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Condensed Schedule of Investments [Parenthetical] | 9 Months Ended
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Sep. 30, 2012
Percentage Of United States Treasury Bill | 0.09%

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- Definition Percentage of united states treasury bill. + References No definition available. + Details
Name: | bno_PercentageOfUnitedStatesTreasuryBill
Namespace Prefix: | bno_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration