EQUITY - Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Other comprehensive income (loss) before reclassifications	$ (96.4)	$ 35.1	$ (22.1)
Amounts reclassified from accumulated other comprehensive net income (loss)	2.6	7.7	11.2
Income tax benefit (expense)	15.6	(10.0)	5.7
Net current period other comprehensive income (loss)	(78.2)	32.8	(5.2)
Accumulated Other Comprehensive Income (Loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Equity beginning balance	(66.4)	(99.1)	(93.9)
Equity ending balance	(144.6)	(66.4)	(99.1)
Foreign Currency Translation Adjustments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Equity beginning balance	(1.7)	(6.2)	(17.4)
Other comprehensive income (loss) before reclassifications	(27.2)	4.5	10.5
Amounts reclassified from accumulated other comprehensive net income (loss)	0.0	0.0	0.8
Income tax benefit (expense)	0.0	0.0	0.0
Net current period other comprehensive income (loss)	(27.2)	4.5	11.3
Equity ending balance	(28.9)	(1.7)	(6.2)
Net Unrealized Gain (Loss) On Derivative Instruments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Equity beginning balance	10.2	(15.1)	(8.1)
Other comprehensive income (loss) before reclassifications	40.1	26.8	(19.7)
Amounts reclassified from accumulated other comprehensive net income (loss)	(9.1)	7.3	10.1
Income tax benefit (expense)	(7.9)	(8.9)	2.5
Net current period other comprehensive income (loss)	23.1	25.2	(7.1)
Equity ending balance	33.3	10.2	(15.1)
Net Unrealized Loss On Securities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Equity beginning balance	(2.3)	0.0	0.0
Other comprehensive income (loss) before reclassifications	(102.0)	(3.1)	0.0
Amounts reclassified from accumulated other comprehensive net income (loss)	0.0	0.0	0.0
Income tax benefit (expense)	24.6	0.8	0.0
Net current period other comprehensive income (loss)	(77.4)	(2.3)	0.0
Equity ending balance	(79.7)	(2.3)	0.0
Net Unrealized Gain (Loss) in Pension and Other Post- Retirement Benefits
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Equity beginning balance	(72.5)	(77.8)	(68.4)
Other comprehensive income (loss) before reclassifications	(7.3)	6.9	(12.9)
Amounts reclassified from accumulated other comprehensive net income (loss)	11.7	0.4	0.3
Income tax benefit (expense)	(1.1)	(1.9)	3.2
Net current period other comprehensive income (loss)	3.3	5.4	(9.4)
Equity ending balance	$ (69.3)	$ (72.5)	$ (77.8)