Business Segment Information (Reconciliation of Operating Income) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Jun. 30, 2022	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021
Segment Reporting Information [Line Items]
Operating income	$ 627.4	$ 577.1		$ 1,712.3	$ 1,664.7
Facility closure	0.0	0.0	$ (23.2)	0.0	(23.2)
Gain on exchange with joint venture partner	0.0	0.0		0.0	36.8
Segment Total
Segment Reporting Information [Line Items]
Operating income	627.4	577.1		1,712.3	1,651.1
Segment Reconciling Items
Segment Reporting Information [Line Items]
Facility closure	0.0	0.0		0.0	(23.2)
Gain on exchange with joint venture partner	$ 0.0	$ 0.0		$ 0.0	$ 36.8

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

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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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- Definition

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

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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

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