Goodwill (Schedule of Accumulated Impairment Losses) (Details) - USD ($) $ in Millions		3 Months Ended	12 Months Ended
		Dec. 31, 2016	Sep. 30, 2016
Goodwill [Line Items]
Goodwill, gross		$ 1,064.6	$ 1,103.7
Goodwill, net		811.1	845.1
Industrial Gases - Americas [Member]
Goodwill [Line Items]
Goodwill, Accumulated impairment losses	[1]	(253.5)	(258.6)
Goodwill, net		305.1	309.1
Goodwill, Accumulated impairment losses currency translation		$ 51.7	$ 46.6

[1] Amount is attributable to the Industrial Gases – Americas segment and includes currency translation of $51.7 and $46.6 as of 31 December 2016 and 30 September 2016, respectively.