Schedule of Amortized Cost and Fair Value of Cash Equivalents, Short-Term Investments and Restricted Investments with Contractual Maturities (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 28, 2014
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Due in one year or less, cost	$ 888,234
Due after one year through five years, cost	1,505,237
Due in more than five years, cost	335,657
Cost	2,729,128
Due in one year or less, estimated fair value	888,312
Due after one year through five years, estimated fair value	1,502,762
Due in more than five years, estimated fair value	334,651
Estimated fair value due, Total	$ 2,725,725