v2.4.0.6
Schedule Of Investments (Short-Term U.S. Government And Agency Obligations) (Parenthetical) (Detail) (USD $)
 3 Months Ended
Mar. 31, 2013
ProShares UltraShort DJ-UBS Commodity [Member]
  
Schedule of Investments [Line Items]  
Short-term U.S. government and agency obligations percentage of shareholders' equity 93.00%
Total short-term U.S. government and agency obligations, cost $ 3,062,693
ProShares UltraShort DJ-UBS Commodity [Member] | U.S. Treasury Bills 0.096% Due 04/18/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.096% [1]
Debt instrument, maturity date Apr. 18, 2013 [1]
ProShares UltraShort DJ-UBS Commodity [Member] | U.S. Treasury Bills 0.101% Due 05/16/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.101% [1]
Debt instrument, maturity date May 16, 2013 [1]
ProShares UltraShort DJ-UBS Commodity [Member] | U.S. Treasury Bills 0.072% due 06/27/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.072%
Debt instrument, maturity date Jun. 27, 2013
ProShares UltraShort DJ-UBS Crude Oil [Member]
  
Schedule of Investments [Line Items]  
Short-term U.S. government and agency obligations percentage of shareholders' equity 103.00%
Total short-term U.S. government and agency obligations, cost 145,470,481
ProShares UltraShort DJ-UBS Crude Oil [Member] | U.S. Treasury Bills 0.055% Due 04/11/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.055%
Debt instrument, maturity date Apr. 11, 2013
ProShares UltraShort DJ-UBS Crude Oil [Member] | U.S. Treasury Bills 0.071% Due 04/18/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.071%
Debt instrument, maturity date Apr. 18, 2013
ProShares UltraShort DJ-UBS Crude Oil [Member] | U.S. Treasury Bills 0.074% Due 04/25/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.074% [1]
Debt instrument, maturity date Apr. 25, 2013 [1]
ProShares UltraShort DJ-UBS Crude Oil [Member] | U.S. Treasury Bills 0.098% Due 05/16/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.098%
Debt instrument, maturity date May 16, 2013
ProShares UltraShort DJ-UBS Crude Oil [Member] | U.S. Treasury Bills 0.084% Due 06/27/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.084% [1]
Debt instrument, maturity date Jun. 27, 2013 [1]
ProShares UltraShort DJ-UBS Natural Gas [Member]
  
Schedule of Investments [Line Items]  
Short-term U.S. government and agency obligations percentage of shareholders' equity 84.00%
Total short-term U.S. government and agency obligations, cost 21,192,907
ProShares UltraShort DJ-UBS Natural Gas [Member] | U.S. Treasury Bills 0.055% Due 04/11/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.055%
Debt instrument, maturity date Apr. 11, 2013
ProShares UltraShort DJ-UBS Natural Gas [Member] | U.S. Treasury Bills 0.091% due 04/18/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.091%
Debt instrument, maturity date Apr. 18, 2013
ProShares UltraShort DJ-UBS Natural Gas [Member] | U.S. Treasury Bills 0.050% Due 04/25/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.05%
Debt instrument, maturity date Apr. 25, 2013
ProShares UltraShort DJ-UBS Natural Gas [Member] | United States Treasury Bills 0.101% due 05/16/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.101%
Debt instrument, maturity date May 16, 2013
ProShares UltraShort DJ-UBS Natural Gas [Member] | U.S. Treasury Bills 0.071% Due 06/27/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.071%
Debt instrument, maturity date Jun. 27, 2013
ProShares UltraShort Gold [Member]
  
