RELATED PARTY TRANSACTIONS (Summary of Related Party Transactions) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Transactions under commercial agreements:
Sales	$ 11,678.3	$ 7,475.3	$ 19,582.6	$ 14,541.7
St. Bernard Renewables LLC \| Equity Method Investment, Nonconsolidated Investee or Group of Investees
Transactions under commercial agreements:
Sales	32.8	16.9	54.4	30.3
Purchases	(253.0)	(121.3)	(410.5)	(181.6)
St. Bernard Renewables LLC \| Equity Method Investment, Nonconsolidated Investee or Group of Investees \| General and Administrative Expense \| Operating agreement
Reimbursements under related party agreements:
Transactions with related party	31.8	34.4	101.9	74.4
St. Bernard Renewables LLC \| Equity Method Investment, Nonconsolidated Investee or Group of Investees \| General and Administrative Expense \| Omnibus agreement
Reimbursements under related party agreements:
Transactions with related party	0.9	0.9	1.9	1.9
St. Bernard Renewables LLC \| Equity Method Investment, Nonconsolidated Investee or Group of Investees \| General and Administrative Expense \| Common asset use and servitude agreement
Reimbursements under related party agreements:
Transactions with related party	1.7	1.8	3.7	4.0
St. Bernard Renewables LLC \| Equity Method Investment, Nonconsolidated Investee or Group of Investees \| Cost of Sales \| Lease Agreements
Reimbursements under related party agreements:
Transactions with related party	$ 0.0	$ (2.8)	$ 0.0	$ (8.1)