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v2.4.1.9

Organization and Business (Additional Information) (Detail) (USD $) | 0 Months Ended |
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Apr. 10, 2006 | Mar. 31, 2015
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items] |  |
Fee paid by Authorized Purchasers for each order placed to create one or more Creation Baskets or to redeem one or more baskets |  | 1,000 uso_FeePaidPerOrder
Limited Partners' Capital Account, Units Authorized | 17,000,000 us-gaap_LimitedPartnersCapitalAccountUnitsAuthorized | 1,627,000,000 us-gaap_LimitedPartnersCapitalAccountUnitsAuthorized
Limited Partners' Capital Account, Units Issued | 200,000 us-gaap_LimitedPartnersCapitalAccountUnitsIssued |
Net asset value per unit | $ 67.39 uso_NetAssetValuePerUnit | $ 16.87 uso_NetAssetValuePerUnit
Value of units issued | $ 13,479,000 uso_UnitsIssuedDuringPeriodValueNewIssues |
Creation Baskets [Member] |  |
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items] |  |
Number of units per basket |  | 100,000 uso_NumberOfUnitPerBasket / invest_InvestmentSecuritiesClassAxis = uso_CreationBasketsMember
Redemption Baskets [Member] |  |
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items] |  |
Number of units per basket |  | 100,000 uso_NumberOfUnitPerBasket / invest_InvestmentSecuritiesClassAxis = uso_RedemptionBasketsMember
Open Futures Contracts, Long [Member] | United States [Member] | NYMEX WTI Crude Oil Futures CL February 2015 contracts, expiring January 2015 |  |
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items] |  |
Number of Contracts |  | 58,662 us-gaap_InvestmentOwnedBalanceContracts / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = uso_NyMember / us-gaap_InvestmentTypeAxis = uso_OpenFuturesContractsLongMember

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