Business Segment Information (Reconciliation of Operating Income) (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Segment Reporting Information [Line Items]
Operating income	$ 561.9	$ 548.5	$ 1,084.9	$ 1,087.6
Facility closure	0.0	(23.2)	0.0	(23.2)
Gain on exchange with joint venture partner	0.0	36.8	0.0	36.8
Segment Total
Segment Reporting Information [Line Items]
Operating income	561.9	534.9	1,084.9	1,074.0
Segment Reconciling Items
Segment Reporting Information [Line Items]
Facility closure	0.0	(23.2)	0.0	(23.2)
Gain on exchange with joint venture partner	$ 0.0	$ 36.8	$ 0.0	$ 36.8

Net gain (loss) resulting from an exchange of equity affiliate investments.

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- Definition

Amount of gain (loss) from the difference between the sale price or salvage price and the book value of an asset that was sold or retired, and gain (loss) from the write down of assets from their carrying value to fair value.

+ References

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-Publisher FASB
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- Definition

The net result for the period of deducting operating expenses from operating revenues.

+ References

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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