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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2016-10-24</periodOfReport>

    <issuer>
        <issuerCik>0001105705</issuerCik>
        <issuerName>TIME WARNER INC.</issuerName>
        <issuerTradingSymbol>TWX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001476398</rptOwnerCik>
            <rptOwnerName>Horne Douglas Edward</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>ONE TIME WARNER CENTER</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10019</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isOfficer>1</isOfficer>
            <officerTitle>SVP and Controller</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Restricted Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2016-10-24</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>12682</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F2"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock, Par Value $.01</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>12682</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>34877</value>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Each restricted stock unit represents the contingent right to receive one share of common stock.</footnote>
        <footnote id="F2">This award of restricted stock units represents a special retention award that was granted in accordance with the Agreement and Plan of Merger, dated as of October 22, 2016, among Time Warner Inc. (the 'Company'), AT&amp;T Inc. and West Merger Sub, Inc. and has a value equal to approximately two times the holder's annual long-term incentive compensation.  Half of this award is scheduled to vest in four equal installments on each anniversary of February 15, 2017, and the remaining half is scheduled to vest in four equal installments on each anniversary of February 15, 2018. The Company has no plan to grant the holder a long-term incentive award in respect of 2017 or 2018.</footnote>
        <footnote id="F3">These restricted stock units include (i) restricted stock units that vest in two equal installments on the third and fourth anniversaries of the date of grant, February 15, 2013; (ii) restricted stock units that vest in four equal installments on the first four anniversaries of the following dates of grant: February 15, 2014, February 15, 2015 and February 15, 2016; (iii) restricted stock units that are scheduled to vest in four equal installments on each anniversary of February 15, 2017; and (iv) restricted stock units that are scheduled to vest in four equal installments on each anniversary of February 15, 2018.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Brenda C. Karickhoff for Douglas E. Horne</signatureName>
        <signatureDate>2016-10-26</signatureDate>
    </ownerSignature>
</ownershipDocument>
