Financial Instruments (Details 1) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Sep. 28, 2013	Mar. 30, 2013
Fair values and gross unrealized losses of the investments
Available-for-Sale Securities, Less Than 12 Months, Fair Value	$ 1,019,343	$ 792,298
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	(16,874)	(5,180)
Available-for-Sale Securities, 12 Months or Greater, Fair Value	55,143	39,790
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses	(3,250)	(3,347)
Available-for-Sale Securities, Fair Value, Total	1,074,486	832,088
Available-for-Sale Securities, Gross Unrealized Losses, Total	(20,124)	(8,527)
Corporate Bonds [Member]
Fair values and gross unrealized losses of the investments
Available-for-Sale Securities, Less Than 12 Months, Fair Value	127,859	27,114
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	(1,977)	(135)
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	127,859	27,114
Available-for-Sale Securities, Gross Unrealized Losses, Total	(1,977)	(135)
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	22,636	28,701
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses	(2,514)	(3,200)
Available-for-Sale Securities, Fair Value, Total	22,636	28,701
Available-for-Sale Securities, Gross Unrealized Losses, Total	(2,514)	(3,200)
Municipal Bonds [Member]
Fair values and gross unrealized losses of the investments
Available-for-Sale Securities, Less Than 12 Months, Fair Value	9,691	8,927
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	(341)	(70)
Available-for-Sale Securities, 12 Months or Greater, Fair Value	862	60
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses	(28)	0
Available-for-Sale Securities, Fair Value, Total	10,553	8,987
Available-for-Sale Securities, Gross Unrealized Losses, Total	(369)	(70)
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	212,267	388,696
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	(217)	(45)
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	212,267	388,696
Available-for-Sale Securities, Gross Unrealized Losses, Total	(217)	(45)
Mortgage-Backed Securities [Member]
Fair values and gross unrealized losses of the investments
Available-for-Sale Securities, Less Than 12 Months, Fair Value	610,583	367,561
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	(11,932)	(4,930)
Available-for-Sale Securities, 12 Months or Greater, Fair Value	31,645	11,029
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses	(708)	(147)
Available-for-Sale Securities, Fair Value, Total	642,228	378,590
Available-for-Sale Securities, Gross Unrealized Losses, Total	(12,640)	(5,077)
Debt Mutual Fund [Member]
Fair values and gross unrealized losses of the investments
Available-for-Sale Securities, Less Than 12 Months, Fair Value	58,943
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	(2,407)
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	58,943
Available-for-Sale Securities, Gross Unrealized Losses, Total	$ (2,407)