Business Segment and Geographic Information (Reconciliation of Equity Affiliates' Income) (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Segment Reporting Information [Line Items]
Equity affiliates' income	$ 481.5	$ 294.1	$ 264.8
Equity method investment impairment charge	(14.8)
India Finance Act 2020			33.8
Segment Reconciling Items
Segment Reporting Information [Line Items]
Equity method investment impairment charge	(14.8)	0.0	0.0
India Finance Act 2020	0.0	0.0	33.8
Segment Total
Segment Reporting Information [Line Items]
Equity affiliates' income	$ 496.3	$ 294.1	$ 231.0