Debt - Trade Receivables Facility (Details)		12 Months Ended
	Mar. 01, 2023 USD ($)	Sep. 30, 2023 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)
Debt Instrument [Line Items]
Repayments of Debt		$ 920,900,000	$ 38,100,000	$ 800,000,000.0
Gain (loss) on extinguishment of debt		$ 0	0	$ (36,400,000)
2022 Credit Facilities | Line of Credit
Debt Instrument [Line Items]
Maximum consolidated leverage ratio		4.5
Minimum consolidated interest coverage ratio		3.0
Secured Debt | Trade Receivables Facility | Line of Credit
Debt Instrument [Line Items]
Repayments of Debt	$ 175,000,000
Gain (loss) on extinguishment of debt		$ 1,000,000
Secured Debt | Trade Receivables Facility | Line of Credit | Financing Subsidiary
Debt Instrument [Line Items]
Accounts receivable pledged as collateral			387,900,000
Revolver | Trade Receivables Facility
Debt Instrument [Line Items]
Trade Receivables Facility		$ 0	$ 105,000,000