XML 37 R3.htm IDEA: XBRL DOCUMENT
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Schedule of Investments (USD $) | Dec. 31, 2014 | Dec. 31, 2013
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Unrealized Gain (Loss) on Open Commodity Contracts | $ (17,096,060)usl_UnrealizedGainLossOnOpenCommodityFuturesContracts |  | $ 1,642,450 usl_UnrealizedGainLossOnOpenCommodityFuturesContracts |
Open Futures Contracts, Long | United States |  |  |  |
Number of Contracts | 658 us-gaap_InvestmentOwnedBalanceContracts / invest_InvestmentGeographicRegionAxis = country_US / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |  |  |
Unrealized Gain (Loss) on Open Commodity Contracts | (17,096,060)usl_UnrealizedGainLossOnOpenCommodityFuturesContracts / invest_InvestmentGeographicRegionAxis = country_US / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember | [1] | 1,642,450 usl_UnrealizedGainLossOnOpenCommodityFuturesContracts / invest_InvestmentGeographicRegionAxis = country_US / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember | [2]
% of Partners' Capital | (45.92%)usl_PercentageOfPartnersCapital / invest_InvestmentGeographicRegionAxis = country_US / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember | [1] | 2.64%usl_PercentageOfPartnersCapital / invest_InvestmentGeographicRegionAxis = country_US / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember | [2]
Open Futures Contracts, Long | United States | NYMEX WTI Crude Oil Futures CL February 2014 contracts, expiring January 2014 |  |  |  |
Number of Contracts |  |  | 55 us-gaap_InvestmentOwnedBalanceContracts / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClFebruary2014ContractsExpiringJanuary2014Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |
Unrealized Gain (Loss) on Open Commodity Contracts |  |  | 184,140 usl_UnrealizedGainLossOnOpenCommodityFuturesContracts / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClFebruary2014ContractsExpiringJanuary2014Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |
% of Partners' Capital |  |  | 0.30%usl_PercentageOfPartnersCapital / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClFebruary2014ContractsExpiringJanuary2014Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |
Open Futures Contracts, Long | United States | NYMEX WTI Crude Oil Futures CL March 2014 contracts, expiring February 2014 |  |  |  |
Number of Contracts |  |  | 54 us-gaap_InvestmentOwnedBalanceContracts / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClMarch2014ContractsExpiringFebruary2014Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |
Unrealized Gain (Loss) on Open Commodity Contracts |  |  | 95,360 usl_UnrealizedGainLossOnOpenCommodityFuturesContracts / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClMarch2014ContractsExpiringFebruary2014Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |
% of Partners' Capital |  |  | 0.15%usl_PercentageOfPartnersCapital / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClMarch2014ContractsExpiringFebruary2014Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |
Open Futures Contracts, Long | United States | NYMEX WTI Crude Oil Futures CL April 2014 contracts, expiring March 2014 |  |  |  |
Number of Contracts |  |  | 54 us-gaap_InvestmentOwnedBalanceContracts / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClApril2014ContractsExpiringMarch2014Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |
Unrealized Gain (Loss) on Open Commodity Contracts |  |  | 404,380 usl_UnrealizedGainLossOnOpenCommodityFuturesContracts / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClApril2014ContractsExpiringMarch2014Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |
% of Partners' Capital |  |  | 0.65%usl_PercentageOfPartnersCapital / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClApril2014ContractsExpiringMarch2014Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |
Open Futures Contracts, Long | United States | NYMEX WTI Crude Oil Futures CL May 2014 contracts, expiring April 2014 |  |  |  |
Number of Contracts |  |  | 54 us-gaap_InvestmentOwnedBalanceContracts / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClMay2014ContractsExpiringApril2014Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |
Unrealized Gain (Loss) on Open Commodity Contracts |  |  | 313,310 usl_UnrealizedGainLossOnOpenCommodityFuturesContracts / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClMay2014ContractsExpiringApril2014Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |
% of Partners' Capital |  |  | 0.51%usl_PercentageOfPartnersCapital / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClMay2014ContractsExpiringApril2014Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |
Open Futures Contracts, Long | United States | NYMEX WTI Crude Oil Futures CL June 2014 contracts, expiring May 2014 |  |  |  |
Number of Contracts |  |  | 54 us-gaap_InvestmentOwnedBalanceContracts / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClJune2014ContractsExpiringMay2014Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |
Unrealized Gain (Loss) on Open Commodity Contracts |  |  | 269,150 usl_UnrealizedGainLossOnOpenCommodityFuturesContracts / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClJune2014ContractsExpiringMay2014Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |
% of Partners' Capital |  |  | 0.43%usl_PercentageOfPartnersCapital / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClJune2014ContractsExpiringMay2014Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |
Open Futures Contracts, Long | United States | NYMEX WTI Crude Oil Futures CL July 2014 contracts, expiring June 2014 |  |  |  |
Number of Contracts |  |  | 54 us-gaap_InvestmentOwnedBalanceContracts / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClJuly2014ContractsExpiringJune2014Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |
Unrealized Gain (Loss) on Open Commodity Contracts |  |  | 261,410 usl_UnrealizedGainLossOnOpenCommodityFuturesContracts / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClJuly2014ContractsExpiringJune2014Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |
% of Partners' Capital |  |  | 0.42%usl_PercentageOfPartnersCapital / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClJuly2014ContractsExpiringJune2014Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |
Open Futures Contracts, Long | United States | NYMEX WTI Crude Oil Futures CL August 2014 contracts, expiring July 2014 |  |  |  |
Number of Contracts |  |  | 54 us-gaap_InvestmentOwnedBalanceContracts / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClAugust2014ContractsExpiringJuly2014Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |
Unrealized Gain (Loss) on Open Commodity Contracts |  |  | 120,620 usl_UnrealizedGainLossOnOpenCommodityFuturesContracts / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClAugust2014ContractsExpiringJuly2014Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |
% of Partners' Capital |  |  | 0.19%usl_PercentageOfPartnersCapital / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClAugust2014ContractsExpiringJuly2014Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |
Open Futures Contracts, Long | United States | NYMEX WTI Crude Oil Futures CL September 2014 contracts, expiring August 2014 |  |  |  |
Number of Contracts |  |  | 54 us-gaap_InvestmentOwnedBalanceContracts / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClSeptember2014ContractsExpiringAugust2014Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |
Unrealized Gain (Loss) on Open Commodity Contracts |  |  | 47,050 usl_UnrealizedGainLossOnOpenCommodityFuturesContracts / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClSeptember2014ContractsExpiringAugust2014Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |
% of Partners' Capital |  |  | 0.08%usl_PercentageOfPartnersCapital / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClSeptember2014ContractsExpiringAugust2014Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |
Open Futures Contracts, Long | United States | NYMEX WTI Crude Oil Futures CL October 2014 contracts, expiring September 2014 |  |  |  |
Number of Contracts |  |  | 54 us-gaap_InvestmentOwnedBalanceContracts / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClOctober2014ContractsExpiringSeptember2014Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |
