Acquisitions - Schedule of Recognized Identified Assets Acquired and Liabilities Assumed - Cubic (Details) - USD ($) $ in Millions	Feb. 28, 2023	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Business Combination [Line Items]
Goodwill		$ 3,839.0	$ 3,993.0	$ 3,529.0
Cubic
Business Combination [Line Items]
Receivables	$ 24.0
Inventory	18.0
Property	28.0
Goodwill	111.0
Intangible assets	54.0
All other assets	21.0
Total assets acquired	256.0
Less: Other liabilities assumed	(13.0)
Less: Deferred income taxes	(57.0)
Net assets acquired, excluding cash	186.0
Total purchase consideration, net of cash acquired	$ 186.0