v2.4.0.8
Investments - Gross Amounts not Offset in the Statement of Financial Condition (Detail) (USD $)
Mar. 31, 2014
Dec. 31, 2013
ProShares UltraShort DJ-UBS Commodity [Member] | Deutsche Bank AG [Member]
   
Derivative [Line Items]    
Amounts of Recognized Assets presented in the Statement of Financial Condition $ 39,020  
Financial Instruments for the Funds /the Counterparties     
Cash Collateral for the Funds / the Counterparties     
Net Amount 39,020  
Amounts of Recognized Liabilities presented in the Statement of Financial Condition   (11,710)
Financial Instruments for the Benefit of /the Counterparties   11,710
Cash Collateral for the Benefit of / the Counterparties     
Net Amount     
ProShares UltraShort DJ-UBS Commodity [Member] | Goldman Sachs International [Member]
   
Derivative [Line Items]    
Amounts of Recognized Assets presented in the Statement of Financial Condition 50,319  
Financial Instruments for the Funds /the Counterparties     
Cash Collateral for the Funds / the Counterparties     
Net Amount 50,319  
Amounts of Recognized Liabilities presented in the Statement of Financial Condition   (12,945)
Financial Instruments for the Benefit of /the Counterparties   12,945
Cash Collateral for the Benefit of / the Counterparties     
Net Amount     
ProShares UltraShort DJ-UBS Commodity [Member] | UBS AG [Member]
   
Derivative [Line Items]    
Amounts of Recognized Assets presented in the Statement of Financial Condition 12,930  
Financial Instruments for the Funds /the Counterparties     
Cash Collateral for the Funds / the Counterparties     
Net Amount 12,930  
Amounts of Recognized Liabilities presented in the Statement of Financial Condition   (3,010)
Financial Instruments for the Benefit of /the Counterparties   3,010
Cash Collateral for the Benefit of / the Counterparties     
Net Amount     
ProShares UltraShort DJ-UBS Crude Oil [Member] | Deutsche Bank AG [Member]
   
Derivative [Line Items]    
Amounts of Recognized Liabilities presented in the Statement of Financial Condition (72,184) (570,114)
Financial Instruments for the Benefit of /the Counterparties 72,184 570,114
Cash Collateral for the Benefit of / the Counterparties      
Net Amount      
ProShares UltraShort DJ-UBS Crude Oil [Member] | Goldman Sachs International [Member]
   
Derivative [Line Items]    
Amounts of Recognized Liabilities presented in the Statement of Financial Condition (543,435) (632,990)
Financial Instruments for the Benefit of /the Counterparties 543,435 632,990
Cash Collateral for the Benefit of / the Counterparties      
Net Amount      
ProShares UltraShort DJ-UBS Crude Oil [Member] | UBS AG [Member]
   
Derivative [Line Items]    
Amounts of Recognized Liabilities presented in the Statement of Financial Condition (148,531) (727,210)
Financial Instruments for the Benefit of /the Counterparties 148,531 727,210
Cash Collateral for the Benefit of / the Counterparties      
Net Amount      
ProShares UltraShort DJ-UBS Crude Oil [Member] | Societe Generale S.A. [Member]
   
Derivative [Line Items]    
Amounts of Recognized Assets presented in the Statement of Financial Condition 71,219  
Financial Instruments for the Funds /the Counterparties (71,219)  
Cash Collateral for the Funds / the Counterparties     
Net Amount     
Amounts of Recognized Liabilities presented in the Statement of Financial Condition   (402,586)
Financial Instruments for the Benefit of /the Counterparties   402,586
Cash Collateral for the Benefit of / the Counterparties     
Net Amount     
ProShares UltraShort DJ-UBS Crude Oil [Member] | Goldman Sachs & Co. [Member]
   
Derivative [Line Items]    
Amounts of Recognized Assets presented in the Statement of Financial Condition 345,825 1,503,943
Financial Instruments for the Funds /the Counterparties      
Cash Collateral for the Funds / the Counterparties      
Net Amount 345,825 1,503,943
ProShares UltraShort DJ-UBS Natural Gas [Member] | Goldman Sachs & Co. [Member]
   
