<?xml version="1.0" encoding="us-ascii"?><InstanceReport xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"><Version>2.4.0.8</Version><ReportLongName>016 - Disclosure - Fair Value Measurements</ReportLongName><DisplayLabelColumn>true</DisplayLabelColumn><ShowElementNames>false</ShowElementNames><RoundingOption /><HasEmbeddedReports>false</HasEmbeddedReports><Columns><Column FlagID="0"><Id>1</Id><IsAbstractGroupTitle>false</IsAbstractGroupTitle><LabelSeparator>

</LabelSeparator><CurrencyCode /><FootnoteIndexer /><hasSegments>false</hasSegments><hasScenarios>false</hasScenarios><MCU><KeyName /><CurrencySymbol /><contextRef><ContextID>Context_6ME__30-Jun-2013</ContextID><EntitySchema>http://www.sec.gov/CIK</EntitySchema><EntityValue>0000086264</EntityValue><PeriodDisplayName /><PeriodType>duration</PeriodType><PeriodStartDate>2013-01-01T00:00:00</PeriodStartDate><PeriodEndDate>2013-06-30T00:00:00</PeriodEndDate><Segments /><Scenarios /></contextRef><UPS /><CurrencyCode /><OriginalCurrencyCode /></MCU><CurrencySymbol /><Labels><Label Key="CalendarSupplement" Id="0" Label="6 Months Ended" /><Label Key="Calendar" Id="1" Label="Jun. 30, 2013" /></Labels></Column></Columns><Rows><Row FlagID="0"><Id>1</Id><IsAbstractGroupTitle>true</IsAbstractGroupTitle><LabelSeparator>

</LabelSeparator><Level>1</Level><ElementName>us-gaap_FairValueDisclosuresAbstract</ElementName><ElementPrefix>us-gaap_</ElementPrefix><IsBaseElement>true</IsBaseElement><BalanceType>na</BalanceType><PeriodType>duration</PeriodType><IsReportTitle>false</IsReportTitle><IsSegmentTitle>false</IsSegmentTitle><IsCalendarTitle>false</IsCalendarTitle><IsEquityPrevioslyReportedAsRow>false</IsEquityPrevioslyReportedAsRow><IsEquityAdjustmentRow>false</IsEquityAdjustmentRow><IsBeginningBalance>false</IsBeginningBalance><IsEndingBalance>false</IsEndingBalance><IsReverseSign>false</IsReverseSign><FootnoteIndexer /><Cells><Cell FlagID="0" ContextID="" UnitID=""><Id>1</Id><IsNumeric>false</IsNumeric><IsRatio>false</IsRatio><DisplayZeroAsNone>false</DisplayZeroAsNone><NumericAmount>0</NumericAmount><RoundedNumericAmount>0</RoundedNumericAmount><NonNumbericText /><FootnoteIndexer /><CurrencyCode /><CurrencySymbol /><IsIndependantCurrency>false</IsIndependantCurrency><ShowCurrencySymbol>false</ShowCurrencySymbol><DisplayDateInUSFormat>false</DisplayDateInUSFormat></Cell></Cells><ElementDataType>xbrli:stringItemType</ElementDataType><SimpleDataType>string</SimpleDataType><IsTotalLabel>false</IsTotalLabel><UnitID>0</UnitID><Label>Fair Value Measurements [Abstract]</Label></Row><Row FlagID="0"><Id>2</Id><IsAbstractGroupTitle>false</IsAbstractGroupTitle><LabelSeparator>

</LabelSeparator><Level>2</Level><ElementName>us-gaap_FairValueDisclosuresTextBlock</ElementName><ElementPrefix>us-gaap_</ElementPrefix><IsBaseElement>true</IsBaseElement><BalanceType>na</BalanceType><PeriodType>duration</PeriodType><IsReportTitle>false</IsReportTitle><IsSegmentTitle>false</IsSegmentTitle><IsCalendarTitle>false</IsCalendarTitle><IsEquityPrevioslyReportedAsRow>false</IsEquityPrevioslyReportedAsRow><IsEquityAdjustmentRow>false</IsEquityAdjustmentRow><IsBeginningBalance>false</IsBeginningBalance><IsEndingBalance>false</IsEndingBalance><IsReverseSign>false</IsReverseSign><PreferredLabelRole>verboseLabel</PreferredLabelRole><FootnoteIndexer /><Cells><Cell FlagID="0" ContextID="Context_6ME__30-Jun-2013" UnitID=""><Id>1</Id><IsNumeric>false</IsNumeric><IsRatio>false</IsRatio><DisplayZeroAsNone>false</DisplayZeroAsNone><NumericAmount>0</NumericAmount><RoundedNumericAmount>0</RoundedNumericAmount><NonNumbericText>&lt;div style="line-height: 11.4pt; text-indent: 0pt; display: block;"&gt;&lt;font style="display: inline; font-family: times new roman; font-size: 10pt; font-weight: bold;"&gt;&lt;font style="display: inline; text-decoration: underline;"&gt;Note 10 &amp;#8211; Fair Value Measurements (continued)&lt;/font&gt;&lt;/font&gt;&lt;/div&gt;
