Marketable Securities (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 29, 2023	Sep. 30, 2022
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Noncurrent, Maximum Contractual Maturity	2 years
Debt Securities, Available-for-sale, Current	$ 15.6	$ 20.3
Debt Securities, Available-for-sale, Noncurrent	4.1	0.5
US Treasury and Government [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Current	15.1	13.1
Debt Securities, Available-for-sale, Noncurrent	4.1	0.5
Corporate Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Current	0.0	0.2
Debt Securities, Available-for-sale, Noncurrent	0.0	0.0
US States and Political Subdivisions Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Current	0.5	7.0
Debt Securities, Available-for-sale, Noncurrent	$ 0.0	$ 0.0