Cost Reduction and Asset Actions (Narrative) (Details) $ in Millions	3 Months Ended			9 Months Ended		12 Months Ended
	Jun. 30, 2017 USD ($)	Dec. 31, 2016 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($) position	Jun. 30, 2016 USD ($)	Sep. 30, 2016 USD ($) position
Restructuring and Related Cost [Abstract]
Cost reduction and asset actions	$ 42.7		$ 13.2	$ 103.0	$ 23.9
Cost Reduction Actions [Member]
Restructuring and Related Cost [Abstract]
Cost reduction and asset actions	42.7			106.4		$ 34.5
Net expense cost reduction and asset actions				103.0
Favorable restructuring reserve settlement				3.4
Cost Reduction Actions [Member] | Severance And Other Benefits [Member]
Restructuring and Related Cost [Abstract]
Cost reduction and asset actions	9.5		$ 13.2	$ 27.5	$ 23.9	$ 34.5
Number of positions eliminated | position				270		610
Cost Reduction Actions [Member] | Asset Actions [Member]
Restructuring and Related Cost [Abstract]
Cost reduction and asset actions	$ 33.2			$ 78.9		$ 0.0
Cost Reduction Actions [Member] | Asset Actions [Member] | Industrial Gases - EMEA [Member]
Restructuring and Related Cost [Abstract]
Cost reduction and asset actions		$ 45.7