Basis of Presentation	9 Months Ended
Basis of Presentation	Sep. 30, 2019
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited consolidated financial statements and related disclosures have been prepared in accordance with accounting principles generally accepted in the United States of America ("GAAP") applicable to interim financial information and with the instructions to Form 10-Q and Rule 10-01 of Regulation S-X. In the opinion of management, all adjustments, consisting of only those of a normal recurring nature, considered necessary for a fair statement of the financial position and interim results of Mattel, Inc. and its subsidiaries ("Mattel") as of and for the periods presented have been included. Mattel adopted Accounting Standards Update ("ASU") No. 2016-02—Leases (Topic 842) and its related amendments (collectively "the new lease standard") on January 1, 2019 using the modified retrospective transition method. Prior periods were not retrospectively adjusted and continue to be reported under the accounting standards in effect for those periods, as further discussed in "Note 5 to the Consolidated Financial Statements—Leases." Mattel modified its reporting structure for revenues and reorganized its regional sales reporting structure in the first quarter of 2019. Prior period amounts have been reclassified to conform to the current period presentation, as further discussed in "Note 23 to the Consolidated Financial Statements—Segment Information." The December 31, 2018 balance sheet data was derived from audited financial statements; however, the accompanying interim notes to the consolidated financial statements do not include all the annual disclosures required by GAAP. As Mattel's business is seasonal, results for interim periods are not necessarily indicative of those that may be expected for a full year. The financial information included herein should be read in conjunction with Mattel's consolidated financial statements and related notes in its 2018 Annual Report on Form 10-K/A. Revision of Consolidated Financial Statements In its 2018 Annual Report on Form 10-K/A filed on November 12, 2019 ("2018 Form 10-K/A"), Mattel revised its audited consolidated financial statements as of December 31, 2018 and 2017, and for each of the three years in the period ended December 31, 2018 to correct for misstatements which the Company has determined to be immaterial, both individually and in the aggregate. The revision of these periods was effective upon the filing of the 2018 Form 10-K/A. Mattel is also revising its unaudited consolidated financial statements for the first and second quarters of 2019 and the first, second, and third quarters of 2018 to correct for prior period misstatements, which Mattel has determined did not, either individually or in the aggregate, materially misstate its previously issued consolidated financial statements. These misstatements related to the improper capitalization of certain advertising costs, the under-accrual of sales adjustments and employee related costs, an increase to the provision for income taxes, and an adjustment for the misclassification between amounts within operating cash flows. Accordingly, the accompanying financial statements as of and for the three and nine months ended September 30, 2018 have been revised to correct for such misstatements. Further information regarding the revision of Mattel's unaudited consolidated financial statements is included in Note 25 - Revision of Quarterly Information. Mattel will also affect the revision of its unaudited consolidated financial statements for the three months ended March 31, 2019 and the three and six months ended June 30, 2019 with the future filing of its Form 10-Q for the three months ended March 31, 2020 and the three and six months ended June 30, 2020. All relevant footnotes to the consolidated financial statements in this Form 10-Q have also been revised to reflect the items discussed above.