Schedule of Investments [Line Items]  
Short-term U.S. government and agency obligations percentage of shareholders' equity 103.00%
Total short-term U.S. government and agency obligations, cost 108,154,807
ProShares UltraShort Gold [Member] | U.S. Treasury Bills 0.055% Due 04/11/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.055%
Debt instrument, maturity date Apr. 11, 2013
ProShares UltraShort Gold [Member] | U.S. Treasury Bills 0.060% due 04/18/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.06% [2]
Debt instrument, maturity date Apr. 18, 2013 [2]
ProShares UltraShort Gold [Member] | U.S. Treasury Bills 0.062% due 04/25/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.062% [2]
Debt instrument, maturity date Apr. 25, 2013 [2]
ProShares UltraShort Gold [Member] | U.S. Treasury Bills 0.110% due 05/16/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.11%
Debt instrument, maturity date May 16, 2013
ProShares UltraShort Gold [Member] | U.S. Treasury Bills 0.087% due 06/27/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.087% [2]
Debt instrument, maturity date Jun. 27, 2013 [2]
ProShares UltraShort Silver [Member]
  
Schedule of Investments [Line Items]  
Short-term U.S. government and agency obligations percentage of shareholders' equity 99.00%
Total short-term U.S. government and agency obligations, cost 105,343,764
ProShares UltraShort Silver [Member] | U.S. Treasury Bills 0.084% due 04/18/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.084% [2]
Debt instrument, maturity date Apr. 18, 2013 [2]
ProShares UltraShort Silver [Member] | U.S. Treasury Bills 0.063% Due 04/25/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.063% [2]
Debt instrument, maturity date Apr. 25, 2013 [2]
ProShares UltraShort Silver [Member] | U.S. Treasury Bills 0.105% Due 05/16/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.105%
Debt instrument, maturity date May 16, 2013
ProShares UltraShort Silver [Member] | U.S. Treasury Bills 0.093% due 06/27/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.093% [2]
Debt instrument, maturity date Jun. 27, 2013 [2]
ProShares Short Euro [Member]
  
Schedule of Investments [Line Items]  
Short-term U.S. government and agency obligations percentage of shareholders' equity 87.00%
Total short-term U.S. government and agency obligations, cost 3,371,937
ProShares Short Euro [Member] | U.S. Treasury Bills 0.101% Due 05/16/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.101%
Debt instrument, maturity date May 16, 2013
ProShares Short Euro [Member] | U.S. Treasury Bills 0.055% Due 04/11/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.055%
Debt instrument, maturity date Apr. 11, 2013
ProShares UltraShort Australian Dollar [Member]
  
Schedule of Investments [Line Items]  
Short-term U.S. government and agency obligations percentage of shareholders' equity 90.00%
Total short-term U.S. government and agency obligations, cost 3,329,947
ProShares UltraShort Australian Dollar [Member] | U.S. Treasury Bills 0.055% Due 04/11/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.055%
Debt instrument, maturity date Apr. 11, 2013
ProShares UltraShort Australian Dollar [Member] | U.S. Treasury Bills 0.050% Due 04/25/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.05%
Debt instrument, maturity date Apr. 25, 2013
ProShares UltraShort Euro [Member]
  
Schedule of Investments [Line Items]  
Short-term U.S. government and agency obligations percentage of shareholders' equity 98.00%
Total short-term U.S. government and agency obligations, cost 507,177,936
ProShares UltraShort Euro [Member] | U.S. Treasury Bills 0.055% Due 04/11/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.055%
Debt instrument, maturity date Apr. 11, 2013
ProShares UltraShort Euro [Member] | U.S. Treasury Bills 0.054% Due 04/18/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.054%
Debt instrument, maturity date Apr. 18, 2013
ProShares UltraShort Euro [Member] | U.S. Treasury Bills 0.068% Due 04/25/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.068% [3]
Debt instrument, maturity date Apr. 25, 2013 [3]
ProShares UltraShort Euro [Member] | U.S. Treasury Bills 0.104% Due 05/16/13[Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.104%
Debt instrument, maturity date May 16, 2013
ProShares UltraShort Euro [Member] | U.S. Treasury Bills 0.095% Due 06/27/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.095% [3]
Debt instrument, maturity date Jun. 27, 2013 [3]
ProShares UltraShort Yen [Member]
  
