<?xml version="1.0" encoding="utf-8"?>
<FilingSummary xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <Version>1.0.0.3</Version>
  <ReportType />
  <MyReports>
    <Report>
      <IsDefault>true</IsDefault>
      <ReportType>Sheet</ReportType>
      <LongName>104000 - Statement - Statement of Financial Position, Classified</LongName>
      <ShortName>Statement of Financial Position, Classified</ShortName>
      <XmlFileName>R1.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <ReportType>Sheet</ReportType>
      <LongName>140400 - Statement - Statement of Income, Securities Based Income</LongName>
      <ShortName>Statement of Income, Securities Based Income</ShortName>
      <XmlFileName>R2.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <ReportType>Sheet</ReportType>
      <LongName>168400 - Statement - Statement of Cash Flows, Securities Based Operations</LongName>
      <ShortName>Statement of Cash Flows, Securities Based Operations</ShortName>
      <XmlFileName>R3.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <ReportType>Sheet</ReportType>
      <LongName>995200 - Document - Document Information</LongName>
      <ShortName>Document Information</ShortName>
      <XmlFileName>R4.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <ReportType>Sheet</ReportType>
      <LongName>995400 - Document - Entity Information</LongName>
      <ShortName>Entity Information</ShortName>
      <XmlFileName>R5.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <ReportType>Notes</ReportType>
      <LongName>Notes to Financial Statements</LongName>
      <ShortName>Notes to Financial Statements</ShortName>
      <XmlFileName>R6.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <ReportType>Book</ReportType>
      <LongName>All Reports</LongName>
      <ShortName>All Reports</ShortName>
      <XmlFileName />
    </Report>
  </MyReports>
  <EntityCount>1</EntityCount>
  <ContextCount>15</ContextCount>
  <SegmentCount>0</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <UnitCount>3</UnitCount>
  <ElementCount>116</ElementCount>
  <FootnotesReported>false</FootnotesReported>
  <TuplesReported>false</TuplesReported>
  <ContextSummary>
    <ContextSummary>
      <ContextName>eol_0001193125-09-017160_STD_p3m_20081231_4</ContextName>
      <ElementCount>17</ElementCount>
    </ContextSummary>
    <ContextSummary>
      <ContextName>eol_0001193125-09-017160_STD_p3m_20071231_4</ContextName>
      <ElementCount>17</ElementCount>
    </ContextSummary>
    <ContextSummary>
      <ContextName>eol_0001193125-09-017160_STD_p6m_20081231_12</ContextName>
      <ElementCount>12</ElementCount>
    </ContextSummary>
    <ContextSummary>
      <ContextName>eol_0001193125-09-017160_STD_Inst_20081231_2</ContextName>
      <ElementCount>38</ElementCount>
    </ContextSummary>
    <ContextSummary>
      <ContextName>eol_0001193125-09-017160_STD_Inst_20070630_3</ContextName>
      <ElementCount>1</ElementCount>
    </ContextSummary>
    <ContextSummary>
      <ContextName>eol_0001193125-09-017160_STD_Inst_20080630_3</ContextName>
      <ElementCount>1</ElementCount>
    </ContextSummary>
    <ContextSummary>
      <ContextName>eol_0001193125-09-017160_STD_Inst_20081231_0</ContextName>
      <ElementCount>1</ElementCount>
    </ContextSummary>
    <ContextSummary>
      <ContextName>eol_0001193125-09-017160_STD_p6m_20071231_4</ContextName>
      <ElementCount>17</ElementCount>
    </ContextSummary>
    <ContextSummary>
      <ContextName>eol_0001193125-09-017160_STD_Inst_20080630_2</ContextName>
      <ElementCount>38</ElementCount>
    </ContextSummary>
    <ContextSummary>
      <ContextName>eol_0001193125-09-017160_STD_p6m_20081231_0</ContextName>
      <ElementCount>13</ElementCount>
    </ContextSummary>
    <ContextSummary>
      <ContextName>eol_0001193125-09-017160_STD_Inst_20071231_3</ContextName>
      <ElementCount>1</ElementCount>
    </ContextSummary>
    <ContextSummary>
      <ContextName>eol_0001193125-09-017160_STD_p6m_20081231_4</ContextName>
      <ElementCount>17</ElementCount>
    </ContextSummary>
    <ContextSummary>
      <ContextName>eol_0001193125-09-017160_STD_p6m_20071231_3</ContextName>
      <ElementCount>34</ElementCount>
    </ContextSummary>
    <ContextSummary>
      <ContextName>eol_0001193125-09-017160_STD_p6m_20081231_3</ContextName>
      <ElementCount>34</ElementCount>
    </ContextSummary>
    <ContextSummary>
      <ContextName>eol_0001193125-09-017160_STD_Inst_20081231_3</ContextName>
      <ElementCount>1</ElementCount>
    </ContextSummary>
  </ContextSummary>
  <BaseTaxonomies />
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
