Note 14 - Accumulated Other Comprehensive Loss - Reclassification Details (Details) - USD ($) $ in Millions |
3 Months Ended | 9 Months Ended | ||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Sep. 30, 2026 |
Sep. 30, 2025 |
Sep. 30, 2026 |
Sep. 30, 2025 |
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| Accumulated Defined Benefit Plans Adjustment, Net Prior Service Including Portion Attributable to Noncontrolling Interest [Member] | ||||||||||||||||||||||||||
| Amounts reclassified from accumulated other comprehensive loss, gross | [1],[2],[3] | $ (2) | $ (2) | $ (6) | $ (6) | |||||||||||||||||||||
| Accumulated Defined Benefit Plans Adjustment, Net Prior Service Including Portion Attributable to Noncontrolling Interest [Member] | Huntsman International LLC [Member] | ||||||||||||||||||||||||||
| Amounts reclassified from accumulated other comprehensive loss, gross | [1],[3],[4] | (2) | (2) | (6) | (6) | |||||||||||||||||||||
| Accumulated Defined Benefit Plans Adjustment, Actuarial Gain (Loss), Including Portion Attributable to Noncontrolling Interest [Member] | ||||||||||||||||||||||||||
| Amounts reclassified from accumulated other comprehensive loss, gross | [1],[2],[3] | 7 | 7 | 21 | 22 | |||||||||||||||||||||
| Accumulated Defined Benefit Plans Adjustment, Actuarial Gain (Loss), Including Portion Attributable to Noncontrolling Interest [Member] | Huntsman International LLC [Member] | ||||||||||||||||||||||||||
| Amounts reclassified from accumulated other comprehensive loss, gross | [1],[3],[4] | 7 | 7 | 21 | 22 | |||||||||||||||||||||
| Accumulated Defined Benefit Plans Adjustment Including Portion Attributable to Noncontrolling Interest [Member] | ||||||||||||||||||||||||||
| Amounts reclassified from accumulated other comprehensive loss, gross | [1],[2] | 5 | 5 | 15 | [5],[6] | 15 | [7],[8] | |||||||||||||||||||
| Tax impact | [1],[2] | 1 | 0 | 0 | [5] | (1) | [7] | |||||||||||||||||||
| Total reclassifications for the period | [1],[2] | 6 | 5 | 15 | 14 | |||||||||||||||||||||
| Accumulated Defined Benefit Plans Adjustment Including Portion Attributable to Noncontrolling Interest [Member] | Huntsman International LLC [Member] | ||||||||||||||||||||||||||
| Amounts reclassified from accumulated other comprehensive loss, gross | [1],[4] | 5 | 5 | 15 | [6],[9] | 15 | [8],[10] | |||||||||||||||||||
| Tax impact | [1],[4] | 1 | 0 | 0 | [9] | (1) | [10] | |||||||||||||||||||
| Total reclassifications for the period | [1],[4] | $ 6 | $ 5 | 15 | 14 | |||||||||||||||||||||
| Accumulated Defined Benefit Plans Adjustment, Settlement Gain (Loss), Including Portion Attributable to Noncontrolling Interest [Member] | ||||||||||||||||||||||||||
| Amounts reclassified from accumulated other comprehensive loss, gross | [1],[2],[3] | 0 | (1) | |||||||||||||||||||||||
| Accumulated Defined Benefit Plans Adjustment, Settlement Gain (Loss), Including Portion Attributable to Noncontrolling Interest [Member] | Huntsman International LLC [Member] | ||||||||||||||||||||||||||
| Amounts reclassified from accumulated other comprehensive loss, gross | [1],[3],[4] | $ 0 | $ (1) | |||||||||||||||||||||||
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