v3.10.0.1
Investments - Offsetting of Financial Assets and Liabilities (Detail) - USD ($)
Jun. 30, 2018
Dec. 31, 2017
ProShares Ultra Bloomberg Crude Oil [Member] | Swap Agreements [Member]    
Derivative [Line Items]    
Gross Amounts of Recognized Assets presented in the Statements of Financial Condition $ 82,428,870 $ 62,238,361
Gross Amounts Offset in the Statements of Financial Condition 0 0
Net Amounts of Assets presented in the Statements of Financial Condition 82,428,870 62,238,361
Gross Amounts Offset in the Statements of Financial Condition 0 0
ProShares Ultra Euro [Member] | Foreign Currency Forward Contracts [Member]    
Derivative [Line Items]    
Gross Amounts of Recognized Assets presented in the Statements of Financial Condition   321,609
Gross Amounts Offset in the Statements of Financial Condition 0 0
Net Amounts of Assets presented in the Statements of Financial Condition   321,609
Gross Amounts of Recognized Liabilities presented in the Statements of Financial Condition 172,054 57,457
Gross Amounts Offset in the Statements of Financial Condition 0 0
Net Amounts of Liabilities presented in the Statements of Financial Condition 172,054 57,457
ProShares Ultra Gold [Member] | Forward Agreements [Member]    
Derivative [Line Items]    
Gross Amounts of Recognized Assets presented in the Statements of Financial Condition   3,646,355
Gross Amounts Offset in the Statements of Financial Condition 0 0
Net Amounts of Assets presented in the Statements of Financial Condition   3,646,355
Gross Amounts of Recognized Liabilities presented in the Statements of Financial Condition 7,152,896  
Gross Amounts Offset in the Statements of Financial Condition 0 0
Net Amounts of Liabilities presented in the Statements of Financial Condition 7,152,896  
ProShares Ultra Silver [Member] | Forward Agreements [Member]    
Derivative [Line Items]    
Gross Amounts of Recognized Assets presented in the Statements of Financial Condition   21,735,334
Gross Amounts Offset in the Statements of Financial Condition 0 0
Net Amounts of Assets presented in the Statements of Financial Condition   21,735,334
Gross Amounts of Recognized Liabilities presented in the Statements of Financial Condition 14,148,711  
Gross Amounts Offset in the Statements of Financial Condition 0 0
Net Amounts of Liabilities presented in the Statements of Financial Condition 14,148,711  
ProShares VIX Short-Term Futures ETF [Member] | Swap Agreements [Member]    
Derivative [Line Items]    
Gross Amounts of Recognized Assets presented in the Statements of Financial Condition 1,302,919  
Gross Amounts Offset in the Statements of Financial Condition 0  
Net Amounts of Assets presented in the Statements of Financial Condition 1,302,919  
Gross Amounts of Recognized Liabilities presented in the Statements of Financial Condition 1,038,439  
Gross Amounts Offset in the Statements of Financial Condition 0  
Net Amounts of Liabilities presented in the Statements of Financial Condition 1,038,439  
ProShares Ultra Yen [Member] | Foreign Currency Forward Contracts [Member]    
Derivative [Line Items]    
Gross Amounts of Recognized Assets presented in the Statements of Financial Condition 311  
Gross Amounts Offset in the Statements of Financial Condition 0 0
Net Amounts of Assets presented in the Statements of Financial Condition 311  
Gross Amounts of Recognized Liabilities presented in the Statements of Financial Condition 24,570 34,824
Gross Amounts Offset in the Statements of Financial Condition 0 0
Net Amounts of Liabilities presented in the Statements of Financial Condition 24,570 34,824
ProShares UltraShort Bloomberg Crude Oil [Member] | Swap Agreements [Member]    
Derivative [Line Items]    
Gross Amounts Offset in the Statements of Financial Condition 0 0
Gross Amounts of Recognized Liabilities presented in the Statements of Financial Condition 33,768,200 30,607,142
Gross Amounts Offset in the Statements of Financial Condition 0 0
Net Amounts of Liabilities presented in the Statements of Financial Condition 33,768,200 30,607,142
ProShares UltraShort Euro [Member] | Foreign Currency Forward Contracts [Member]    
Derivative [Line Items]    
Gross Amounts of Recognized Assets presented in the Statements of Financial Condition 3,399,950 449,302
Gross Amounts Offset in the Statements of Financial Condition 0 0
Net Amounts of Assets presented in the Statements of Financial Condition 3,399,950 449,302
Gross Amounts of Recognized Liabilities presented in the Statements of Financial Condition   6,793,571
Gross Amounts Offset in the Statements of Financial Condition 0 0
Net Amounts of Liabilities presented in the Statements of Financial Condition   6,793,571
ProShares UltraShort Gold [Member] | Forward Agreements [Member]    
Derivative [Line Items]    
Gross Amounts of Recognized Assets presented in the Statements of Financial Condition 2,276,610  
Gross Amounts Offset in the Statements of Financial Condition 0 0
Net Amounts of Assets presented in the Statements of Financial Condition 2,276,610  
Gross Amounts of Recognized Liabilities presented in the Statements of Financial Condition   1,488,259
Gross Amounts Offset in the Statements of Financial Condition 0 0
Net Amounts of Liabilities presented in the Statements of Financial Condition   1,488,259
ProShares UltraShort Silver [Member] | Forward Agreements [Member]    
Derivative [Line Items]    
Gross Amounts of Recognized Assets presented in the Statements of Financial Condition 1,452,785  
Gross Amounts Offset in the Statements of Financial Condition 0 0
Net Amounts of Assets presented in the Statements of Financial Condition 1,452,785  
Gross Amounts of Recognized Liabilities presented in the Statements of Financial Condition   1,716,163
Gross Amounts Offset in the Statements of Financial Condition 0 0
Net Amounts of Liabilities presented in the Statements of Financial Condition   1,716,163
ProShares UltraShort Yen [Member] | Foreign Currency Forward Contracts [Member]    
Derivative [Line Items]    
Gross Amounts of Recognized Assets presented in the Statements of Financial Condition 751,278 1,568,997
Gross Amounts Offset in the Statements of Financial Condition 0 0
Net Amounts of Assets presented in the Statements of Financial Condition 751,278 1,568,997
Gross Amounts of Recognized Liabilities presented in the Statements of Financial Condition 57,960 41,734
Gross Amounts Offset in the Statements of Financial Condition 0 0
Net Amounts of Liabilities presented in the Statements of Financial Condition $ 57,960 $ 41,734