| Document and Entity Information | Aug. 01, 2019 |
| Cover [Abstract] | |
| Entity Registrant Name | MATTEL INC /DE/ |
| Amendment Flag | false |
| Entity Central Index Key | 0000063276 |
| Document Type | 8-K |
| Document Period End Date | Aug. 1, 2019 |
| Entity Incorporation, State or 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 |
| Title of 12(b) Security | Common Stock, $1.00 per share |
| Trading Symbol | MAT |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
