Business Segment Information (Reconciliation of Operating Income) (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Operating income	$ 455.0	$ 460.7
Facility closure	(29.0)	0.0
Segment Reconciling Items
Segment Reporting Information [Line Items]
Facility closure	(29.0)	0.0
Segment Total
Segment Reporting Information [Line Items]
Operating income	$ 484.0	$ 460.7