Accumulated Other Comprehensive Loss - Reclassifications out of Other Comprehensive Loss (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net income	$ (24.1)	$ (23.6)
Sales	(1,586.6)	(1,490.3)
Cost of sales	(889.5)	(848.0)
Selling, general and administrative expenses	(389.3)	(370.0)
Accumulated Defined Benefit Plans Adjustment, Net Prior Service Attributable to Parent [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income before income taxes	(1.1)	(2.3)
Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Attributable to Parent [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income before income taxes	28.7	38.5
Accumulated Defined Benefit Plans Adjustment, Net Transition Attributable to Parent [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income before income taxes	0.0	0.2
Pension and other postretirement benefit plan adjustments [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income before income taxes	27.6	36.4
Net income	(20.2)	(23.8)
Income tax provision	(7.4)	(12.6)
Accumulated Net Gain (Loss) from Cash Flow Hedges Including Portion Attributable to Noncontrolling Interest [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income before income taxes	5.2	(0.2)
Net income	3.9	(0.2)
Income tax provision	(1.3)	0.0
Accumulated Net Gain (Loss) from Cash Flow Hedges Including Portion Attributable to Noncontrolling Interest [Member] | Foreign Exchange Forward [Member] | Reclassification out of Accumulated Other Comprehensive Loss [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Sales	(0.5)	0.5
Cost of sales	5.9	(1.0)
Selling, general and administrative expenses	$ (0.2)	$ 0.3