Pension Plans (Schedule of Defined Benefit Plans Disclosures) (Details) - USD ($) $ in Millions	Sep. 30, 2018	Sep. 30, 2017
Amounts Recognized in the Consolidated Balance Sheets
Noncurrent liabilities	$ (70.2)	$ (87.7)
United States | Pension Plan
Amounts Recognized in the Consolidated Balance Sheets
Noncurrent assets	0.0	0.0
Current liabilities	(2.5)	(3.0)
Noncurrent liabilities	(36.0)	(45.7)
Net amount recognized	(38.5)	(48.7)
Amounts Recognized in Accumulated Other Comprehensive Loss
Net loss, pre tax	(149.2)	(149.7)
International | Pension Plan
Amounts Recognized in the Consolidated Balance Sheets
Noncurrent assets	17.1	4.1
Current liabilities	(0.6)	(0.6)
Noncurrent liabilities	(27.5)	(33.2)
Net amount recognized	(11.0)	(29.7)
Amounts Recognized in Accumulated Other Comprehensive Loss
Net loss, pre tax	$ (29.9)	$ (57.1)