Investments and Fair Value Measurements-AFS Investments (Details 4) (USD $) In Thousands, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 29, 2014	Dec. 29, 2013
Fixed Income Securities [Member]
Available-for-sale investments
Amortized Cost	$ 5,367,344	$ 5,128,833
Gross Unrealized Gain	21,729	20,599
Gross Unrealized Loss	(916)	(4,179)
Fair Value	5,388,157	5,145,253
U.S. Treasury securities [Member]
Available-for-sale investments
Amortized Cost	128,594	160,598
Gross Unrealized Gain	91	21
Gross Unrealized Loss	(64)	(424)
Fair Value	128,621	160,195
U.S. Government-sponsored agency securities [Member]
Available-for-sale investments
Amortized Cost	11,030	8,112
Gross Unrealized Gain	0	10
Gross Unrealized Loss	(12)	(1)
Fair Value	11,018	8,121
International Government Securities [Member]
Available-for-sale investments
Amortized Cost	57,343	38,492
Gross Unrealized Gain	30	1
Gross Unrealized Loss	(56)	(224)
Fair Value	57,317	38,269
Corporate notes and bonds [Member]
Available-for-sale investments
Amortized Cost	936,927	864,331
Gross Unrealized Gain	1,677	1,504
Gross Unrealized Loss	(316)	(1,565)
Fair Value	938,288	864,270
Asset-backed securities [Member]
Available-for-sale investments
Amortized Cost	218,261	226,620
Gross Unrealized Gain	210	114
Gross Unrealized Loss	(41)	(170)
Fair Value	218,430	226,564
Mortgage-backed securities [Member]
Available-for-sale investments
Amortized Cost	86,448	86,542
Gross Unrealized Gain	66	18
Gross Unrealized Loss	(160)	(554)
Fair Value	86,354	86,006
Municipal notes and bonds [Member]
Available-for-sale investments
Amortized Cost	3,928,741	3,744,138
Gross Unrealized Gain	19,655	18,931
Gross Unrealized Loss	(267)	(1,241)
Fair Value	$ 3,948,129	$ 3,761,828