Commitments and Contingencies - Warranty Claims (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024	Mar. 31, 2025	Sep. 30, 2024	Mar. 31, 2024	Sep. 30, 2023
Movement in Standard Product Warranty Accrual [Roll Forward]
Standard Product Warranty Accrual	$ 564.7	$ 567.6	$ 564.7	$ 567.6	$ 557.3	$ 566.9	$ 544.6	$ 512.4
Standard Product Warranty Accrual, Increase for Warranties Issued	51.5	58.1	138.5	156.6
Standard Product Warranty Accrual, Increase (Decrease) for Preexisting Warranties	(13.4)	(4.9)	(51.4)	(12.5)
Standard Product Warranty Accrual, Decrease for Payments	$ 30.7	$ 30.2	$ 89.3	$ 88.9

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

No definition available.

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- Definition

Amount as of the balance sheet date of the aggregate standard product warranty liability. Does not include the balance for the extended product warranty liability.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 460
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 8
-Subparagraph (c)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482425/460-10-50-8

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 460
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 8
-Subparagraph (c)(5)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482425/460-10-50-8

+ Details

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- Definition

Amount of decrease in the standard product warranty accrual from payments made in cash or in kind to satisfy claims under the terms of the standard product warranty. Excludes extended product warranties.

+ References

+ Details

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- Definition

Amount of increase (decrease) in the standard product warranty accrual from changes in estimates attributable to preexisting product warranties. Excludes extended product warranties.

+ References

+ Details

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- Definition

Amount of increase in the standard product warranty accrual from warranties issued. Excludes extended product warranties.

+ References

+ Details

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