Derivative [Line Items]    
Amounts of Recognized Assets presented in the Statement of Financial Condition 2,752,495 1,520,548
Financial Instruments for the Funds /the Counterparties      
Cash Collateral for the Funds / the Counterparties      
Net Amount 2,752,495 1,520,548
ProShares UltraShort Gold [Member] | Deutsche Bank AG [Member]
   
Derivative [Line Items]    
Amounts of Recognized Assets presented in the Statement of Financial Condition 4,557,728 2,258,281
Financial Instruments for the Funds /the Counterparties      
Cash Collateral for the Funds / the Counterparties (4,200,000) (2,258,281)
Net Amount 357,728   
ProShares UltraShort Gold [Member] | Goldman Sachs International [Member]
   
Derivative [Line Items]    
Amounts of Recognized Assets presented in the Statement of Financial Condition 1,618,593 1,411,290
Financial Instruments for the Funds /the Counterparties (1,508,282) (1,411,290)
Cash Collateral for the Funds / the Counterparties      
Net Amount 110,311   
ProShares UltraShort Gold [Member] | UBS AG [Member]
   
Derivative [Line Items]    
Amounts of Recognized Assets presented in the Statement of Financial Condition 1,528,284 1,298,438
Financial Instruments for the Funds /the Counterparties (1,442,325) (1,298,438)
Cash Collateral for the Funds / the Counterparties      
Net Amount 85,959   
ProShares UltraShort Gold [Member] | Societe Generale S.A. [Member]
   
Derivative [Line Items]    
Amounts of Recognized Assets presented in the Statement of Financial Condition 827,157 665,044
Financial Instruments for the Funds /the Counterparties (827,157) (665,044)
Cash Collateral for the Funds / the Counterparties      
Net Amount      
ProShares UltraShort Gold [Member] | Goldman Sachs & Co. [Member]
   
Derivative [Line Items]    
Amounts of Recognized Assets presented in the Statement of Financial Condition 2,100 300
Financial Instruments for the Funds /the Counterparties      
Cash Collateral for the Funds / the Counterparties      
Net Amount 2,100 300
ProShares UltraShort Silver [Member] | Deutsche Bank AG [Member]
   
Derivative [Line Items]    
Amounts of Recognized Assets presented in the Statement of Financial Condition 3,858,673  
Financial Instruments for the Funds /the Counterparties     
Cash Collateral for the Funds / the Counterparties (3,858,673)  
Net Amount     
Amounts of Recognized Liabilities presented in the Statement of Financial Condition   (445,752)
Financial Instruments for the Benefit of /the Counterparties   445,752
Cash Collateral for the Benefit of / the Counterparties     
Net Amount     
ProShares UltraShort Silver [Member] | Goldman Sachs International [Member]
   
Derivative [Line Items]    
Amounts of Recognized Assets presented in the Statement of Financial Condition 1,401,484  
Financial Instruments for the Funds /the Counterparties (1,401,484)  
Cash Collateral for the Funds / the Counterparties     
Net Amount     
Amounts of Recognized Liabilities presented in the Statement of Financial Condition   (1,257,636)
Financial Instruments for the Benefit of /the Counterparties   1,257,636
Cash Collateral for the Benefit of / the Counterparties     
Net Amount     
ProShares UltraShort Silver [Member] | UBS AG [Member]
   
Derivative [Line Items]    
Amounts of Recognized Assets presented in the Statement of Financial Condition 1,561,440  
Financial Instruments for the Funds /the Counterparties (1,561,440)  
Cash Collateral for the Funds / the Counterparties     
Net Amount     
Amounts of Recognized Liabilities presented in the Statement of Financial Condition   (517,110)
Financial Instruments for the Benefit of /the Counterparties   517,110
Cash Collateral for the Benefit of / the Counterparties     
Net Amount     
ProShares UltraShort Silver [Member] | Societe Generale S.A. [Member]
   
