    <SEC-DOCUMENT>0000089439-20-000083-index.html : 20201020
    <SEC-HEADER>0000089439-20-000083.hdr.sgml : 20201020
    <ACCEPTANCE-DATETIME>20201020141259
    ACCESSION NUMBER:		0000089439-20-000083
    CONFORMED SUBMISSION TYPE:	8-K
    PUBLIC DOCUMENT COUNT:		17
    CONFORMED PERIOD OF REPORT:	20201020
    ITEM INFORMATION:		Financial Statements and Exhibits
    FILED AS OF DATE:		20201020
    DATE AS OF CHANGE:		20201020

    FILER:

    	COMPANY DATA:
    		COMPANY CONFORMED NAME:			MUELLER INDUSTRIES INC
    		CENTRAL INDEX KEY:			0000089439
    		STANDARD INDUSTRIAL CLASSIFICATION:	ROLLING DRAWING & EXTRUDING OF NONFERROUS METALS [3350]
    		IRS NUMBER:				250790410
    		STATE OF INCORPORATION:			DE
    		FISCAL YEAR END:			1226

    	FILING VALUES:
    		FORM TYPE:		8-K
    		SEC ACT:		1934 Act
    		SEC FILE NUMBER:	001-06770
    		FILM NUMBER:		201248000

    	BUSINESS ADDRESS:
    		STREET 1:		SUITE 100
    		STREET 2:		150 SCHILLING BOULEVARD
    		CITY:			COLLIERVILLE
    		STATE:			TN
    		ZIP:			38017
    		BUSINESS PHONE:		(901)753-3200

    	MAIL ADDRESS:
    		STREET 1:		SUITE 100
    		STREET 2:		150 SCHILLING BOULEVARD
    		CITY:			COLLIERVILLE
    		STATE:			TN
    		ZIP:			38017

    	FORMER COMPANY:
    		FORMER CONFORMED NAME:	SHARON STEEL CORP
    		DATE OF NAME CHANGE:	19910103
    </SEC-HEADER>
    <DOCUMENT>
    <TYPE>8-K
    <SEQUENCE>1
    <FILENAME>mli-20201020.htm
    <DESCRIPTION>8-K
    <TEXT>
    Document 1 - file: mli-20201020.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-99.1
    <SEQUENCE>2
    <FILENAME>exhibit991q32020earnin.htm
    <DESCRIPTION>EX-99.1
    <TEXT>
    Document 2 - file: exhibit991q32020earnin.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-101.SCH
    <SEQUENCE>3
    <FILENAME>mli-20201020.xsd
    <DESCRIPTION>XBRL TAXONOMY EXTENSION SCHEMA DOCUMENT
    <TEXT>
    Document 3 - file: mli-20201020.xsd

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-101.CAL
    <SEQUENCE>4
    <FILENAME>mli-20201020_cal.xml
    <DESCRIPTION>XBRL TAXONOMY EXTENSION CALCULATION LINKBASE DOCUMENT
    <TEXT>
    Document 4 - file: mli-20201020_cal.xml

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-101.DEF
    <SEQUENCE>5
    <FILENAME>mli-20201020_def.xml
    <DESCRIPTION>XBRL TAXONOMY EXTENSION DEFINITION LINKBASE DOCUMENT
    <TEXT>
    Document 5 - file: mli-20201020_def.xml

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-101.LAB
    <SEQUENCE>6
    <FILENAME>mli-20201020_lab.xml
    <DESCRIPTION>XBRL TAXONOMY EXTENSION LABEL LINKBASE DOCUMENT
    <TEXT>
    Document 6 - file: mli-20201020_lab.xml

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-101.PRE
    <SEQUENCE>7
    <FILENAME>mli-20201020_pre.xml
    <DESCRIPTION>XBRL TAXONOMY EXTENSION PRESENTATION LINKBASE DOCUMENT
    <TEXT>
    Document 7 - file: mli-20201020_pre.xml

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>8
    <FILENAME>mli-20201020_g1.jpg
    <TEXT>
    Document 8 - file: mli-20201020_g1.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>9
    <FILENAME>muellerlogoa071.jpg
    <TEXT>
    Document 9 - file: muellerlogoa071.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>10
    <FILENAME>mli-20201020_htm.xml
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 10 - file: mli-20201020_htm.html

    Document 10 - RAW XML: mli-20201020_htm.xml

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>11
    <FILENAME>R1.htm
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 11 - file: R1.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EXCEL
    <SEQUENCE>12
    <FILENAME>Financial_Report.xlsx
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 12 - file: Financial_Report.xlsx

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>13
    <FILENAME>Show.js
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 13 - file: Show.js

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>14
    <FILENAME>report.css
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 14 - file: report.css

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>15
    <FILENAME>FilingSummary.xml
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 15 - file: FilingSummary.html

    Document 15 - RAW XML: FilingSummary.xml

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>JSON
    <SEQUENCE>17
    <FILENAME>MetaLinks.json
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 17 - file: MetaLinks.json

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>ZIP
    <SEQUENCE>18
    <FILENAME>0000089439-20-000083-xbrl.zip
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 18 - file: 0000089439-20-000083-xbrl.zip

    </DOCUMENT>
    </SEC-DOCUMENT>