&lt;div align="justify" style="line-height: 11.4pt; text-indent: 0pt; display: block; margin-left: 0pt; margin-right: 0pt;"&gt;&amp;#160;&lt;/div&gt;
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&lt;div align="justify" style="line-height: 11.4pt; text-indent: 0pt; display: block; margin-left: 0pt; margin-right: 0pt;"&gt;&amp;#160;&lt;/div&gt;
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&lt;tr&gt;
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&lt;tr&gt;
&lt;td align="left" style="border-bottom: black 2px solid;" valign="bottom"&gt;
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 10pt;"&gt;&amp;#160;&lt;/font&gt;&lt;/td&gt;
&lt;td style="text-align: left; padding-bottom: 2px;" valign="bottom" nowrap="nowrap"&gt;&lt;font style="display: inline; font-family: times new roman; font-size: 10pt;"&gt;&amp;#160;&lt;/font&gt;&lt;/td&gt;
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&lt;td valign="bottom" colspan="2"&gt;&lt;font style="display: inline; font-family: times new roman; font-size: 10pt;"&gt;&amp;#160;&lt;/font&gt;&lt;/td&gt;
&lt;td style="text-align: left;" valign="bottom" nowrap="nowrap"&gt;&lt;font style="display: inline; font-family: times new roman; font-size: 10pt;"&gt;&amp;#160;&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom"&gt;&lt;font style="display: inline; font-family: times new roman; font-size: 10pt;"&gt;&amp;#160;&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom" colspan="2"&gt;&lt;font style="display: inline; font-family: times new roman; font-size: 10pt;"&gt;&amp;#160;&lt;/font&gt;&lt;/td&gt;
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&lt;td valign="bottom"&gt;&lt;font style="display: inline; font-family: times new roman; font-size: 10pt;"&gt;&amp;#160;&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom" colspan="2"&gt;&lt;font style="display: inline; font-family: times new roman; font-size: 10pt;"&gt;&amp;#160;&lt;/font&gt;&lt;/td&gt;
&lt;td style="text-align: left;" valign="bottom" nowrap="nowrap"&gt;&lt;font style="display: inline; font-family: times new roman; font-size: 10pt;"&gt;&amp;#160;&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom"&gt;&lt;font style="display: inline; font-family: times new roman; font-size: 10pt;"&gt;&amp;#160;&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom" colspan="2"&gt;&lt;font style="display: inline; font-family: times new roman; font-size: 10pt;"&gt;&amp;#160;&lt;/font&gt;&lt;/td&gt;
&lt;td style="text-align: left;" valign="bottom" nowrap="nowrap"&gt;&lt;font style="display: inline; font-family: times new roman; font-size: 10pt;"&gt;&amp;#160;&lt;/font&gt;&lt;/td&gt;
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&lt;td align="left" style="padding-left: 0pt; margin-left: 9pt;" valign="bottom" width="40%"&gt;
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&lt;td align="left" valign="bottom" width="1%"&gt;&lt;font style="display: inline; font-family: times new roman; font-size: 10pt;"&gt;&amp;#160;&lt;/font&gt;&lt;/td&gt;
&lt;td style="text-align: left;" valign="bottom" width="1%"&gt;&lt;font style="display: inline; font-family: times new roman; font-size: 10pt;"&gt;$&lt;/font&gt;&lt;/td&gt;
