Fair Value Measurements for Investments (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 30, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable Securities	$ 6,628,889	$ 6,433,311
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable Securities	2,774,860	2,545,320
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable Securities	3,854,029	3,887,991
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable Securities	$ 0	$ 0