Income Taxes	9 Months Ended
Sep. 30, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Mattel’s provision for income taxes was $66.3 million and $70.6 million for the three and nine months ended September 30, 2018, respectively, as compared to a provision for income taxes of $664.5 million and $614.4 million for the three and nine months ended September 30, 2017, respectively. Excluding discrete tax items, Mattel's 2018 tax expense or benefit is driven by income or loss in foreign taxable jurisdictions due to the U.S. valuation allowance. Mattel recognized a net discrete tax expense of $42.1 million and $44.3 million for the three and nine months ended September 30, 2018, respectively. For the three months ended September 30, 2018, Mattel recognized discrete tax expense primarily related to the provisional tax of $9.3 million for deemed repatriation of accumulated foreign earnings (net of related valuation allowance change), $14.6 million related to changes to the indefinite reinvestment assertion, and $17.8 million net tax expense related to reassessments of prior years' tax liabilities and income taxes recorded on a discrete basis in various jurisdictions. Mattel recognized a net discrete tax expense of $561.5 million and $558.8 million for the three and nine months ended September 30, 2017, respectively, primarily related to the establishment of a valuation allowance against U.S. deferred tax assets in the third quarter of 2017 and reassessments of prior years' tax liabilities based on the status of audits and tax filings in various jurisdictions around the world. On December 22, 2017, H.R.1, also known as the Tax Cuts and Jobs Act ("Tax Act" or "U.S. Tax Reform"), was enacted. The Securities Exchange Commission has issued guidance under Staff Accounting Bulletin 118 that allows for companies to provide provisional amounts for certain income tax effects of the Tax Act for which the company can provide a reasonable estimate. The guidance also provides that a company may not have the necessary information available, prepared, or analyzed for certain income tax effects of the Tax Act, in which case the company would not be expected to provide a provisional amount for those specific items. Additionally, the guidance allows for a measurement period of up to one year after the enactment date of the Tax Act to finalize the recording of the related tax impacts. As of December 31, 2017, Mattel reasonably estimated and recorded provisional amounts associated with the impact of the corporate tax rate change. Mattel continues to gather additional information to complete the accounting for these items and will complete our accounting within the prescribed measurement period. In January 2018, the Financial Accounting Standards Board ("FASB") issued guidance stating that a company must make an accounting policy election of either (i) treating taxes due on future U.S. inclusions in taxable income related to Global Intangible Low-Taxed Income ("GILTI") as a current-period expense when incurred (the "period cost method") or (ii) factoring such amounts into a company’s measurement of its deferred taxes (the "deferred method"). Mattel has elected the period cost method and has considered the estimated 2018 GILTI impact in its 2018 tax expense. On January 1, 2018, Mattel adopted ASU 2016-16, Intra-Entity Transfers of Assets Other Than Inventory, which required Mattel to recognize the income tax effects of intercompany sales and transfers of assets other than inventory in the period in which the transfer occurs. Previously, the income tax effect of intercompany transfers of assets was deferred until the asset was sold to an outside party or otherwise recognized (e.g., depreciated, amortized, impaired). The new guidance requires Mattel to defer only the income tax effects of intercompany transfers of inventory. A cumulative effect adjustment of approximately $9 million was recorded as an increase to beginning retained earnings in the first quarter of 2018. As of September 30, 2018, Mattel reasonably estimated and recorded a provisional tax of $9.3 million, associated with the impact of the deemed repatriation of accumulated foreign earnings. Mattel recorded a gross tax of $268.5 million, prior to the utilization of tax attributes, and released a valuation allowance of $259.2 million related to tax attributes utilized against the provisional tax. Mattel is continuing to evaluate the impact of this provision of the Tax Act and will complete the accounting for this item within the prescribed measurement period. The net tax due related to the deemed repatriation of accumulated foreign earnings is payable over eight years. In addition, U.S. Tax Reform will provide Mattel with a reduced cost to access the earnings of its foreign subsidiaries. As such, Mattel has re-evaluated its intentions related to its indefinite reinvestment assertion, and has recorded a $14.6 million tax charge related to state income taxes and withholding taxes on $300 million of prior year foreign earnings that will not be indefinitely reinvested. In the normal course of business, Mattel is regularly audited by federal, state, and foreign tax authorities. Based on the current status of federal, state, and foreign audits, Mattel believes it is reasonably possible that in the next twelve months, the total unrecognized tax benefits could decrease by approximately $3.5 million related to the settlement of tax audits and/or the expiration of statutes of limitations. The ultimate settlement of any issue with the applicable taxing authority could have a material impact on Mattel’s consolidated financial statements.