Derivative [Line Items]    
Amounts of Recognized Assets presented in the Statement of Financial Condition 920,983  
Financial Instruments for the Funds /the Counterparties (920,983)  
Cash Collateral for the Funds / the Counterparties     
Net Amount     
Amounts of Recognized Liabilities presented in the Statement of Financial Condition   (7,359)
Financial Instruments for the Benefit of /the Counterparties   7,359
Cash Collateral for the Benefit of / the Counterparties     
Net Amount     
ProShares UltraShort Silver [Member] | Goldman Sachs & Co. [Member]
   
Derivative [Line Items]    
Amounts of Recognized Assets presented in the Statement of Financial Condition   2,450
Financial Instruments for the Funds /the Counterparties     
Cash Collateral for the Funds / the Counterparties     
Net Amount   2,450
Amounts of Recognized Liabilities presented in the Statement of Financial Condition (440)  
Financial Instruments for the Benefit of /the Counterparties     
Cash Collateral for the Benefit of / the Counterparties 440  
Net Amount     
ProShares Short Euro [Member] | RBC Capital Markets [Member]
   
Derivative [Line Items]    
Amounts of Recognized Assets presented in the Statement of Financial Condition   9,100
Financial Instruments for the Funds /the Counterparties     
Cash Collateral for the Funds / the Counterparties     
Net Amount   9,100
Amounts of Recognized Liabilities presented in the Statement of Financial Condition (12,300)  
Financial Instruments for the Benefit of /the Counterparties     
Cash Collateral for the Benefit of / the Counterparties 12,300  
Net Amount     
ProShares UltraShort Australian Dollar [Member] | RBC Capital Markets [Member]
   
Derivative [Line Items]    
Amounts of Recognized Liabilities presented in the Statement of Financial Condition (89,099) (86,166)
Financial Instruments for the Benefit of /the Counterparties      
Cash Collateral for the Benefit of / the Counterparties 89,099 86,166
Net Amount      
ProShares UltraShort Euro [Member] | Goldman Sachs International [Member]
   
Derivative [Line Items]    
Amounts of Recognized Assets presented in the Statement of Financial Condition   64,104
Financial Instruments for the Funds /the Counterparties     
Cash Collateral for the Funds / the Counterparties     
Net Amount   64,104
Amounts of Recognized Liabilities presented in the Statement of Financial Condition (1,698,852) (6,820,802)
Financial Instruments for the Benefit of /the Counterparties 1,698,852 6,820,802
Cash Collateral for the Benefit of / the Counterparties      
Net Amount      
ProShares UltraShort Euro [Member] | UBS AG [Member]
   
Derivative [Line Items]    
Amounts of Recognized Assets presented in the Statement of Financial Condition   87,247
Financial Instruments for the Funds /the Counterparties     
Cash Collateral for the Funds / the Counterparties     
Net Amount   87,247
Amounts of Recognized Liabilities presented in the Statement of Financial Condition (2,025,458) (7,079,056)
Financial Instruments for the Benefit of /the Counterparties 2,025,458 7,079,056
Cash Collateral for the Benefit of / the Counterparties      
Net Amount      
ProShares UltraShort Yen [Member] | Goldman Sachs International [Member]
   
Derivative [Line Items]    
Amounts of Recognized Assets presented in the Statement of Financial Condition 3,209,960 15,716,318
Financial Instruments for the Funds /the Counterparties (739,761) (13,635,426)
Cash Collateral for the Funds / the Counterparties      
Net Amount 2,470,199 2,080,892
Amounts of Recognized Liabilities presented in the Statement of Financial Condition (874,876) (884,849)
Financial Instruments for the Benefit of /the Counterparties 874,876 884,849
Cash Collateral for the Benefit of / the Counterparties      
Net Amount      
ProShares UltraShort Yen [Member] | UBS AG [Member]
   
Derivative [Line Items]    
Amounts of Recognized Assets presented in the Statement of Financial Condition 2,911,574 15,601,250
Financial Instruments for the Funds /the Counterparties (915,232) (14,004,926)
Cash Collateral for the Funds / the Counterparties      
Net Amount 1,996,342 1,596,324
Amounts of Recognized Liabilities presented in the Statement of Financial Condition (400,274) (1,046,035)
Financial Instruments for the Benefit of /the Counterparties 400,274 1,046,035
Cash Collateral for the Benefit of / the Counterparties      
Net Amount      
ProShares Ultra DJ-UBS Commodity [Member] | Deutsche Bank AG [Member]
   
