Goodwill (Narrative) (Details) - USD ($) $ in Millions		3 Months Ended	12 Months Ended
		Sep. 30, 2014	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2013
Goodwill [Line Items]
Goodwill, net		$ 1,237.3	$ 1,237.3	$ 1,131.3	$ 1,653.8
Goodwill impairment charge		305.2	305.2
Goodwill accumulated impairment losses	[1]	$ 284.8	$ 284.8	$ 243.7	$ 0.0

[1] Amount is attributable to the Industrial Gases – Americas segment and includes currency translation of $61.5 and $20.4 as of 30 September 2015 and 30 September 2014, respectively.