Unrealized Gain (Loss) on Open Commodity Contracts |  |  | (93,940)usl_UnrealizedGainLossOnOpenCommodityFuturesContracts / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClOctober2014ContractsExpiringSeptember2014Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |
% of Partners' Capital |  |  | (0.15%)usl_PercentageOfPartnersCapital / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClOctober2014ContractsExpiringSeptember2014Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |
Open Futures Contracts, Long | United States | NYMEX WTI Crude Oil Futures CL November 2014 contracts, expiring October 2014 |  |  |  |
Number of Contracts |  |  | 54 us-gaap_InvestmentOwnedBalanceContracts / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClNovember2014ContractsExpiringOctober2014Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |
Unrealized Gain (Loss) on Open Commodity Contracts |  |  | (79,520)usl_UnrealizedGainLossOnOpenCommodityFuturesContracts / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClNovember2014ContractsExpiringOctober2014Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |
% of Partners' Capital |  |  | (0.13%)usl_PercentageOfPartnersCapital / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClNovember2014ContractsExpiringOctober2014Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |
Open Futures Contracts, Long | United States | NYMEX WTI Crude Oil Futures CL December 2014 contracts, expiring November 2014 |  |  |  |
Number of Contracts |  |  | 54 us-gaap_InvestmentOwnedBalanceContracts / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClDecember2014ContractsExpiringNovember2014Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |
Unrealized Gain (Loss) on Open Commodity Contracts |  |  | 94,480 usl_UnrealizedGainLossOnOpenCommodityFuturesContracts / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClDecember2014ContractsExpiringNovember2014Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |
% of Partners' Capital |  |  | 0.15%usl_PercentageOfPartnersCapital / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClDecember2014ContractsExpiringNovember2014Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |
Open Futures Contracts, Long | United States | NYMEX WTI Crude Oil Futures CL January 2015 contracts, expiring December 2014 |  |  |  |
Number of Contracts |  |  | 54 us-gaap_InvestmentOwnedBalanceContracts / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClJanuary2015ContractsExpiringDecember2014Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |
Unrealized Gain (Loss) on Open Commodity Contracts |  |  | 26,010 usl_UnrealizedGainLossOnOpenCommodityFuturesContracts / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClJanuary2015ContractsExpiringDecember2014Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |
% of Partners' Capital |  |  | 0.04%usl_PercentageOfPartnersCapital / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClJanuary2015ContractsExpiringDecember2014Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |
Open Futures Contracts, Long | United States | NYMEX WTI Crude Oil Futures CL February 2015 contracts, expiring January 2015 |  |  |  |
Number of Contracts | 54 us-gaap_InvestmentOwnedBalanceContracts / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClFebruary2015ContractsExpiringJanuary2015Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |  |  |
Unrealized Gain (Loss) on Open Commodity Contracts | (1,577,330)usl_UnrealizedGainLossOnOpenCommodityFuturesContracts / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClFebruary2015ContractsExpiringJanuary2015Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |  |  |
% of Partners' Capital | (4.24%)usl_PercentageOfPartnersCapital / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClFebruary2015ContractsExpiringJanuary2015Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |  |  |
Open Futures Contracts, Long | United States | NYMEX WTI Crude Oil Futures CL March 2015 contracts, expiring February 2015 |  |  |  |
Number of Contracts | 55 us-gaap_InvestmentOwnedBalanceContracts / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClMarch2015ContractsExpiringFebruary2015Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |  |  |
