<SEC-DOCUMENT>0001127602-12-006992.txt : 20120221
<SEC-HEADER>0001127602-12-006992.hdr.sgml : 20120220
<ACCEPTANCE-DATETIME>20120221140923
ACCESSION NUMBER:		0001127602-12-006992
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20120217
FILED AS OF DATE:		20120221
DATE AS OF CHANGE:		20120221

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Woodworth John K
		CENTRAL INDEX KEY:			0001377945

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-03285
		FILM NUMBER:		12626260

	MAIL ADDRESS:	
		STREET 1:		3M CENTER - OFFICE OF GENERAL COUNSEL
		CITY:			ST. PAUL
		STATE:			MN
		ZIP:			55144-1000

	FORMER NAME:	
		FORMER CONFORMED NAME:	Woodward John K
		DATE OF NAME CHANGE:	20061011

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			3M CO
		CENTRAL INDEX KEY:			0000066740
		STANDARD INDUSTRIAL CLASSIFICATION:	SURGICAL & MEDICAL INSTRUMENTS & APPARATUS [3841]
		IRS NUMBER:				410417775
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		3M CENTER
		STREET 2:		BLDG. 220-11W-02
		CITY:			ST PAUL
		STATE:			MN
		ZIP:			55144-1000
		BUSINESS PHONE:		6517332204

	MAIL ADDRESS:	
		STREET 1:		3M CENTER
		STREET 2:		BLDG. 220-11W-02
		CITY:			ST. PAUL
		STATE:			MN
		ZIP:			55144-1000

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	MINNESOTA MINING & MANUFACTURING CO
		DATE OF NAME CHANGE:	19920703
</SEC-HEADER>
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<SEQUENCE>1
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    <schemaVersion>X0304</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2012-02-17</periodOfReport>

    <issuer>
        <issuerCik>0000066740</issuerCik>
        <issuerName>3M CO</issuerName>
        <issuerTradingSymbol>MMM</issuerTradingSymbol>
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            <rptOwnerName>Woodworth John K</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>3M CENTER</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>ST. PAUL</rptOwnerCity>
            <rptOwnerState>MN</rptOwnerState>
            <rptOwnerZipCode>55144-1000</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isOfficer>1</isOfficer>
            <officerTitle>VICE PRESIDENT CORP SC OPERTNS</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
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                <value>Common Stock</value>
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                <equitySwapInvolved>0</equitySwapInvolved>
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            <transactionAmounts>
                <transactionShares>
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                <transactionPricePerShare>
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                <transactionShares>
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                <transactionPricePerShare>
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            <securityTitle>
                <value>Common Stock</value>
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            <transactionDate>
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            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
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            <transactionTimeliness></transactionTimeliness>
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                <transactionShares>
                    <value>321</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>87.824</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
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                <sharesOwnedFollowingTransaction>
                    <value>14684</value>
                </sharesOwnedFollowingTransaction>
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                    <value>D</value>
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        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2012-02-17</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>100</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>87.8307</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
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            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>14584</value>
                </sharesOwnedFollowingTransaction>
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        </nonDerivativeTransaction>
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            <transactionDate>
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                <transactionFormType>4</transactionFormType>
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                <equitySwapInvolved>0</equitySwapInvolved>
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            <transactionTimeliness></transactionTimeliness>
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                <transactionShares>
                    <value>100</value>
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                <transactionPricePerShare>
                    <value>87.8311</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
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                <sharesOwnedFollowingTransaction>
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                </sharesOwnedFollowingTransaction>
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                </directOrIndirectOwnership>
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        </nonDerivativeTransaction>
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                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
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                </transactionShares>
                <transactionPricePerShare>
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                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
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                </sharesOwnedFollowingTransaction>
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            <securityTitle>
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                </sharesOwnedFollowingTransaction>
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            <ownershipNature>
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    </nonDerivativeTable>

    <footnotes></footnotes>

    <ownerSignature>
        <signatureName>George Ann Biros, attorney-in-fact for John K. Woodworth</signatureName>
        <signatureDate>2012-02-21</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
