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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2021-03-01</periodOfReport>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001676160</rptOwnerCik>
            <rptOwnerName>Thomason David S.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O PG&amp;E CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>77 BEALE ST., P.O. BOX 770000</rptOwnerStreet2>
            <rptOwnerCity>SAN FRANCISCO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94177</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isOfficer>1</isOfficer>
            <officerTitle>VP and Controller</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2021-03-01</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>486</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>10.97</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>7967</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>259.18</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Held by Trustee of PG&amp;E Corporation Retirement Savings Plan</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>663.3</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Held by Trustee of PG&amp;E Corporation Retirement Savings Plan for spouse</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Represents the approximate number of shares of PG&amp;E Corporation common stock held for the reporting person in the PG&amp;E Corporation Stock Fund of the PG&amp;E Corporation Retirement Savings Plan (RSP).  That fund holds units consisting of PG&amp;E Corporation common stock and a small short-term investments component.  The number of shares is computed by dividing the value of the units by the daily closing price.  Dividends are automatically invested in additional units at the election of the participant.  These holdings have been trued up to conform to the RSP balance as of 3/1/2021.</footnote>
        <footnote id="F2">Represents the approximate number of shares of PG&amp;E Corporation common stock held for the reporting person's spouse in the PG&amp;E Corporation Stock Fund of the PG&amp;E Corporation RSP.  That fund holds units consisting of PG&amp;E Corporation common stock and a small short-term investments component.  The number of shares is computed by dividing the value of the units by the daily closing price.  Dividends are automatically invested in additional units at the election of the participant.  These holdings have been trued up to conform to the RSP balance as of 3/1/2021.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ J. Ellen Conti, attorney-in-fact for David S. Thomason (signed Power of Attorney on file with SEC)</signatureName>
        <signatureDate>2021-03-03</signatureDate>
    </ownerSignature>
</ownershipDocument>
