New Accounting Pronouncements (Policies)	9 Months Ended
Sep. 30, 2017
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Earnings Per Share	Unvested share-based payment awards that contain nonforfeitable rights to dividends or dividend equivalents (whether paid or unpaid) are participating securities and are included in the computation of earnings per share pursuant to the two-class method. Certain of Mattel’s restricted stock units (“RSUs”) are considered participating securities because they contain nonforfeitable rights to dividend equivalents. Under the two-class method, net income is reduced by the amount of dividends declared in the period for each class of common stock and participating securities. The remaining undistributed earnings are then allocated to common stock and participating securities as if all of the net income for the period had been distributed. Basic earnings per common share excludes dilution and is calculated by dividing net income allocable to common shares by the weighted average number of common shares outstanding for the period. Diluted earnings per common share is calculated by dividing net income allocable to common shares by the weighted average number of common shares for the period, as adjusted for the potential dilutive effect of non-participating share-based awards.
New Accounting Pronouncements	In May 2014, the Financial Accounting Standards Board (“FASB”) issued ASU 2014-09, Revenue from Contracts with Customers, which supersedes the revenue recognition requirements in Accounting Standards Codification (“ASC”) 605, Revenue Recognition, and most industry-specific guidance. The core principle of the guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The new guidance establishes a five-step model to achieve that core principle and also requires additional disclosures about the nature, amount, timing, and uncertainty of revenue and cash flows arising from customer contracts. ASU 2014-09 was originally effective for interim and annual reporting periods beginning after December 15, 2016. In August 2015, the FASB issued ASU 2015-14, Revenue from Contracts with Customers - Deferral of the Effective Date, which defers the effective date to annual reporting periods beginning after December 15, 2017. Early application is permitted after December 15, 2016. In March 2016, the FASB issued ASU 2016-08, Principal versus Agent Considerations (Reporting Revenue Gross versus Net), which clarifies the implementation guidance on principal versus agent considerations, and ASU 2016-10, Identifying Performance Obligations and Licensing, which clarifies the identification of performance obligations and the licensing implementation guidance. In May 2016, the FASB issued ASU 2016-12, Revenue from Contracts with Customers - Narrow-Scope Improvements and Practical Expedients, which clarifies guidance on assessing collectibility, presenting sales taxes and other similar taxes collected from customers, measuring noncash consideration, and certain transition matters. ASU 2014-09, ASU 2015-14, ASU 2016-08, ASU 2016-10, and ASU 2016-12 (collectively, the “new revenue standards”) will be effective for interim and annual reporting periods beginning on January 1, 2018. Upon adoption, Mattel will recognize the cumulative effect of adopting this guidance as an adjustment to the opening balance of retained earnings. Prior periods will not be retrospectively adjusted. Mattel continues to make progress in its implementation and assessment of the new revenue standards. While the completion of this assessment is still ongoing and certain licensing contracts will be impacted by the new revenue standards, Mattel does not expect the new standards to have a material impact on its revenue recognition accounting policy and its consolidated financial statements. In February 2016, the FASB issued ASU 2016-02, Leases, which requires a lessee to recognize a lease asset and lease liability on its balance sheet for all leases with a term greater than 12 months. ASU 2016-02 will be effective for interim and annual reporting periods beginning on January 1, 2019. Mattel is currently evaluating the impact of the adoption of ASU 2016-02 on its operating results and financial position. In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows - Classification of Certain Cash Receipts and Cash Payments, which adds and clarifies guidance on the classification of certain cash receipts and payments in the statement of cash flows. ASU 2016-15 will be effective for interim and annual reporting periods beginning on January 1, 2018. Mattel is currently evaluating the impact of the adoption of ASU 2016-15 on its operating results and financial position. In October 2016, the FASB issued ASU 2016-16, Income Taxes: Intra-Entity Transfers of Assets Other Than Inventory, which requires an entity to recognize the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. ASU 2016-16 will be effective for interim and annual reporting periods beginning on January 1, 2018. Mattel is currently evaluating the impact of the adoption of ASU 2016-16 on its operating results and financial position. In January 2017, the FASB issued ASU 2017-01, Business Combinations: Clarifying the Definition of a Business, which clarifies the definition of a business to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses and refines the definition of the term output. ASU 2017-01 will be effective for interim and annual reporting periods beginning on January 1, 2018. Mattel is currently evaluating the impact of the adoption of ASU 2017-01 on its operating results and financial position. In February 2017, the FASB issued ASU 2017-05, Other Income - Gains and Losses from the Derecognition of Nonfinancial Assets, which clarifies the scope on recently established guidance on nonfinancial asset derecognition as well as the accounting for partial sales of nonfinancial assets. ASU 2017-05 will be effective for interim and annual reporting periods beginning on January 1, 2018. Mattel is currently evaluating the impact of the adoption of ASU 2017-05 on its operating results and financial position. In March 2017, the FASB issued ASU 2017-07, Compensation - Retirement Benefits: Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost, which requires entities that sponsor defined benefit plans to (i) present service cost within operations, if such a subtotal is presented, (ii) other components of net benefit costs should be presented separately outside of income from operations, if such a subtotal is presented, and (iii) only the service cost component should be capitalized, when applicable. If a separate line item is not used, the line item in the income statement where the other components of net benefit costs are included must be disclosed. Further, gains and losses from curtailments and settlements, and the cost of certain termination benefits should be reported in the same manner as other components of net benefit cost. ASU 2017-07 will be effective for interim and annual reporting periods beginning on January 1, 2018. Mattel is currently evaluating the impact of the adoption of ASU 2017-07 on its operating results and financial position. In May 2017, the FASB issued ASU 2017-09, Compensation - Stock Compensation: Scope of Modification Accounting, which clarifies when to account for a change to the terms or conditions of a share-based payment award as a modification. ASU 2017-09 will be effective prospectively for interim and annual reporting periods beginning on January 1, 2018. Mattel is currently evaluating the impact of the adoption of ASU 2017-09 on its operating results and financial position. In August 2017, the FASB issued ASU 2017-12, Derivatives and Hedging: Targeted Improvements to Accounting for Hedging Activities, which expands the hedging strategies eligible for hedge accounting and changes both how companies assess hedge effectiveness and presentation and disclosure requirements. ASU 2017-12 will be effective for interim and annual reporting periods beginning on January 1, 2019. Early application is permitted in any interim period after issuance of the update. Mattel is currently evaluating the impact of the adoption of ASU 2017-12 on its operating results and financial position.