Income Taxes

Mattel’s provision for income taxes was $66.3 million and $70.6 million for the three and nine months ended September 30, 2018, respectively, as compared to a provision for income taxes of $664.5 million and $614.4 million for the three and nine months ended September 30, 2017, respectively. Excluding discrete tax items, Mattel's 2018 tax expense or benefit is driven by income or loss in foreign taxable jurisdictions due to the U.S. valuation allowance. Mattel recognized a net discrete tax expense of $42.1 million and $44.3 million for the three and nine months ended September 30, 2018, respectively. For the three months ended September 30, 2018, Mattel recognized discrete tax expense primarily related to the provisional tax of $9.3 million for deemed repatriation of accumulated foreign earnings (net of related valuation allowance change), $14.6 million related to changes to the indefinite reinvestment assertion, and $17.8 million net tax expense related to reassessments of prior years' tax liabilities and income taxes recorded on a discrete basis in various jurisdictions. Mattel recognized a net discrete tax expense of $561.5 million and $558.8 million for the three and nine months ended September 30, 2017, respectively, primarily related to the establishment of a valuation allowance against U.S. deferred tax assets in the third quarter of 2017 and reassessments of prior years' tax liabilities based on the status of audits and tax filings in various jurisdictions around the world.

On December 22, 2017, H.R.1, also known as the Tax Cuts and Jobs Act ("Tax Act" or "U.S. Tax Reform"), was enacted. The Securities Exchange Commission has issued guidance under Staff Accounting Bulletin 118 that allows for companies to provide provisional amounts for certain income tax effects of the Tax Act for which the company can provide a reasonable estimate. The guidance also provides that a company may not have the necessary information available, prepared, or analyzed for certain income tax effects of the Tax Act, in which case the company would not be expected to provide a provisional amount for those specific items. Additionally, the guidance allows for a measurement period of up to one year after the enactment date of the Tax Act to finalize the recording of the related tax impacts.

As of December 31, 2017, Mattel reasonably estimated and recorded provisional amounts associated with the impact of the corporate tax rate change. Mattel continues to gather additional information to complete the accounting for these items and will complete our accounting within the prescribed measurement period.

In January 2018, the Financial Accounting Standards Board ("FASB") issued guidance stating that a company must make an accounting policy election of either (i) treating taxes due on future U.S. inclusions in taxable income related to Global Intangible Low-Taxed Income ("GILTI") as a current-period expense when incurred (the "period cost method") or (ii) factoring such amounts into a company’s measurement of its deferred taxes (the "deferred method"). Mattel has elected the period cost method and has considered the estimated 2018 GILTI impact in its 2018 tax expense.

On January 1, 2018, Mattel adopted ASU 2016-16, Intra-Entity Transfers of Assets Other Than Inventory, which required Mattel to recognize the income tax effects of intercompany sales and transfers of assets other than inventory in the period in which the transfer occurs. Previously, the income tax effect of intercompany transfers of assets was deferred until the asset was sold to an outside party or otherwise recognized (e.g., depreciated, amortized, impaired). The new guidance requires Mattel to defer only the income tax effects of intercompany transfers of inventory. A cumulative effect adjustment of approximately $9 million was recorded as an increase to beginning retained earnings in the first quarter of 2018.

As of September 30, 2018, Mattel reasonably estimated and recorded a provisional tax of $9.3 million, associated with the impact of the deemed repatriation of accumulated foreign earnings. Mattel recorded a gross tax of $268.5 million, prior to the utilization of tax attributes, and released a valuation allowance of $259.2 million related to tax attributes utilized against the provisional tax. Mattel is continuing to evaluate the impact of this provision of the Tax Act and will complete the accounting for this item within the prescribed measurement period. The net tax due related to the deemed repatriation of accumulated foreign earnings is payable over eight years.

In addition, U.S. Tax Reform will provide Mattel with a reduced cost to access the earnings of its foreign subsidiaries. As such, Mattel has re-evaluated its intentions related to its indefinite reinvestment assertion, and has recorded a $14.6 million tax charge related to state income taxes and withholding taxes on $300 million of prior year foreign earnings that will not be indefinitely reinvested.

In the normal course of business, Mattel is regularly audited by federal, state, and foreign tax authorities. Based on the current status of federal, state, and foreign audits, Mattel believes it is reasonably possible that in the next twelve months, the total unrecognized tax benefits could decrease by approximately $3.5 million related to the settlement of tax audits and/or the expiration of statutes of limitations. The ultimate settlement of any issue with the applicable taxing authority could have a material impact on Mattel’s consolidated financial statements.