Financial Instruments (Details 1) (USD $) In Thousands, unless otherwise specified	Jun. 28, 2014	Mar. 29, 2014
Fair values and gross unrealized losses of the investments
Available-for-Sale Securities, Less Than 12 Months, Fair Value	$ 677,338	$ 751,113
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	(2,415)	(13,394)
Available-for-Sale Securities, 12 Months or Greater, Fair Value	382,665	158,767
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses	(8,514)	(4,759)
Available-for-Sale Securities, Fair Value, Total	1,060,003	909,880
Available-for-Sale Securities, Gross Unrealized Losses, Total	(10,929)	(18,153)
Non-financial institution securities [Member]
Fair values and gross unrealized losses of the investments
Available-for-Sale Securities, Less Than 12 Months, Fair Value	32,613	112,470
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	(84)	(1,167)
Available-for-Sale Securities, 12 Months or Greater, Fair Value	19,902	4,488
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses	(260)	(77)
Available-for-Sale Securities, Fair Value, Total	52,515	116,958
Available-for-Sale Securities, Gross Unrealized Losses, Total	(344)	(1,244)
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	20,704	20,160
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses	(796)	(1,340)
Available-for-Sale Securities, Fair Value, Total	20,704	20,160
Available-for-Sale Securities, Gross Unrealized Losses, Total	(796)	(1,340)
Municipal Bonds [Member]
Fair values and gross unrealized losses of the investments
Available-for-Sale Securities, Less Than 12 Months, Fair Value	4,026	5,917
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	(6)	(166)
Available-for-Sale Securities, 12 Months or Greater, Fair Value	4,603	1,743
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses	(137)	(39)
Available-for-Sale Securities, Fair Value, Total	8,629	7,660
Available-for-Sale Securities, Gross Unrealized Losses, Total	(143)	(205)
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	250,910	118,125
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	(31)	(184)
Available-for-Sale Securities, 12 Months or Greater, Fair Value	4,369	0
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses	(49)	0
Available-for-Sale Securities, Fair Value, Total	255,279	118,125
Available-for-Sale Securities, Gross Unrealized Losses, Total	(80)	(184)
Foreign Government Debt Securities [Member]
Fair values and gross unrealized losses of the investments
Available-for-Sale Securities, Less Than 12 Months, Fair Value	124,968
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	(6)
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	124,968
Available-for-Sale Securities, Gross Unrealized Losses, Total	(6)
Mortgage-Backed Securities [Member]
Fair values and gross unrealized losses of the investments
Available-for-Sale Securities, Less Than 12 Months, Fair Value	234,724	457,903
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	(2,223)	(7,225)
Available-for-Sale Securities, 12 Months or Greater, Fair Value	274,363	132,376
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses	(4,647)	(3,303)
Available-for-Sale Securities, Fair Value, Total	509,087	590,279
Available-for-Sale Securities, Gross Unrealized Losses, Total	(6,870)	(10,528)
Debt Mutual Fund [Member]
Fair values and gross unrealized losses of the investments
Available-for-Sale Securities, Less Than 12 Months, Fair Value	0	56,698
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	0	(4,652)
Available-for-Sale Securities, 12 Months or Greater, Fair Value	58,724	0
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses	(2,625)	0
Available-for-Sale Securities, Fair Value, Total	58,724	56,698
Available-for-Sale Securities, Gross Unrealized Losses, Total	(2,625)	(4,652)
Bank Loans [Member]
Fair values and gross unrealized losses of the investments
Available-for-Sale Securities, Less Than 12 Months, Fair Value	30,097
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	(65)
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	30,097
Available-for-Sale Securities, Gross Unrealized Losses, Total	$ (65)