In May 2014, the Financial Accounting Standards Board (“FASB”) issued ASU 2014-09, Revenue from Contracts with Customers, which supersedes the revenue recognition requirements in Accounting Standards Codification (“ASC”) 605, Revenue Recognition, and most industry-specific guidance. The core principle of the guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The new guidance establishes a five-step model to achieve that core principle and also requires additional disclosures about the nature, amount, timing, and uncertainty of revenue and cash flows arising from customer contracts. ASU 2014-09 was originally effective for interim and annual reporting periods beginning after December 15, 2016. In August 2015, the FASB issued ASU 2015-14, Revenue from Contracts with Customers - Deferral of the Effective Date, which defers the effective date to annual reporting periods beginning after December 15, 2017. Early application is permitted after December 15, 2016. In March 2016, the FASB issued ASU 2016-08, Principal versus Agent Considerations (Reporting Revenue Gross versus Net), which clarifies the implementation guidance on principal versus agent considerations, and ASU 2016-10, Identifying Performance Obligations and Licensing, which clarifies the identification of performance obligations and the licensing implementation guidance. In May 2016, the FASB issued ASU 2016-12, Revenue from Contracts with Customers - Narrow-Scope Improvements and Practical Expedients, which clarifies guidance on assessing collectibility, presenting sales taxes and other similar taxes collected from customers, measuring noncash consideration, and certain transition matters. ASU 2014-09, ASU 2015-14, ASU 2016-08, ASU 2016-10, and ASU 2016-12 (collectively, the “new revenue standards”) will be effective for interim and annual reporting periods beginning on January 1, 2018. Upon adoption, Mattel will recognize the cumulative effect of adopting this guidance as an adjustment to the opening balance of retained earnings. Prior periods will not be retrospectively adjusted. Mattel continues to make progress in its implementation and assessment of the new revenue standards. While the completion of this assessment is still ongoing and certain licensing contracts will be impacted by the new revenue standards, Mattel does not expect the new standards to have a material impact on its revenue recognition accounting policy and its consolidated financial statements.

