CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE EARNINGS - USD ($) $ in Thousands	3 Months Ended
	Mar. 27, 2021	Mar. 28, 2020
Statement of Comprehensive Income [Abstract]
Net earnings	$ 1,495,093	$ 667,335
Other Comprehensive Earnings [Abstract]
Unrealized loss on debt securities net of income taxes of $(35,287) and $(46,904) in 2021 and 2020, respectively.	(103,548)	(137,583)
Reclassification adjustment for net realized gain on debt securities net of income taxes of $(1,904) and $(588) in 2021 and 2020, respectively.	(5,583)	(1,726)
Adjustment to postretirement benefit obligation	1,379	815
Comprehensive earnings	$ 1,387,341	$ 528,841