Financial Instruments (Details 1) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Apr. 02, 2011
Fair values and gross unrealized losses of the investments
Available-for-Sale Securities, Less Than 12 Months, Fair Value	$ 731,520	$ 435,492
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	(1,617)	(1,627)
Available-for-Sale Securities, 12 Months or Greater, Fair Value	45,218	36,980
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses	(3,795)	(3,317)
Available-for-Sale Securities, Fair Value, Total	776,738	472,472
Available-for-Sale Securities, Gross Unrealized Losses, Total	(5,412)	(4,944)
Commercial Paper [Member]
Fair values and gross unrealized losses of the investments
Available-for-Sale Securities, Less Than 12 Months, Fair Value	79,994	44,982
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	(1)	(1)
Available-for-Sale Securities, 12 Months or Greater, Fair Value
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses
Available-for-Sale Securities, Fair Value, Total	79,994	44,982
Available-for-Sale Securities, Gross Unrealized Losses, Total	(1)	(1)
Corporate Bonds [Member]
Fair values and gross unrealized losses of the investments
Available-for-Sale Securities, Less Than 12 Months, Fair Value	21,111	6,129
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	(184)	(4)
Available-for-Sale Securities, 12 Months or Greater, Fair Value
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses
Available-for-Sale Securities, Fair Value, Total	21,111	6,129
Available-for-Sale Securities, Gross Unrealized Losses, Total	(184)	(4)
Auction Rate Securities [Member]
Fair values and gross unrealized losses of the investments
Available-for-Sale Securities, Less Than 12 Months, Fair Value
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses
Available-for-Sale Securities, 12 Months or Greater, Fair Value	28,929	34,950
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses	(3,671)	(3,300)
Available-for-Sale Securities, Fair Value, Total	28,929	34,950
Available-for-Sale Securities, Gross Unrealized Losses, Total	(3,671)	(3,300)
Municipal Bonds [Member]
Fair values and gross unrealized losses of the investments
Available-for-Sale Securities, Less Than 12 Months, Fair Value	2,173	4,992
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	(24)	(42)
Available-for-Sale Securities, 12 Months or Greater, Fair Value	366	936
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses	(4)	(10)
Available-for-Sale Securities, Fair Value, Total	2,539	5,928
Available-for-Sale Securities, Gross Unrealized Losses, Total	(28)	(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	460,735	108,464
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	(149)	(207)
Available-for-Sale Securities, 12 Months or Greater, Fair Value
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses
Available-for-Sale Securities, Fair Value, Total	460,735	108,464
Available-for-Sale Securities, Gross Unrealized Losses, Total	(149)	(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		67,061
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses		(16)
Available-for-Sale Securities, 12 Months or Greater, Fair Value
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses
Available-for-Sale Securities, Fair Value, Total		67,061
Available-for-Sale Securities, Gross Unrealized Losses, Total		(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
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses
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	147,726	178,844
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	(1,040)	(1,356)
Available-for-Sale Securities, 12 Months or Greater, Fair Value	15,923	1,094
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses	(120)	(7)
Available-for-Sale Securities, Fair Value, Total	163,649	179,938
Available-for-Sale Securities, Gross Unrealized Losses, Total	(1,160)	(1,363)
Debt Mutual Fund [Member]
Fair values and gross unrealized losses of the investments
Available-for-Sale Securities, Less Than 12 Months, Fair Value	19,781
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	(219)
Available-for-Sale Securities, 12 Months or Greater, Fair Value
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses
Available-for-Sale Securities, Fair Value, Total	19,781
Available-for-Sale Securities, Gross Unrealized Losses, Total	$ (219)