Supplemental Financial Information - Summary of Accounts Receivable (Details) - USD ($) $ in Millions	Jun. 30, 2023	Sep. 30, 2022
Current
Trade	$ 59.4	$ 56.2
Other	15.3	14.5
Receivables, gross	74.7	70.7
Allowance for credit losses	(2.8)	(4.6)
Receivables, net	71.9	66.1
Non-current
Other	7.6	0.1
Notes receivable	2.2	2.1
Noncurrent notes receivable, gross	9.8	2.2
Allowance for losses	(2.3)	(2.2)
Noncurrent notes receivable, net	$ 7.5	$ 0.0