Condensed Statement of Changes in Capital - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Net income (loss)			$ 41,946,702	$ (32,807,530)
United States Commodity Index Fund
Balances, Beginning			110,783,068
Net income (loss)	$ 2,842,102	$ 15,258,027	39,939,638	(35,439,060)
Balances, Ending	235,500,454		235,500,454
United States Copper Index Fund
Balances, Beginning			65,163,704
Net income (loss)	(14,429,475)	2,286,451	2,007,064	2,631,530
Balances, Ending	237,771,844		237,771,844
USCF Crescent Crypto Index Fund
Net income (loss)	0	0	0	0
United States Commodity Index Funds Trust
Balances, Beginning			175,946,772
Net income (loss)	(11,587,373)	17,544,478	41,946,702	(32,807,530)
Balances, Ending	473,272,298		473,272,298
Sponsor | USCF Crescent Crypto Index Fund
Balances, Beginning	0	0	0	1,000
Additions	0	0	0
Redemptions	0	0	0	(1,000)
Net income (loss)	0	0	0
Balances, Ending	0	0	0	0
Shareholders | United States Commodity Index Fund
Balances, Beginning	234,673,948	126,548,740	110,783,068	189,895,482
Additions	6,003,054	8,105,031	109,014,826	18,654,333
Redemptions	(8,018,650)	(42,883,678)	(24,237,078)	(66,082,635)
Net income (loss)	2,842,102	15,258,027	39,939,638	(35,439,060)
Balances, Ending	235,500,454	107,028,120	235,500,454	107,028,120
Shareholders | United States Copper Index Fund
Balances, Beginning	306,368,077	15,293,972	65,163,704	7,015,377
Additions	28,896,874	21,609,433	321,311,058	30,237,701
Redemptions	(83,063,632)	(11,038,374)	(150,709,982)	(11,733,126)
Net income (loss)	(14,429,475)	2,286,451	2,007,064	2,631,530
Balances, Ending	237,771,844	28,151,482	237,771,844	28,151,482
Shareholders | USCF Crescent Crypto Index Fund
Balances, Ending	0	0	0	0
Shareholders | United States Commodity Index Funds Trust
Balances, Beginning	541,042,025	141,842,712	175,946,772	196,911,859
Additions	34,899,928	29,714,464	430,325,884	48,892,034
Redemptions	(91,082,282)	(53,922,052)	(174,947,060)	(77,816,761)
Net income (loss)	(11,587,373)	17,544,478	41,946,702	(32,807,530)
Balances, Ending	$ 473,272,298	$ 135,179,602	$ 473,272,298	$ 135,179,602