Derivative [Line Items]    
Amounts of Recognized Assets presented in the Statement of Financial Condition   6,454
Financial Instruments for the Funds /the Counterparties     
Cash Collateral for the Funds / the Counterparties     
Net Amount   6,454
Amounts of Recognized Liabilities presented in the Statement of Financial Condition (49,579)  
Financial Instruments for the Benefit of /the Counterparties 49,579  
Cash Collateral for the Benefit of / the Counterparties     
Net Amount     
ProShares Ultra DJ-UBS Commodity [Member] | Goldman Sachs International [Member]
   
Derivative [Line Items]    
Amounts of Recognized Assets presented in the Statement of Financial Condition   4,974
Financial Instruments for the Funds /the Counterparties     
Cash Collateral for the Funds / the Counterparties     
Net Amount   4,974
Amounts of Recognized Liabilities presented in the Statement of Financial Condition (40,052)  
Financial Instruments for the Benefit of /the Counterparties 40,052  
Cash Collateral for the Benefit of / the Counterparties     
Net Amount     
ProShares Ultra DJ-UBS Commodity [Member] | UBS AG [Member]
   
Derivative [Line Items]    
Amounts of Recognized Assets presented in the Statement of Financial Condition   3,650
Financial Instruments for the Funds /the Counterparties     
Cash Collateral for the Funds / the Counterparties     
Net Amount   3,650
Amounts of Recognized Liabilities presented in the Statement of Financial Condition (24,497)  
Financial Instruments for the Benefit of /the Counterparties 24,497  
Cash Collateral for the Benefit of / the Counterparties     
Net Amount     
ProShares Ultra DJ-UBS Crude Oil [Member] | Deutsche Bank AG [Member]
   
Derivative [Line Items]    
Amounts of Recognized Assets presented in the Statement of Financial Condition 136,953 622,117
Financial Instruments for the Funds /the Counterparties      
Cash Collateral for the Funds / the Counterparties    (622,117)
Net Amount 136,953   
ProShares Ultra DJ-UBS Crude Oil [Member] | Goldman Sachs International [Member]
   
Derivative [Line Items]    
Amounts of Recognized Assets presented in the Statement of Financial Condition 289,177 576,723
Financial Instruments for the Funds /the Counterparties (289,177) (576,723)
Cash Collateral for the Funds / the Counterparties      
Net Amount      
ProShares Ultra DJ-UBS Crude Oil [Member] | UBS AG [Member]
   
Derivative [Line Items]    
Amounts of Recognized Assets presented in the Statement of Financial Condition 444,513 483,237
Financial Instruments for the Funds /the Counterparties (342,234) (483,237)
Cash Collateral for the Funds / the Counterparties      
Net Amount 102,279   
ProShares Ultra DJ-UBS Crude Oil [Member] | Societe Generale S.A. [Member]
   
Derivative [Line Items]    
Amounts of Recognized Assets presented in the Statement of Financial Condition 89,308 275,816
Financial Instruments for the Funds /the Counterparties (89,308) (275,816)
Cash Collateral for the Funds / the Counterparties      
Net Amount      
ProShares Ultra DJ-UBS Crude Oil [Member] | Goldman Sachs & Co. [Member]
   
Derivative [Line Items]    
Amounts of Recognized Assets presented in the Statement of Financial Condition 121,862  
Financial Instruments for the Funds /the Counterparties     
Cash Collateral for the Funds / the Counterparties     
Net Amount 121,862  
Amounts of Recognized Liabilities presented in the Statement of Financial Condition   (997,210)
Financial Instruments for the Benefit of /the Counterparties     
Cash Collateral for the Benefit of / the Counterparties   997,210
Net Amount     
ProShares Ultra DJ-UBS Natural Gas [Member] | Goldman Sachs & Co. [Member]
   
Derivative [Line Items]    
Amounts of Recognized Liabilities presented in the Statement of Financial Condition (1,050,517) (5,628,532)
Financial Instruments for the Benefit of /the Counterparties      
Cash Collateral for the Benefit of / the Counterparties 1,050,517 4,630,277
Net Amount    (998,255)
ProShares Ultra Gold [Member] | Deutsche Bank AG [Member]
   
