<?xml version='1.0' encoding='UTF-8'?>
<FilingSummary>
  <Version>3.3.1.900</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>250</ContextCount>
  <ElementCount>403</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>true</FootnotesReported>
  <SegmentCount>75</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>4</UnitCount>
  <MyReports>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>0001000 - Document - Document and Entity Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/DocumentAndEntityInformation</Role>
      <ShortName>Document and Entity Information</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>1001000 - Statement - Consolidated Balance Sheets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/ConsolidatedBalanceSheets</Role>
      <ShortName>Consolidated Balance Sheets</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>1001501 - Statement - Consolidated Balance Sheets (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/ConsolidatedBalanceSheetsParenthetical</Role>
      <ShortName>Consolidated Balance Sheets (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>1002000 - Statement - Consolidated Statements of Income</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/ConsolidatedStatementsOfIncome</Role>
      <ShortName>Consolidated Statements of Income</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>1003000 - Statement - Consolidated Statements of Comprehensive Income</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/ConsolidatedStatementsOfComprehensiveIncome</Role>
      <ShortName>Consolidated Statements of Comprehensive Income</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>1004000 - Statement - Consolidated Statements of Changes in Equity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/ConsolidatedStatementsOfChangesInEquity</Role>
      <ShortName>Consolidated Statements of Changes in Equity</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>1005000 - Statement - Consolidated Statements of Cash Flows</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/ConsolidatedStatementsOfCashFlows</Role>
      <ShortName>Consolidated Statements of Cash Flows</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>2102100 - Disclosure - Summary of Significant Accounting Policies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/SummaryOfSignificantAccountingPolicies</Role>
      <ShortName>Summary of Significant Accounting Policies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>2105100 - Disclosure - Recent Accounting Pronouncements Recent Accounting Pronouncements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/RecentAccountingPronouncementsRecentAccountingPronouncements</Role>
      <ShortName>Recent Accounting Pronouncements Recent Accounting Pronouncements</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>2106100 - Disclosure - Concentration Risk</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/ConcentrationRisk</Role>
      <ShortName>Concentration Risk</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>2107100 - Disclosure - Consolidation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/Consolidation</Role>
      <ShortName>Consolidation</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>2108100 - Disclosure - Fair Value Measurements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/FairValueMeasurements</Role>
      <ShortName>Fair Value Measurements</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>2109100 - Disclosure - Investments</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/Investments</Role>
      <ShortName>Investments</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>2110100 - Disclosure - Intangible Assets and Goodwill</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/IntangibleAssetsAndGoodwill</Role>
      <ShortName>Intangible Assets and Goodwill</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>2112100 - Disclosure - Property and Equipment</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/PropertyAndEquipment</Role>
      <ShortName>Property and Equipment</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>2114100 - Disclosure - Debt and Interest Rate Swap</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/DebtAndInterestRateSwap</Role>
      <ShortName>Debt and Interest Rate Swap</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>2115100 - Disclosure - Employee Benefit Plans</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/EmployeeBenefitPlans</Role>
      <ShortName>Employee Benefit Plans</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>2116100 - Disclosure - Share-Based Compensation Plans</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/ShareBasedCompensationPlans</Role>
      <ShortName>Share-Based Compensation Plans</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>2117100 - Disclosure - Common Stock</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/CommonStock</Role>
      <ShortName>Common Stock</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>2118100 - Disclosure - Income Taxes</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/IncomeTaxes</Role>
      <ShortName>Income Taxes</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>2119100 - Disclosure - Earnings Per Share Attributable to Federated Investors, Inc. Shareholders</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/EarningsPerShareAttributableToFederatedInvestorsIncShareholders</Role>
      <ShortName>Earnings Per Share Attributable to Federated Investors, Inc. Shareholders</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>21</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>2121100 - Disclosure - Leases</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/Leases</Role>
      <ShortName>Leases</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>22</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>2122100 - Disclosure - Accumulated Other Comprehensive (Loss) Income Attributable to Federated Shareholders</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/AccumulatedOtherComprehensiveLossIncomeAttributableToFederatedShareholders</Role>
      <ShortName>Accumulated Other Comprehensive (Loss) Income Attributable to Federated Shareholders</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>23</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>2123100 - Disclosure - Commitments and Contingencies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/CommitmentsAndContingencies</Role>
      <ShortName>Commitments and Contingencies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>24</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>2124100 - Disclosure - Subsequent Events</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/SubsequentEvents</Role>
