Goodwill (Schedule of Goodwill by Segment) (Details) - USD ($) $ in Millions		3 Months Ended	12 Months Ended
		Dec. 31, 2015	Sep. 30, 2015	Dec. 31, 2015	Sep. 30, 2015
Goodwill [Roll Forward]
Goodwill, net, Beginning Balance		$ 1,131.3
Goodwill, Currency Translation		(15.9)
Goodwill, net, Ending Balance		1,115.4	$ 1,131.3
Goodwill Impaired Accumulated Impairment Loss Abstract
Goodwill, gross				$ 1,354.8	$ 1,375.0
Goodwill, Accumulated impairment losses	[1]			(239.4)	(243.7)
Goodwill, net		1,131.3	1,131.3	1,115.4	1,131.3
Industrial Gases - Americas [Member]
Goodwill [Roll Forward]
Goodwill, net, Beginning Balance		297.6
Goodwill, Currency Translation		(3.3)
Goodwill, net, Ending Balance		294.3	297.6
Goodwill Impaired Accumulated Impairment Loss Abstract
Goodwill, Accumulated impairment losses	[1]			(239.4)	(243.7)
Goodwill, net		294.3	297.6	294.3	297.6
Goodwill, Accumulated impairment losses currency translation		65.8	61.5
Industrial Gases - EMEA [Member]
Goodwill [Roll Forward]
Goodwill, net, Beginning Balance		386.5
Goodwill, Currency Translation		(12.2)
Goodwill, net, Ending Balance		374.3	386.5
Goodwill Impaired Accumulated Impairment Loss Abstract
Goodwill, net		386.5	386.5	374.3	386.5
Industrial Gases - Asia [Member]
Goodwill [Roll Forward]
Goodwill, net, Beginning Balance		133.1
Goodwill, Currency Translation		0.1
Goodwill, net, Ending Balance		133.2	133.1
Goodwill Impaired Accumulated Impairment Loss Abstract
Goodwill, net		133.1	133.1	133.2	133.1
Industrial Gases - Global [Member]
Goodwill [Roll Forward]
Goodwill, net, Beginning Balance		19.9
Goodwill, Currency Translation		(0.2)
Goodwill, net, Ending Balance		19.7	19.9
Goodwill Impaired Accumulated Impairment Loss Abstract
Goodwill, net		19.9	19.9	19.7	19.9
Materials Technologies [Member]
Goodwill [Roll Forward]
Goodwill, net, Beginning Balance		294.2
Goodwill, Currency Translation		(0.3)
Goodwill, net, Ending Balance		293.9	294.2
Goodwill Impaired Accumulated Impairment Loss Abstract
Goodwill, net		$ 294.2	$ 294.2	$ 293.9	$ 294.2

[1] Amount is attributable to the Industrial Gases – Americas segment and includes currency translation of $65.8 and $61.5 as of 31 December 2015 and 30 September 2015, respectively.