v3.10.0.1
Significant Accounting Policies - Valuation of Investments using Fair Value Hierarchy (Detail) - USD ($)
Jun. 30, 2018
Dec. 31, 2017
ProShares Short Euro [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure $ 5,774,277 $ 6,829,947
ProShares Short VIX Short-Term Futures ETF [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 70,467,597 511,952,093
ProShares Ultra Bloomberg Crude Oil [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 465,673,601 533,700,242
ProShares Ultra Bloomberg Natural Gas [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 17,841,803 58,187,166
ProShares Ultra Euro [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 3,116,986 7,260,387
ProShares Ultra Gold [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 80,679,374 92,536,679
ProShares Ultra Silver [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 198,352,203 257,318,650
ProShares Ultra VIX Short-Term Futures ETF [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 83,060,057 253,067,012
ProShares Ultra Yen [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 973,825 1,963,109
Proshares Ultra Pro 3x Crude Oil ETF [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 9,905,484 1,417,998
ProShares UltraPro 3X Short Crude Oil ETF [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure (5,442,454) (2,988,155)
ProShares UltraShort Australian Dollar [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 5,380,099 11,090,684
ProShares UltraShort Bloomberg Crude Oil [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 132,722,064 219,077,033
ProShares UltraShort Bloomberg Natural Gas [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 4,099,474 2,902,702
ProShares UltraShort Euro [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 145,052,935 198,425,897
ProShares UltraShort Gold [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 25,246,424 30,484,181
ProShares UltraShort Silver [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 21,433,180 16,632,048
ProShares UltraShort Yen [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 81,530,454 133,361,615
ProShares VIX Mid-Term Futures ETF [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure (378,240) 18,778,235
ProShares VIX Short-Term Futures ETF [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 31,425,513 130,083,727
Total Trust [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 1,376,914,656 2,482,081,250
Level I - Quoted Prices [Member] | ProShares Short Euro [Member] | Short-Term U.S. Government and Agencies [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 5,687,064 6,996,235
Level I - Quoted Prices [Member] | ProShares Short Euro [Member] | Futures Contracts [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 87,213 (166,288)
Level I - Quoted Prices [Member] | ProShares Short VIX Short-Term Futures ETF [Member] | Short-Term U.S. Government and Agencies [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 92,995,995 494,910,644
Level I - Quoted Prices [Member] | ProShares Short VIX Short-Term Futures ETF [Member] | Futures Contracts [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure (22,528,398) 17,041,449
Level I - Quoted Prices [Member] | ProShares Ultra Bloomberg Crude Oil [Member] | Short-Term U.S. Government and Agencies [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 365,955,628 459,515,902
Level I - Quoted Prices [Member] | ProShares Ultra Bloomberg Crude Oil [Member] | Futures Contracts [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 17,289,103 11,945,979
Level I - Quoted Prices [Member] | ProShares Ultra Bloomberg Natural Gas [Member] | Short-Term U.S. Government and Agencies [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 17,960,426 50,961,356
Level I - Quoted Prices [Member] | ProShares Ultra Bloomberg Natural Gas [Member] | Futures Contracts [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure (118,623) 7,225,810
Level I - Quoted Prices [Member] | ProShares Ultra Euro [Member] | Short-Term U.S. Government and Agencies [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 3,289,040 6,996,235
Level I - Quoted Prices [Member] | ProShares Ultra Gold [Member] | Short-Term U.S. Government and Agencies [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 87,847,390 88,884,844
Level I - Quoted Prices [Member] | ProShares Ultra Gold [Member] | Futures Contracts [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure (15,120) 5,480
Level I - Quoted Prices [Member] | ProShares Ultra Silver [Member] | Short-Term U.S. Government and Agencies [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 212,508,884 235,581,716
Level I - Quoted Prices [Member] | ProShares Ultra Silver [Member] | Futures Contracts [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure (7,970) 1,600
Level I - Quoted Prices [Member] | ProShares Ultra VIX Short-Term Futures ETF [Member] | Short-Term U.S. Government and Agencies [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 42,998,148 287,533,132
Level I - Quoted Prices [Member] | ProShares Ultra VIX Short-Term Futures ETF [Member] | Futures Contracts [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 39,797,429 (34,466,120)
Level I - Quoted Prices [Member] | ProShares Ultra Yen [Member] | Short-Term U.S. Government and Agencies [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 998,084 1,997,933
Level I - Quoted Prices [Member] | Proshares Ultra Pro 3x Crude Oil ETF [Member] | Futures Contracts [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 9,905,484 1,417,998
Level I - Quoted Prices [Member] | ProShares UltraPro 3X Short Crude Oil ETF [Member] | Futures Contracts [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure (5,442,454) (2,988,155)
Level I - Quoted Prices [Member] | ProShares UltraShort Australian Dollar [Member] | Short-Term U.S. Government and Agencies [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 4,988,329 11,983,904
