Goodwill (Schedule of Goodwill by Segment) (Details) $ in Millions	3 Months Ended
	Dec. 31, 2016 USD ($)
Goodwill [Roll Forward]
Goodwill, net, beginning balance	$ 845.1
Currency translation	(34.0)
Goodwill, net, ending balance	811.1
Industrial Gases - Americas [Member]
Goodwill [Roll Forward]
Goodwill, net, beginning balance	309.1
Currency translation	(4.0)
Goodwill, net, ending balance	305.1
Industrial Gases - EMEA [Member]
Goodwill [Roll Forward]
Goodwill, net, beginning balance	380.6
Currency translation	(26.9)
Goodwill, net, ending balance	353.7
Industrial Gases - Asia [Member]
Goodwill [Roll Forward]
Goodwill, net, beginning balance	135.2
Currency translation	(2.7)
Goodwill, net, ending balance	132.5
Industrial Gases - Global [Member]
Goodwill [Roll Forward]
Goodwill, net, beginning balance	20.2
Currency translation	(0.4)
Goodwill, net, ending balance	$ 19.8