<SEC-DOCUMENT>0001109357-18-000037.txt : 20180131
<SEC-HEADER>0001109357-18-000037.hdr.sgml : 20180131
<ACCEPTANCE-DATETIME>20180131150356
ACCESSION NUMBER:		0001109357-18-000037
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20180129
FILED AS OF DATE:		20180131
DATE AS OF CHANGE:		20180131

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Thayer Jonathan W
		CENTRAL INDEX KEY:			0001448765

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-16169
		FILM NUMBER:		18562393

	MAIL ADDRESS:	
		STREET 1:		CONSTELLATION ENERGY GROUP, INC.
		STREET 2:		100 CONSTELLATION WAY, SUITE 1800P
		CITY:			BALTIMORE
		STATE:			MD
		ZIP:			21202

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			EXELON CORP
		CENTRAL INDEX KEY:			0001109357
		STANDARD INDUSTRIAL CLASSIFICATION:	ELECTRIC & OTHER SERVICES COMBINED [4931]
		IRS NUMBER:				232990190
		STATE OF INCORPORATION:			PA
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		PO BOX 805398
		CITY:			CHICAGO
		STATE:			IL
		ZIP:			60680-5398
		BUSINESS PHONE:		3123947399

	MAIL ADDRESS:	
		STREET 1:		PO BOX 805398
		CITY:			CHICAGO
		STATE:			IL
		ZIP:			60680-5398
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
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    <periodOfReport>2018-01-29</periodOfReport>

    <issuer>
        <issuerCik>0001109357</issuerCik>
        <issuerName>EXELON CORP</issuerName>
        <issuerTradingSymbol>EXC</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001448765</rptOwnerCik>
            <rptOwnerName>Thayer Jonathan W</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>10 SOUTH DEARBORN STREET</rptOwnerStreet1>
            <rptOwnerStreet2>54TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>CHICAGO</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60603</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Senior EVP and CFO</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
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                <value>Common Stock</value>
            </securityTitle>
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            </transactionDate>
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                <transactionCode>M</transactionCode>
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                <transactionPricePerShare>
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                <transactionAcquiredDisposedCode>
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        <nonDerivativeHolding>
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        </nonDerivativeHolding>
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    <derivativeTable>
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            <conversionOrExercisePrice>
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            <transactionDate>
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                </underlyingSecurityTitle>
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                </underlyingSecurityShares>
            </underlyingSecurity>
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                </sharesOwnedFollowingTransaction>
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                <directOrIndirectOwnership>
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                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
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            </securityTitle>
            <conversionOrExercisePrice>
                <value>0</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2018-01-29</value>
            </transactionDate>
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                <transactionPricePerShare>
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                </directOrIndirectOwnership>
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        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
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                </transactionShares>
                <transactionPricePerShare>
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                    <value>53906</value>
                </sharesOwnedFollowingTransaction>
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                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
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        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Performance Shares- Stock Units</value>
            </securityTitle>
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                    <value>53906</value>
                </transactionShares>
                <transactionPricePerShare>
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                <transactionAcquiredDisposedCode>
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                </transactionAcquiredDisposedCode>
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            <exerciseDate>
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                <footnoteId id="F5"/>
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                <underlyingSecurityTitle>
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                </underlyingSecurityShares>
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                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
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            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
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                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Shares withheld by the Issuer for reporting person's tax obligation.</footnote>
        <footnote id="F2">Shares settled in cash on a 1 for 1 basis.</footnote>
        <footnote id="F3">Shares held as of December 31, 2017 in a multi-fund 401(k) Plan to be settled in cash upon the reporting person's termination of employment for any reason on a 1:1 basis. Shares are acquired through regular periodic contributions, company matching contributions, and the automatic reinvestment of dividends.</footnote>
        <footnote id="F4">Restricted stock unit awards made pursuant to the Exelon Long Term Incentive Plan.  Share awards are made annually in January at the Compensation and Leadership Development committee's meeting and vest in 1/3 increments on the date of the committee's January meeting in the first, second and third years after the award was made.</footnote>
        <footnote id="F5">Performance share stock units award made pursuant to the Exelon Long Term Incentive Plan for the three-year performance period from January 1, 2015 to December 31, 2017. Shares vest immediately upon award.  This grant was settled in cash on a 1 for 1 basis based on the cash value of the underlying stock on the date of vesting because the reporting person had attained 200% of their required stock ownership target.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Scott N. Peters, Attorney in Fact for Jonathan W. Thayer</signatureName>
        <signatureDate>2018-01-31</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
