Earnings Per Share (Details) - $ / shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 27, 2020	Sep. 29, 2019	Sep. 27, 2020	Sep. 29, 2019
Reconciliation of basic net earnings per share to diluted net earnings per share
Basic net earnings per share	$ 1.35	$ 0.67	$ 4.93	$ 4.19
Average shares outstanding — basic	2,632,500	2,635,200	2,633,000	2,649,500
Potential shares exercisable under stock option plans	115,700	117,800	120,200	137,600
Less: shares which could be repurchased under treasury stock method	(78,900)	(83,800)	(82,400)	(99,700)
Convertible debt shares	0	700	0	700
Average shares outstanding — diluted	2,669,300	2,669,900	2,670,800	2,688,100
Diluted net earnings per share	$ 1.33	$ 0.66	$ 4.86	$ 4.13
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	20,000	19,000	17,000