Related Party Transactions (Details) - USD ($) $ in Millions		12 Months Ended
	Oct. 01, 2016	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Related Party Transaction [Line Items]
Transition Service Agreement, Additional Fee Due Over Cost, Percentage	5.00%
Minimum
Related Party Transaction [Line Items]
Transition Services Agreement Term	12 months
Maximum
Related Party Transaction [Line Items]
Transition Services Agreement Term	24 months
Air Products
Related Party Transaction [Line Items]
Total Allocated Costs		$ 0.0	$ 21.3	$ 26.3
Cost of sales | Air Products
Related Party Transaction [Line Items]
Total Allocated Costs		0.0	2.8	3.6
Selling and administrative | Air Products
Related Party Transaction [Line Items]
Total Allocated Costs		0.0	16.8	17.8
Research and development | Air Products
Related Party Transaction [Line Items]
Total Allocated Costs		0.0	1.0	1.4
Business restructuring and cost reduction actions | Air Products
Related Party Transaction [Line Items]
Total Allocated Costs		$ 0.0	$ 0.7	$ 3.5