v3.10.0.1
Schedule of Investments - Total Return Swap Agreements (Detail) - USD ($)
 6 Months Ended
Jun. 30, 2018
Dec. 31, 2017
Schedule of Investments [Line Items]    
Total Unrealized Appreciation $ 83,731,789 $ 62,238,361
ProShares Ultra Bloomberg Crude Oil [Member]    
Schedule of Investments [Line Items]    
Unrealized Appreciation (Depreciation) [1] 82,428,870  
Total Unrealized Appreciation 82,428,870 $ 62,238,361
ProShares Ultra VIX Short-Term Futures ETF [Member]    
Schedule of Investments [Line Items]    
Unrealized Appreciation (Depreciation) [2] 264,480  
Total Unrealized Appreciation [2] 1,302,919  
Total Unrealized Depreciation [2] (1,038,439)  
ProShares UltraShort Bloomberg Crude Oil [Member]    
Schedule of Investments [Line Items]    
Unrealized Appreciation (Depreciation) [3] $ (33,768,200)  
Swap Agreement with Citibank, N.A. based on Bloomberg Crude Oil Sub-Index [Member] | ProShares Ultra Bloomberg Crude Oil [Member]    
Schedule of Investments [Line Items]    
Rate Paid (Received) [1],[4] 0.18%  
Termination Date [1] Jul. 06, 2018  
Notional Amount at Value [1],[5] $ 226,255,400  
Unrealized Appreciation (Depreciation) [1] $ 29,027,266  
Swap Agreement with Citibank, N.A. based on Bloomberg Crude Oil Sub-Index [Member] | ProShares UltraShort Bloomberg Crude Oil [Member]    
Schedule of Investments [Line Items]    
Rate Paid (Received) [3],[4] (0.18%)  
Termination Date [3] Jul. 06, 2018  
Notional Amount at Value [3],[5] $ (91,601,590)  
Unrealized Appreciation (Depreciation) [3] $ (11,914,957)  
Swap Agreement with Goldman Sachs International based on Bloomberg Crude Oil Sub-Index [Member] | ProShares Ultra Bloomberg Crude Oil [Member]    
Schedule of Investments [Line Items]    
Rate Paid (Received) [1],[4] 0.25%  
Termination Date [1] Jul. 06, 2018  
Notional Amount at Value [1],[5] $ 189,842,536  
Unrealized Appreciation (Depreciation) [1] $ 21,365,763  
Swap Agreement with Goldman Sachs International based on Bloomberg Crude Oil Sub-Index [Member] | ProShares UltraShort Bloomberg Crude Oil [Member]    
Schedule of Investments [Line Items]    
Rate Paid (Received) [3],[4] (0.25%)  
Termination Date [3] Jul. 06, 2018  
Notional Amount at Value [3],[5] $ (62,787,144)  
Unrealized Appreciation (Depreciation) [3] $ (8,713,478)  
Swap agreement with Royal Bank of Canada International based on Bloomberg Crude Oil Sub- Index [Member] | ProShares Ultra Bloomberg Crude Oil [Member]    
Schedule of Investments [Line Items]    
Rate Paid (Received) [1],[4] 0.23%  
Termination Date [1] Jul. 06, 2018  
Notional Amount at Value [1],[5] $ 21,173,182  
Unrealized Appreciation (Depreciation) [1] $ 1,172,552  
Swap Agreement with Societe Generale based on Bloomberg Crude Oil Sub-Index [Member] | ProShares Ultra Bloomberg Crude Oil [Member]    
Schedule of Investments [Line Items]    
Rate Paid (Received) [1],[4] 0.25%  
Termination Date [1] Jul. 06, 2018  
Notional Amount at Value [1],[5] $ 80,696,770  
Unrealized Appreciation (Depreciation) [1] $ 8,999,126  
Swap Agreement with Societe Generale based on Bloomberg Crude Oil Sub-Index [Member] | ProShares UltraShort Bloomberg Crude Oil [Member]    
Schedule of Investments [Line Items]    
Rate Paid (Received) [3],[4] (0.25%)  
Termination Date [3] Jul. 06, 2018  
Notional Amount at Value [3],[5] $ (32,467,552)  
Unrealized Appreciation (Depreciation) [3] $ (3,627,720)  
Swap Agreement with UBS AG based on Bloomberg Crude Oil Sub-Index [Member] | ProShares Ultra Bloomberg Crude Oil [Member]    
Schedule of Investments [Line Items]    
Rate Paid (Received) [1],[4] 0.25%  
Termination Date [1] Jul. 06, 2018  
Notional Amount at Value [1],[5] $ 197,792,801  
Unrealized Appreciation (Depreciation) [1] $ 21,864,163  
Swap Agreement with UBS AG based on Bloomberg Crude Oil Sub-Index [Member] | ProShares UltraShort Bloomberg Crude Oil [Member]    
Schedule of Investments [Line Items]    
Rate Paid (Received) [3],[4] (0.25%)  
Termination Date [3] Jul. 06, 2018  
Notional Amount at Value [3],[5] $ (67,673,814)  
Unrealized Appreciation (Depreciation) [3] $ (8,567,454)  
Swap Agreement With Deutsche Bank Based On S And P500VIX Short Term Futures Index [Member] | ProShares Ultra VIX Short-Term Futures ETF [Member]    
Schedule of Investments [Line Items]    
Rate Paid (Received) [2],[4] 11.98%  
Termination Date [2] Jul. 20, 2018  
Notional Amount at Value [2],[5] $ 18,250,660  
Unrealized Appreciation (Depreciation) [2] $ 1,302,919  
Swap Agreement With Goldman Sachs Based Oni Path S And P 500 VIX Short Term Futures [Member] | ProShares Ultra VIX Short-Term Futures ETF [Member]    
Schedule of Investments [Line Items]    
Rate Paid (Received) [2],[4] 3.10%  
Termination Date [2] Jul. 25, 2018  
Notional Amount at Value [2],[5] $ 95,963,878  
Unrealized Appreciation (Depreciation) [2] $ (1,038,439)  
Swap Agreement With Royal Bank of Canada NA based on Bloomberg Crude Oil Sub- Index [Member] | ProShares UltraShort Bloomberg Crude Oil [Member]    
Schedule of Investments [Line Items]    
Rate Paid (Received) [3],[4] (0.23%)  
Termination Date [3] Jul. 06, 2018  
Notional Amount at Value [3],[5] $ (25,944,244)  
Unrealized Appreciation (Depreciation) [3] $ (944,591)  
[1] The positions and counterparties herein are as of June 30, 2018. The Funds continually evaluate different counterparties for their transactions and counterparties are subject to change. New counterparties can be added at any time.
[2] The positions and counterparties herein are as of June 30, 2018. The Funds continually evaluate different counterparties for their transactions and counterparties are subject to change. New counterparties can be added at any time.
[3] Total Return Swap Agreements
[4] Reflects the floating financing rate, as of June 30, 2018, on the notional amount of the swap agreement paid to the counterparty or received from the counterparty, excluding any commissions. Total Return Swap Agreements payment is due at termination/maturity.
[5] For swap agreements, a positive amount represents "long" exposure to the benchmark index. A negative amount represents "short" exposure to the benchmark index.