Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2018	Oct. 12, 2018
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q3
Trading Symbol	MAT
Entity Registrant Name	MATTEL INC /DE/
Entity Central Index Key	0000063276
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Emerging Growth Company	false
Small Business	false
Entity Common Stock, Shares Outstanding		345,150,787