Financial Instrument Risk	12 Months Ended
Dec. 31, 2018
Investments Debt And Equity Securities [Abstract]
Financial Instrument Risk	Note 3 - Financial Instrument Risk In the normal course of its business, the Fund is a party to financial instruments with off-balance sheet risk. The term “off-balance sheet risk” refers to an unrecorded potential liability that, even though it does not appear on the balance sheet, may result in a future obligation or loss in excess of the amounts shown on the Statements of Financial Condition. The financial instruments used by the Fund are commodity futures contracts, the values of which are based upon an underlying asset and generally represent future commitments that have a reasonable possibility of being settled in cash or through physical delivery. The financial instruments are traded on an exchange and are standardized contracts. Market risk is the potential for changes in the value of the financial instruments traded by the Fund due to market changes, including fluctuations in commodity prices. In entering into these futures contracts, there exists a market risk that such futures contracts may be significantly influenced by adverse market conditions, resulting in such futures contracts being less valuable. If the markets should move against all of the futures contracts at the same time, the Fund could experience substantial losses. Credit risk is the possibility that a loss may occur due to the failure of the Commodity Broker and/or clearing house to perform according to the terms of a futures contract. Credit risk with respect to exchange-traded instruments is reduced to the extent that an exchange or clearing organization acts as a counterparty to the transactions. The Commodity Broker, when acting as the Fund’s futures commission merchant in accepting orders for the purchase or sale of domestic futures contracts, is required by CFTC regulations to separately account for and segregate as belonging to the Fund all assets of the Fund relating to domestic futures trading. The Commodity Broker is not allowed to commingle such assets with other assets of the Commodity Broker. In addition, CFTC regulations also require the Commodity Broker to hold in a secure account assets of the Fund related to foreign futures trading. The Fund’s risk of loss in the event of counterparty default is typically limited to the amounts recognized in the Statements of Financial Condition and not represented by the futures contract or notional amounts of the instruments. The Fund has not utilized, nor does it expect to utilize in the future, special purpose entities to facilitate off-balance sheet financing arrangements and has no loan guarantee arrangements or off-balance sheet arrangements of any kind, other than agreements entered into in the normal course of business noted above.

Financial Instrument Risk

12 Months Ended

Dec. 31, 2018

Investments Debt And Equity Securities [Abstract]

Note 3 - Financial Instrument Risk

In the normal course of its business, the Fund is a party to financial instruments with off-balance sheet risk. The term “off-balance sheet risk” refers to an unrecorded potential liability that, even though it does not appear on the balance sheet, may result in a future obligation or loss in excess of the amounts shown on the Statements of Financial Condition. The financial instruments used by the Fund are commodity futures contracts, the values of which are based upon an underlying asset and generally represent future commitments that have a reasonable possibility of being settled in cash or through physical delivery. The financial instruments are traded on an exchange and are standardized contracts.

Market risk is the potential for changes in the value of the financial instruments traded by the Fund due to market changes, including fluctuations in commodity prices. In entering into these futures contracts, there exists a market risk that such futures contracts may be significantly influenced by adverse market conditions, resulting in such futures contracts being less valuable. If the markets should move against all of the futures contracts at the same time, the Fund could experience substantial losses.

Credit risk is the possibility that a loss may occur due to the failure of the Commodity Broker and/or clearing house to perform according to the terms of a futures contract. Credit risk with respect to exchange-traded instruments is reduced to the extent that an exchange or clearing organization acts as a counterparty to the transactions. The Commodity Broker, when acting as the Fund’s futures commission merchant in accepting orders for the purchase or sale of domestic futures contracts, is required by CFTC regulations to separately account for and segregate as belonging to the Fund all assets of the Fund relating to domestic futures trading. The Commodity Broker is not allowed to commingle such assets with other assets of the Commodity Broker. In addition, CFTC regulations also require the Commodity Broker to hold in a secure account assets of the Fund related to foreign futures trading. The Fund’s risk of loss in the event of counterparty default is typically limited to the amounts recognized in the Statements of Financial Condition and not represented by the futures contract or notional amounts of the instruments.

The Fund has not utilized, nor does it expect to utilize in the future, special purpose entities to facilitate off-balance sheet financing arrangements and has no loan guarantee arrangements or off-balance sheet arrangements of any kind, other than agreements entered into in the normal course of business noted above.