Borrowings and Credit Arrangements - Interest Expense Senior Notes (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 27, 2020	Jun. 29, 2019	Jun. 27, 2020	Jun. 29, 2019	Jan. 19, 2018
Line of Credit Facility [Line Items]
Interest expense	$ 15.7	$ 15.7	$ 47.1	$ 47.1
2025 Senior Notes
Line of Credit Facility [Line Items]
Stated interest rate	4.375%		4.375%
Senior Notes | 2028 Senior Notes
Line of Credit Facility [Line Items]
Stated interest rate	4.625%		4.625%		4.625%
Interest expense	$ 4.8	4.8	$ 14.4	14.4
Senior Notes | 2025 Senior Notes
Line of Credit Facility [Line Items]
Stated interest rate	4.375%		4.375%
Interest expense	$ 10.9	$ 10.9	$ 32.7	$ 32.7