Business Segment Information (Reconciliation of Operating Income) (Details) - USD ($) $ in Millions		3 Months Ended
		Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Operating income		$ 561.0	$ 455.0
Facility closure		0.0	(29.0)
Segment Reconciling Items
Segment Reporting Information [Line Items]
Facility closure		0.0	(29.0)
Segment Total
Segment Reporting Information [Line Items]
Operating income	[1]	$ 561.0	$ 484.0

[1] Refer to the Reconciliation to Consolidated Results section below.