Goodwill (Schedule of Accumulated Impairment Losses) (Details) - USD ($) $ in Millions		Mar. 31, 2019	Sep. 30, 2018
Goodwill [Line Items]
Goodwill, gross		$ 1,203.8	$ 1,194.7
Goodwill, net		811.9	788.9
Industrial Gases - Americas
Goodwill [Line Items]
Goodwill, accumulated impairment losses	[1]	(391.9)	(405.8)
Goodwill, net		$ 160.1	$ 162.1

[1] Accumulated impairment losses are attributable to our Latin America reporting unit (LASA) within the Industrial Gases – Americas segment and include the impacts of currency translation.