Unrealized Gain (Loss) on Open Commodity Contracts | (1,635,460)usl_UnrealizedGainLossOnOpenCommodityFuturesContracts / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClMarch2015ContractsExpiringFebruary2015Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |  |  |
% of Partners' Capital | (4.39%)usl_PercentageOfPartnersCapital / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClMarch2015ContractsExpiringFebruary2015Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |  |  |
Open Futures Contracts, Long | United States | NYMEX WTI Crude Oil Futures CL April 2015 contracts, expiring March 2015 |  |  |  |
Number of Contracts | 55 us-gaap_InvestmentOwnedBalanceContracts / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClApril2015ContractsExpiringMarch2015Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |  |  |
Unrealized Gain (Loss) on Open Commodity Contracts | (1,675,980)usl_UnrealizedGainLossOnOpenCommodityFuturesContracts / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClApril2015ContractsExpiringMarch2015Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |  |  |
% of Partners' Capital | (4.50%)usl_PercentageOfPartnersCapital / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClApril2015ContractsExpiringMarch2015Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |  |  |
Open Futures Contracts, Long | United States | NYMEX WTI Crude Oil Futures CL May 2015 contracts, expiring April 2015 |  |  |  |
Number of Contracts | 55 us-gaap_InvestmentOwnedBalanceContracts / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClMay2015ContractsExpiringApril2015Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |  |  |
Unrealized Gain (Loss) on Open Commodity Contracts | (1,705,350)usl_UnrealizedGainLossOnOpenCommodityFuturesContracts / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClMay2015ContractsExpiringApril2015Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |  |  |
% of Partners' Capital | (4.58%)usl_PercentageOfPartnersCapital / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClMay2015ContractsExpiringApril2015Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |  |  |
Open Futures Contracts, Long | United States | NYMEX WTI Crude Oil Futures CL June 2015 contracts, expiring May 2015 |  |  |  |
Number of Contracts | 55 us-gaap_InvestmentOwnedBalanceContracts / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClJune2015ContractsExpiringMay2015Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |  |  |
Unrealized Gain (Loss) on Open Commodity Contracts | (1,573,830)usl_UnrealizedGainLossOnOpenCommodityFuturesContracts / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClJune2015ContractsExpiringMay2015Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |  |  |
% of Partners' Capital | (4.23%)usl_PercentageOfPartnersCapital / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClJune2015ContractsExpiringMay2015Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |  |  |
Open Futures Contracts, Long | United States | NYMEX WTI Crude Oil Futures CL July 2015 contracts, expiring June 2015 |  |  |  |
Number of Contracts | 55 us-gaap_InvestmentOwnedBalanceContracts / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClJuly2015ContractsExpiringJune2015Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |  |  |
Unrealized Gain (Loss) on Open Commodity Contracts | (1,669,200)usl_UnrealizedGainLossOnOpenCommodityFuturesContracts / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClJuly2015ContractsExpiringJune2015Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |  |  |
% of Partners' Capital | (4.48%)usl_PercentageOfPartnersCapital / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClJuly2015ContractsExpiringJune2015Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |  |  |
Open Futures Contracts, Long | United States | NYMEX WTI Crude Oil Futures CL August 2015 contracts, expiring July 2015 |  |  |  |
Number of Contracts | 54 us-gaap_InvestmentOwnedBalanceContracts / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClAugust2015ContractsExpiringJuly2015Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |  |  |
