Pension, Retiree Medical and Savings Plans (Level 3 Assets) (Details)	Dec. 25, 2021	Dec. 26, 2020
Corporate Bonds
Change in fair value of plan assets
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Percentage	32.00%	30.00%

Percentage of investment to total investment within defined benefit plan asset category.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (d)(ii)
-URI http://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 55
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=123450688&loc=d3e4179-114921

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Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant