XML 40 R23.htm IDEA: XBRL DOCUMENT
v2.4.0.6

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details Textual) | Feb. 29, 2012
--- | ---
Numbe Rof Units Per Basket | 50,000
Redemption Baskets [Member] | Prior to July 1, 2011 [Member] |
Numbe Rof Units Per Basket | 100,000

X
- Definition Number of Units per Basket. + References No definition available. + Details
Name: | bno_NumbeRofUnitsPerBasket
Namespace Prefix: | bno_
Data Type: | us-types:perUnitItemType
Balance Type: | na
Period Type: | instant