Summary of Significant Accounting Policies - Other (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Trade receivables, net	$ 297.3	$ 350.1
Total operating lease liabilities	$ 96.7	$ 163.1
Treasury Stock
Shares Repurchased and Classified as Treasury Stock (shares)	0
Shares issued from treasury stock under various stock compensation programs (in shares)	300,000	300,000	1,000,000
Preferred stock
Authorized shares of preferred stock (in shares)	1,000,000
Preferred stock par value (in dollars per share)	$ 0
Shares issued	0
Accumulated other comprehensive loss
Currency translation	$ (51.9)	$ (55.4)
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Plan Amendments, Tax Effect	4.8	4.9
Pension and postretirement (net of taxes of $4.8 and $4.9)	(13.8)	(15.6)
Unrealized Gain (Loss), Investment and Derivative, Operating, Tax Expense (Benefit)	0.2	(0.4)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	1,424.2	1,457.4	$ 1,662.9	$ 1,108.0
Accumulated other comprehensive loss	(128.1)	(96.6)
Research and Development Costs
Research and development costs	34.1	36.7	25.4
Warranty costs
Warranty reserves	46.0	47.9
Warranty costs	12.3	19.4	15.2
Business acquisitions and related business acquisition and transition costs
Operating lease right-of-use assets, net	104.1	168.7
Supplier Finance Program
Contractual Obligation	13.7	16.0
Accumulated Other Comprehensive Loss
Accumulated other comprehensive loss
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	(128.1)	(96.6)	(147.1)	(155.6)
Retained Earnings
Accumulated other comprehensive loss
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	1,024.0	1,045.2	1,319.6	812.0
Net Unrealized (Loss) Gain on Derivative Instruments
Accumulated other comprehensive loss
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	$ (62.4)	(25.6)	$ (5.5)	$ (9.1)
Maximum
Length of Time Hedged in Currency Exchange Rates	24 months
Accounting Standards Update 2016-02 [Member]
Business acquisitions and related business acquisition and transition costs
Operating lease right-of-use assets, net		$ 168.7