v3.10.0.1

Investments - Fair Value of Derivative Instruments (Detail) - USD ($) | Jun. 30, 2018 | Dec. 31, 2017
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Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Derivative asset not accounted as hedging instrument, Unrealized Appreciation | [1] | $ 168,821,224 | $ 136,734,724
Derivative liability not accounted as hedging instrument, Unrealized Depreciation | [1] | 92,297,304 | 100,433,347
VIX Futures Contracts [Member] | Payable on Open Futures Contracts [Member] | ProShares Short VIX Short-Term Futures ETF [Member] |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Derivative liability not accounted as hedging instrument, Unrealized Depreciation | [1] |  | 4,452,100
VIX Futures Contracts [Member] | Payable on Open Futures Contracts [Member] | ProShares Ultra VIX Short-Term Futures ETF [Member] |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Derivative liability not accounted as hedging instrument, Unrealized Depreciation | [1] |  | 38,440,762
VIX Futures Contracts [Member] | Payable on Open Futures Contracts [Member] | ProShares VIX Mid-Term Futures ETF [Member] |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Derivative liability not accounted as hedging instrument, Unrealized Depreciation | [1] |  | 2,215,280
VIX Futures Contracts [Member] | Payable on Open Futures Contracts [Member] | ProShares VIX Short-Term Futures ETF [Member] |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Derivative liability not accounted as hedging instrument, Unrealized Depreciation | [1] |  | 5,471,585
VIX Futures Contracts [Member] | Payable On Open Futures Contracts And Unrealized Depreciation On Swap Agreements [Member] | ProShares Ultra VIX Short-Term Futures ETF [Member] |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Derivative liability not accounted as hedging instrument, Unrealized Depreciation | [1] | 1,038,439 |
VIX Futures Contracts [Member] | Payable On Open Futures Contracts And Unrealized Depreciation On Swap Agreements [Member] | ProShares VIX Mid-Term Futures ETF [Member] |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Derivative liability not accounted as hedging instrument, Unrealized Depreciation | [1] | 659,960 |
VIX Futures Contracts [Member] | Payable On Open Futures Contracts And Unrealized Depreciation On Swap Agreements [Member] | ProShares VIX Short-Term Futures ETF [Member] |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Derivative liability not accounted as hedging instrument, Unrealized Depreciation | [1] | 22,528,398 |
VIX Futures Contracts [Member] | Receivables On Open Futures Contracts And Unrealized Appreciation On Swap Agreements [Member] | ProShares Ultra VIX Short-Term Futures ETF [Member] |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Derivative asset not accounted as hedging instrument, Unrealized Appreciation | [1] | 41,100,348 |
VIX Futures Contracts [Member] | Receivables On Open Futures Contracts And Unrealized Appreciation On Swap Agreements [Member] | ProShares VIX Mid-Term Futures ETF [Member] |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Derivative asset not accounted as hedging instrument, Unrealized Appreciation | [1] | 281,720 |
VIX Futures Contracts [Member] | Receivables On Open Futures Contracts And Unrealized Appreciation On Swap Agreements [Member] | ProShares VIX Short-Term Futures ETF [Member] |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Derivative asset not accounted as hedging instrument, Unrealized Appreciation | [1] | 9,426,460 |
VIX Futures Contracts [Member] | Receivables on Open Futures Contracts [Member] | ProShares Short VIX Short-Term Futures ETF [Member] |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Derivative asset not accounted as hedging instrument, Unrealized Appreciation | [1] |  | 21,493,549
VIX Futures Contracts [Member] | Receivables on Open Futures Contracts [Member] | ProShares Ultra VIX Short-Term Futures ETF [Member] |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Derivative asset not accounted as hedging instrument, Unrealized Appreciation | [1] |  | 3,974,642
VIX Futures Contracts [Member] | Receivables on Open Futures Contracts [Member] | ProShares VIX Short-Term Futures ETF [Member] |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Derivative asset not accounted as hedging instrument, Unrealized Appreciation | [1] |  | 709,708
Commodity Contracts [Member] | Payable on Open Futures Contracts, Unrealized Depreciation on Swaps and/or Forward Agreements [Member] | ProShares UltraShort Bloomberg Crude Oil [Member] |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Derivative liability not accounted as hedging instrument, Unrealized Depreciation | [1] | 40,930,149 | 34,569,790
Commodity Contracts [Member] | Payable on Open Futures Contracts, Unrealized Depreciation on Swaps and/or Forward Agreements [Member] | ProShares UltraShort Bloomberg Natural Gas [Member] |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Derivative liability not accounted as hedging instrument, Unrealized Depreciation | [1] |  | 1,097,049
Commodity Contracts [Member] | Payable on Open Futures Contracts, Unrealized Depreciation on Swaps and/or Forward Agreements [Member] | ProShares UltraShort Gold [Member] |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Derivative liability not accounted as hedging instrument, Unrealized Depreciation | [1] |  | 1,493,719