      <ShortName>Subsequent Events</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>25</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>2125100 - Disclosure - Supplementary Quarterly Financial Data (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/SupplementaryQuarterlyFinancialDataUnaudited</Role>
      <ShortName>Supplementary Quarterly Financial Data (Unaudited)</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>26</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>2202201 - Disclosure - Summary of Significant Accounting Policies (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/SummaryOfSignificantAccountingPoliciesPolicies</Role>
      <ShortName>Summary of Significant Accounting Policies (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://www.federatedinvestors.com/role/SummaryOfSignificantAccountingPolicies</ParentRole>
      <Position>27</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>2205201 - Disclosure - Recent Accounting Pronouncements New Accounting Pronouncements and Changes in Accounting Principles [Abstract]</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/RecentAccountingPronouncementsNewAccountingPronouncementsAndChangesInAccountingPrinciplesAbstract</Role>
      <ShortName>Recent Accounting Pronouncements New Accounting Pronouncements and Changes in Accounting Principles [Abstract]</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>28</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>2306301 - Disclosure - Concentration Risk Concentration Risk (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/ConcentrationRiskConcentrationRiskTables</Role>
      <ShortName>Concentration Risk Concentration Risk (Tables)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>29</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>2307301 - Disclosure - Consolidation (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/ConsolidationTables</Role>
      <ShortName>Consolidation (Tables)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>30</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>2308301 - Disclosure - Fair Value Measurements (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/FairValueMeasurementsTables</Role>
      <ShortName>Fair Value Measurements (Tables)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>31</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>2309301 - Disclosure - Investments (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/InvestmentsTables</Role>
      <ShortName>Investments (Tables)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>32</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>2310301 - Disclosure - Intangible Assets and Goodwill (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/IntangibleAssetsAndGoodwillTables</Role>
      <ShortName>Intangible Assets and Goodwill (Tables)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>33</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>2312301 - Disclosure - Property and Equipment (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/PropertyAndEquipmentTables</Role>
      <ShortName>Property and Equipment (Tables)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>34</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>2314301 - Disclosure - Debt and Interest Rate Swap (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/DebtAndInterestRateSwapTables</Role>
      <ShortName>Debt and Interest Rate Swap (Tables)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>35</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>2316301 - Disclosure - Share-Based Compensation Plans (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/ShareBasedCompensationPlansTables</Role>
      <ShortName>Share-Based Compensation Plans (Tables)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>36</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>2318301 - Disclosure - Income Taxes (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/IncomeTaxesTables</Role>
      <ShortName>Income Taxes (Tables)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>37</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>2319301 - Disclosure - Earnings Per Share Attributable to Federated Investors, Inc. Shareholders (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/EarningsPerShareAttributableToFederatedInvestorsIncShareholdersTables</Role>
      <ShortName>Earnings Per Share Attributable to Federated Investors, Inc. Shareholders (Tables)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>38</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>2321301 - Disclosure - Leases (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/LeasesTables</Role>
      <ShortName>Leases (Tables)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>39</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>2322301 - Disclosure - Accumulated Other Comprehensive (Loss) Income Attributable to Federated Shareholders (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/AccumulatedOtherComprehensiveLossIncomeAttributableToFederatedShareholdersTables</Role>
      <ShortName>Accumulated Other Comprehensive (Loss) Income Attributable to Federated Shareholders (Tables)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>40</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>2323301 - Disclosure - Commitments and Contingencies (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/CommitmentsAndContingenciesTables</Role>
      <ShortName>Commitments and Contingencies (Tables)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>41</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>2325301 - Disclosure - Supplementary Quarterly Financial Data (Unaudited) (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/SupplementaryQuarterlyFinancialDataUnauditedTables</Role>
      <ShortName>Supplementary Quarterly Financial Data (Unaudited) (Tables)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>42</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>2402402 - Disclosure - Summary of Significant Accounting Policies Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/SummaryOfSignificantAccountingPoliciesNarrativeDetails</Role>
      <ShortName>Summary of Significant Accounting Policies Narrative (Details)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>43</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>2406402 - Disclosure - Concentration Risk (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/ConcentrationRiskDetails</Role>
      <ShortName>Concentration Risk (Details)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>44</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>2406403 - Disclosure - Concentration Risk Schedule of Revenue Concentration (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/ConcentrationRiskScheduleOfRevenueConcentrationDetails</Role>
