Business Segment Information (Reconciliation of Operating Income) (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Business separation costs	$ (30.2)	$ (12.0)
Cost reduction and asset actions	(50.0)	0.0
Operating Income	328.1	372.5
Operating Segments [Member]
Segment Reporting Information [Line Items]
Operating Income	408.3	384.5
Segment Reconciling Items [Member]
Segment Reporting Information [Line Items]
Business separation costs	(30.2)	(12.0)
Cost reduction and asset actions	$ (50.0)	$ 0.0