Supplemental Balance Sheet Information - Property, Plant, and Equipment (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Property, Plant, and Equipment
Property, plant and equipment, gross	$ 1,233.8	$ 1,015.9
Accumulated depreciation	(415.5)	(347.3)
Property, plant and equipment, net	818.3	668.6
Accumulated depreciation	(50.0)	(34.2)
Net finance lease assets	240.0	217.1
Depreciation	72.0	54.7	$ 46.8
Land
Property, Plant, and Equipment
Property, plant and equipment, gross	148.5	134.7
Total finance lease assets	85.4	75.3
Buildings
Property, Plant, and Equipment
Property, plant and equipment, gross	725.1	562.8
Total finance lease assets	154.6	141.8
Machinery and equipment
Property, Plant, and Equipment
Property, plant and equipment, gross	302.6	236.0
Construction in progress
Property, Plant, and Equipment
Property, plant and equipment, gross	57.6	82.4
Assets held under capital and finance leases
Property, Plant, and Equipment
Total finance lease assets	240.0	217.1
Accumulated depreciation	(50.0)	(34.2)
Net finance lease assets	$ 190.0	$ 182.9