Income Taxes (Schedule of Unrecognized Tax Benefits Activity) (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Unrecognized Tax Benefits [Rollforward]
Unrecognized tax benefits, beginning of year	$ 21.0	$ 21.8	$ 25.5
Additions based on current year tax positions and acquisitions	1.8	1.7	1.8
Reductions for prior year tax positions and dispositions	0.0	0.0	(1.7)
Settlements with taxing authorities and statute expirations	(4.6)	(2.5)	(3.8)
Unrecognized tax benefits, end of year	$ 18.2	$ 21.0	$ 21.8