Equity and Other Comprehensive Income (Loss) - Schedule of Changes in Accumulated Other Comprehensive Loss, Net of Tax (Details) - USD ($) $ in Millions		9 Months Ended
		Jun. 30, 2019	Jun. 30, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	[1]	$ (695.3)	$ (457.3)
Other comprehensive (loss) income before reclassifications	[1]	(13.7)	(227.6)
Amounts reclassified from accumulated other comprehensive loss (income)	[1]	13.6	10.6
Net current period other comprehensive income (loss)	[1]	(0.1)	(217.0)
Balance at end of period	[1]	(695.4)	(674.3)
Accumulated Net Gain (Loss) from Designated or Quality Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period		(0.2)	(0.7)
Amounts reclassified from accumulated other comprehensive loss (income)			0.5
Net current period other comprehensive income (loss)			0.5
Balance at end of period		(0.2)	(0.2)
Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period		(465.9)	(462.5)
Other comprehensive (loss) income before reclassifications			(3.1)
Amounts reclassified from accumulated other comprehensive loss (income)		13.6	11.6
Net current period other comprehensive income (loss)		13.6	8.5
Balance at end of period		(452.3)	(454.0)
Accumulated Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period		(229.2)	5.2
Other comprehensive (loss) income before reclassifications		(13.7)	(225.3)
Net current period other comprehensive income (loss)		(13.7)	(225.3)
Balance at end of period		$ (242.9)	(220.1)
Accumulated Net Investment Gain (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period			0.7
Other comprehensive (loss) income before reclassifications			0.8
Amounts reclassified from accumulated other comprehensive loss (income)			(1.5)
Net current period other comprehensive income (loss)			$ (0.7)

[1] All amounts are net of tax and noncontrolling interests.