Unrealized Gain (Loss) on Open Commodity Contracts | (1,762,850)usl_UnrealizedGainLossOnOpenCommodityFuturesContracts / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClAugust2015ContractsExpiringJuly2015Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |  |  |
% of Partners' Capital | (4.74%)usl_PercentageOfPartnersCapital / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClAugust2015ContractsExpiringJuly2015Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |  |  |
Open Futures Contracts, Long | United States | NYMEX WTI Crude Oil Futures CL September 2015 contracts, expiring August 2015 |  |  |  |
Number of Contracts | 55 us-gaap_InvestmentOwnedBalanceContracts / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClSeptember2015ContractsExpiringAugust2015Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |  |  |
Unrealized Gain (Loss) on Open Commodity Contracts | (1,595,970)usl_UnrealizedGainLossOnOpenCommodityFuturesContracts / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClSeptember2015ContractsExpiringAugust2015Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |  |  |
% of Partners' Capital | (4.29%)usl_PercentageOfPartnersCapital / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClSeptember2015ContractsExpiringAugust2015Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |  |  |
Open Futures Contracts, Long | United States | NYMEX WTI Crude Oil Futures CL October 2015 contracts, expiring September 2015 |  |  |  |
Number of Contracts | 55 us-gaap_InvestmentOwnedBalanceContracts / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClOctober2015ContractsExpiringSeptember2015Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |  |  |
Unrealized Gain (Loss) on Open Commodity Contracts | (1,464,030)usl_UnrealizedGainLossOnOpenCommodityFuturesContracts / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClOctober2015ContractsExpiringSeptember2015Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |  |  |
% of Partners' Capital | (3.93%)usl_PercentageOfPartnersCapital / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClOctober2015ContractsExpiringSeptember2015Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |  |  |
Open Futures Contracts, Long | United States | NYMEX WTI Crude Oil Futures CL November 2015 contracts, expiring October 2015 |  |  |  |
Number of Contracts | 55 us-gaap_InvestmentOwnedBalanceContracts / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClNovember2015ContractsExpiringOctober2015Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |  |  |
Unrealized Gain (Loss) on Open Commodity Contracts | (1,191,540)usl_UnrealizedGainLossOnOpenCommodityFuturesContracts / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClNovember2015ContractsExpiringOctober2015Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |  |  |
% of Partners' Capital | (3.20%)usl_PercentageOfPartnersCapital / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClNovember2015ContractsExpiringOctober2015Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |  |  |
Open Futures Contracts, Long | United States | NYMEX WTI Crude Oil Futures CL December 2015 contracts, expiring November 2015 |  |  |  |
Number of Contracts | 55 us-gaap_InvestmentOwnedBalanceContracts / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClDecember2015ContractsExpiringNovember2015Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |  |  |
Unrealized Gain (Loss) on Open Commodity Contracts | (868,870)usl_UnrealizedGainLossOnOpenCommodityFuturesContracts / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClDecember2015ContractsExpiringNovember2015Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |  |  |
% of Partners' Capital | (2.33%)usl_PercentageOfPartnersCapital / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClDecember2015ContractsExpiringNovember2015Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |  |  |
Open Futures Contracts, Long | United States | NYMEX WTI Crude Oil Futures CL January 2016 contracts, expiring December 2015 |  |  |  |
Number of Contracts | 55 us-gaap_InvestmentOwnedBalanceContracts / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClJanuary2016ContractsExpiringDecember2015Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |  |  |
