Investments (Details) (USD $) In Thousands, unless otherwise specified	Jun. 28, 2014	Dec. 28, 2013
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	$ 1,257,224	$ 1,287,802
Available-for-Sale Investments, Gross Unrealized Gains	793	715
Available-for-Sale Investments, Gross Unrealized Losses	(428)	(367)
Available-for-sale Securities	1,257,589	1,288,150
Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	118,188	68,435
Available-for-Sale Investments, Gross Unrealized Gains	0	0
Available-for-Sale Investments, Gross Unrealized Losses	0	0
Available-for-sale Securities	118,188	68,435
Cash and Cash Equivalents [Member] | Money Market Funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	108,180	57,254
Available-for-Sale Investments, Gross Unrealized Gains	0	0
Available-for-Sale Investments, Gross Unrealized Losses	0	0
Available-for-sale Securities	108,180	57,254
Cash and Cash Equivalents [Member] | Bank Time Deposits [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	10,008	7,771
Available-for-Sale Investments, Gross Unrealized Gains	0	0
Available-for-Sale Investments, Gross Unrealized Losses	0	0
Available-for-sale Securities	10,008	7,771
Cash and Cash Equivalents [Member] | Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis		3,000
Available-for-Sale Investments, Gross Unrealized Gains		0
Available-for-Sale Investments, Gross Unrealized Losses		0
Available-for-sale Securities		3,000
Cash and Cash Equivalents [Member] | Government And Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis		410
Available-for-Sale Investments, Gross Unrealized Gains		0
Available-for-Sale Investments, Gross Unrealized Losses		0
Available-for-sale Securities		410
Short-term Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	673,111	676,723
Available-for-Sale Investments, Gross Unrealized Gains	470	369
Available-for-Sale Investments, Gross Unrealized Losses	(49)	(88)
Available-for-sale Securities	673,532	677,004
Short-term Investments [Member] | Bank Time Deposits [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	78,955	70,303
Available-for-Sale Investments, Gross Unrealized Gains	2	12
Available-for-Sale Investments, Gross Unrealized Losses	(2)	0
Available-for-sale Securities	78,955	70,315
Short-term Investments [Member] | Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	33,000	33,750
Available-for-Sale Investments, Gross Unrealized Gains	12	1
Available-for-Sale Investments, Gross Unrealized Losses	(2)	(9)
Available-for-sale Securities	33,010	33,742
Short-term Investments [Member] | Government And Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	561,156	572,670
Available-for-Sale Investments, Gross Unrealized Gains	456	356
Available-for-Sale Investments, Gross Unrealized Losses	(45)	(79)
Available-for-sale Securities	561,567	572,947
Long-term investments [Member] | Government And Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	465,925	542,644
Available-for-Sale Investments, Gross Unrealized Gains	323	346
Available-for-Sale Investments, Gross Unrealized Losses	(379)	(279)
Available-for-sale Securities	$ 465,869	$ 542,711