Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Net Earnings (Loss) Including Noncontrolling Interest	$ 91.8	$ (2.1)	$ 387.0	$ 99.7
Pension and postretirement benefits adjustments:
Reclassifications to net earnings	(0.8)	(0.6)	(1.6)	(1.2)
Hedging adjustments:
Unrealized net gain on derivatives	5.4	0.0	3.9	0.0
Reclassifications to net earnings	(1.8)	0.0	(1.5)	0.0
Other reclassifications	(0.5)	0.0	(0.5)	0.0
Foreign currency translation adjustments:
Unrealized foreign currency translation adjustments	69.4	0.6	83.3	(1.3)
Tax benefit (expense) on other comprehensive income:
Pension and postretirement benefits	1.2	0.3	1.4	0.5
Hedging	(3.1)	0.0	(2.8)	0.0
Total Other Comprehensive Income (Loss)	69.8	0.3	82.2	(2.0)
Less: Comprehensive income attributable to noncontrolling interest	0.9	0.0	1.2	0.0
Total Comprehensive Income (Loss)	$ 160.7	$ (1.8)	$ 468.0	$ 97.7