Marketable Securities (Details) - USD ($) $ in Millions	Dec. 29, 2023	Sep. 29, 2023
Other Current Assets [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Current	$ 15.9	$ 15.6
Other Noncurrent Assets [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Noncurrent	2.0	4.1
US Treasury and Government [Member] | Other Current Assets [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Current	15.7	15.1
US Treasury and Government [Member] | Other Noncurrent Assets [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Noncurrent	2.0	4.1
Corporate Debt Securities [Member] | Other Current Assets [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Current	0.2	0.0
Corporate Debt Securities [Member] | Other Noncurrent Assets [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Noncurrent	0.0	0.0
US States and Political Subdivisions Debt Securities [Member] | Other Current Assets [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Current	0.0	0.5
US States and Political Subdivisions Debt Securities [Member] | Other Noncurrent Assets [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Noncurrent	$ 0.0	$ 0.0