DEBT (Details 1) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	May 19, 2020
Debt Instrument [Line Items]
Notes payable	$ 2,802.1	$ 3,905.2
Receivables Financing Agreement (See Note 6)	300.0	125.0
Finance lease obligations	3.0	4.3
Deferred debt issuance costs	(22.5)	(37.4)
Unamortized bond original issue discount	0.3	2.2
Interest rate swaps	0.0	(1.8)
Total debt	2,779.3	3,863.8
Amounts due within one year	201.1	26.3
Total long-term debt	2,578.2	3,837.5
$500.0 million Senior Delayed Draw Term Loan
Debt Instrument [Line Items]
Notes payable	$ 350.0	$ 500.0
Interest rate	1.604%	4.13%
Variable-Rate Recovery Zone Bonds
Debt Instrument [Line Items]
Notes payable	$ 103.0	$ 103.0
Interest rate	1.10%	3.63%
Variable-Rate Go Zone Bonds
Debt Instrument [Line Items]
Notes payable	$ 50.0	$ 50.0
Interest rate	1.10%	3.63%
Industrial Development and Environmental Improvement Obligations
Debt Instrument [Line Items]
Notes payable	$ 2.9	$ 2.9
Interest rate	0.17%	0.21%
2025 Notes 10.00%
Debt Instrument [Line Items]
Notes payable	$ 0.0	$ 500.0
Interest rate	10.00%	10.00%
2023 Notes
Debt Instrument [Line Items]
Notes payable	$ 0.0	$ 120.0
Interest rate	9.75%	9.75%
2025 Notes 9.50%
Debt Instrument [Line Items]
Notes payable	$ 108.6	$ 500.0
Interest rate	9.50%	9.50%	9.50%
2029 Notes
Debt Instrument [Line Items]
Notes payable	$ 669.3	$ 750.0
Interest rate	5.625%	5.625%
2022 Notes
Debt Instrument [Line Items]
Notes payable	$ 200.0	$ 200.0
Interest rate	5.50%	5.50%
2027 Notes
Debt Instrument [Line Items]
Notes payable	$ 500.0	$ 500.0
Interest rate	5.125%	5.125%
2030 Notes
Debt Instrument [Line Items]
Notes payable	$ 515.3	$ 550.0
Interest rate	5.00%	5.00%

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