Pension, Postretirement and Postemployment Benefits - Assumptions used to determine year-end Pension and Postretirement Benefit Obligation (Details)	12 Months Ended
	Dec. 26, 2021	Dec. 27, 2020
Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Weighted average discount rate	2.91%	2.51%
Postretirement
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Weighted average discount rate	3.03%	2.72%
Health care cost trend rate assumed for next year	6.00%	6.25%
Rate to which the cost trend rate is assumed to decline (ultimate trend rate)	5.00%	5.00%