Level I - Quoted Prices [Member] | ProShares UltraShort Australian Dollar [Member] | Futures Contracts [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 391,770 (893,220)
Level I - Quoted Prices [Member] | ProShares UltraShort Bloomberg Crude Oil [Member] | Short-Term U.S. Government and Agencies [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 173,652,213 253,646,823
Level I - Quoted Prices [Member] | ProShares UltraShort Bloomberg Crude Oil [Member] | Futures Contracts [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure (7,161,949) (3,962,648)
Level I - Quoted Prices [Member] | ProShares UltraShort Bloomberg Natural Gas [Member] | Short-Term U.S. Government and Agencies [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 4,093,202 3,999,751
Level I - Quoted Prices [Member] | ProShares UltraShort Bloomberg Natural Gas [Member] | Futures Contracts [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 6,272 (1,097,049)
Level I - Quoted Prices [Member] | ProShares UltraShort Euro [Member] | Short-Term U.S. Government and Agencies [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 141,652,985 204,770,166
Level I - Quoted Prices [Member] | ProShares UltraShort Gold [Member] | Short-Term U.S. Government and Agencies [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 22,954,734 31,977,900
Level I - Quoted Prices [Member] | ProShares UltraShort Gold [Member] | Futures Contracts [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 15,080 (5,460)
Level I - Quoted Prices [Member] | ProShares UltraShort Silver [Member] | Short-Term U.S. Government and Agencies [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 19,972,425 18,349,861
Level I - Quoted Prices [Member] | ProShares UltraShort Silver [Member] | Futures Contracts [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 7,970 (1,650)
Level I - Quoted Prices [Member] | ProShares UltraShort Yen [Member] | Short-Term U.S. Government and Agencies [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 80,837,136 131,834,352
Level I - Quoted Prices [Member] | ProShares VIX Mid-Term Futures ETF [Member] | Short-Term U.S. Government and Agencies [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure   20,993,515
Level I - Quoted Prices [Member] | ProShares VIX Mid-Term Futures ETF [Member] | Futures Contracts [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure (378,240) (2,215,280)
Level I - Quoted Prices [Member] | ProShares VIX Short-Term Futures ETF [Member] | Short-Term U.S. Government and Agencies [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 21,999,053 134,845,604
Level I - Quoted Prices [Member] | ProShares VIX Short-Term Futures ETF [Member] | Futures Contracts [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 9,426,460 (4,761,877)
Level I - Quoted Prices [Member] | Total Trust [Member] | Short-Term U.S. Government and Agencies [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 1,300,390,736 2,445,779,873
Level I - Quoted Prices [Member] | Total Trust [Member] | Futures Contracts [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 41,274,027 (12,919,431)
Level II - Other Significant Observable Inputs [Member] | ProShares Ultra Bloomberg Crude Oil [Member] | Swap Agreements [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 82,428,870 62,238,361
Level II - Other Significant Observable Inputs [Member] | ProShares Ultra Euro [Member] | Foreign Currency Forward Contracts [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure (172,054) 264,152
Level II - Other Significant Observable Inputs [Member] | ProShares Ultra Gold [Member] | Forward Agreements [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure (7,152,896) 3,646,355
Level II - Other Significant Observable Inputs [Member] | ProShares Ultra Silver [Member] | Forward Agreements [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure (14,148,711) 21,735,334
Level II - Other Significant Observable Inputs [Member] | ProShares Ultra VIX Short-Term Futures ETF [Member] | Swap Agreements [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 264,480  
Level II - Other Significant Observable Inputs [Member] | ProShares Ultra Yen [Member] | Foreign Currency Forward Contracts [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure (24,259) (34,824)
Level II - Other Significant Observable Inputs [Member] | ProShares UltraShort Bloomberg Crude Oil [Member] | Swap Agreements [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure (33,768,200) (30,607,142)
Level II - Other Significant Observable Inputs [Member] | ProShares UltraShort Euro [Member] | Foreign Currency Forward Contracts [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 3,399,950 (6,344,269)
Level II - Other Significant Observable Inputs [Member] | ProShares UltraShort Gold [Member] | Forward Agreements [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 2,276,610 (1,488,259)
Level II - Other Significant Observable Inputs [Member] | ProShares UltraShort Silver [Member] | Forward Agreements [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 1,452,785 (1,716,163)
Level II - Other Significant Observable Inputs [Member] | ProShares UltraShort Yen [Member] | Foreign Currency Forward Contracts [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 693,318 1,527,263
Level II - Other Significant Observable Inputs [Member] | Total Trust [Member] | Forward Agreements [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure (17,572,212) 22,177,267
Level II - Other Significant Observable Inputs [Member] | Total Trust [Member] | Foreign Currency Forward Contracts [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 3,896,955 (4,587,678)
Level II - Other Significant Observable Inputs [Member] | Total Trust [Member] | Swap Agreements [Member]    
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure $ 48,925,150 $ 31,631,219