Unrealized Gain (Loss) on Open Commodity Contracts | (375,650)usl_UnrealizedGainLossOnOpenCommodityFuturesContracts / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClJanuary2016ContractsExpiringDecember2015Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |  |  |
% of Partners' Capital | (1.01%)usl_PercentageOfPartnersCapital / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesSeriesAxis = usl_NymexWtiCrudeOilFuturesClJanuary2016ContractsExpiringDecember2015Member / us-gaap_InvestmentTypeAxis = usl_OpenFuturesContractsLongMember |  |  |
Cash Equivalents |  |  |  |
Market Value | 30,998,094 us-gaap_InvestmentOwnedUnderlyingFaceAmountAtMarketValue / invest_InvestmentAxis = us-gaap_CashEquivalentsMember |  | 59,154,742 us-gaap_InvestmentOwnedUnderlyingFaceAmountAtMarketValue / invest_InvestmentAxis = us-gaap_CashEquivalentsMember |
% of Partners' Capital | 83.25%usl_PercentageOfPartnersCapital / invest_InvestmentAxis = us-gaap_CashEquivalentsMember |  | 95.25%usl_PercentageOfPartnersCapital / invest_InvestmentAxis = us-gaap_CashEquivalentsMember |
Cash Equivalents | United States | US Treasury Securities |  |  |  |
Market Value | 6,998,094 us-gaap_InvestmentOwnedUnderlyingFaceAmountAtMarketValue / invest_InvestmentAxis = us-gaap_CashEquivalentsMember / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesClassAxis = us-gaap_USTreasurySecuritiesMember |  |  |
% of Partners' Capital | 18.79%usl_PercentageOfPartnersCapital / invest_InvestmentAxis = us-gaap_CashEquivalentsMember / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesClassAxis = us-gaap_USTreasurySecuritiesMember |  |  |
Cash Equivalents | United States | US Treasury Securities | U.S. Treasury Bill, 0.05%, 1/15/2015 |  |  |  |
Principal Amount | 3,000,000 us-gaap_InvestmentOwnedBalancePrincipalAmount / invest_InvestmentAxis = us-gaap_CashEquivalentsMember / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesClassAxis = us-gaap_USTreasurySecuritiesMember / invest_InvestmentSecuritiesSeriesAxis = us-gaap_USTreasuryBillSecuritiesMember |  |  |
Market Value | 2,999,941 us-gaap_InvestmentOwnedUnderlyingFaceAmountAtMarketValue / invest_InvestmentAxis = us-gaap_CashEquivalentsMember / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesClassAxis = us-gaap_USTreasurySecuritiesMember / invest_InvestmentSecuritiesSeriesAxis = us-gaap_USTreasuryBillSecuritiesMember |  |  |
% of Partners' Capital | 8.05%usl_PercentageOfPartnersCapital / invest_InvestmentAxis = us-gaap_CashEquivalentsMember / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesClassAxis = us-gaap_USTreasurySecuritiesMember / invest_InvestmentSecuritiesSeriesAxis = us-gaap_USTreasuryBillSecuritiesMember |  |  |
Cash Equivalents | United States | US Treasury Securities | U.S. Treasury Bill 0.10%, 6/25/2015 |  |  |  |
Principal Amount | 4,000,000 us-gaap_InvestmentOwnedBalancePrincipalAmount / invest_InvestmentAxis = us-gaap_CashEquivalentsMember / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesClassAxis = us-gaap_USTreasurySecuritiesMember / invest_InvestmentSecuritiesSeriesAxis = usl_UsTreasuryBillSecurities1Member |  |  |
Market Value | 3,998,153 us-gaap_InvestmentOwnedUnderlyingFaceAmountAtMarketValue / invest_InvestmentAxis = us-gaap_CashEquivalentsMember / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesClassAxis = us-gaap_USTreasurySecuritiesMember / invest_InvestmentSecuritiesSeriesAxis = usl_UsTreasuryBillSecurities1Member |  |  |
% of Partners' Capital | 10.74%usl_PercentageOfPartnersCapital / invest_InvestmentAxis = us-gaap_CashEquivalentsMember / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesClassAxis = us-gaap_USTreasurySecuritiesMember / invest_InvestmentSecuritiesSeriesAxis = usl_UsTreasuryBillSecurities1Member |  |  |
Cash Equivalents | United States | US Treasury Securities | U.S. Treasury Bill 0.7%, 3/27/2014 |  |  |  |
Principal Amount |  |  | 8,000,000 us-gaap_InvestmentOwnedBalancePrincipalAmount / invest_InvestmentAxis = us-gaap_CashEquivalentsMember / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesClassAxis = us-gaap_USTreasurySecuritiesMember / invest_InvestmentSecuritiesSeriesAxis = usl_UsTreasuryBillSecurities3Member |