Derivative [Line Items]    
Amounts of Recognized Liabilities presented in the Statement of Financial Condition (6,314,073) (3,543,937)
Financial Instruments for the Benefit of /the Counterparties 6,314,073 3,543,937
Cash Collateral for the Benefit of / the Counterparties      
Net Amount      
ProShares Ultra Gold [Member] | Goldman Sachs International [Member]
   
Derivative [Line Items]    
Amounts of Recognized Liabilities presented in the Statement of Financial Condition (2,340,133) (1,327,335)
Financial Instruments for the Benefit of /the Counterparties 2,340,133 1,327,335
Cash Collateral for the Benefit of / the Counterparties      
Net Amount      
ProShares Ultra Gold [Member] | UBS AG [Member]
   
Derivative [Line Items]    
Amounts of Recognized Liabilities presented in the Statement of Financial Condition (2,227,725) (1,156,664)
Financial Instruments for the Benefit of /the Counterparties 2,227,725 1,156,664
Cash Collateral for the Benefit of / the Counterparties      
Net Amount      
ProShares Ultra Gold [Member] | Societe Generale S.A. [Member]
   
Derivative [Line Items]    
Amounts of Recognized Liabilities presented in the Statement of Financial Condition (1,128,141) (785,038)
Financial Instruments for the Benefit of /the Counterparties 1,128,141 785,038
Cash Collateral for the Benefit of / the Counterparties      
Net Amount      
ProShares Ultra Gold [Member] | Goldman Sachs & Co. [Member]
   
Derivative [Line Items]    
Amounts of Recognized Liabilities presented in the Statement of Financial Condition (2,200) (300)
Financial Instruments for the Benefit of /the Counterparties      
Cash Collateral for the Benefit of / the Counterparties 2,200 300
Net Amount      
ProShares Ultra Silver [Member] | Deutsche Bank AG [Member]
   
Derivative [Line Items]    
Amounts of Recognized Liabilities presented in the Statement of Financial Condition (30,257,024) (350,663)
Financial Instruments for the Benefit of /the Counterparties 30,257,024 350,663
Cash Collateral for the Benefit of / the Counterparties      
Net Amount      
ProShares Ultra Silver [Member] | Goldman Sachs International [Member]
   
Derivative [Line Items]    
Amounts of Recognized Liabilities presented in the Statement of Financial Condition (11,457,887) (1,345,433)
Financial Instruments for the Benefit of /the Counterparties 11,457,887 1,345,433
Cash Collateral for the Benefit of / the Counterparties      
Net Amount      
ProShares Ultra Silver [Member] | UBS AG [Member]
   
Derivative [Line Items]    
Amounts of Recognized Liabilities presented in the Statement of Financial Condition (11,397,997) (768,203)
Financial Instruments for the Benefit of /the Counterparties 11,397,997 768,203
Cash Collateral for the Benefit of / the Counterparties      
Net Amount      
ProShares Ultra Silver [Member] | Societe Generale S.A. [Member]
   
Derivative [Line Items]    
Amounts of Recognized Liabilities presented in the Statement of Financial Condition (5,025,453) (28,581)
Financial Instruments for the Benefit of /the Counterparties 5,025,453 28,581
Cash Collateral for the Benefit of / the Counterparties      
Net Amount      
ProShares Ultra Silver [Member] | Goldman Sachs & Co. [Member]
   
Derivative [Line Items]    
Amounts of Recognized Liabilities presented in the Statement of Financial Condition (380) (2,450)
Financial Instruments for the Benefit of /the Counterparties      
Cash Collateral for the Benefit of / the Counterparties 380 2,450
Net Amount      
ProShares Ultra Australian Dollar [Member] | RBC Capital Markets [Member]
   
Derivative [Line Items]    
Amounts of Recognized Assets presented in the Statement of Financial Condition 13,503 10,650
Financial Instruments for the Funds /the Counterparties      
Cash Collateral for the Funds / the Counterparties      
Net Amount 13,503 10,650
ProShares Ultra Euro [Member] | Goldman Sachs International [Member]
   
