Share-Based Compensation (Compensation Cost Recognized in Income Statement) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Share-based Payment Arrangement, Additional Disclosure [Abstract]
Before-tax share-based compensation cost	$ 17.6	$ 14.5	$ 46.0	$ 46.9
Income tax benefit	(4.2)	(3.5)	(11.1)	(11.4)
After-tax share-based compensation cost	$ 13.4	$ 11.0	$ 34.9	$ 35.5