Investments and Fair Value Measurements-AFS Investments (Details 4) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 30, 2014	Dec. 29, 2013
Fixed Income Securities [Member]
Available-for-sale investments
Amortized Cost	$ 5,233,370	$ 5,128,833
Gross Unrealized Gain	20,676	20,599
Gross Unrealized Loss	(3,201)	(4,179)
Fair Value	5,250,845	5,145,253
U.S. Treasury securities [Member]
Available-for-sale investments
Amortized Cost	143,141	160,598
Gross Unrealized Gain	6	21
Gross Unrealized Loss	(261)	(424)
Fair Value	142,886	160,195
U.S. Government-sponsored agency securities [Member]
Available-for-sale investments
Amortized Cost	0	8,112
Gross Unrealized Gain	0	10
Gross Unrealized Loss	0	(1)
Fair Value	0	8,121
International Government Securities [Member]
Available-for-sale investments
Amortized Cost	55,090	38,492
Gross Unrealized Gain	2	1
Gross Unrealized Loss	(200)	(224)
Fair Value	54,892	38,269
Corporate notes and bonds [Member]
Available-for-sale investments
Amortized Cost	948,512	864,331
Gross Unrealized Gain	1,660	1,504
Gross Unrealized Loss	(928)	(1,565)
Fair Value	949,244	864,270
Asset-backed securities [Member]
Available-for-sale investments
Amortized Cost	216,385	226,620
Gross Unrealized Gain	137	114
Gross Unrealized Loss	(239)	(170)
Fair Value	216,283	226,564
Mortgage-backed securities [Member]
Available-for-sale investments
Amortized Cost	83,951	86,542
Gross Unrealized Gain	107	18
Gross Unrealized Loss	(277)	(554)
Fair Value	83,781	86,006
Municipal notes and bonds [Member]
Available-for-sale investments
Amortized Cost	3,786,291	3,744,138
Gross Unrealized Gain	18,764	18,931
Gross Unrealized Loss	(1,296)	(1,241)
Fair Value	$ 3,803,759	$ 3,761,828