&lt;td style="text-align: right;" valign="bottom" width="12%"&gt;&lt;font style="display: inline; font-family: times new roman; font-size: 10pt;"&gt;&lt;font style="margin-left: 5.85pt;" &gt;&lt;/font&gt;-&lt;/font&gt;&lt;/td&gt;
&lt;td style="text-align: left;" valign="bottom" width="1%" nowrap="nowrap"&gt;&lt;font style="display: inline; font-family: times new roman; font-size: 10pt;"&gt;&amp;#160;&lt;/font&gt;&lt;/td&gt;
&lt;td align="left" valign="bottom" width="1%"&gt;&lt;font style="display: inline; font-family: times new roman; font-size: 10pt;"&gt;&amp;#160;&lt;/font&gt;&lt;/td&gt;
&lt;td style="text-align: left;" valign="bottom" width="1%"&gt;&lt;font style="display: inline; font-family: times new roman; font-size: 10pt;"&gt;$&lt;/font&gt;&lt;/td&gt;
&lt;td style="text-align: right;" valign="bottom" width="12%"&gt;&lt;font style="display: inline; font-family: times new roman; font-size: 10pt;"&gt;&lt;font style="margin-left: 10.35pt;" &gt;&lt;/font&gt;85&lt;/font&gt;&lt;/td&gt;
&lt;td style="text-align: left;" valign="bottom" width="1%" nowrap="nowrap"&gt;&lt;font style="display: inline; font-family: times new roman; font-size: 10pt;"&gt;&amp;#160;&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom" width="1%"&gt;&lt;font style="display: inline; font-family: times new roman; font-size: 10pt;"&gt;&amp;#160;&lt;/font&gt;&lt;/td&gt;
&lt;td style="text-align: left;" valign="bottom" width="1%"&gt;&lt;font style="display: inline; font-family: times new roman; font-size: 10pt;"&gt;$&lt;/font&gt;&lt;/td&gt;
&lt;td style="text-align: right;" valign="bottom" width="12%"&gt;&lt;font style="display: inline; font-family: times new roman; font-size: 10pt;"&gt;&lt;font style="margin-left: 4.3pt;" &gt;&lt;/font&gt;-&lt;/font&gt;&lt;/td&gt;
&lt;td style="text-align: left;" valign="bottom" width="1%" nowrap="nowrap"&gt;&lt;font style="display: inline; font-family: times new roman; font-size: 10pt;"&gt;&amp;#160;&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom" width="1%"&gt;&lt;font style="display: inline; font-family: times new roman; font-size: 10pt;"&gt;&amp;#160;&lt;/font&gt;&lt;/td&gt;
&lt;td style="text-align: left;" valign="bottom" width="1%"&gt;&lt;font style="display: inline; font-family: times new roman; font-size: 10pt;"&gt;$&lt;/font&gt;&lt;/td&gt;
&lt;td style="text-align: right;" valign="bottom" width="12%"&gt;&lt;font style="display: inline; font-family: times new roman; font-size: 10pt;"&gt;&lt;font style="margin-left: 4.3pt;" &gt;&lt;/font&gt;85&lt;/font&gt;&lt;/td&gt;
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&lt;td valign="bottom" width="40%"&gt;&lt;font style="display: inline; font-family: times new roman; font-size: 10pt;"&gt;&amp;#160; &lt;/font&gt;&lt;/td&gt;
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&lt;td
 style="text-align: left;" valign="bottom" width="1%" nowrap="nowrap"&gt;&lt;font style="display: inline; font-family: times new roman; font-size: 10pt;"&gt;&amp;#160;&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom" width="1%"&gt;&lt;font style="display: inline; font-family: times new roman; font-size: 10pt;"&gt;&amp;#160;&lt;/font&gt;&lt;/td&gt;
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&lt;td style="text-align: left;" valign="bottom" width="1%" nowrap="nowrap"&gt;&lt;font style="display: inline; font-family: times new roman; font-size: 10pt;"&gt;&amp;#160;&lt;/font&gt;&lt;/td&gt;
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&lt;td align="left" style="border-bottom: black 2px solid;" valign="bottom" width="40%"&gt;
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