Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	$ (1,334.6)	$ (948.0)
Other comprehensive income (loss) before reclassifications	(17.9)	(80.7)
Amounts reclassified from accumulated other comprehensive loss	13.5	12.8
Other comprehensive income (loss)	(4.4)	(67.9)
Balance at end of period	(1,339.0)	(1,015.9)
Pension and other postretirement benefit plan adjustments [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	(1,097.1)	(909.4)
Other comprehensive income (loss) before reclassifications	0.0	0.0
Amounts reclassified from accumulated other comprehensive loss	18.4	17.6
Other comprehensive income (loss)	18.4	17.6
Balance at end of period	(1,078.7)	(891.8)
Accumulated currency translation adjustments [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	(252.4)	(52.5)
Other comprehensive income (loss) before reclassifications	(24.4)	(92.9)
Amounts reclassified from accumulated other comprehensive loss	0.0	0.0
Other comprehensive income (loss)	(24.4)	(92.9)
Balance at end of period	(276.8)	(145.4)
Net unrealized gains (losses) on cash flow hedges [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	14.9	13.9
Other comprehensive income (loss) before reclassifications	6.5	12.2
Amounts reclassified from accumulated other comprehensive loss	(4.9)	(4.8)
Other comprehensive income (loss)	1.6	7.4
Balance at end of period	$ 16.5	$ 21.3