Operating Segments and Geographic Data (Schedule Of Concentration Of Revenue From Individual Geographic Regions) (Details)	12 Months Ended
	Sep. 24, 2021	Sep. 25, 2020	Sep. 27, 2019
Revenue from External Customer [Line Items]
Document Period End Date	Sep. 24, 2021
Concentration of revenue from individual geographic regions	100.00%	100.00%	100.00%
United States
Revenue from External Customer [Line Items]
Concentration of revenue from individual geographic regions	33.00%	40.00%	36.00%
South Korea [Member]
Revenue from External Customer [Line Items]
Concentration of revenue from individual geographic regions	14.00%	12.00%	12.00%
China [Member]
Revenue from External Customer [Line Items]
Concentration of revenue from individual geographic regions	23.00%	20.00%	20.00%
Japan [Member]
Revenue from External Customer [Line Items]
Concentration of revenue from individual geographic regions	11.00%	9.00%	11.00%
Europe [Member]
Revenue from External Customer [Line Items]
Concentration of revenue from individual geographic regions	10.00%	10.00%	12.00%
Other [Member]
Revenue from External Customer [Line Items]
Concentration of revenue from individual geographic regions	9.00%	9.00%	9.00%