Supplemental Information (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021	Sep. 30, 2021
Related Party Transaction [Line Items]
Trade receivables, net	$ 185.0		$ 185.0		$ 90.0
Related party debt, including current portion	371.1		371.1		$ 358.4
Facility closure	0.0	$ 23.2	0.0	$ 23.2
Noncash ROU asset additions			150.0
Equity affiliate and joint venture partner
Related Party Transaction [Line Items]
Sales to and other income from related parties	$ 60.0	$ 40.0	$ 125.0	$ 90.0

Amount of receivables arising from transactions with related parties due within one year or the normal operating cycle, if longer.

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