Business Separation Costs (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2017	Mar. 31, 2016
Restructuring Cost and Reserve [Line Items]
Business separation costs	$ 0.0	$ 7.4	$ 30.2	$ 19.4
Materials Technologies [Member]
Restructuring Cost and Reserve [Line Items]
Business separation costs	$ 0.0	$ 7.4	$ 30.2	$ 19.4

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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