Market Value |  |  | 7,998,678 us-gaap_InvestmentOwnedUnderlyingFaceAmountAtMarketValue / invest_InvestmentAxis = us-gaap_CashEquivalentsMember / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesClassAxis = us-gaap_USTreasurySecuritiesMember / invest_InvestmentSecuritiesSeriesAxis = usl_UsTreasuryBillSecurities3Member |
% of Partners' Capital |  |  | 12.88%usl_PercentageOfPartnersCapital / invest_InvestmentAxis = us-gaap_CashEquivalentsMember / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesClassAxis = us-gaap_USTreasurySecuritiesMember / invest_InvestmentSecuritiesSeriesAxis = usl_UsTreasuryBillSecurities3Member |
Cash Equivalents | United States | Money Market Funds |  |  |  |
Market Value | 24,000,000 us-gaap_InvestmentOwnedUnderlyingFaceAmountAtMarketValue / invest_InvestmentAxis = us-gaap_CashEquivalentsMember / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesClassAxis = us-gaap_MoneyMarketFundsMember |  | 51,156,064 us-gaap_InvestmentOwnedUnderlyingFaceAmountAtMarketValue / invest_InvestmentAxis = us-gaap_CashEquivalentsMember / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesClassAxis = us-gaap_MoneyMarketFundsMember |
% of Partners' Capital | 64.46%usl_PercentageOfPartnersCapital / invest_InvestmentAxis = us-gaap_CashEquivalentsMember / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesClassAxis = us-gaap_MoneyMarketFundsMember |  | 82.37%usl_PercentageOfPartnersCapital / invest_InvestmentAxis = us-gaap_CashEquivalentsMember / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesClassAxis = us-gaap_MoneyMarketFundsMember |
Cash Equivalents | United States | Money Market Funds | Fidelity Institutional Government Portfolio - Class I |  |  |  |
Principal Amount |  |  | 161,900 us-gaap_InvestmentOwnedBalancePrincipalAmount / invest_InvestmentAxis = us-gaap_CashEquivalentsMember / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesClassAxis = us-gaap_MoneyMarketFundsMember / invest_InvestmentSecuritiesSeriesAxis = usl_FidelityInstitutionalGovernmentPortfolioClassIMember |
Market Value |  |  | 161,900 us-gaap_InvestmentOwnedUnderlyingFaceAmountAtMarketValue / invest_InvestmentAxis = us-gaap_CashEquivalentsMember / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesClassAxis = us-gaap_MoneyMarketFundsMember / invest_InvestmentSecuritiesSeriesAxis = usl_FidelityInstitutionalGovernmentPortfolioClassIMember |
% of Partners' Capital |  |  | 0.26%usl_PercentageOfPartnersCapital / invest_InvestmentAxis = us-gaap_CashEquivalentsMember / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesClassAxis = us-gaap_MoneyMarketFundsMember / invest_InvestmentSecuritiesSeriesAxis = usl_FidelityInstitutionalGovernmentPortfolioClassIMember |
Cash Equivalents | United States | Money Market Funds | Goldman Sachs Financial Square Funds - Government Fund - Class FS |  |  |  |
Principal Amount |  |  | 455,359 us-gaap_InvestmentOwnedBalancePrincipalAmount / invest_InvestmentAxis = us-gaap_CashEquivalentsMember / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesClassAxis = us-gaap_MoneyMarketFundsMember / invest_InvestmentSecuritiesSeriesAxis = usl_GoldmanSachsFinancialSquareFundsGovernmentFundClassFsMember |
Market Value |  |  | 455,359 us-gaap_InvestmentOwnedUnderlyingFaceAmountAtMarketValue / invest_InvestmentAxis = us-gaap_CashEquivalentsMember / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesClassAxis = us-gaap_MoneyMarketFundsMember / invest_InvestmentSecuritiesSeriesAxis = usl_GoldmanSachsFinancialSquareFundsGovernmentFundClassFsMember |
% of Partners' Capital |  |  | 0.73%usl_PercentageOfPartnersCapital / invest_InvestmentAxis = us-gaap_CashEquivalentsMember / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesClassAxis = us-gaap_MoneyMarketFundsMember / invest_InvestmentSecuritiesSeriesAxis = usl_GoldmanSachsFinancialSquareFundsGovernmentFundClassFsMember |
Cash Equivalents | United States | Money Market Funds | Morgan Stanley Institutional Liquidity Funds - Government Portfolio |  |  |  |
