XML 18 R25.htm IDEA: XBRL DOCUMENT
v2.4.0.6

Contracts and Agreements - Additional information (Detail) (USD $) | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2012 | Sep. 30, 2011 | Sep. 30, 2012 | Sep. 30, 2011
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items] |  |  |  |
Annual Fee for transfer agency services |  |  | $ 20,000 |
Brokerage commissions | 3,486 | 1,073 | 11,485 | 5,451
Rebalancing Cost |  |  | 5,746 | 3,416
Creation And Redemption Activity Costs |  |  | 5,739 | 2,035
Average Daily Total Net Asset Percentage |  |  | 0.05% | 0.02%
Maximum |  |  |  |
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 Natural Gas-Related Futures Contracts and options on Futures Contracts |  |  | $ 15 |
Minimum |  |  |  |
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items] |  |  |  |
Annual Fee for custody, fund accounting and fund administration services |  |  | 75,000 |
Transaction fees per transaction |  |  | $ 7 |
Commissions per round-turn trade, including applicable exchange and NFA fees for Natural Gas-Related Futures Contracts and options on Futures Contracts |  |  | $ 7 |
First $500 million of US12NG's, USOF's, USNG's, US12OF's, UGA's, USDHO's, USSO's, USBO's, USCI's, CPER's, USAG's and USMI's combined net assets |  |  |  |
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items] |  |  |  |
Fee percentage |  |  | 0.06% |
First $500 million of US12NG's, USOF's, USNG's, US12OF's, UGA's, USDHO's, USSO's, USBO's, USCI's, CPER's, USAG's and USMI's combined net assets | Maximum |  |  |  |
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items] |  |  |  |
Base amount for determining fee percentage | 500,000,000 |  | 500,000,000 |
US12NG's, USOF's, USNG's, US12OF's, UGA's, USDHO's, USSO's, USBO's, USCI's, CPER's, USAG's and USMI's combined net assets greater than $500 million but less than $1 billion |  |  |  |
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items] |  |  |  |
Fee percentage |  |  | 0.0465% |
US12NG's, USOF's, USNG's, US12OF's, UGA's, USDHO's, USSO's, USBO's, USCI's, CPER's, USAG's and USMI's combined net assets greater than $500 million but less than $1 billion | Maximum |  |  |  |
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items] |  |  |  |
Base amount for determining fee percentage | 1,000,000,000 |  | 1,000,000,000 |
US12NG's, USOF's, USNG's, US12OF's, UGA's, USDHO's, USSO's, USBO's, USCI's, CPER's, USAG's and USMI's combined net assets greater than $500 million but less than $1 billion | Minimum |  |  |  |
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items] |  |  |  |
Base amount for determining fee percentage | 500,000,000 |  | 500,000,000 |
US12NG's, USOF's, USNG's, US12OF's, UGA's, USDHO's, USSO's, USBO's, USCI's, CPER's, USAG's and USMI's combined net assets exceed $1 billion |  |  |  |
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items] |  |  |  |
Fee percentage |  |  | 0.035% |
US12NG's, USOF's, USNG's, US12OF's, UGA's, USDHO's, USSO's, USBO's, USCI's, CPER's, USAG's and USMI's combined net assets exceed $1 billion | Minimum |  |  |  |
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 | US12NG's assets up to $3 billion |  |  |  |
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items] |  |  |  |
Fee percentage |  |  | 0.06% |
Marketing Agreement | US12NG's assets up to $3 billion | Maximum |  |  |  |
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 | US12NG's assets in excess of $3 billion |  |  |  |
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items] |  |  |  |
Fee percentage |  |  | 0.04% |
Marketing Agreement | US12NG's assets in excess of $3 billion | Minimum |  |  |  |
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 Percentage of average daily total net assets during the period. + References No definition available. + Details
Name: | unl_AverageDailyTotalNetAssetPercentage
Namespace Prefix: | unl_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

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

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

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

X
- Definition The anount of commission accrued as a result of trades necessitated by creation and redemption activity. + References No definition available. + Details
Name: | unl_CreationAndRedemptionActivityCosts
Namespace Prefix: | unl_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The amount attributable to commission accrued as a result of rebalancing costs during the reporting period. + References No definition available. + Details
Name: | unl_RebalancingCost
Namespace Prefix: | unl_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

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

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=6880815&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 Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Audit and Accounting Guide (AAG) -Number AAG-BRD -Paragraph 61 -IssueDate 2006-05-01 -Chapter 4 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Audit and Accounting Guide (AAG) -Number AAG-BRD -Paragraph 60 -IssueDate 2006-05-01 -Chapter 4 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. + 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 Fees paid to an agent employed by a corporation or mutual fund to maintain shareholder records, including purchases, sales, and account balances. Also includes custodian fees incurred during an accounting period from an agent, bank, trust company, or other organization that holds and safeguards an individual's, mutual fund's, or investment company's assets for them. These fees will be billed back to the client and are a component of noninterest expense. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-04.14) -URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882 + Details
Name: | us-gaap_NoninterestExpenseTransferAgentAndCustodianFees
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration