v3.25.2
INVESTMENTS IN UNCONSOLIDATED AFFILIATES - Americas Styrenics (Details) - USD ($)
$ in Millions
3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Dec. 31, 2024
Investments in Unconsolidated Affiliates          
Investments in unconsolidated affiliate $ 224.0 $ 269.0 $ 224.0 $ 269.0 $ 222.6
AmSty          
Investments in Unconsolidated Affiliates          
Investments in unconsolidated affiliate 224.0   224.0   222.6
Investment in unconsolidated affiliates-difference between carrying amount and underlying equity $ 8.8   $ 8.8   $ 9.5
Percentage of ownership underlying net assets 50.00%   50.00%   50.00%
Amortized weighted average remaining useful life     2.2 years    
Dividends received from operating activities $ 5.0 $ 5.0 $ 5.0 $ 5.0