v2.4.0.6
Financial Highlights - Per Share Operating Performance (Detail) (USD $)
 3 Months Ended
Mar. 31, 2013
Mar. 31, 2012
ProShares UltraShort DJ-UBS Commodity [Member]
    
Financial Highlights [Line Items]    
Net asset value, beginning balance $ 54.10 $ 56.9207
Net investment income (loss) $ (0.1143) $ (0.1219)
Net realized and unrealized gain (loss) $ 1.1149 $ (1.7902)
Change in net asset value from operations $ 1.0006 $ (1.9121)
Net asset value, ending balance $ 55.10 $ 55.0086
Market value per share, beginning balance $ 51.64 [1] $ 56.19 [1]
Market value per share, ending balance $ 51.14 [1] $ 54.71 [1]
Total Return, at net asset value 1.80% [2] (3.40%) [3]
Total Return, at market value (1.00%) [2] (2.60%) [3]
Ratios to Average Net Assets    
Expense ratio (0.95%) (0.95%)
Expense ratio, excluding brokerage commissions (0.95%) (0.95%)
Net investment income (loss) (0.86%) (0.92%)
ProShares UltraShort DJ-UBS Crude Oil [Member]
    
Financial Highlights [Line Items]    
Net asset value, beginning balance $ 40.31 $ 38.8151
Net investment income (loss) $ (0.0850) $ (0.0823)
Net realized and unrealized gain (loss) $ (3.7437) $ (3.4880)
Change in net asset value from operations $ (3.8287) $ (3.5703)
Net asset value, ending balance $ 36.48 $ 35.2448
Market value per share, beginning balance $ 40.44 [1] $ 38.69 [1]
Market value per share, ending balance $ 36.62 [1] $ 35.16 [1]
Total Return, at net asset value (9.50%) [2] (9.20%) [3]
Total Return, at market value (9.40%) [2] (9.10%) [3]
Ratios to Average Net Assets    
Expense ratio (0.97%) (0.97%)
Expense ratio, excluding brokerage commissions (0.95%) (0.95%)
Net investment income (loss) (0.90%) (0.94%)
ProShares UltraShort DJ-UBS Natural Gas [Member]
    
Financial Highlights [Line Items]    
Net asset value, beginning balance $ 25.54 $ 23.8053 [4]
Net investment income (loss) $ (0.0641) $ (0.1081) [4]
Net realized and unrealized gain (loss) $ (7.5049) $ 25.2447 [4]
Change in net asset value from operations $ (7.5690) $ 25.1366 [4]
Net asset value, ending balance $ 17.97 $ 48.9419 [4]
Market value per share, beginning balance $ 25.41 [1] $ 23.96 [1],[4]
Market value per share, ending balance $ 18.06 [1] $ 49.35 [1],[4]
Total Return, at net asset value (29.60%) [2] 105.60% [3],[4]
Total Return, at market value (28.90%) [2] 106.00% [3],[4]
Ratios to Average Net Assets    
Expense ratio (1.21%) (1.36%) [4]
Expense ratio, excluding brokerage commissions (0.95%) (0.95%) [4]
Net investment income (loss) (1.15%) (1.34%) [4]
ProShares UltraShort Gold [Member]
    
Financial Highlights [Line Items]    
Net asset value, beginning balance $ 63.87 $ 82.7114 [4]
Net investment income (loss) $ (0.1428) $ (0.1556) [4]
Net realized and unrealized gain (loss) $ 4.1421 $ (14.8151) [4]
Change in net asset value from operations $ 3.9993 $ (14.9707) [4]
Net asset value, ending balance $ 67.87 $ 67.7407 [4]
Market value per share, beginning balance $ 62.60 [1] $ 79.24 [1],[4]
Market value per share, ending balance $ 68.01 [1] $ 67.24 [1],[4]
Total Return, at net asset value 6.30% [2] (18.10%) [3],[4]
Total Return, at market value 8.60% [2] (15.10%) [3],[4]
Ratios to Average Net Assets    
Expense ratio (0.95%) (0.95%) [4]
Expense ratio, excluding brokerage commissions (0.95%) (0.95%) [4]
Net investment income (loss) (0.88%) (0.93%) [4]
ProShares UltraShort Silver [Member]
    
