CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) (Parenthetical) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 28, 2019	Sep. 29, 2018	Sep. 28, 2019	Sep. 29, 2018
Other comprehensive income/(loss):
Change in fair value of marketable securities, tax benefit (cost)	$ 176	$ 5,853	$ (288)	$ 5,435
Change in fair value of interest rate swap and marketable securities, tax benefit (cost)	15,720	12,263	85,537	71,428
Change in pension and postretirement benefit costs, tax	$ 75,138	$ 65,842	$ 217,014	$ 197,527