Condensed Statements of Cash Flows (Parenthetical) - USD ($)	Sep. 30, 2021	Dec. 31, 2020	Sep. 30, 2020	Dec. 31, 2019
Components of Cash and Cash Equivalents:
Cash and cash Equivalents	$ 467,105,470		$ 124,713,160
Equity in Trading Accounts:
Cash and cash equivalents	26,805,822		3,746,721
Total Cash, Cash Equivalents and Equity in Trading Accounts	493,911,292	$ 166,206,573	128,459,881	$ 197,413,898
United States Commodity Index Fund
Components of Cash and Cash Equivalents:
Cash and cash Equivalents	218,105,747	103,318,538	98,495,028
Equity in Trading Accounts:
Cash and cash equivalents	11,711,481		3,408,539
Total Cash, Cash Equivalents and Equity in Trading Accounts	229,817,228	103,873,008	101,903,567	190,313,994
Sponsor Capital Account	0	0
United States Copper Index Fund
Components of Cash and Cash Equivalents:
Cash and cash Equivalents	248,999,723	62,333,565	26,218,132
Equity in Trading Accounts:
Cash and cash equivalents	15,094,341		338,182
Total Cash, Cash Equivalents and Equity in Trading Accounts	264,094,064	62,333,565	26,556,314	7,098,904
Sponsor Capital Account	0	0
USCF Crescent Crypto Index Fund
Components of Cash and Cash Equivalents:
Cash and cash Equivalents	0		0
Equity in Trading Accounts:
Cash and cash equivalents	0		0
Total Cash, Cash Equivalents and Equity in Trading Accounts	0	0	$ 0	$ 1,000
United States Commodity Index Funds Trust
Components of Cash and Cash Equivalents:
Cash and cash Equivalents	467,105,470	165,652,103
Equity in Trading Accounts:
Sponsor Capital Account	$ 0	$ 0