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v2.4.1.9

Summary of Significant Accounting Policies (Additional Information) (Detail) | 3 Months Ended
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Mar. 31, 2015
Significant Accounting Policies [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
Maximum [Member] |
Significant Accounting Policies [Line Items] |
Minimum likelihood of tax benefits being recognized upon ultimate settlement | 50.00%uso_PercentageOfIncomeTaxExaminationMinimumLikelihoodOfTaxBenefitsBeingRealizedUponSettlement / us-gaap_RangeAxis = us-gaap_MaximumMember
Cash equivalents maturity period | 6 months
Creations and Redemptions Basket [Member] |
Significant Accounting Policies [Line Items] |
Number of units per basket | 100,000 uso_NumberOfUnitPerBasket / invest_InvestmentSecuritiesClassAxis = uso_RedemptionBasketsMember

X
- Definition Cash Equivalents, Maturity Period + References No definition available. + Details
Name: | uso_CashEquivalentsMaturityPeriod
Namespace Prefix: | uso_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Fee Paid Per Order + References No definition available. + Details
Name: | uso_FeePaidPerOrder
Namespace Prefix: | uso_
Data Type: | us-types:perUnitItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number of units per basket. + References No definition available. + Details
Name: | uso_NumberOfUnitPerBasket
Namespace Prefix: | uso_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Percentage Of Income Tax Examination Minimum Likelihood of Tax Benefits Being Realized Upon Settlement + References No definition available. + Details
Name: | uso_PercentageOfIncomeTaxExaminationMinimumLikelihoodOfTaxBenefitsBeingRealizedUponSettlement
Namespace Prefix: | uso_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | uso_SignificantAccountingPoliciesLineItems
Namespace Prefix: | uso_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | invest_InvestmentSecuritiesClassAxis=uso_RedemptionBasketsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |