Trading Activities - Offsetting of Derivative Assets and Liabilities (Detail)	Dec. 31, 2018 USD ($)
Derivative [Line Items]
Gross Amounts Recognized, Assets	$ 15,181
Gross Amounts Offset in the Statements of Financial Condition, Assets	(15,181)
Amounts Presented in the Statements of Financial Condition, Assets	0
Gross Amounts Not Offset in the Statements of Financial Condition, Financial Instruments, Assets	0
Gross Amounts Not Offset in the Statements of Financial Condition, Cash Collateral Received/ Pledged, Assets	0
Net Amount, Assets	0
Gross Amounts Recognized, Liabilities	(25,826)
Gross Amounts Offset in the Statements of Financial Condition, Liabilities	15,181
Amounts Presented in the Statements of Financial Condition, Liabilities	(10,645)
Gross Amounts Not Offset in the Statements of Financial Condition, Financial Instruments, Liabilities	0
Gross Amounts Not Offset in the Statements of Financial Condition, Cash Collateral Received/ Pledged, Liabilities	0
Net Amount, Liabilities	(10,645)
Net fair value	(10,645)
Futures Contracts [Member]
Derivative [Line Items]
Amounts Presented in the Statements of Financial Condition, Liabilities	(10,645)
Futures Contracts [Member] \| MS&Co. [Member]
Derivative [Line Items]
Gross Amounts Recognized, Assets	15,181
Gross Amounts Offset in the Statements of Financial Condition, Assets	(15,181)
Amounts Presented in the Statements of Financial Condition, Assets	0
Gross Amounts Not Offset in the Statements of Financial Condition, Financial Instruments, Assets	0
Gross Amounts Not Offset in the Statements of Financial Condition, Cash Collateral Received/ Pledged, Assets	0
Net Amount, Assets	0
Gross Amounts Recognized, Liabilities	(25,826)
Gross Amounts Offset in the Statements of Financial Condition, Liabilities	15,181
Amounts Presented in the Statements of Financial Condition, Liabilities	(10,645)
Gross Amounts Not Offset in the Statements of Financial Condition, Financial Instruments, Liabilities	0
Gross Amounts Not Offset in the Statements of Financial Condition, Cash Collateral Received/ Pledged, Liabilities	0
Net Amount, Liabilities	$ (10,645)

Fair value of liability associated with financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset.

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