Financial Highlights [Line Items]    
Net asset value, beginning balance $ 51.40 $ 76.6771
Net investment income (loss) $ (0.1068) $ (0.1245)
Net realized and unrealized gain (loss) $ 2.7733 $ (24.1170)
Change in net asset value from operations $ 2.6665 $ (24.2415)
Net asset value, ending balance $ 54.06 $ 52.4356
Market value per share, beginning balance $ 50.07 [1] $ 79.35 [1]
Market value per share, ending balance $ 55.02 [1] $ 52.75 [1]
Total Return, at net asset value 5.20% [2] (31.60%) [3]
Total Return, at market value 9.90% [2] (33.50%) [3]
Ratios to Average Net Assets    
Expense ratio (0.95%) (0.95%)
Expense ratio, excluding brokerage commissions (0.95%) (0.95%)
Net investment income (loss) (0.87%) (0.92%)
ProShares Short Euro [Member]
    
Financial Highlights [Line Items]    
Net asset value, beginning balance $ 37.63  
Net investment income (loss) $ (0.0840)  
Net realized and unrealized gain (loss) $ 1.0874  
Change in net asset value from operations $ 1.0034  
Net asset value, ending balance $ 38.63  
Market value per share, beginning balance $ 37.64 [1]  
Market value per share, ending balance $ 38.65 [1]  
Total Return, at net asset value 2.70% [2]  
Total Return, at market value 2.70% [2]  
Ratios to Average Net Assets    
Expense ratio (0.96%)  
Expense ratio, excluding brokerage commissions (0.95%)  
Net investment income (loss) (0.91%)  
ProShares UltraShort Australian Dollar [Member]
    
Financial Highlights [Line Items]    
Net asset value, beginning balance $ 37.81  
Net investment income (loss) $ (0.0867)  
Net realized and unrealized gain (loss) $ (0.8315)  
Change in net asset value from operations $ (0.9182)  
Net asset value, ending balance $ 36.89  
Market value per share, beginning balance $ 37.74 [1]  
Market value per share, ending balance $ 36.41 [1]  
Total Return, at net asset value (2.40%) [2]  
Total Return, at market value (3.50%) [2]  
Ratios to Average Net Assets    
Expense ratio (0.99%)  
Expense ratio, excluding brokerage commissions (0.95%)  
Net investment income (loss) (0.94%)  
ProShares UltraShort Euro [Member]
    
Financial Highlights [Line Items]    
Net asset value, beginning balance $ 19.02 $ 20.3357
Net investment income (loss) $ (0.0411) $ (0.0457)
Net realized and unrealized gain (loss) $ 1.0374 $ (1.3187)
Change in net asset value from operations $ 0.9963 $ (1.3644)
Net asset value, ending balance $ 20.01 $ 18.9713
Market value per share, beginning balance $ 19.01 [1] $ 20.35 [1]
Market value per share, ending balance $ 20.00 [1] $ 18.97 [1]
Total Return, at net asset value 5.20% [2] (6.70%) [3]
Total Return, at market value 5.20% [2] (6.80%) [3]
Ratios to Average Net Assets    
Expense ratio (0.95%) (0.95%)
Expense ratio, excluding brokerage commissions (0.95%) (0.95%)
Net investment income (loss) (0.88%) (0.93%)
ProShares UltraShort Yen [Member]
    
Financial Highlights [Line Items]    
Net asset value, beginning balance $ 50.76 $ 40.9557
Net investment income (loss) $ (0.1244) $ (0.0990)
Net realized and unrealized gain (loss) $ 8.3770 $ 6.1883
Change in net asset value from operations $ 8.2526 $ 6.0893
Net asset value, ending balance $ 59.01 $ 47.0450
Market value per share, beginning balance $ 50.77 [1] $ 40.95 [1]
Market value per share, ending balance $ 59.00 [1] $ 47.05 [1]
Total Return, at net asset value 16.30% [2] 14.90% [3]
Total Return, at market value 16.20% [2] 14.90% [3]
Ratios to Average Net Assets    
Expense ratio (0.95%) (0.95%)
Expense ratio, excluding brokerage commissions (0.95%) (0.95%)
Net investment income (loss) (0.88%) (0.92%)
ProShares Ultra DJ-UBS Commodity [Member]
    
