Equity and Other Comprehensive Income (Loss) - Schedule of Changes in Accumulated Other Comprehensive Loss, Net of Tax (Details) - USD ($) $ in Millions		3 Months Ended
		Dec. 31, 2019	Dec. 31, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	[1]	$ (1,069.2)	$ (695.3)
Other comprehensive (loss) income before reclassifications	[1]	99.9	(64.9)
Amounts reclassified from accumulated other comprehensive (income) loss	[1]	7.8	5.4
Net current period other comprehensive (loss) income	[1]	107.7	(59.5)
Reclassification of stranded tax effects	[1]	(73.4)
Balance at end of period	[1]	(1,034.9)	(754.8)
Accumulated Net Gain (Loss) from Designated or Quality Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period		0.7	(0.2)
Other comprehensive (loss) income before reclassifications		(0.5)
Amounts reclassified from accumulated other comprehensive (income) loss		(1.3)
Net current period other comprehensive (loss) income		(1.8)
Balance at end of period		(1.1)	(0.2)
Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period		(698.0)	(465.9)
Amounts reclassified from accumulated other comprehensive (income) loss		9.1	5.4
Net current period other comprehensive (loss) income		9.1	5.4
Reclassification of stranded tax effects		(73.4)
Balance at end of period		(762.3)	(460.5)
Accumulated Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period		(371.9)	(229.2)
Other comprehensive (loss) income before reclassifications		100.4	(64.9)
Net current period other comprehensive (loss) income		100.4	(64.9)
Balance at end of period		$ (271.5)	$ (294.1)

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