Less Than 12 Months, Fair Value		25,020
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses		(1)
Available-for-Sale Securities, 12 Months or Greater, Fair Value		0
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses		0
Available-for-Sale Securities, Fair Value, Total		25,020
Available-for-Sale Securities, Gross Unrealized Losses, Total		(1)
Mortgage-Backed Securities [Member]
Fair values and gross unrealized losses of the investments
Available-for-Sale Securities, Less Than 12 Months, Fair Value	171,611	178,844
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	(1,488)	(1,356)
Available-for-Sale Securities, 12 Months or Greater, Fair Value	4,051	1,094
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses	(34)	(7)
Available-for-Sale Securities, Fair Value, Total	175,662	179,938
Available-for-Sale Securities, Gross Unrealized Losses, Total	$ (1,522)	$ (1,363)

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