Financial Highlights [Line Items]    
Net asset value, beginning balance $ 24.39 $ 25.8805
Net investment income (loss) $ (0.0535) $ (0.0629)
Net realized and unrealized gain (loss) $ (0.7240) $ 0.2837
Change in net asset value from operations $ (0.7775) $ 0.2208
Net asset value, ending balance $ 23.61 $ 26.1013
Market value per share, beginning balance $ 23.93 [1] $ 25.64 [1]
Market value per share, ending balance $ 23.92 [1] $ 25.90 [1]
Total Return, at net asset value (3.20%) [2] 0.90% [3]
Total Return, at market value 0.00% [2] 1.00% [3]
Ratios to Average Net Assets    
Expense ratio (0.95%) (0.95%)
Expense ratio, excluding brokerage commissions (0.95%) (0.95%)
Net investment income (loss) (0.89%) (0.93%)
ProShares Ultra DJ-UBS Crude Oil [Member]
    
Financial Highlights [Line Items]    
Net asset value, beginning balance $ 29.39 $ 40.8828
Net investment income (loss) $ (0.0674) $ (0.1023)
Net realized and unrealized gain (loss) $ 2.3426 $ 2.0318
Change in net asset value from operations $ 2.2752 $ 1.9295
Net asset value, ending balance $ 31.67 $ 42.8123
Market value per share, beginning balance $ 29.32 [1] $ 40.94 [1]
Market value per share, ending balance $ 31.56 [1] $ 42.91 [1]
Total Return, at net asset value 7.70% [2] 4.70% [3]
Total Return, at market value 7.60% [2] 4.80% [3]
Ratios to Average Net Assets    
Expense ratio (0.97%) (0.96%)
Expense ratio, excluding brokerage commissions (0.95%) (0.95%)
Net investment income (loss) (0.90%) (0.94%)
ProShares Ultra DJ-UBS Natural Gas [Member]
    
Financial Highlights [Line Items]    
Net asset value, beginning balance $ 39.05 $ 101.9786 [4]
Net investment income (loss) $ (0.1040) $ (0.1657) [4]
Net realized and unrealized gain (loss) $ 11.3070 $ (64.1194) [4]
Change in net asset value from operations $ 11.2030 $ (64.2851) [4]
Net asset value, ending balance $ 50.25 $ 37.6935 [4]
Market value per share, beginning balance $ 39.24 [1] $ 101.35 [1],[4]
Market value per share, ending balance $ 49.95 [1] $ 37.40 [1],[4]
Total Return, at net asset value 28.70% [2] (63.00%) [3],[4]
Total Return, at market value 27.30% [2] (63.10%) [3],[4]
Ratios to Average Net Assets    
Expense ratio (1.13%) (1.23%) [4]
Expense ratio, excluding brokerage commissions (0.95%) (0.95%) [4]
Net investment income (loss) (1.06%) (1.20%) [4]
ProShares Ultra Gold [Member]
    
Financial Highlights [Line Items]    
Net asset value, beginning balance $ 83.76 $ 75.9066
Net investment income (loss) $ (0.1744) $ (0.2085)
Net realized and unrealized gain (loss) $ (6.4032) $ 12.0919
Change in net asset value from operations $ (6.5776) $ 11.8834
Net asset value, ending balance $ 77.19 $ 87.7900
Market value per share, beginning balance $ 85.34 [1] $ 79.01 [1]
Market value per share, ending balance $ 77.01 [1] $ 88.40 [1]
Total Return, at net asset value (7.90%) [2] 15.70% [3]
Total Return, at market value (9.80%) [2] 11.90% [3]
Ratios to Average Net Assets    
Expense ratio (0.95%) (0.95%)
Expense ratio, excluding brokerage commissions (0.95%) (0.95%)
Net investment income (loss) (0.88%) (0.92%)
ProShares Ultra Silver [Member]
    
