Cost Reduction and Asset Actions (Carrying Amount of Accrual) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2017	Mar. 31, 2016	Sep. 30, 2016
Restructuring Cost and Reserve [Line Items]
Cost reduction and asset actions	$ 10.3	$ 10.7	$ 60.3	$ 10.7
Cost Reduction Actions [Member]
Restructuring Cost and Reserve [Line Items]
Cost reduction and asset actions			63.7		$ 34.5
Noncash expenses			(45.7)
Amount reflected in pension liability			(0.2)		(0.9)
Cash expenditures			(18.8)		(21.6)
Currency translation adjustment			(0.5)		0.3
Accrued balance	10.8		10.8		12.3
Cost Reduction Actions [Member] | Severance And Other Benefits [Member]
Restructuring Cost and Reserve [Line Items]
Cost reduction and asset actions	10.3	$ 10.7	18.0	$ 10.7	34.5
Noncash expenses			0.0
Amount reflected in pension liability			(0.2)		(0.9)
Cash expenditures			(18.8)		(21.6)
Currency translation adjustment			(0.5)		0.3
Accrued balance	10.8		10.8		12.3
Cost Reduction Actions [Member] | Asset Actions [Member]
Restructuring Cost and Reserve [Line Items]
Cost reduction and asset actions			45.7		0.0
Noncash expenses			(45.7)
Amount reflected in pension liability			0.0		0.0
Cash expenditures			0.0		0.0
Currency translation adjustment			0.0		0.0
Accrued balance	$ 0.0		$ 0.0		$ 0.0