Financial Instruments (Details) - USD ($) $ in Thousands	Dec. 28, 2019	Mar. 30, 2019
Available-for-sale securities
Amortized Cost	$ 2,302,010	$ 3,096,631
Gross Unrealized Gains	1,344	893
Gross Unrealized Losses	(3,164)	(17,437)
Estimated Fair Value	2,300,190	3,080,087
Money Market Funds [Member]
Available-for-sale securities
Amortized Cost	444,604	428,150
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Value	444,604	428,150
Financial institution securities [Member]
Available-for-sale securities
Amortized Cost	400,000	537,795
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Value	400,000	537,795
Non-financial institution securities [Member]
Available-for-sale securities
Amortized Cost	426,959	702,483
Gross Unrealized Gains	20	3
Gross Unrealized Losses	(27)	(562)
Estimated Fair Value	426,952	701,924
U.S. Government and Agency Securities [Member]
Available-for-sale securities
Amortized Cost	211,644	334,185
Gross Unrealized Gains	10	39
Gross Unrealized Losses	(3)	(139)
Estimated Fair Value	211,651	334,085
Foreign Government and Agency Securities [Member]
Available-for-sale securities
Amortized Cost	334,353	214,455
Gross Unrealized Gains	5	0
Gross Unrealized Losses	0	0
Estimated Fair Value	334,358	214,455
Mortgage-Backed Securities [Member]
Available-for-sale securities
Amortized Cost	396,873	684,596
Gross Unrealized Gains	1,261	809
Gross Unrealized Losses	(2,683)	(14,635)
Estimated Fair Value	395,451	670,770
Asset-backed Securities [Member]
Available-for-sale securities
Amortized Cost	23,244	76,852
Gross Unrealized Gains	16	0
Gross Unrealized Losses	(22)	(483)
Estimated Fair Value	23,238	76,369
Commercial Mortgage Backed Securities [Member]
Available-for-sale securities
Amortized Cost	64,333	118,115
Gross Unrealized Gains	32	42
Gross Unrealized Losses	(429)	(1,618)
Estimated Fair Value	$ 63,936	$ 116,539