SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) - USD ($)	9 Months Ended
	Sep. 30, 2021	Nov. 15, 2011	Nov. 10, 2010	Aug. 10, 2010
Significant Accounting Policies
Income tax interest expense or penalties	$ 0
Cash equivalents maturity period	6 months
Fee paid by Authorized Purchasers for each order placed to create one or more Creation Baskets or to redeem one or more baskets				$ 1,000
United States Commodity Index Fund
Significant Accounting Policies
Weighted Average Number of Shares Outstanding, Basic	0
United States Commodity Index Fund | Creation Baskets | Effective as of May 1, 2012
Significant Accounting Policies
Weighted Average Number of Shares Outstanding, Basic	50,000
United States Commodity Index Fund | Redemption Baskets
Significant Accounting Policies
Fee paid by Authorized Purchasers for each order placed to create one or more Creation Baskets or to redeem one or more baskets	$ 350
United States Copper Index Fund
Significant Accounting Policies
Weighted Average Number of Shares Outstanding, Basic	0
Fee paid by Authorized Purchasers for each order placed to create one or more Creation Baskets or to redeem one or more baskets		$ 1,000	$ 1,000