Schedule of Investments [Line Items]  
Short-term U.S. government and agency obligations percentage of shareholders' equity 98.00%
Total short-term U.S. government and agency obligations, cost 463,610,208
ProShares UltraShort Yen [Member] | U.S. Treasury Bills 0.055% Due 04/11/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.055%
Debt instrument, maturity date Apr. 11, 2013
ProShares UltraShort Yen [Member] | U.S. Treasury Bills 0.063% Due 04/25/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.063% [3]
Debt instrument, maturity date Apr. 25, 2013
ProShares UltraShort Yen [Member] | U.S. Treasury Bills 0.105% Due 05/16/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.105%
Debt instrument, maturity date May 16, 2013
ProShares UltraShort Yen [Member] | U.S. Treasury Bills 0.056% Due 04/18/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.056%
Debt instrument, maturity date Apr. 18, 2013
ProShares UltraShort Yen [Member] | U.S. Treasury Bills 0.079% Due 06/27/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.079% [3]
Debt instrument, maturity date Jun. 27, 2013
ProShares Ultra DJ-UBS Commodity [Member]
  
Schedule of Investments [Line Items]  
Short-term U.S. government and agency obligations percentage of shareholders' equity 71.00%
Total short-term U.S. government and agency obligations, cost 3,350,591
ProShares Ultra DJ-UBS Commodity [Member] | U.S. Treasury Bills 0.050% Due 04/25/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.05% [1]
Debt instrument, maturity date Apr. 25, 2013 [1]
ProShares Ultra DJ-UBS Commodity [Member] | U.S. Treasury Bills 0.105% Due 05/16/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.105%
Debt instrument, maturity date May 16, 2013
ProShares Ultra DJ-UBS Commodity [Member] | U.S. Treasury Bills 0.056% Due 04/18/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.056% [1]
Debt instrument, maturity date Apr. 18, 2013 [1]
ProShares Ultra DJ-UBS Commodity [Member] | U.S. Treasury Bills 0.076% Due 06/27/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.076%
Debt instrument, maturity date Jun. 27, 2013
ProShares Ultra DJ-UBS Crude Oil [Member]
  
Schedule of Investments [Line Items]  
Short-term U.S. government and agency obligations percentage of shareholders' equity 93.00%
Total short-term U.S. government and agency obligations, cost 303,993,548
ProShares Ultra DJ-UBS Crude Oil [Member] | U.S. Treasury Bills 0.055% Due 04/11/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.055%
Debt instrument, maturity date Apr. 11, 2013
ProShares Ultra DJ-UBS Crude Oil [Member] | U.S. Treasury Bills 0.105% Due 05/16/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.105%
Debt instrument, maturity date May 16, 2013
ProShares Ultra DJ-UBS Crude Oil [Member] | U.S. Treasury Bills 0.079% Due 06/27/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.079% [1]
Debt instrument, maturity date Jun. 27, 2013 [1]
ProShares Ultra DJ-UBS Crude Oil [Member] | U.S. Treasury Bills 0.103% Due 04/18/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.103%
Debt instrument, maturity date Apr. 18, 2013
ProShares Ultra DJ-UBS Crude Oil [Member] | U.S. Treasury Bills 0.055% Due 04/25/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.055% [1]
Debt instrument, maturity date Apr. 25, 2013 [1]
ProShares Ultra DJ-UBS Natural Gas [Member]
  
Schedule of Investments [Line Items]  
Short-term U.S. government and agency obligations percentage of shareholders' equity 105.00%
Total short-term U.S. government and agency obligations, cost 53,700,121
ProShares Ultra DJ-UBS Natural Gas [Member] | U.S. Treasury Bills 0.103% Due 04/18/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.103%
Debt instrument, maturity date Apr. 18, 2013
ProShares Ultra DJ-UBS Natural Gas [Member] | U.S. Treasury Bills 0.059% Due 04/25/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.059%
Debt instrument, maturity date Apr. 25, 2013
ProShares Ultra DJ-UBS Natural Gas [Member] | U.S. Treasury Bills 0.103% Due 05/16/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.103%
Debt instrument, maturity date May 16, 2013
ProShares Ultra DJ-UBS Natural Gas [Member] | U.S. Treasury Bills 0.082% Due 06/27/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.082%
Debt instrument, maturity date Jun. 27, 2013
ProShares Ultra Gold [Member]
  