Financial Highlights [Line Items]    
Net asset value, beginning balance $ 42.97 $ 43.1903
Net investment income (loss) $ (0.0911) $ (0.1297)
Net realized and unrealized gain (loss) $ (4.4031) $ 11.8333
Change in net asset value from operations $ (4.4942) $ 11.7036
Net asset value, ending balance $ 38.48 $ 54.8939
Market value per share, beginning balance $ 44.10 [1] $ 41.65 [1]
Market value per share, ending balance $ 37.75 [1] $ 54.46 [1]
Total Return, at net asset value (10.50%) [2] 27.10% [3]
Total Return, at market value (14.40%) [2] 30.80% [3]
Ratios to Average Net Assets    
Expense ratio (0.95%) (0.95%)
Expense ratio, excluding brokerage commissions (0.95%) (0.95%)
Net investment income (loss) (0.87%) (0.92%)
ProShares Ultra Australian Dollar [Member]
    
Financial Highlights [Line Items]    
Net asset value, beginning balance $ 41.50  
Net investment income (loss) $ (0.0949)  
Net realized and unrealized gain (loss) $ 0.7443  
Change in net asset value from operations $ 0.6494  
Net asset value, ending balance $ 42.15  
Market value per share, beginning balance $ 41.45 [1]  
Market value per share, ending balance $ 42.55 [1]  
Total Return, at net asset value 1.60% [2]  
Total Return, at market value 2.70% [2]  
Ratios to Average Net Assets    
Expense ratio (0.99%)  
Expense ratio, excluding brokerage commissions (0.95%)  
Net investment income (loss) (0.92%)  
ProShares Ultra Euro [Member]
    
Financial Highlights [Line Items]    
Net asset value, beginning balance $ 24.35 $ 23.8860
Net investment income (loss) $ (0.0536) $ (0.0565)
Net realized and unrealized gain (loss) $ (1.4326) $ 1.4163
Change in net asset value from operations $ (1.4862) $ 1.3598
Net asset value, ending balance $ 22.86 $ 25.2458
Market value per share, beginning balance $ 24.32 [1] $ 23.87 [1]
Market value per share, ending balance $ 22.92 [1] $ 25.21 [1]
Total Return, at net asset value (6.10%) [2] 5.70% [3]
Total Return, at market value (5.80%) [2] 5.60% [3]
Ratios to Average Net Assets    
Expense ratio (0.95%) (0.95%)
Expense ratio, excluding brokerage commissions (0.95%) (0.95%)
Net investment income (loss) (0.89%) (0.93%)
ProShares Ultra Yen [Member]
    
Financial Highlights [Line Items]    
Net asset value, beginning balance $ 28.18 $ 36.4704
Net investment income (loss) $ (0.0537) $ (0.0787)
Net realized and unrealized gain (loss) $ (4.3565) $ (5.0241)
Change in net asset value from operations $ (4.4102) $ (5.1028)
Net asset value, ending balance $ 23.77 $ 31.3676
Market value per share, beginning balance $ 28.28 [1] $ 36.50 [1]
Market value per share, ending balance $ 23.69 [1] $ 31.36 [1]
Total Return, at net asset value (15.60%) [2] (14.00%) [3]
Total Return, at market value (16.20%) [2] (14.10%) [3]
Ratios to Average Net Assets    
Expense ratio (0.95%) (0.95%)
Expense ratio, excluding brokerage commissions (0.95%) (0.95%)
Net investment income (loss) (0.88%) (0.92%)
ProShares VIX Short-Term Futures ETF [Member]
    