      <ShortName>Concentration Risk Schedule of Revenue Concentration (Details)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>45</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>2406404 - Disclosure - Concentration Risk Voluntary Fee Waivers (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/ConcentrationRiskVoluntaryFeeWaiversDetails</Role>
      <ShortName>Concentration Risk Voluntary Fee Waivers (Details)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>46</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>2407402 - Disclosure - Consolidation (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/ConsolidationDetails</Role>
      <ShortName>Consolidation (Details)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>47</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>2407403 - Disclosure - Consolidation Consolidated Investment Companies (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/ConsolidationConsolidatedInvestmentCompaniesDetails</Role>
      <ShortName>Consolidation Consolidated Investment Companies (Details)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>48</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>2408402 - Disclosure - Fair Value Measurements Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/FairValueMeasurementsNarrativeDetails</Role>
      <ShortName>Fair Value Measurements Narrative (Details)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>49</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>2408403 - Disclosure - Fair Value Measurements Classes of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/FairValueMeasurementsClassesOfFinancialAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails</Role>
      <ShortName>Fair Value Measurements Classes of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Details)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>50</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>2408404 - Disclosure - Fair Value Measurements Reconciliation of Fair Value Measurements of Liability for Future Consideration Payments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/FairValueMeasurementsReconciliationOfFairValueMeasurementsOfLiabilityForFutureConsiderationPaymentsDetails</Role>
      <ShortName>Fair Value Measurements Reconciliation of Fair Value Measurements of Liability for Future Consideration Payments (Details)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>51</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>2409402 - Disclosure - Investments Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/InvestmentsNarrativeDetails</Role>
      <ShortName>Investments Narrative (Details)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>52</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>2409403 - Disclosure - Investments Available-For-Sale Securities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/InvestmentsAvailableForSaleSecuritiesDetails</Role>
      <ShortName>Investments Available-For-Sale Securities (Details)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>53</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>2409404 - Disclosure - Investments Gain on Securities, Net of Investment Income (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/InvestmentsGainOnSecuritiesNetOfInvestmentIncomeDetails</Role>
      <ShortName>Investments Gain on Securities, Net of Investment Income (Details)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>54</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>2410402 - Disclosure - Intangible Assets and Goodwill Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/IntangibleAssetsAndGoodwillNarrativeDetails</Role>
      <ShortName>Intangible Assets and Goodwill Narrative (Details)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>55</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>2410403 - Disclosure - Finite-Lived Intangibles Table (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/FiniteLivedIntangiblesTableDetails</Role>
      <ShortName>Finite-Lived Intangibles Table (Details)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>56</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>2410404 - Disclosure - Intangible Assets and Goodwill Indefinite-Lived Intangible Assets Table (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/IntangibleAssetsAndGoodwillIndefiniteLivedIntangibleAssetsTableDetails</Role>
      <ShortName>Intangible Assets and Goodwill Indefinite-Lived Intangible Assets Table (Details)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>57</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>2410405 - Disclosure - Intangible Assets and Goodwill Goodwill Table (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/IntangibleAssetsAndGoodwillGoodwillTableDetails</Role>
      <ShortName>Intangible Assets and Goodwill Goodwill Table (Details)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>58</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>2412402 - Disclosure - Property and Equipment Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/PropertyAndEquipmentNarrativeDetails</Role>
      <ShortName>Property and Equipment Narrative (Details)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>59</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R60.htm</HtmlFileName>
      <LongName>2412403 - Disclosure - Property and Equipment Table (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/PropertyAndEquipmentTableDetails</Role>
      <ShortName>Property and Equipment Table (Details)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>60</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R61.htm</HtmlFileName>
      <LongName>2414402 - Disclosure - Debt and Interest Rate Swap Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/DebtAndInterestRateSwapNarrativeDetails</Role>
      <ShortName>Debt and Interest Rate Swap Narrative (Details)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>61</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R62.htm</HtmlFileName>
      <LongName>2414403 - Disclosure - Debt and Interest Rate Swap Table (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/DebtAndInterestRateSwapTableDetails</Role>
      <ShortName>Debt and Interest Rate Swap Table (Details)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>62</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R63.htm</HtmlFileName>
      <LongName>2415401 - Disclosure - Employee Benefit Plans Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/EmployeeBenefitPlansNarrativeDetails</Role>
      <ShortName>Employee Benefit Plans Narrative (Details)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>63</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R64.htm</HtmlFileName>
      <LongName>2416402 - Disclosure - Share-Based Compensation Plans Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/ShareBasedCompensationPlansNarrativeDetails</Role>
