Borrowings and Credit Arrangements - Interest Expense Senior Notes (Details) - USD ($)	3 Months Ended		6 Months Ended
	Mar. 30, 2019	Mar. 31, 2018	Mar. 30, 2019	Mar. 31, 2018	Jan. 19, 2018
Line of Credit Facility [Line Items]
Interest expense	$ 15,700,000	$ 20,200,000	$ 31,400,000	$ 37,700,000
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	$ 4,800,000	4,000,000	$ 9,600,000	4,000,000
Senior Notes | 2025 Senior Notes
Line of Credit Facility [Line Items]
Stated interest rate	4.375%		4.375%
Interest expense	$ 10,900,000	9,400,000	$ 21,800,000	12,900,000
Senior Notes | 2022 Senior Notes
Line of Credit Facility [Line Items]
Stated interest rate	5.25%		5.25%
Interest expense	$ 0	$ 7,100,000	$ 0	$ 21,100,000