v2.4.0.6
Investments (Financial Assets, Derivative Assets, And Collateral Held By Counterparty) (Detail) (USD $)
Mar. 31, 2013
Dec. 31, 2012
ProShares UltraShort DJ-UBS Commodity [Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition    $ 148,502
Financial Instruments     
Cash Collateral Received     
Net Amount    148,502
ProShares UltraShort DJ-UBS Commodity [Member] | Goldman Sachs International (Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition   104,181
Net Amount   104,181
ProShares UltraShort DJ-UBS Commodity [Member] | UBS AG [Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition   44,321
Net Amount   44,321
ProShares UltraShort DJ-UBS Crude Oil [Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition     
Financial Instruments     
Cash Collateral Received     
Net Amount     
ProShares UltraShort DJ-UBS Natural Gas [Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition 442,358 632,777
Net Amount 442,358 632,777
ProShares UltraShort DJ-UBS Natural Gas [Member] | Goldman Sachs & Co.Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition 442,358 632,777
Net Amount 442,358 632,777
ProShares UltraShort Gold [Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition 2,300 3,729,856
Net Amount 2,300 3,729,856
ProShares UltraShort Gold [Member] | Goldman Sachs & Co.Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition 2,300  
Net Amount 2,300  
ProShares UltraShort Gold [Member] | Deutsche Bank AG [Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition   2,389,236
Net Amount   2,389,236
ProShares UltraShort Gold [Member] | Goldman Sachs International (Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition   452,059
Net Amount   452,059
ProShares UltraShort Gold [Member] | Societe Generale S.A. [Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition   499,264
Net Amount   499,264
ProShares UltraShort Gold [Member] | UBS AG [Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition   389,297
Net Amount   389,297
ProShares UltraShort Silver [Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition 269,491 19,307,685
Net Amount 269,491 19,307,685
ProShares UltraShort Silver [Member] | Goldman Sachs & Co.Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition 2,890  
Net Amount 2,890  
ProShares UltraShort Silver [Member] | Deutsche Bank AG [Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition 55,643 10,786,801
Net Amount 55,643 10,786,801
ProShares UltraShort Silver [Member] | Goldman Sachs International (Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition 63,340 3,141,119
Net Amount 63,340 3,141,119
ProShares UltraShort Silver [Member] | Societe Generale S.A. [Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition 147,618 3,255,649
Net Amount 147,618 3,255,649
ProShares UltraShort Silver [Member] | UBS AG [Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition   2,124,116
Net Amount   2,124,116
ProShares Short Euro [Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition    6,612
Financial Instruments     
Cash Collateral Received     
Net Amount    6,612
ProShares Short Euro [Member] | RBC Capital Markets [Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition   6,612
Net Amount   6,612
ProShares UltraShort Australian Dollar [Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition 21,300  
Net Amount 21,300  
ProShares UltraShort Australian Dollar [Member] | RBC Capital Markets [Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition 21,300  
Net Amount 21,300  
ProShares UltraShort Euro [Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition 15,104,660 251,047
Net Amount 15,104,660 251,047
ProShares UltraShort Euro [Member] | Goldman Sachs International (Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition 7,182,101 251,047
Net Amount 7,182,101 251,047
ProShares UltraShort Euro [Member] | UBS AG [Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition 7,922,559  
Net Amount 7,922,559  
ProShares UltraShort Yen [Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition 2,732,626 38,346,817
Net Amount 2,732,626 38,346,817
ProShares UltraShort Yen [Member] | Goldman Sachs International (Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition 1,222,105 18,518,532
Net Amount 1,222,105 18,518,532
ProShares UltraShort Yen [Member] | UBS AG [Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition 1,510,521 19,828,285
Net Amount 1,510,521 19,828,285
ProShares Ultra DJ-UBS Commodity [Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition 115,047  
Net Amount 115,047  
ProShares Ultra DJ-UBS Commodity [Member] | Goldman Sachs International (Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition 63,644  
Net Amount 63,644  
