Accounts Receivable Facility (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2024	Mar. 31, 2023	Sep. 30, 2023
Accounts receivable sales agreement
Transfer of Financial Assets Accounted for as Sales [Line Items]
Loss on sale of accounts receivable	$ 1.6	$ 1.5	$ 2.8	$ 2.4
Accounts receivable sales agreement
Transfer of Financial Assets Accounted for as Sales [Line Items]
Accounts receivable sold through AR Facility	316.4	$ 315.5	532.5	$ 527.6
Transfer of accounts receivable, sales amount derecognized	$ 119.3		$ 119.3		$ 82.1