Fair Value of Financial Instruments (Fair Value of Derivative Instrument held by Usci, Cper, Usag and Usmi) (Details) (Commodity Contracts [Member], Futures [Member], Assets [Member], USD $)
Dec. 31, 2013
Dec. 31, 2012
United States Commodity Index Fund [Member]
   
Derivatives, Fair Value [Line Items]    
Derivatives not Accounted for as Hedging Instruments $ 10,789,747 $ (5,220,900)
United States Copper Index Fund [Member]
   
Derivatives, Fair Value [Line Items]    
Derivatives not Accounted for as Hedging Instruments 130,163 6,575
United States Agriculture Index Fund [Member]
   
Derivatives, Fair Value [Line Items]    
Derivatives not Accounted for as Hedging Instruments (44,533) (119,155)
United States Metals Index Fund [Member]
   
Derivatives, Fair Value [Line Items]    
Derivatives not Accounted for as Hedging Instruments $ (46,293) $ 46,058