<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2014-05-14</periodOfReport>

    <issuer>
        <issuerCik>0001004980</issuerCik>
        <issuerName>PG&amp;E Corp</issuerName>
        <issuerTradingSymbol>PCG</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001221221</rptOwnerCik>
            <rptOwnerName>RAMBO BARBARA L</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O PG&amp;E CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>77 BEALE ST., P.O. BOX 77000</rptOwnerStreet2>
            <rptOwnerCity>SAN FRANCISCO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94177</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2014-05-14</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>2398</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>22670.79</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Restricted Stock Units (RSUs) granted under the PG&amp;E Corporation 2014 Long-Term Incentive Plan (LTIP).  RSUs are payable in shares of PG&amp;E Corporation common stock on a one-for-one basis upon the earliest of one year from the date of grant, a director's death, disability, or certain change-in-control-related events as described in the LTIP.</footnote>
        <footnote id="F2">This total includes 1,298.66 units of phantom stock granted under the PG&amp;E Corporation Non-Employee Director Stock Incentive Plan (SIP), and reflects the acquisition of 12.26 units of phantom stock on 7/15/13, 14.26 units of phantom stock on 10/15/13, 14.28 units of phantom stock on 1/15/14, and 12.92 units of phantom stock on 4/15/14, pursuant to a dividend reinvestment feature of the SIP.  This total also reflects the acquisition of 84.04 RSUs on 7/15/13, 97.71 RSUs on 10/15/13, 97.87 RSUs on 1/15/14, and 88.56 RSUs on 4/15/14 pursuant to a dividend reinvestment feature of the LTIP.  The phantom stock units and the RSUs are automatically payable in shares of PG&amp;E Corporation common stock only.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Linda Y.H. Cheng, attorney-in-fact for Barbara L. Rambo (signed Power of Attorney on file with SEC)</signatureName>
        <signatureDate>2014-05-16</signatureDate>
    </ownerSignature>
</ownershipDocument>