In February 2016, the FASB issued ASU 2016-02, Leases, which requires a lessee to recognize a lease asset and lease liability on its balance sheet for all leases with a term greater than 12 months. ASU 2016-02 will be effective for interim and annual reporting periods beginning on January 1, 2019. Mattel is currently evaluating the impact of the adoption of ASU 2016-02 on its operating results and financial position.

In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows - Classification of Certain Cash Receipts and Cash Payments, which adds and clarifies guidance on the classification of certain cash receipts and payments in the statement of cash flows. ASU 2016-15 will be effective for interim and annual reporting periods beginning on January 1, 2018. Mattel is currently evaluating the impact of the adoption of ASU 2016-15 on its operating results and financial position.

In October 2016, the FASB issued ASU 2016-16, Income Taxes: Intra-Entity Transfers of Assets Other Than Inventory, which requires an entity to recognize the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. ASU 2016-16 will be effective for interim and annual reporting periods beginning on January 1, 2018. Mattel is currently evaluating the impact of the adoption of ASU 2016-16 on its operating results and financial position.

In January 2017, the FASB issued ASU 2017-01, Business Combinations: Clarifying the Definition of a Business, which clarifies the definition of a business to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses and refines the definition of the term output. ASU 2017-01 will be effective for interim and annual reporting periods beginning on January 1, 2018. Mattel is currently evaluating the impact of the adoption of ASU 2017-01 on its operating results and financial position.

In February 2017, the FASB issued ASU 2017-05, Other Income - Gains and Losses from the Derecognition of Nonfinancial Assets, which clarifies the scope on recently established guidance on nonfinancial asset derecognition as well as the accounting for partial sales of nonfinancial assets. ASU 2017-05 will be effective for interim and annual reporting periods beginning on January 1, 2018. Mattel is currently evaluating the impact of the adoption of ASU 2017-05 on its operating results and financial position.

In March 2017, the FASB issued ASU 2017-07, Compensation - Retirement Benefits: Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost, which requires entities that sponsor defined benefit plans to (i) present service cost within operations, if such a subtotal is presented, (ii) other components of net benefit costs should be presented separately outside of income from operations, if such a subtotal is presented, and (iii) only the service cost component should be capitalized, when applicable. If a separate line item is not used, the line item in the income statement where the other components of net benefit costs are included must be disclosed. Further, gains and losses from curtailments and settlements, and the cost of certain termination benefits should be reported in the same manner as other components of net benefit cost. ASU 2017-07 will be effective for interim and annual reporting periods beginning on January 1, 2018. Mattel is currently evaluating the impact of the adoption of ASU 2017-07 on its operating results and financial position.

In May 2017, the FASB issued ASU 2017-09, Compensation - Stock Compensation: Scope of Modification Accounting, which clarifies when to account for a change to the terms or conditions of a share-based payment award as a modification. ASU 2017-09 will be effective prospectively for interim and annual reporting periods beginning on January 1, 2018. Mattel is currently evaluating the impact of the adoption of ASU 2017-09 on its operating results and financial position.

In August 2017, the FASB issued ASU 2017-12, Derivatives and Hedging: Targeted Improvements to Accounting for Hedging Activities, which expands the hedging strategies eligible for hedge accounting and changes both how companies assess hedge effectiveness and presentation and disclosure requirements. ASU 2017-12 will be effective for interim and annual reporting periods beginning on January 1, 2019. Early application is permitted in any interim period after issuance of the update. Mattel is currently evaluating the impact of the adoption of ASU 2017-12 on its operating results and financial position.