Debt - Schedule of Long-term Debt Instruments (Details) - USD ($) $ in Millions	Jun. 30, 2023	Sep. 30, 2022	Jul. 01, 2020
Debt Instrument [Line Items]
Capital lease obligations	$ 32.0	$ 32.3
Long-term Debt and Lease Obligation	3,423.1	3,551.4
Less current portion	(12.3)	(12.4)
Less unamortized debt premium and debt issuance fees	(33.8)	(39.6)
Total long-term debt	3,377.0	3,499.4
Secured Debt | Senior Secured Term Loan Facility due 2027
Debt Instrument [Line Items]
Total long-term debt, including current maturities	$ 1,007.0	1,182.0
Stated interest rate of debt	0.25%
Face amount of debt	$ 3.0
Senior Notes | 4.625% Senior Notes due 2026
Debt Instrument [Line Items]
Total long-term debt, including current maturities	791.3	800.0
Senior Notes | 6.500% Senior Notes due 2027
Debt Instrument [Line Items]
Total long-term debt, including current maturities	300.0	300.0
Senior Notes | Senior Notes, 4.375%, Due 2029
Debt Instrument [Line Items]
Total long-term debt, including current maturities	$ 583.7	600.0
Stated interest rate of debt	4.375%
Senior Notes | Senior Notes, 4.750%, Due 2028
Debt Instrument [Line Items]
Stated interest rate of debt			475.00%
Senior Notes | 3.50% Senior Notes due 2029
Debt Instrument [Line Items]
Total long-term debt, including current maturities	$ 709.1	$ 637.1