FAIR VALUE OF FINANCIAL INSTRUMENTS - Schedule of Carrying Values and Fair Values for Financial Instruments (Details) - USD ($) $ in Millions	Sep. 30, 2021	Sep. 30, 2020
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	$ 0.0	$ 66.9
Derivative Assets	6.8	0.4
Derivative Liabilities	2.5	13.5
Debt	2,628.2	2,538.7
Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	0.0	66.9
Derivative Assets	6.8	0.4
Derivative Liabilities	2.5	13.5
Debt	2,506.3	2,419.5
Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	0.0	66.9
Derivative Assets	0.0	0.0
Derivative Liabilities	0.0	0.0
Debt	0.0	0.0
Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	0.0	0.0
Derivative Assets	6.8	0.4
Derivative Liabilities	2.5	13.5
Debt	2,628.2	2,538.7
Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	0.0	0.0
Derivative Assets	0.0	0.0
Derivative Liabilities	0.0	0.0
Debt	$ 0.0	$ 0.0

Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

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