Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2019	Jul. 12, 2019
Document And Entity Information [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2019
Document Transition Report	false
Entity File Number	001-05647
Entity Registrant Name	MATTEL INC /DE/
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	95-1567322
Entity Address, Address Line One	333 Continental Blvd.
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
Title of 12(b) Security	Common stock, $1.00 per share
Trading Symbol	MAT
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Small Business	false
Emerging Growth Company	false
Entity Shell Company	false
Document Fiscal Period Focus	Q2
Entity Central Index Key	0000063276
Current Fiscal Year End Date	--12-31
Entity Common Stock, Shares Outstanding		345,535,050
Document Fiscal Year Focus	2019
Amendment Flag	false