      <ShortName>Share-Based Compensation Plans Narrative (Details)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>64</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R65.htm</HtmlFileName>
      <LongName>2416403 - Disclosure - Share-Based Compensation Plans Nonvested Restricted Stock Units (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/ShareBasedCompensationPlansNonvestedRestrictedStockUnitsDetails</Role>
      <ShortName>Share-Based Compensation Plans Nonvested Restricted Stock Units (Details)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>65</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R66.htm</HtmlFileName>
      <LongName>2416404 - Disclosure - Share-Based Compensation Plans Stock Options (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/ShareBasedCompensationPlansStockOptionsDetails</Role>
      <ShortName>Share-Based Compensation Plans Stock Options (Details)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>66</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R67.htm</HtmlFileName>
      <LongName>2417401 - Disclosure - Common Stock Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/CommonStockNarrativeDetails</Role>
      <ShortName>Common Stock Narrative (Details)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>67</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R68.htm</HtmlFileName>
      <LongName>2418402 - Disclosure - Income Taxes Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/IncomeTaxesNarrativeDetails</Role>
      <ShortName>Income Taxes Narrative (Details)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>68</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R69.htm</HtmlFileName>
      <LongName>2418403 - Disclosure - Income Taxes Components of Income Tax Expense (Benefit) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/IncomeTaxesComponentsOfIncomeTaxExpenseBenefitDetails</Role>
      <ShortName>Income Taxes Components of Income Tax Expense (Benefit) (Details)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>69</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R70.htm</HtmlFileName>
      <LongName>2418404 - Disclosure - Income Taxes Effective Income Tax Rate Reconciliation (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/IncomeTaxesEffectiveIncomeTaxRateReconciliationDetails</Role>
      <ShortName>Income Taxes Effective Income Tax Rate Reconciliation (Details)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>70</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R71.htm</HtmlFileName>
      <LongName>2418405 - Disclosure - Income Taxes Deferred Tax Assets and Liabilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/IncomeTaxesDeferredTaxAssetsAndLiabilitiesDetails</Role>
      <ShortName>Income Taxes Deferred Tax Assets and Liabilities (Details)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>71</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R72.htm</HtmlFileName>
      <LongName>2419402 - Disclosure - Earnings Per Share Attributable to Federated Investors, Inc. Shareholders Computation of Basic and Diluted Earnings Per Share (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/EarningsPerShareAttributableToFederatedInvestorsIncShareholdersComputationOfBasicAndDilutedEarningsPerShareDetails</Role>
      <ShortName>Earnings Per Share Attributable to Federated Investors, Inc. Shareholders Computation of Basic and Diluted Earnings Per Share (Details)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>72</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R73.htm</HtmlFileName>
      <LongName>2421402 - Disclosure - Leases Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/LeasesNarrativeDetails</Role>
      <ShortName>Leases Narrative (Details)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>73</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R74.htm</HtmlFileName>
      <LongName>2421403 - Disclosure - Leases Future Minimum Rental Payments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/LeasesFutureMinimumRentalPaymentsDetails</Role>
      <ShortName>Leases Future Minimum Rental Payments (Details)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>74</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R75.htm</HtmlFileName>
      <LongName>2422402 - Disclosure - Accumulated Other Comprehensive (Loss) Income Attributable to Federated Shareholders Schedule (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/AccumulatedOtherComprehensiveLossIncomeAttributableToFederatedShareholdersScheduleDetails</Role>
      <ShortName>Accumulated Other Comprehensive (Loss) Income Attributable to Federated Shareholders Schedule (Details)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>75</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R76.htm</HtmlFileName>
      <LongName>2423402 - Disclosure - Commitments and Contingencies Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/CommitmentsAndContingenciesNarrativeDetails</Role>
      <ShortName>Commitments and Contingencies Narrative (Details)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>76</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R77.htm</HtmlFileName>
      <LongName>2423403 - Disclosure - Commitments and Contingencies Unrecorded Unconditional Purchase Obligations Disclosure (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/CommitmentsAndContingenciesUnrecordedUnconditionalPurchaseObligationsDisclosureDetails</Role>
      <ShortName>Commitments and Contingencies Unrecorded Unconditional Purchase Obligations Disclosure (Details)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>77</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R78.htm</HtmlFileName>
      <LongName>2424401 - Disclosure - Subsequent Events (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/SubsequentEventsDetails</Role>
      <ShortName>Subsequent Events (Details)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>78</Position>
    </Report>
    <Report instance="fii-20151231.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R79.htm</HtmlFileName>
      <LongName>2425402 - Disclosure - Supplementary Quarterly Financial Data Schedule (Unaudited) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.federatedinvestors.com/role/SupplementaryQuarterlyFinancialDataScheduleUnauditedDetails</Role>
      <ShortName>Supplementary Quarterly Financial Data Schedule (Unaudited) (Details)</ShortName>
      <MenuCategory>Uncategorized</MenuCategory>
      <Position>79</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <InputFiles>
    <File>fii-20151231.xml</File>
    <File>fii-20151231.xsd</File>
    <File>fii-20151231_cal.xml</File>
    <File>fii-20151231_def.xml</File>
    <File>fii-20151231_lab.xml</File>
    <File>fii-20151231_pre.xml</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies/>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
