xbrli:dateUnion 

The union of the date and dateTime simple types.

Simple Type Information

Used By

Complex Type xbrli:dateTimeItemType
Elements xbrli:contextPeriodType/xbrli:endDate, xbrli:contextPeriodType/xbrli:instant, xbrli:contextPeriodType/xbrli:startDate

Source 

<simpleType name="dateUnion">
  <annotation>
    <documentation>The union of the date and dateTime simple types.</documentation>
  </annotation>
  <union memberTypes="date dateTime "/>
</simpleType>