Cover - shares	9 Months Ended
	Sep. 25, 2021	Oct. 15, 2021
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 25, 2021
Document Transition Report	false
Entity File Number	1-6770
Entity Registrant Name	MUELLER INDUSTRIES INC
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	25-0790410
Entity Address, Address Line One	150 Schilling Boulevard
Entity Address, Address Line Two	Suite 100
Entity Address, City or Town	Collierville
Entity Address, State or Province	TN
Entity Address, Postal Zip Code	38017
City Area Code	901
Local Phone Number	753-3200
Title of 12(b) Security	Common Stock
Trading Symbol	MLI
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		57,366,709
Entity Central Index Key	0000089439
Current Fiscal Year End Date	--12-25
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Amendment Flag	false