Summary of Significant Accounting Policies - Trade receivables, Inventories and Property, plant, and equipment (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Trade Receivables
Reserve for trade receivables	$ 11.3	$ 13.6
Inventories
Raw materials and components	164.7	247.0
Work in process	81.9	127.6
Finished goods	97.4	150.6
Total inventories	344.0	525.2
Properties
Depreciation expense	39.8	51.4	$ 42.1
Cost	483.5	582.2
Accumulated Depreciation	(245.0)	(265.6)
Impairment, Long-Lived Asset, Held-for-Use	$ 0.0	0.0	$ 0.0
Minimum
Properties
Finite-Lived Intangible Asset, Useful Life	3 years
Maximum
Properties
Finite-Lived Intangible Asset, Useful Life	21 years
Land and land improvements
Properties
Cost	$ 23.7	28.6
Accumulated Depreciation	(0.4)	(0.8)
Buildings and building equipment
Properties
Cost	133.6	143.0
Accumulated Depreciation	$ (52.0)	(51.1)
Buildings and building equipment | Minimum
Properties
Estimated useful lives	3 years
Buildings and building equipment | Maximum
Properties
Estimated useful lives	50 years
Machinery and equipment
Properties
Cost	$ 326.2	410.6
Accumulated Depreciation	$ (192.6)	$ (213.7)
Machinery and equipment | Minimum
Properties
Estimated useful lives	3 years
Machinery and equipment | Maximum
Properties
Estimated useful lives	25 years