Financial Highlights [Line Items]    
Net asset value, beginning balance $ 16.79 $ 76.3738
Net investment income (loss) $ (0.0240) $ (0.0979)
Net realized and unrealized gain (loss) $ (5.9388) $ (40.7796)
Change in net asset value from operations $ (5.9628) $ (40.8775)
Net asset value, ending balance $ 10.82 $ 35.4963
Market value per share, beginning balance $ 17.01 [1] $ 75.74 [1]
Market value per share, ending balance $ 10.90 [1] $ 35.77 [1]
Total Return, at net asset value (35.50%) [2] (53.50%) [3]
Total Return, at market value (35.90%) [2] (52.80%) [3]
Ratios to Average Net Assets    
Expense ratio (0.85%) (0.85%)
Expense ratio, excluding brokerage commissions (0.85%) (0.85%)
Net investment income (loss) (0.79%) (0.81%)
ProShares VIX Mid-Term Futures ETF [Member]
    
Financial Highlights [Line Items]    
Net asset value, beginning balance $ 34.70 $ 74.1396
Net investment income (loss) $ (0.0539) $ (0.1356)
Net realized and unrealized gain (loss) $ (8.2105) $ (18.0538)
Change in net asset value from operations $ (8.2644) $ (18.1894)
Net asset value, ending balance $ 26.44 $ 55.9502
Market value per share, beginning balance $ 34.22 [1] $ 74.13 [1]
Market value per share, ending balance $ 26.43 [1] $ 56.74 [1]
Total Return, at net asset value (23.80%) [2] (24.50%) [3]
Total Return, at market value (22.80%) [2] (23.50%) [3]
Ratios to Average Net Assets    
Expense ratio (0.85%) (0.85%)
Expense ratio, excluding brokerage commissions (0.85%) (0.85%)
Net investment income (loss) (0.79%) (0.83%)
ProShares Ultra VIX Short-Term Futures ETF [Member]
    
Financial Highlights [Line Items]    
Net asset value, beginning balance $ 20.13 $ 741.0464 [4]
Net investment income (loss) $ (0.0464) $ (1.2046) [4]
Net realized and unrealized gain (loss) $ (12.5093) $ (596.8653) [4]
Change in net asset value from operations $ (12.5557) $ (598.0699) [4]
Net asset value, ending balance $ 7.58 $ 142.9765 [4]
Market value per share, beginning balance $ 20.90 [1] $ 729.60 [1],[4]
Market value per share, ending balance $ 7.69 [1] $ 145.60 [1],[4]
Total Return, at net asset value (62.40%) [2] (80.70%) [3],[4]
Total Return, at market value (63.20%) [2] (80.00%) [3],[4]
Ratios to Average Net Assets    
Expense ratio (1.94%) (2.02%) [4]
Expense ratio, excluding brokerage commissions (0.95%) (0.95%) [4]
Net investment income (loss) (1.91%) (2.01%) [4]
ProShares Short VIX Short-Term Futures ETF [Member]
    
Financial Highlights [Line Items]    
Net asset value, beginning balance $ 66.13 $ 25.8664 [4]
Net investment income (loss) $ (0.3013) $ (0.1788) [4]
Net realized and unrealized gain (loss) $ 26.3688 $ 23.7982 [4]
Change in net asset value from operations $ 26.0675 $ 23.6194 [4]
Net asset value, ending balance $ 92.20 $ 49.4858 [4]
Market value per share, beginning balance $ 65.45 [1] $ 26.14 [1],[4]
Market value per share, ending balance $ 91.08 [1] $ 49.07 [1],[4]
Total Return, at net asset value 39.40% [2] 91.30% [3],[4]
Total Return, at market value 39.20% [2] 87.70% [3],[4]
Ratios to Average Net Assets    
Expense ratio (1.54%) (2.00%) [4]
Expense ratio, excluding brokerage commissions (0.95%) (0.95%) [4]
Net investment income (loss) (1.47%) (1.97%) [4]
[1] Market values are determined at the close of the New York Stock Exchange, which may be later than when the Funds' net asset value is calculated.
[2] Percentages are not annualized for the period ended March 31, 2013.
[3] Percentages are not annualized for the period ended March 31, 2012.
[4] See Note 1 of these Notes to Financial Statements.