Accumulated Other Comprehensive Loss (Details 1) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2016	Mar. 31, 2015
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income before income taxes	$ 217.0	$ 276.5	$ 453.9	$ 564.0
Income tax provision	(49.0)	(70.5)	(100.4)	(143.8)
Net income	168.0	206.0	353.5	420.2
Reclassification out of Accumulated Other Comprehensive Loss [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net income	11.7	11.5	25.2	24.3
Pension and other postretirement benefit plan adjustments [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amortization of prior service credit	(3.6)	(4.3)	(7.1)	(8.7)
Amortization of net actuarial loss	31.8	30.7	63.5	61.9
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	28.2	26.4	56.4	53.2
Income tax provision	(9.8)	(9.2)	(19.6)	(18.4)
Net income	18.4	17.2	36.8	34.8
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	(8.6)	(5.4)	(14.9)	(10.0)
Income tax provision	1.9	(0.3)	3.3	(0.5)
Net income	(6.7)	(5.7)	(11.6)	(10.5)
Foreign Exchange Forward [Member] | Sales [Member] | Net unrealized gains (losses) on cash flow hedges [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from accumulated other comprehensive loss	1.6	2.4	4.1	3.6
Foreign Exchange Forward [Member] | Cost of sales [Member] | Net unrealized gains (losses) on cash flow hedges [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from accumulated other comprehensive loss	$ (10.2)	$ (7.8)	$ (19.0)	$ (13.6)