Financial Instruments (Details 1) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Jun. 29, 2013	Mar. 30, 2013
Fair values and gross unrealized losses of the investments
Available-for-Sale Securities, Less Than 12 Months, Fair Value	$ 1,275,108	$ 792,298
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	(20,102)	(5,180)
Available-for-Sale Securities, 12 Months or Greater, Fair Value	51,157	39,790
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses	(2,882)	(3,347)
Available-for-Sale Securities, Fair Value, Total	1,326,265	832,088
Available-for-Sale Securities, Gross Unrealized Losses, Total	(22,984)	(8,527)
Corporate Bonds [Member]
Fair values and gross unrealized losses of the investments
Available-for-Sale Securities, Less Than 12 Months, Fair Value	147,496	27,114
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	(3,156)	(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	147,496	27,114
Available-for-Sale Securities, Gross Unrealized Losses, Total	(3,156)	(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	22,896	28,701
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses	(2,254)	(3,200)
Available-for-Sale Securities, Fair Value, Total	22,896	28,701
Available-for-Sale Securities, Gross Unrealized Losses, Total	(2,254)	(3,200)
Municipal Bonds [Member]
Fair values and gross unrealized losses of the investments
Available-for-Sale Securities, Less Than 12 Months, Fair Value	9,454	8,927
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	(254)	(70)
Available-for-Sale Securities, 12 Months or Greater, Fair Value	876	60
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses	(30)	0
Available-for-Sale Securities, Fair Value, Total	10,330	8,987
Available-for-Sale Securities, Gross Unrealized Losses, Total	(284)	(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	355,573	388,696
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	(317)	(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	355,573	388,696
Available-for-Sale Securities, Gross Unrealized Losses, Total	(317)	(45)
Mortgage-Backed Securities [Member]
Fair values and gross unrealized losses of the investments
Available-for-Sale Securities, Less Than 12 Months, Fair Value	702,968	367,561
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	(14,642)	(4,930)
Available-for-Sale Securities, 12 Months or Greater, Fair Value	27,385	11,029
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses	(598)	(147)
Available-for-Sale Securities, Fair Value, Total	730,353	378,590
Available-for-Sale Securities, Gross Unrealized Losses, Total	(15,240)	(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	59,617
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	(1,733)
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	59,617
Available-for-Sale Securities, Gross Unrealized Losses, Total	$ (1,733)