FAIR VALUE MEASUREMENTS - FINANCIAL INSTRUMENTS (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Financial instruments
Preferred stock of subsidiary	$ 30.4	$ 30.4
Carrying amount
Financial instruments
Preferred stock of subsidiary	30.4	30.4
Long-term debt, including current portion	15,871.6	16,631.1
Finance lease obligations	144.7	145.9
Fair value
Financial instruments
Preferred stock of subsidiary	20.3	21.4
Long-term debt, including current portion	$ 14,669.6	$ 15,564.3