Basis of Presentation (Policies)	6 Months Ended
Jun. 30, 2020
Basis of Presentation
Basis of Presentation	The unaudited interim condensed consolidated financial statements of Trinseo S.A. and its subsidiaries (the “Company”) as of and for the periods ended June 30, 2020 and 2019 were prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) and reflect all adjustments, consisting only of normal recurring adjustments, which, in the opinion of management, are considered necessary for the fair statement of the results for the periods presented. Because they cover interim periods, the statements and related notes to the financial statements do not include all disclosures normally provided in annual financial statements, and therefore, these statements should be read in conjunction with the 2019 audited consolidated financial statements included within the Company’s Annual Report on Form 10-K (“Annual Report”) filed with the Securities and Exchange Commission (“SEC”) on February 28, 2020. The effects of the COVID-19 pandemic have negatively impacted the Company’s results of operations, cash flows and financial position in 2020. The Company expects these negative effects to continue, which future impacts could be material, and dependent on numerous factors that are highly uncertain, for which the ultimate impact cannot be predicted at this time, including the duration and scope of the COVID-19 pandemic. The Company’s condensed consolidated financial statements presented herein reflect the latest estimates and assumptions made by management that affect the reported amounts and related disclosures as of and for the period ended June 30, 2020. However, actual results could differ from these estimates and assumptions. The December 31, 2019 condensed consolidated balance sheet data presented herein was derived from the Company’s December 31, 2019 audited consolidated financial statements, but does not include all disclosures required by GAAP for annual periods.

Disclosure of accounting policy regarding (1) the principles it follows in consolidating or combining the separate financial statements, including the principles followed in determining the inclusion or exclusion of subsidiaries or other entities in the consolidated or combined financial statements and (2) its treatment of interests (for example, common stock, a partnership interest or other means of exerting influence) in other entities, for example consolidation or use of the equity or cost methods of accounting. The accounting policy may also address the accounting treatment for intercompany accounts and transactions, noncontrolling interest, and the income statement treatment in consolidation for issuances of stock by a subsidiary.

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