Financial Instruments - Schedule of Cash, Cash Equivalents, Short-Term Investments and Restricted Cash and Investments Unrealized Loss Positions (Details) $ in Thousands	Jun. 28, 2020 USD ($)
Fair Value
Unrealized Losses Less than 12 Months	$ 534,040
Unrealized Losses 12 Months or Greater	5,011
Total	539,051
Gross Unrealized Loss
Unrealized Losses Less than 12 Months	(605)
Unrealized Losses 12 Months or Greater	(639)
Total	(1,244)
U.S. Treasury and agencies
Fair Value
Unrealized Losses Less than 12 Months, available for sale	189,437
Unrealized Losses 12 Months or Greater, available for sale	0
Total, available for sale	189,437
Gross Unrealized Loss
Unrealized Losses Less than 12 Months, available for sale	(9)
Unrealized Losses 12 Months or Greater, available for sale	0
Total, available for sale	(9)
Mutual funds
Fair Value
Unrealized Losses Less than 12 Months, trading	2,623
Unrealized Losses 12 Months or Greater, trading	5,011
Total, trading	7,634
Gross Unrealized Loss
Unrealized Losses Less than 12 Months, trading	(289)
Unrealized Losses 12 Months or Greater	(639)
Total, trading	(928)
Foreign government bonds
Fair Value
Unrealized Losses Less than 12 Months, available for sale	9,056
Unrealized Losses 12 Months or Greater, available for sale	0
Total, available for sale	9,056
Gross Unrealized Loss
Unrealized Losses Less than 12 Months, available for sale	(5)
Unrealized Losses 12 Months or Greater, available for sale	0
Total, available for sale	(5)
Corporate notes and bonds
Fair Value
Unrealized Losses Less than 12 Months, available for sale	332,924
Unrealized Losses 12 Months or Greater, available for sale	0
Total, available for sale	332,924
Gross Unrealized Loss
Unrealized Losses Less than 12 Months, available for sale	(302)
Unrealized Losses 12 Months or Greater, available for sale	0
Total, available for sale	$ (302)