Accumulated Other Comprehensive Loss (Details 1) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2017	Mar. 31, 2016
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income before income taxes	$ 230.3	$ 217.0	$ 487.9	$ 453.9
Income tax provision	(40.8)	(49.0)	(83.7)	(100.4)
Net income	189.5	168.0	404.2	353.5
Reclassification out of Accumulated Other Comprehensive Loss [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net income	22.5	11.7	46.1	25.2
Pension and other postretirement benefit plan adjustments [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amortization of prior service credit	(2.6)	(3.6)	(4.9)	(7.1)
Amortization of net actuarial loss	38.8	31.8	77.3	63.5
Settlements	0.0	0.0	0.2	0.0
Pension and other postretirement benefit plan adjustments [Member] | Reclassification out of Accumulated Other Comprehensive Loss [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income before income taxes	36.2	28.2	72.6	56.4
Income tax provision	(12.4)	(9.8)	(25.0)	(19.6)
Net income	23.8	18.4	47.6	36.8
Net unrealized gains (losses) on cash flow hedges [Member] | Reclassification out of Accumulated Other Comprehensive Loss [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income before income taxes	(1.3)	(8.6)	(1.5)	(14.9)
Income tax provision	0.0	1.9	0.0	3.3
Net income	(1.3)	(6.7)	(1.5)	(11.6)
Net unrealized gains (losses) on cash flow hedges [Member] | Foreign Exchange Forward [Member] | Sales [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from accumulated other comprehensive loss	1.0	1.6	1.5	4.1
Net unrealized gains (losses) on cash flow hedges [Member] | Foreign Exchange Forward [Member] | Cost of sales [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from accumulated other comprehensive loss	(2.6)	(10.2)	(3.6)	(19.0)
Net unrealized gains (losses) on cash flow hedges [Member] | Foreign Exchange Forward [Member] | Selling, General and Administrative Expenses [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from accumulated other comprehensive loss	$ 0.3	$ 0.0	$ 0.6	$ 0.0