Fee Paid Per Order

No definition available.

Name:	usl_FeePaidPerOrder
Namespace Prefix:	usl_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The successive valuation days used in the measurement of average daily percentage change in net asset value.

+ References

No definition available.

+ Details

Name:	usl_InvestmentObjectiveSuccessiveValuationDays
Namespace Prefix:	usl_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Threshold adjustment on average daily percentage change in price of the derivatives.

+ References

No definition available.

+ Details

Name:	usl_InvestmentObjectiveThresholdAdjustmentOnAverageDailyPercentageChangeInPrice
Namespace Prefix:	usl_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of net asset value per unit.

+ References

No definition available.

+ Details

Name:	usl_NetAssetValuePerUnit
Namespace Prefix:	usl_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of oil futures contracts held during period.

+ References

No definition available.

+ Details

Name:	usl_NumberOfOilFuturesContractsHeldDuringPeriod
Namespace Prefix:	usl_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of shares registered.

+ References

No definition available.

+ Details

Name:	usl_NumberOfRegisteredUnits
Namespace Prefix:	usl_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of shares per basket.

+ References

No definition available.

+ Details

Name:	usl_NumberOfUnitsPerBasket
Namespace Prefix:	usl_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Organization, Consolidation and Presentation of Financial Statements Disclosure.

+ References

No definition available.

+ Details

Name:	usl_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureLineItems
Namespace Prefix:	usl_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The allowed range of change in the daily percentage change in NAV of the company compared to the benchmark of futures contract.

+ References

No definition available.

+ Details

Name:	usl_RangeOfAllowedChangeInNavComparedToBenchmarkPercentage
Namespace Prefix:	usl_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of shares issued during the period.

+ References

No definition available.

+ Details

Name:	usl_UnitsIssuedDuringPeriodUnitsNewIssues
Namespace Prefix:	usl_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount received from the issuance of new shares during the period.

+ References

No definition available.

+ Details

Name:	usl_UnitsIssuedDuringPeriodValueNewIssues
Namespace Prefix:	usl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	usl_InvestmentSecondaryCategorization1Axis=usl_CreationBasketsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

ORGANIZATION AND BUSINESS (Details)		6 Months Ended
ORGANIZATION AND BUSINESS (Details)	Dec. 06, 2007 USD ($) $ / shares shares	Jun. 30, 2026 USD ($) contract $ / shares shares	Mar. 31, 2026 $ / shares	Dec. 31, 2025 $ / shares	Jun. 30, 2025 $ / shares	Mar. 31, 2025 $ / shares	Dec. 31, 2024 $ / shares	Dec. 04, 2007 shares
ORGANIZATION AND BUSINESS
Investment objective successive valuation days		30 days
Investment objective threshold adjustment on average daily percentage change in price		10.00%
Number of oil futures contracts held \| contract		597
Number of registered shares								11,000,000
Net asset value per share \| $ / shares	$ 50	$ 45.08	$ 47.79	$ 33.31	$ 35.19	$ 38.21	$ 38.01
Number of shares issued	300,000
Value of shares issued \| $	$ 15,000,000
Minimum [Member]
ORGANIZATION AND BUSINESS
Range of allowed change in nav compared to benchmark, percentage		(10.00%)
Maximum [Member]
ORGANIZATION AND BUSINESS
Range of allowed change in nav compared to benchmark, percentage		10.00%
Creation Baskets
ORGANIZATION AND BUSINESS
Number of shares per basket		50,000
Fee paid by authorized purchasers for each order they place to create one or more creation baskets or to redeem one or more baskets \| $		$ 350