| Document and Entity Information | Mar. 09, 2021 |
| Cover [Abstract] | |
| Entity Registrant Name | MATTEL INC /DE/ |
| Amendment Flag | false |
| Entity Central Index Key | 0000063276 |
| Document Type | 8-K |
| Document Period End Date | Mar. 9, 2021 |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 001-05647 |
| Entity Tax Identification Number | 95-1567322 |
| Entity Address, Address Line One | 333 Continental Boulevard |
| Entity Address, City or Town | El Segundo |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 90245-5012 |
| City Area Code | (310) |
| Local Phone Number | 252-2000 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Common Stock, $1.00 per share |
| Trading Symbol | MAT |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