ProShares Ultra DJ-UBS Commodity [Member] | UBS AG [Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition 51,403  
Net Amount 51,403  
ProShares Ultra DJ-UBS Crude Oil [Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition 27,579,874 36,764,035
Net Amount 27,579,874 36,764,035
ProShares Ultra DJ-UBS Crude Oil [Member] | Goldman Sachs & Co.Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition 2,386,303 3,430,415
Net Amount 2,386,303 3,430,415
ProShares Ultra DJ-UBS Crude Oil [Member] | Goldman Sachs International (Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition 8,318,017 14,334,730
Net Amount 8,318,017 14,334,730
ProShares Ultra DJ-UBS Crude Oil [Member] | Societe Generale S.A. [Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition 4,601,585 8,989,866
Net Amount 4,601,585 8,989,866
ProShares Ultra DJ-UBS Crude Oil [Member] | UBS AG [Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition 12,273,969 10,009,024
Net Amount 12,273,969 10,009,024
ProShares Ultra DJ-UBS Natural Gas [Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition     
Financial Instruments     
Cash Collateral Received     
Net Amount     
ProShares Ultra Gold [Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition 9,222,440 3,980
Net Amount 9,222,440 3,980
ProShares Ultra Gold [Member] | Goldman Sachs & Co.Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition   3,980
Net Amount   3,980
ProShares Ultra Gold [Member] | Deutsche Bank AG [Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition 4,465,287  
Net Amount 4,465,287  
ProShares Ultra Gold [Member] | Goldman Sachs International (Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition 1,574,862  
Net Amount 1,574,862  
ProShares Ultra Gold [Member] | Societe Generale S.A. [Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition 1,671,035  
Net Amount 1,671,035  
ProShares Ultra Gold [Member] | UBS AG [Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition 1,511,256  
Net Amount 1,511,256  
ProShares Ultra Silver [Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition    2,520
Financial Instruments     
Cash Collateral Received     
Net Amount    2,520
ProShares Ultra Silver [Member] | Goldman Sachs & Co.Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition   2,520
Net Amount   2,520
ProShares Ultra Australian Dollar [Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition    12,000
Financial Instruments     
Cash Collateral Received     
Net Amount    12,000
ProShares Ultra Australian Dollar [Member] | RBC Capital Markets [Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition   12,000
Net Amount   12,000
ProShares Ultra Euro [Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition 3,138 89,473
Net Amount 3,138 89,473
ProShares Ultra Euro [Member] | Goldman Sachs International (Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition 737 38,327
Net Amount 737 38,327
ProShares Ultra Euro [Member] | UBS AG [Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition 2,401 51,146
Net Amount 2,401 51,146
ProShares Ultra Yen [Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition    13,523
Financial Instruments     
Cash Collateral Received     
Net Amount    13,523
ProShares Ultra Yen [Member] | Goldman Sachs International (Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition   7,325
Net Amount   7,325
ProShares Ultra Yen [Member] | UBS AG [Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition   6,198
Net Amount   6,198
ProShares VIX Short-Term Futures ETF [Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition     
Financial Instruments     
Cash Collateral Received     
Net Amount     
ProShares VIX Mid-Term Futures ETF [Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition 211,350  
Net Amount 211,350  
ProShares VIX Mid-Term Futures ETF [Member] | RBC Capital Markets [Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition 211,350  
Net Amount 211,350  
ProShares Ultra VIX Short-Term Futures ETF [Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition    301,351
Financial Instruments     
Cash Collateral Received     
Net Amount    301,351
ProShares Ultra VIX Short-Term Futures ETF [Member] | Societe Generale S.A. [Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition   301,351
Net Amount   301,351
ProShares Short VIX Short-Term Futures ETF [Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition 472,022 5,524,721
Net Amount 472,022 5,524,721
ProShares Short VIX Short-Term Futures ETF [Member] | RBC Capital Markets [Member]
   
Derivative [Line Items]    
Net Amounts of Assets Presented in the Statement of Financial Condition 472,022 5,524,721
Net Amount $ 472,022 $ 5,524,721