Principal Amount | 16,000,000 us-gaap_InvestmentOwnedBalancePrincipalAmount / invest_InvestmentAxis = us-gaap_CashEquivalentsMember / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesClassAxis = us-gaap_MoneyMarketFundsMember / invest_InvestmentSecuritiesSeriesAxis = usl_MorganStanleyInstitutionalLiquidityFundGovernmentPortfolioMember |  | 30,537,560 us-gaap_InvestmentOwnedBalancePrincipalAmount / invest_InvestmentAxis = us-gaap_CashEquivalentsMember / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesClassAxis = us-gaap_MoneyMarketFundsMember / invest_InvestmentSecuritiesSeriesAxis = usl_MorganStanleyInstitutionalLiquidityFundGovernmentPortfolioMember |
Market Value | 16,000,000 us-gaap_InvestmentOwnedUnderlyingFaceAmountAtMarketValue / invest_InvestmentAxis = us-gaap_CashEquivalentsMember / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesClassAxis = us-gaap_MoneyMarketFundsMember / invest_InvestmentSecuritiesSeriesAxis = usl_MorganStanleyInstitutionalLiquidityFundGovernmentPortfolioMember |  | 30,537,560 us-gaap_InvestmentOwnedUnderlyingFaceAmountAtMarketValue / invest_InvestmentAxis = us-gaap_CashEquivalentsMember / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesClassAxis = us-gaap_MoneyMarketFundsMember / invest_InvestmentSecuritiesSeriesAxis = usl_MorganStanleyInstitutionalLiquidityFundGovernmentPortfolioMember |
% of Partners' Capital | 42.97%usl_PercentageOfPartnersCapital / invest_InvestmentAxis = us-gaap_CashEquivalentsMember / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesClassAxis = us-gaap_MoneyMarketFundsMember / invest_InvestmentSecuritiesSeriesAxis = usl_MorganStanleyInstitutionalLiquidityFundGovernmentPortfolioMember |  | 49.17%usl_PercentageOfPartnersCapital / invest_InvestmentAxis = us-gaap_CashEquivalentsMember / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesClassAxis = us-gaap_MoneyMarketFundsMember / invest_InvestmentSecuritiesSeriesAxis = usl_MorganStanleyInstitutionalLiquidityFundGovernmentPortfolioMember |
Cash Equivalents | United States | Money Market Funds | Wells Fargo Advantage Government Money Market Fund - Class I |  |  |  |
Principal Amount | 8,000,000 us-gaap_InvestmentOwnedBalancePrincipalAmount / invest_InvestmentAxis = us-gaap_CashEquivalentsMember / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesClassAxis = us-gaap_MoneyMarketFundsMember / invest_InvestmentSecuritiesSeriesAxis = usl_WellsFargoAdvantageGovernmentMoneyMarketFundClassIMember |  | 20,001,245 us-gaap_InvestmentOwnedBalancePrincipalAmount / invest_InvestmentAxis = us-gaap_CashEquivalentsMember / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesClassAxis = us-gaap_MoneyMarketFundsMember / invest_InvestmentSecuritiesSeriesAxis = usl_WellsFargoAdvantageGovernmentMoneyMarketFundClassIMember |
Market Value | $ 8,000,000 us-gaap_InvestmentOwnedUnderlyingFaceAmountAtMarketValue / invest_InvestmentAxis = us-gaap_CashEquivalentsMember / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesClassAxis = us-gaap_MoneyMarketFundsMember / invest_InvestmentSecuritiesSeriesAxis = usl_WellsFargoAdvantageGovernmentMoneyMarketFundClassIMember |  | $ 20,001,245 us-gaap_InvestmentOwnedUnderlyingFaceAmountAtMarketValue / invest_InvestmentAxis = us-gaap_CashEquivalentsMember / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesClassAxis = us-gaap_MoneyMarketFundsMember / invest_InvestmentSecuritiesSeriesAxis = usl_WellsFargoAdvantageGovernmentMoneyMarketFundClassIMember |
% of Partners' Capital | 21.49%usl_PercentageOfPartnersCapital / invest_InvestmentAxis = us-gaap_CashEquivalentsMember / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesClassAxis = us-gaap_MoneyMarketFundsMember / invest_InvestmentSecuritiesSeriesAxis = usl_WellsFargoAdvantageGovernmentMoneyMarketFundClassIMember |  | 32.21%usl_PercentageOfPartnersCapital / invest_InvestmentAxis = us-gaap_CashEquivalentsMember / invest_InvestmentGeographicRegionAxis = country_US / invest_InvestmentSecuritiesClassAxis = us-gaap_MoneyMarketFundsMember / invest_InvestmentSecuritiesSeriesAxis = usl_WellsFargoAdvantageGovernmentMoneyMarketFundClassIMember |
[1] | Collateral amounted to $19,785,491 on open futures contracts.
[2] | Collateral amounted to $3,548,144 on open futures contracts.

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