XML 58 R23.htm IDEA: XBRL DOCUMENT
v2.4.0.8

Contracts and Agreements (Additional Information) (Details) (USD $) | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2013 | Jun. 30, 2012 | Jun. 30, 2013 | Jun. 30, 2012
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items] |  |  |  |
Annual Fee for transfer agency services |  |  | $ 20,000 |
Brokerage commissions | 2,289 | 6,454 | 6,271 | 11,344
Ratio of expense to Average Net Assets |  |  | 0.01% | 0.01%
Maximum [Member] |  |  |  |
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items] |  |  |  |
Transaction fees per transaction |  |  | 15 |
Commissions per round-turn trade, including applicable exchange and NFA fees for Oil Futures Contracts and options on Oil Futures Contracts |  |  | 15 |
Minimum [Member] |  |  |  |
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items] |  |  |  |
Annual Fee for transfer agency services |  |  | 75,000 |
Transaction fees per transaction |  |  | 7 |
Commissions per round-turn trade, including applicable exchange and NFA fees for Oil Futures Contracts and options on Oil Futures Contracts |  |  | 7 |
Re balancing Investments Transaction [Member] |  |  |  |
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items] |  |  |  |
Brokerage commissions |  |  | 2,449 | 3,587
Trades Necessitated By Creation And Redemption Activity [Member] |  |  |  |
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items] |  |  |  |
Brokerage commissions |  |  | 3,822 | 7,757
First $500 million of US12OF's, USOF's, USNG's, UGA's, USDHO's, USSO's, US12NG's, USBO's, USCI's, CPER's, USAG's and USMI's combined net assets [Member] |  |  |  |
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items] |  |  |  |
Fee percentage |  |  | 0.06% |
First $500 million of US12OF's, USOF's, USNG's, UGA's, USDHO's, USSO's, US12NG's, USBO's, USCI's, CPER's, USAG's and USMI's combined net assets [Member] | Maximum [Member] |  |  |  |
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items] |  |  |  |
Base amount for determining fee percentage | 500,000,000 |  | 500,000,000 |
US12OF's, USOF's, USNG's, UGA's, USDHO's, USSO's, US12NG's, USBO's, USCI's, CPER's, USAG's and USMI's combined net assets greater than $500 million but less than $1 billion [Member] |  |  |  |
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items] |  |  |  |
Fee percentage |  |  | 0.0465% |
US12OF's, USOF's, USNG's, UGA's, USDHO's, USSO's, US12NG's, USBO's, USCI's, CPER's, USAG's and USMI's combined net assets greater than $500 million but less than $1 billion [Member] | Maximum [Member] |  |  |  |
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items] |  |  |  |
Base amount for determining fee percentage | 1,000,000,000 |  | 1,000,000,000 |
US12OF's, USOF's, USNG's, UGA's, USDHO's, USSO's, US12NG's, USBO's, USCI's, CPER's, USAG's and USMI's combined net assets greater than $500 million but less than $1 billion [Member] | Minimum [Member] |  |  |  |
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items] |  |  |  |
Base amount for determining fee percentage | 500,000,000 |  | 500,000,000 |
US12OF's, USOF's, USNG's, UGA's, USDHO's, USSO's, US12NG's, USBO's, USCI's, CPER's, USAG's and USMI's combined net assets exceed $1 billion [Member] |  |  |  |
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items] |  |  |  |
Fee percentage |  |  | 0.035% |
US12OF's, USOF's, USNG's, UGA's, USDHO's, USSO's, US12NG's, USBO's, USCI's, CPER's, USAG's and USMI's combined net assets exceed $1 billion [Member] | Minimum [Member] |  |  |  |
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items] |  |  |  |
Base amount for determining fee percentage | 1,000,000,000 |  | 1,000,000,000 |
Marketing Agreement [Member] | US12OF's assets up to $3 billion [Member] |  |  |  |
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items] |  |  |  |
Fee percentage |  |  | 0.06% |
Marketing Agreement [Member] | US12OF's assets up to $3 billion [Member] | Maximum [Member] |  |  |  |
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items] |  |  |  |
Base amount for determining fee percentage | 3,000,000,000 |  | 3,000,000,000 |
Marketing Agreement [Member] | US12OF's assets in excess of $3 billion [Member] |  |  |  |
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items] |  |  |  |
Fee percentage |  |  | 0.04% |
Marketing Agreement [Member] | US12OF's assets in excess of $3 billion [Member] | Minimum [Member] |  |  |  |
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items] |  |  |  |
Base amount for determining fee percentage | $ 3,000,000,000 |  | $ 3,000,000,000 |

X
- Definition Those fees charged for services related to holding, advising, and managing customer investment assets. These account fees usually charged annually or semi-annually, on a per security basis, for the costs of services. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.3) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688 + Details
Name: | us-gaap_CustodyFees
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The amount of expense during the period for floor brokerage fees paid to other broker-dealers to execute trades on their behalf, stock exchange fees, order flow fees, and clearance fees. + References No definition available. + Details
Name: | us-gaap_FloorBrokerageExchangeAndClearanceFees
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_LongDurationContractsAssumptionsByProductAndGuaranteeLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Base Fee Percentage + References No definition available. + Details
Name: | usl_BaseFeePercentage
Namespace Prefix: | usl_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Basis Amount for Fee Percentage + References No definition available. + Details
Name: | usl_BasisAmountForFeePercentage
Namespace Prefix: | usl_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | instant

X
- Definition Commissions Paid + References No definition available. + Details
Name: | usl_CommissionsPaid
Namespace Prefix: | usl_
Data Type: | us-types:perUnitItemType
Balance Type: | na
Period Type: | duration

X
- Definition Ratio Of Expenses To Average Net Assets + References No definition available. + Details
Name: | usl_RatioOfExpensesToAverageNetAssets
Namespace Prefix: | usl_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Transaction Fees Paid + References No definition available. + Details
Name: | usl_TransactionFeesPaid
Namespace Prefix: | usl_
Data Type: | us-types:perUnitItemType
Balance Type: | na
Period Type: | duration