Statement of Changes in Capital (USD $)
 12 Months Ended 3 Months Ended 12 Months Ended 3 Months Ended 12 Months Ended 3 Months Ended 12 Months Ended 3 Months Ended 12 Months Ended
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2013
United States Commodity Index Fund [Member]
Mar. 31, 2013
United States Commodity Index Fund [Member]
Dec. 31, 2012
United States Commodity Index Fund [Member]
Mar. 31, 2012
United States Commodity Index Fund [Member]
Dec. 31, 2013
United States Commodity Index Fund [Member]
Dec. 31, 2012
United States Commodity Index Fund [Member]
Dec. 31, 2011
United States Commodity Index Fund [Member]
Dec. 31, 2013
United States Copper Index Fund [Member]
Mar. 31, 2013
United States Copper Index Fund [Member]
Dec. 31, 2012
United States Copper Index Fund [Member]
Mar. 31, 2012
United States Copper Index Fund [Member]
Dec. 31, 2013
United States Copper Index Fund [Member]
Dec. 31, 2012
United States Copper Index Fund [Member]
Dec. 31, 2011
United States Copper Index Fund [Member]
Dec. 31, 2013
United States Agriculture Index Fund [Member]
Mar. 31, 2013
United States Agriculture Index Fund [Member]
Dec. 31, 2012
United States Agriculture Index Fund [Member]
Mar. 31, 2012
United States Agriculture Index Fund [Member]
Dec. 31, 2013
United States Agriculture Index Fund [Member]
Dec. 31, 2012
United States Agriculture Index Fund [Member]
Dec. 31, 2011
United States Agriculture Index Fund [Member]
Dec. 31, 2013
United States Metals Index Fund [Member]
Mar. 31, 2013
United States Metals Index Fund [Member]
Dec. 31, 2012
United States Metals Index Fund [Member]
Mar. 31, 2012
United States Metals Index Fund [Member]
Dec. 31, 2013
United States Metals Index Fund [Member]
Dec. 31, 2012
United States Metals Index Fund [Member]
Dec. 31, 2011
United States Metals Index Fund [Member]
Dec. 31, 2013
Sponsor [Member]
Dec. 31, 2012
Sponsor [Member]
Dec. 31, 2011
Sponsor [Member]
Dec. 31, 2013
Sponsor [Member]
United States Commodity Index Fund [Member]
Dec. 31, 2012
Sponsor [Member]
United States Commodity Index Fund [Member]
Dec. 31, 2011
Sponsor [Member]
United States Commodity Index Fund [Member]
Dec. 31, 2013
Sponsor [Member]
United States Copper Index Fund [Member]
Dec. 31, 2012
Sponsor [Member]
United States Copper Index Fund [Member]
Dec. 31, 2011
Sponsor [Member]
United States Copper Index Fund [Member]
Dec. 31, 2013
Sponsor [Member]
United States Agriculture Index Fund [Member]
Dec. 31, 2012
Sponsor [Member]
United States Agriculture Index Fund [Member]
Dec. 31, 2011
Sponsor [Member]
United States Agriculture Index Fund [Member]
Dec. 31, 2013
Sponsor [Member]
United States Metals Index Fund [Member]
Dec. 31, 2012
Sponsor [Member]
United States Metals Index Fund [Member]
Dec. 31, 2011
Sponsor [Member]
United States Metals Index Fund [Member]
Dec. 31, 2013
Shareholders [Member]
Dec. 31, 2012
Shareholders [Member]
Dec. 31, 2011
Shareholders [Member]
Dec. 31, 2013
Shareholders [Member]
United States Commodity Index Fund [Member]
Dec. 31, 2012
Shareholders [Member]
United States Commodity Index Fund [Member]
Dec. 31, 2011
Shareholders [Member]
United States Commodity Index Fund [Member]
Dec. 31, 2013
Shareholders [Member]
United States Copper Index Fund [Member]
Dec. 31, 2012
Shareholders [Member]
United States Copper Index Fund [Member]
Dec. 31, 2011
Shareholders [Member]
United States Copper Index Fund [Member]
Dec. 31, 2013
Shareholders [Member]
United States Agriculture Index Fund [Member]
Dec. 31, 2012
Shareholders [Member]
United States Agriculture Index Fund [Member]
Dec. 31, 2011
Shareholders [Member]
United States Agriculture Index Fund [Member]
Dec. 31, 2013
Shareholders [Member]
United States Metals Index Fund [Member]
Dec. 31, 2012
Shareholders [Member]
United States Metals Index Fund [Member]
Dec. 31, 2011
Shareholders [Member]
United States Metals Index Fund [Member]
Balances $ 495,831,542 $ 353,298,410 $ 102,995,334   $ 488,085,727   $ 350,849,296 $ 488,085,727 $ 350,849,296 $ 102,992,334   $ 2,542,946   $ 2,447,114 $ 2,542,946 $ 2,447,114 $ 1,000   $ 2,555,692   $ 1,000 $ 2,555,692 $ 1,000 $ 1,000   $ 2,647,177   $ 1,000 $ 2,647,177 $ 1,000 $ 1,000 $ 0 $ 2,000 $ 4,000 $ 0 $ 0 $ 1,000 $ 0 $ 0 $ 1,000 $ 0 $ 1,000 $ 1,000 $ 0 $ 1,000 $ 1,000 $ 495,831,542 $ 353,296,410 $ 102,991,334 $ 488,085,727 $ 350,849,296 $ 102,991,334 $ 2,542,946 $ 2,447,114 $ 0 $ 2,555,692 $ 0 $ 0 $ 2,647,177 $ 0 $ 0
