FAIR VALUE OF FINANCIAL INSTRUMENTS (Valuation of Securities Using Fair Value Hierarchy) (Details) - USD ($)
Dec. 31, 2016
Dec. 31, 2015
United States Commodity Index Fund [Member] | Short-Term Investments [Member]    
Schedule of Trading Securities and Other Trading Assets [Line Items]    
Securities, fair value $ 514,192,445 $ 299,704,608
United States Commodity Index Fund [Member] | Exchange-Traded Futures Contracts [Member] | Foreign [Member]    
Schedule of Trading Securities and Other Trading Assets [Line Items]    
Securities, fair value (3,366,242) (4,020,212)
United States Commodity Index Fund [Member] | Exchange-Traded Futures Contracts [Member] | United States [Member]    
Schedule of Trading Securities and Other Trading Assets [Line Items]    
Securities, fair value 5,421,702 (4,562,015)
United States Commodity Index Fund [Member] | Fair Value, Inputs, Level 1 [Member] | Short-Term Investments [Member]    
Schedule of Trading Securities and Other Trading Assets [Line Items]    
Securities, fair value 514,192,445 299,704,608
United States Commodity Index Fund [Member] | Fair Value, Inputs, Level 1 [Member] | Exchange-Traded Futures Contracts [Member] | Foreign [Member]    
Schedule of Trading Securities and Other Trading Assets [Line Items]    
Securities, fair value (3,366,242) (4,020,212)
United States Commodity Index Fund [Member] | Fair Value, Inputs, Level 1 [Member] | Exchange-Traded Futures Contracts [Member] | United States [Member]    
Schedule of Trading Securities and Other Trading Assets [Line Items]    
Securities, fair value 5,421,702 (4,562,015)
United States Commodity Index Fund [Member] | Fair Value, Inputs, Level 2 [Member] | Short-Term Investments [Member]    
Schedule of Trading Securities and Other Trading Assets [Line Items]    
Securities, fair value 0 0
United States Commodity Index Fund [Member] | Fair Value, Inputs, Level 2 [Member] | Exchange-Traded Futures Contracts [Member] | Foreign [Member]    
Schedule of Trading Securities and Other Trading Assets [Line Items]    
Securities, fair value 0 0
United States Commodity Index Fund [Member] | Fair Value, Inputs, Level 2 [Member] | Exchange-Traded Futures Contracts [Member] | United States [Member]    
Schedule of Trading Securities and Other Trading Assets [Line Items]    
Securities, fair value 0 0
United States Commodity Index Fund [Member] | Fair Value, Inputs, Level 3 [Member] | Short-Term Investments [Member]    
Schedule of Trading Securities and Other Trading Assets [Line Items]    
Securities, fair value 0 0
United States Commodity Index Fund [Member] | Fair Value, Inputs, Level 3 [Member] | Exchange-Traded Futures Contracts [Member] | Foreign [Member]    
Schedule of Trading Securities and Other Trading Assets [Line Items]    
Securities, fair value 0 0
United States Commodity Index Fund [Member] | Fair Value, Inputs, Level 3 [Member] | Exchange-Traded Futures Contracts [Member] | United States [Member]    
Schedule of Trading Securities and Other Trading Assets [Line Items]    
Securities, fair value 0 0
United States Copper Index Fund [Member] | Short-Term Investments [Member]    
Schedule of Trading Securities and Other Trading Assets [Line Items]    
Securities, fair value 4,541,320 998,899
United States Copper Index Fund [Member] | Exchange-Traded Futures Contracts [Member] | United States [Member]    
Schedule of Trading Securities and Other Trading Assets [Line Items]    
Securities, fair value 88,575 (180,625)
United States Copper Index Fund [Member] | Fair Value, Inputs, Level 1 [Member] | Short-Term Investments [Member]    
Schedule of Trading Securities and Other Trading Assets [Line Items]    
Securities, fair value 4,541,320 998,899
United States Copper Index Fund [Member] | Fair Value, Inputs, Level 1 [Member] | Exchange-Traded Futures Contracts [Member] | United States [Member]    
Schedule of Trading Securities and Other Trading Assets [Line Items]    