Schedule of Investments [Line Items]  
Short-term U.S. government and agency obligations percentage of shareholders' equity 97.00%
Total short-term U.S. government and agency obligations, cost 307,376,479
ProShares Ultra Gold [Member] | U.S. Treasury Bills 0.050% Due 04/25/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.05% [2]
Debt instrument, maturity date Apr. 25, 2013 [2]
ProShares Ultra Gold [Member] | U.S. Treasury Bills 0.056% Due 04/18/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.056% [2]
Debt instrument, maturity date Apr. 18, 2013 [2]
ProShares Ultra Gold [Member] | U.S. Treasury Bills 0.076% Due 06/27/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.076%
Debt instrument, maturity date Jun. 27, 2013
ProShares Ultra Gold [Member] | U.S. Treasury Bills 0.094% Due 05/16/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.094% [2]
Debt instrument, maturity date May 16, 2013 [2]
ProShares Ultra Silver [Member]
  
Schedule of Investments [Line Items]  
Short-term U.S. government and agency obligations percentage of shareholders' equity 101.00%
Total short-term U.S. government and agency obligations, cost 754,938,086
ProShares Ultra Silver [Member] | U.S. Treasury Bills 0.105% Due 05/16/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.105% [2]
Debt instrument, maturity date May 16, 2013 [2]
ProShares Ultra Silver [Member] | U.S. Treasury Bills 0.055% Due 04/25/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.055% [2]
Debt instrument, maturity date Apr. 25, 2013 [2]
ProShares Ultra Silver [Member] | U.S. Treasury Bills 0.069% Due 04/11/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.069% [2]
Debt instrument, maturity date Apr. 11, 2013 [2]
ProShares Ultra Silver [Member] | U.S. Treasury Bills 0.078% Due 06/27/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.078% [2]
Debt instrument, maturity date Jun. 27, 2013 [2]
ProShares Ultra Australian Dollar [Member]
  
Schedule of Investments [Line Items]  
Short-term U.S. government and agency obligations percentage of shareholders' equity 87.00%
Total short-term U.S. government and agency obligations, cost 3,676,855
ProShares Ultra Australian Dollar [Member] | U.S. Treasury Bills 0.055% Due 04/11/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.055%
Debt instrument, maturity date Apr. 11, 2013
ProShares Ultra Australian Dollar [Member] | U.S. Treasury Bills 0.105% Due 05/16/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.105%
Debt instrument, maturity date May 16, 2013
ProShares Ultra Australian Dollar [Member] | U.S. Treasury Bills 0.051% Due 04/18/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.051%
Debt instrument, maturity date Apr. 18, 2013
ProShares Ultra Australian Dollar [Member] | U.S. Treasury Bills 0.065% Due 04/25/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.065%
Debt instrument, maturity date Apr. 25, 2013
ProShares Ultra Australian Dollar [Member] | U.S. Treasury Bills 0.070% Due 06/27/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.07%
Debt instrument, maturity date Jun. 27, 2013
ProShares Ultra Euro [Member]
  
Schedule of Investments [Line Items]  
Short-term U.S. government and agency obligations percentage of shareholders' equity 98.00%
Total short-term U.S. government and agency obligations, cost 4,478,870
ProShares Ultra Euro [Member] | U.S. Treasury Bills 0.105% Due 05/16/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.105%
Debt instrument, maturity date May 16, 2013
ProShares Ultra Euro [Member] | U.S. Treasury Bills 0.056% Due 04/18/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.056% [3]
Debt instrument, maturity date Apr. 18, 2013
ProShares Ultra Euro [Member] | U.S. Treasury Bills 0.058% Due 04/25/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.058% [3]
Debt instrument, maturity date Apr. 25, 2013
ProShares Ultra Yen [Member]
  
