Business Segment Information (Reconciliation of Operating Income) (Details) - USD ($) $ in Millions		3 Months Ended			9 Months Ended
	May 01, 2019	Jun. 30, 2019	Dec. 31, 2018	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Segment Reporting Information [Line Items]
Operating income		$ 569.7		$ 515.8	$ 1,541.2	$ 1,431.9
Facility closure		0.0	$ (29.0)	0.0	(29.0)	0.0
Cost reduction actions		(25.5)		0.0	(25.5)	0.0
Gain on exchange of equity affiliate investments	$ 29.1	29.1		0.0	29.1	0.0
Segment Reconciling Items
Segment Reporting Information [Line Items]
Facility closure		0.0		0.0	(29.0)	0.0
Cost reduction actions		(25.5)		0.0	(25.5)	0.0
Gain on exchange of equity affiliate investments		29.1		0.0	29.1	0.0
Segment Total
Segment Reporting Information [Line Items]
Operating income		$ 566.1		$ 515.8	$ 1,566.6	$ 1,431.9