Securities, fair value 88,575 (180,625)
United States Copper Index Fund [Member] | Fair Value, Inputs, Level 2 [Member] | Short-Term Investments [Member]    
Schedule of Trading Securities and Other Trading Assets [Line Items]    
Securities, fair value 0 0
United States Copper Index Fund [Member] | Fair Value, Inputs, Level 2 [Member] | Exchange-Traded Futures Contracts [Member] | United States [Member]    
Schedule of Trading Securities and Other Trading Assets [Line Items]    
Securities, fair value 0 0
United States Copper Index Fund [Member] | Fair Value, Inputs, Level 3 [Member] | Short-Term Investments [Member]    
Schedule of Trading Securities and Other Trading Assets [Line Items]    
Securities, fair value 0 0
United States Copper Index Fund [Member] | Fair Value, Inputs, Level 3 [Member] | Exchange-Traded Futures Contracts [Member] | United States [Member]    
Schedule of Trading Securities and Other Trading Assets [Line Items]    
Securities, fair value 0 0
United States Agriculture Index Fund [Member] | Short-Term Investments [Member]    
Schedule of Trading Securities and Other Trading Assets [Line Items]    
Securities, fair value 1,397,843 749,059
United States Agriculture Index Fund [Member] | Exchange-Traded Futures Contracts [Member] | Foreign [Member]    
Schedule of Trading Securities and Other Trading Assets [Line Items]    
Securities, fair value (90,442) 48,270
United States Agriculture Index Fund [Member] | Exchange-Traded Futures Contracts [Member] | United States [Member]    
Schedule of Trading Securities and Other Trading Assets [Line Items]    
Securities, fair value 742 (42,113)
United States Agriculture Index Fund [Member] | Fair Value, Inputs, Level 1 [Member] | Short-Term Investments [Member]    
Schedule of Trading Securities and Other Trading Assets [Line Items]    
Securities, fair value 1,397,843 749,059
United States Agriculture Index Fund [Member] | Fair Value, Inputs, Level 1 [Member] | Exchange-Traded Futures Contracts [Member] | Foreign [Member]    
Schedule of Trading Securities and Other Trading Assets [Line Items]    
Securities, fair value (90,442) 48,270
United States Agriculture Index Fund [Member] | Fair Value, Inputs, Level 1 [Member] | Exchange-Traded Futures Contracts [Member] | United States [Member]    
Schedule of Trading Securities and Other Trading Assets [Line Items]    
Securities, fair value 742 (42,113)
United States Agriculture Index Fund [Member] | Fair Value, Inputs, Level 2 [Member] | Short-Term Investments [Member]    
Schedule of Trading Securities and Other Trading Assets [Line Items]    
Securities, fair value 0 0
United States Agriculture Index Fund [Member] | Fair Value, Inputs, Level 2 [Member] | Exchange-Traded Futures Contracts [Member] | Foreign [Member]    
Schedule of Trading Securities and Other Trading Assets [Line Items]    
Securities, fair value 0 0
United States Agriculture Index Fund [Member] | Fair Value, Inputs, Level 2 [Member] | Exchange-Traded Futures Contracts [Member] | United States [Member]    
Schedule of Trading Securities and Other Trading Assets [Line Items]    
Securities, fair value 0 0
United States Agriculture Index Fund [Member] | Fair Value, Inputs, Level 3 [Member] | Short-Term Investments [Member]    
Schedule of Trading Securities and Other Trading Assets [Line Items]    
Securities, fair value 0 0
United States Agriculture Index Fund [Member] | Fair Value, Inputs, Level 3 [Member] | Exchange-Traded Futures Contracts [Member] | Foreign [Member]    
Schedule of Trading Securities and Other Trading Assets [Line Items]    
Securities, fair value 0 0
United States Agriculture Index Fund [Member] | Fair Value, Inputs, Level 3 [Member] | Exchange-Traded Futures Contracts [Member] | United States [Member]    
Schedule of Trading Securities and Other Trading Assets [Line Items]    
Securities, fair value $ 0 $ 0