Schedule of Investments [Line Items]  
Short-term U.S. government and agency obligations percentage of shareholders' equity 99.00%
Total short-term U.S. government and agency obligations, cost 3,534,876
ProShares Ultra Yen [Member] | U.S. Treasury Bills 0.105% Due 05/16/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.105%
Debt instrument, maturity date May 16, 2013
ProShares Ultra Yen [Member] | U.S. Treasury Bills 0.066% Due 04/18/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.066% [3]
Debt instrument, maturity date Apr. 18, 2013
ProShares VIX Short-Term Futures ETF [Member]
  
Schedule of Investments [Line Items]  
Short-term U.S. government and agency obligations percentage of shareholders' equity 70.00%
Total short-term U.S. government and agency obligations, cost 152,933,255
ProShares VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.050% Due 04/25/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.05%
Debt instrument, maturity date Apr. 25, 2013
ProShares VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.103% Due 04/18/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.103%
Debt instrument, maturity date Apr. 18, 2013
ProShares VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.103% Due 05/16/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.103%
Debt instrument, maturity date May 16, 2013
ProShares VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.070% Due 06/27/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.07%
Debt instrument, maturity date Jun. 27, 2013
ProShares VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.058% Due 04/11/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.058%
Debt instrument, maturity date Apr. 11, 2013
ProShares VIX Mid-Term Futures ETF [Member]
  
Schedule of Investments [Line Items]  
Short-term U.S. government and agency obligations percentage of shareholders' equity 73.00%
Total short-term U.S. government and agency obligations, cost 49,700,662
ProShares VIX Mid-Term Futures ETF [Member] | U.S. Treasury Bills 0.103% Due 05/16/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.103%
Debt instrument, maturity date May 16, 2013
ProShares VIX Mid-Term Futures ETF [Member] | U.S. Treasury Bills 0.078% Due 06/27/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.078%
Debt instrument, maturity date Jun. 27, 2013
ProShares VIX Mid-Term Futures ETF [Member] | U.S. Treasury Bills 0.068% Due 04/18/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.068%
Debt instrument, maturity date Apr. 18, 2013
ProShares VIX Mid-Term Futures ETF [Member] | U.S. Treasury Bills 0.051% Due 04/25/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.051%
Debt instrument, maturity date Apr. 25, 2013
ProShares Ultra VIX Short-Term Futures ETF [Member]
  
Schedule of Investments [Line Items]  
Short-term U.S. government and agency obligations percentage of shareholders' equity 34.00%
Total short-term U.S. government and agency obligations, cost 118,784,627
ProShares Ultra VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.101% Due 05/16/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.101%
Debt instrument, maturity date May 16, 2013
ProShares Ultra VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.103% Due 04/18/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.103%
Debt instrument, maturity date Apr. 18, 2013
ProShares Ultra VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.056% Due 04/11/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.056%
Debt instrument, maturity date Apr. 11, 2013
ProShares Ultra VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.052% Due 04/25/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.052%
Debt instrument, maturity date Apr. 25, 2013
ProShares Ultra VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.069% Due 06/27/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.069%
Debt instrument, maturity date Jun. 27, 2013
ProShares Short VIX Short-Term Futures ETF [Member]
  
Schedule of Investments [Line Items]  
Short-term U.S. government and agency obligations percentage of shareholders' equity 66.00%
Total short-term U.S. government and agency obligations, cost $ 45,829,953
ProShares Short VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.072% due 06/27/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.072%
Debt instrument, maturity date Jun. 27, 2013
ProShares Short VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.103% Due 04/18/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.103%
Debt instrument, maturity date Apr. 18, 2013
ProShares Short VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.108% Due 04/25/13 [Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.108%
Debt instrument, maturity date Apr. 25, 2013
ProShares Short VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.096% Due 05/16/13[Member]
  
Schedule of Investments [Line Items]  
Interest rate 0.096%
Debt instrument, maturity date May 16, 2013
[1] All or partial amount pledged as collateral for swap agreements.
[2] All or partial amount pledged as collateral for forward agreements.
[3] All or partial amount pledged as collateral for foreign currency forward contracts.