Additions 129,180,334 181,729,927 472,181,512         128,090,557 171,692,032 469,681,512         0 1,224,883 2,500,000         0 5,085,695 0         1,089,777 3,727,317 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 129,180,334 181,729,927 472,181,512 128,090,557 171,692,032 469,681,512 0 1,224,883 2,500,000 0 5,085,695 0 1,089,777 3,727,317 0
Redemptions (82,000,053) (31,585,138) (153,724,157)         (80,864,053) (26,356,666) (153,723,138)         0 (1,240,510) (1,019)         0 (2,723,566) 0         (1,136,000) (1,264,396) 0 0 (2,035) (2,019) 0 0 (1,000) 0 0 (1,019) 0 (1,009) 0 0 (1,026) 0 (82,000,053) (31,583,103) (153,722,138) (80,864,053) (26,356,666) (153,722,138) 0 (1,240,510) 0 0 (2,722,557) 0 (1,136,000) (1,263,370) 0
Net income (loss) (23,298,441) (7,611,657) (68,154,279) (1,162,174) (13,323,660) (23,471,584) 15,738,571 (22,367,209) (8,098,935) (68,101,412) 30,517 (174,362) (87,355) 260,937 (250,747) [1] 111,459 [1] (52,867) [1] (88,531) (154,845) (182,055) 0 (276,753) [2] 192,563 [2] 0 [2] (78,397) (129,842) (119,351) 0 (403,732) [3] 183,256 [3] 0 [3] 0 35 19 0 0 0 0 0 19 0 9 0 0 26 0 (23,298,441) (7,611,692) (68,154,298) (22,367,209) (8,098,935) (68,101,412) (250,747) 111,459 (52,886) (276,753) 192,554 0 (403,732) 183,230 0
Balances $ 519,713,382 $ 495,831,542 $ 353,298,410 $ 512,945,022   $ 488,085,727   $ 512,945,022 $ 488,085,727 $ 350,849,296 $ 2,292,199   $ 2,542,946   $ 2,292,199 $ 2,542,946 $ 2,447,114 $ 2,278,939   $ 2,555,692   $ 2,278,939 $ 2,555,692 $ 1,000 $ 2,197,222   $ 2,647,177   $ 2,197,222 $ 2,647,177 $ 1,000 $ 0 $ 0 $ 2,000 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 1,000 $ 0 $ 0 $ 1,000 $ 519,713,382 $ 495,831,542 $ 353,296,410 $ 512,945,022 $ 488,085,727 $ 350,849,296 $ 2,292,199 $ 2,542,946 $ 2,447,114 $ 2,278,939 $ 2,555,692 $ 0 $ 2,197,222 $ 2,647,177 $ 0
Units Outstanding 8,650,000 6,100,000 1,600,020   8,350,000   6,000,000 8,350,000 6,000,000 1,600,020   100,000   100,000 100,000 100,000 0   100,000   0 100,000 0 0   100,000   0 100,000 0 0 0 0 20 0 0 20 0 0 0 0 0 0 0 0 0 8,650,000 6,100,000 1,600,000 8,350,000 6,000,000 1,600,000 100,000 100,000 0 100,000 0 0 100,000 0 0
Additions 2,300,000 3,200,080 7,000,040         2,250,000 2,800,000 6,900,000         0 50,000 100,040         0 200,040 0         50,000 150,040 0 0 80 40 0 0 0 0 0 40 0 40 0 0 40 0 2,300,000 3,200,000 7,000,000 2,250,000 2,800,000 6,900,000 0 50,000 100,000 0 200,000 0 50,000 150,000 0
Redemptions (1,500,000) (650,080) (2,500,060)         (1,450,000) (450,000) (2,500,020)         0 (50,000) (40)         0 (100,040) 0         (50,000) (50,040) 0 0 (80) (60) 0 0 (20) 0 0 (40) 0 (40) 0 0 (40) 0 (1,500,000) (650,000) (2,500,000) (1,450,000) (450,000) (2,500,000) 0 (50,000) 0 0 (100,000) 0 (50,000) (50,000) 0
Units Outstanding 9,450,000 8,650,000 6,100,000 9,150,000   8,350,000   9,150,000 8,350,000 6,000,000 100,000   100,000   100,000 100,000 100,000 100,000   100,000   100,000 100,000 0 100,000   100,000   100,000 100,000 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 9,450,000 8,650,000 6,100,000 9,150,000 8,350,000 6,000,000 100,000 100,000 100,000 100,000 100,000 0 100,000 100,000 0
Net Asset Value Per Share:                                                                                                                          
Net asset value per share       $ 56.06   $ 58.45   $ 56.06 $ 58.45 $ 58.47 $ 22.92   $ 25.43   $ 22.92 $ 25.43 $ 24.47 [4] $ 22.79   $ 25.56 [5]   $ 22.79 $ 25.56 [5] $ 25.00 [5] $ 21.97   $ 26.47 [6]   $ 21.97 $ 26.47 [6] $ 25.00 [6]                                                            
[1] The commencement of operations of the United States Copper Index Fund was November 15, 2011.
[2] The commencement of operations of the United States Agriculture Index Fund was April 13, 2012.
[3] The commencement of operations of the United States Metals Index Fund was June 19, 2012.
[4] The commencement of operations of CPER was November 15, 2011.
[5] The commencement of operations of USAG was April 13, 2012.
[6] The commencement of operations of USMI was June 19, 2012.