Note 9 - Postretirement and Postemployment Benefits - Allocation of Benefit Plan Assets (Details) - Other Postretirement Benefits Plan [Member]	Sep. 26, 2021	Sep. 27, 2020
Defined Benefit Plan, Equity Securities [Member]
Asset Percentage, Policy Allocation	20.00%
Asset Percentage, Actual Allocation	20.00%	20.00%
Defined Benefit Plan, Debt Security [Member]
Asset Percentage, Policy Allocation	70.00%
Asset Percentage, Actual Allocation	68.00%	70.00%
Hedge Funds [Member]
Asset Percentage, Policy Allocation	10.00%
Asset Percentage, Actual Allocation	12.00%	10.00%
Defined Benefit Plan, Cash and Cash Equivalents [Member]
Asset Percentage, Policy Allocation	0.00%
Asset Percentage, Actual Allocation	0.00%	0.00%

Percentage of target investment allocation to total plan assets. Includes, but is not limited to, percentage on weighted-average basis if more than one plan.

Reference 1: 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

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (d)(i)
-URI http://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920

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