CONDENSED COMBINED DEBTOR-IN-POSSESSION FINANCIAL INFORMATION - Debtors' Balance Sheet (Parenthetical) (Details) - USD ($) $ in Millions |
Jun. 30, 2026 |
Dec. 31, 2025 |
|---|---|---|
| CONDENSED COMBINED DEBTOR-IN-POSSESSION FINANCIAL INFORMATION | ||
| Allowance for doubtful accounts | $ 8.5 | $ 10.2 |
| Trinseo PLC and certain direct and indirect subsidiaries | ||
| CONDENSED COMBINED DEBTOR-IN-POSSESSION FINANCIAL INFORMATION | ||
| Allowance for doubtful accounts | 0.6 | |
| Accumulated depreciation | $ 220.5 |
| X | ||||||||||
- Definition Amount of allowance for credit loss on accounts receivable, classified as current. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
|
| X | ||||||||||
- Definition Amount of accumulated depreciation and amortization from plant, property, and equipment and right-of-use asset from finance lease. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
|
| X | ||||||||||
- Details
|