Amortized Cost and Fair Value of Available for Sale Securities by Expected Maturity (Detail) - USD ($) $ in Thousands	Sep. 26, 2020	Dec. 28, 2019
Cost
Due in one year or less	$ 645,524	$ 437,236
Due after one year through five years	5,089,321	3,836,333
Due after five years through ten years	2,503,518	1,661,143
Due after ten years	3,946	5,238
Total	8,242,309	5,939,950
Fair Value
Due in one year or less	650,446	438,105
Due after one year through five years	5,277,428	3,900,904
Due after five years through ten years	2,603,665	1,727,594
Due after ten years	4,240	5,436
Total	$ 8,535,779	$ 6,072,039