Derivative [Line Items]    
Amounts of Recognized Assets presented in the Statement of Financial Condition 4,438 56,991
Financial Instruments for the Funds /the Counterparties      
Cash Collateral for the Funds / the Counterparties      
Net Amount 4,438 56,991
Amounts of Recognized Liabilities presented in the Statement of Financial Condition   (19,770)
Financial Instruments for the Benefit of /the Counterparties   19,770
Cash Collateral for the Benefit of / the Counterparties     
Net Amount     
ProShares Ultra Euro [Member] | UBS AG [Member]
   
Derivative [Line Items]    
Amounts of Recognized Assets presented in the Statement of Financial Condition 16,581 63,917
Financial Instruments for the Funds /the Counterparties      
Cash Collateral for the Funds / the Counterparties      
Net Amount 16,581 63,917
Amounts of Recognized Liabilities presented in the Statement of Financial Condition (35) (176)
Financial Instruments for the Benefit of /the Counterparties 35 176
Cash Collateral for the Benefit of / the Counterparties      
Net Amount      
ProShares Ultra Yen [Member] | Goldman Sachs International [Member]
   
Derivative [Line Items]    
Amounts of Recognized Assets presented in the Statement of Financial Condition 929 2,462
Financial Instruments for the Funds /the Counterparties      
Cash Collateral for the Funds / the Counterparties      
Net Amount 929 2,462
Amounts of Recognized Liabilities presented in the Statement of Financial Condition (20,852) (78,309)
Financial Instruments for the Benefit of /the Counterparties 20,852 78,309
Cash Collateral for the Benefit of / the Counterparties      
Net Amount      
ProShares Ultra Yen [Member] | UBS AG [Member]
   
Derivative [Line Items]    
Amounts of Recognized Assets presented in the Statement of Financial Condition 75 1,590
Financial Instruments for the Funds /the Counterparties      
Cash Collateral for the Funds / the Counterparties      
Net Amount 75 1,590
Amounts of Recognized Liabilities presented in the Statement of Financial Condition (21,381) (85,052)
Financial Instruments for the Benefit of /the Counterparties 21,381 85,052
Cash Collateral for the Benefit of / the Counterparties      
Net Amount      
ProShares VIX Short-Term Futures ETF [Member] | RBC Capital Markets [Member]
   
Derivative [Line Items]    
Amounts of Recognized Assets presented in the Statement of Financial Condition   3,179,017
Financial Instruments for the Funds /the Counterparties     
Cash Collateral for the Funds / the Counterparties     
Net Amount   3,179,017
Amounts of Recognized Liabilities presented in the Statement of Financial Condition (3,088,786)  
Financial Instruments for the Benefit of /the Counterparties     
Cash Collateral for the Benefit of / the Counterparties 3,088,786  
Net Amount     
ProShares VIX Mid-Term Futures ETF [Member] | RBC Capital Markets [Member]
   
Derivative [Line Items]    
Amounts of Recognized Assets presented in the Statement of Financial Condition   100,734
Financial Instruments for the Funds /the Counterparties     
Cash Collateral for the Funds / the Counterparties     
Net Amount   100,734
Amounts of Recognized Liabilities presented in the Statement of Financial Condition (1,009,664)  
Financial Instruments for the Benefit of /the Counterparties     
Cash Collateral for the Benefit of / the Counterparties 1,009,664  
Net Amount     
ProShares Ultra VIX Short-Term Futures ETF [Member] | RBC Capital Markets [Member]
   
Derivative [Line Items]    
Amounts of Recognized Liabilities presented in the Statement of Financial Condition (24,525,510) (3,356,803)
Financial Instruments for the Benefit of /the Counterparties      
Cash Collateral for the Benefit of / the Counterparties 24,525,510 3,356,803
Net Amount      
ProShares Short VIX Short-Term Futures ETF [Member] | RBC Capital Markets [Member]
   
Derivative [Line Items]    
Amounts of Recognized Assets presented in the Statement of Financial Condition 6,484,331 603,833
Financial Instruments for the Funds /the Counterparties      
Cash Collateral for the Funds / the Counterparties      
Net Amount $ 6,484,331 $ 603,833