CONTRACTS AND AGREEMENTS (Additional Information) (Details) (USD $)	3 Months Ended
Mar. 31, 2014	Mar. 31, 2013
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]
Annual Fee for transfer agency services	$ 20,000
Brokerage commissions	2,070	3,288
Rebalancing Cost	1,072	1,587
Creation And Redemption Activity Costs	998	1,701
Average Daily Total Net Asset Percentage	0.03%	0.03%
Brokerage Commmission Rebalancing Cost Of Percentage	51.79%	48.27%
Creation And Redemption Activity Costs Of Percentage	48.21%	51.73%
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 Natural Gas-Related Futures Contracts and options on Futures Contracts	15
Minimum [Member]
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 the Related Public Funds’ combined net assets [Member]
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]
Fee percentage	0.06%
first $500 million of the Related Public Funds’ 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
Related Public Funds’ 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%
Related Public Funds’ 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
Related Public Funds’ 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
Related Public Funds’ combined net assets exceed $1 billion [Member]
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]
Fee percentage	0.035%
Related Public Funds’ 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
Marketing Agreement [Member] \| UNL's assets up to $3 billion [Member]
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]
Fee percentage	0.06%
Marketing Agreement [Member] \| UNL'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
Marketing Agreement [Member] \| UNL'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] \| UNL'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

Percentage of average daily total net assets during the period.

No definition available.

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- Definition

Base Fee Percentage

+ References

No definition available.

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- Definition

Basis Amount for Fee Percentage

+ References

No definition available.

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- Definition

The percentage of commission accrued as a result of rebalancing costs during the reporting period.

+ References

No definition available.

+ Details

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- Definition

Commissions Paid

+ References

No definition available.

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- Definition

The amount of commission accrued as a result of trades necessitated by creation and redemption activity.

+ References

No definition available.

+ Details

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- Definition

The Percentage of commission accrued as a result of trades necessitated by creation and redemption activity.

+ References

No definition available.

+ Details

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- Definition

The amount attributable to commission accrued as a result of rebalancing costs during the reporting period.

+ References

No definition available.

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- Definition

Transaction Fees Paid

+ References

No definition available.

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- 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

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Balance Type:	debit
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- 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.

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- 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

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