New Accounting Pronouncements (Policies)	3 Months Ended
New Accounting Pronouncements (Policies)	Mar. 31, 2022
Accounting Standards Update and Change in Accounting Principle [Abstract]
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.
Revision of Previously Issued Consolidated Financial Statements	During the quarter ended June 30, 2021, Mattel identified a misstatement in its accounting for inventory tooling expenses, which were expensed to cost of sales rather than first being capitalized into the cost of inventory, which resulted in an understatement of inventory balances and a misstatement of cost of sales. Mattel also identified a misstatement related to the timing of disbursements for certain capital expenditures, which resulted in a cash flow misclassification between operating activities and investing activities. Mattel evaluated the misstatements and concluded that the misstatements were not material, either individually or in the aggregate, to its current or previously issued consolidated financial statements. To correct the immaterial misstatements, during the quarter ended June 30, 2021, Mattel elected to revise its previously issued consolidated financial statements as of December 31, 2020 and 2019, and for each of the three years ended December 31, 2020, 2019, and 2018 and its unaudited consolidated financial statements as of and for the quarters and year-to-date periods ended March 31, 2020 and 2021, June 30, 2020, and September 30, 2020. The revision of the historical consolidated financial statements also includes the correction of other immaterial misstatements in its consolidated statement of operations that Mattel had previously recorded as out of period adjustments, as well as other previously identified balance sheet misclassifications. Mattel had previously determined that these misstatements did not, either individually or in the aggregate, result in a material misstatement of its previously issued consolidated financial statements and reached the same conclusion when aggregating with the recently identified misstatements. Further information regarding the misstatements and related revision is included in "Note 23 to the Consolidated Financial Statements— Revision for Immaterial Misstatements." Mattel presented the revision of its previously issued consolidated financial statements as of December 31, 2020 and for the year ended December 31, 2020 in connection with the filing of its 2021 Annual Report on Form 10-K. Mattel is presenting the revision of its previously issued unaudited consolidated financial statements as of and for the three months ended March 31, 2021 in the accompanying unaudited consolidated financial statements and related disclosures.
Accounting Pronouncements Not Yet Adopted	Accounting Pronouncements Recently Adopted In November 2021, the FASB issued ASU 2021-10, Government Assistance (Topic 832): Disclosure by Business Entities about Government Assistance, which requires business entities to disclose information about certain government assistance by applying the grant or contribution model. Mattel adopted the guidance on January 1, 2022. The adoption of the new accounting standard does not currently have a material impact on Mattel's consolidated financial statements. Accounting Pronouncements Not Yet Adopted In March 2020 and January 2021, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting and ASU 2021-01, Reference Rate Reform (Topic 848): Scope, respectively. ASU 2020-04 and ASU 2021-01 provide optional expedients and exceptions for applying U.S. GAAP, to contracts, hedging relationships, and other transactions that reference the London Interbank Offered Rate or another reference rate expected to be discontinued because of reference rate reform, if certain criteria are met. The guidance in ASU 2020- 04 and ASU 2021-01 was effective upon issuance and, once adopted, may be applied prospectively to contract modifications and hedging relationships through December 31, 2022. Mattel is currently evaluating the impact of the adoption of ASU 2020-04 and ASU 2021-01 on its consolidated financial statements.