Commodity Contracts [Member] | Payable on Open Futures Contracts, Unrealized Depreciation on Swaps and/or Forward Agreements [Member] | ProShares UltraShort Silver [Member] |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Derivative liability not accounted as hedging instrument, Unrealized Depreciation | [1] |  | 1,717,813
Commodity Contracts [Member] | Payable on Open Futures Contracts, Unrealized Depreciation on Swaps and/or Forward Agreements [Member] | ProShares Ultra Bloomberg Natural Gas [Member] |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Derivative liability not accounted as hedging instrument, Unrealized Depreciation | [1] | 118,623 |
Commodity Contracts [Member] | Payable on Open Futures Contracts, Unrealized Depreciation on Swaps and/or Forward Agreements [Member] | ProShares Ultra Gold [Member] |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Derivative liability not accounted as hedging instrument, Unrealized Depreciation | [1] | 7,168,016 |
Commodity Contracts [Member] | Payable on Open Futures Contracts, Unrealized Depreciation on Swaps and/or Forward Agreements [Member] | ProShares Ultra Silver [Member] |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Derivative liability not accounted as hedging instrument, Unrealized Depreciation | [1] | 14,156,681 |
Commodity Contracts [Member] | Payable on Open Futures Contracts, Unrealized Depreciation on Swaps and/or Forward Agreements [Member] | ProShares UltraPro 3X Short Crude Oil ETF [Member] |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Derivative liability not accounted as hedging instrument, Unrealized Depreciation | [1] | 5,442,454 | 2,988,155
Commodity Contracts [Member] | Receivables on Open Futures Contracts, Unrealized Appreciation on Swaps and/or Forwards Agreements [Member] | ProShares UltraPro 3x Crude Oil ETF [Member] |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Derivative asset not accounted as hedging instrument, Unrealized Appreciation | [1] |  | 1,417,998
Commodity Contracts [Member] | Receivables on Open Futures Contracts, Unrealized Appreciation on Swaps and/or Forwards Agreements [Member] | ProShares UltraShort Bloomberg Natural Gas [Member] |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Derivative asset not accounted as hedging instrument, Unrealized Appreciation | [1] | 6,272 |
Commodity Contracts [Member] | Receivables on Open Futures Contracts, Unrealized Appreciation on Swaps and/or Forwards Agreements [Member] | ProShares UltraShort Gold [Member] |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Derivative asset not accounted as hedging instrument, Unrealized Appreciation | [1] | 2,291,690 |
Commodity Contracts [Member] | Receivables on Open Futures Contracts, Unrealized Appreciation on Swaps and/or Forwards Agreements [Member] | ProShares UltraShort Silver [Member] |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Derivative asset not accounted as hedging instrument, Unrealized Appreciation | [1] | 1,460,755 |
Commodity Contracts [Member] | Receivables on Open Futures Contracts, Unrealized Appreciation on Swaps and/or Forwards Agreements [Member] | ProShares Ultra Bloomberg Crude Oil [Member] |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Derivative asset not accounted as hedging instrument, Unrealized Appreciation | [1] | 99,717,973 | 74,184,340
Commodity Contracts [Member] | Receivables on Open Futures Contracts, Unrealized Appreciation on Swaps and/or Forwards Agreements [Member] | ProShares Ultra Bloomberg Natural Gas [Member] |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Derivative asset not accounted as hedging instrument, Unrealized Appreciation | [1] |  | 7,225,810
Commodity Contracts [Member] | Receivables on Open Futures Contracts, Unrealized Appreciation on Swaps and/or Forwards Agreements [Member] | ProShares Ultra Gold [Member] |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Derivative asset not accounted as hedging instrument, Unrealized Appreciation | [1] |  | 3,651,835
Commodity Contracts [Member] | Receivables on Open Futures Contracts, Unrealized Appreciation on Swaps and/or Forwards Agreements [Member] | ProShares Ultra Silver [Member] |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Derivative asset not accounted as hedging instrument, Unrealized Appreciation | [1] |  | 21,736,934
Commodity Contracts [Member] | Receivables on Open Futures Contracts, Unrealized Appreciation on Swaps and/or Forwards Agreements [Member] | Proshares Ultra Pro 3x Crude Oil ETF [Member] |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Derivative asset not accounted as hedging instrument, Unrealized Appreciation | [1] | 9,905,484 |
Foreign Exchange Contracts [Member] | Unrealized Depreciation on Foreign Currency Forward Contracts and Payable on Open Futures Contracts [Member] | ProShares Short Euro [Member] |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Derivative liability not accounted as hedging instrument, Unrealized Depreciation | [1] |  | 166,288
Foreign Exchange Contracts [Member] | Unrealized Depreciation on Foreign Currency Forward Contracts and Payable on Open Futures Contracts [Member] | ProShares Ultra Euro [Member] |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Derivative liability not accounted as hedging instrument, Unrealized Depreciation |  | 172,054 | 57,457
Foreign Exchange Contracts [Member] | Unrealized Depreciation on Foreign Currency Forward Contracts and Payable on Open Futures Contracts [Member] | ProShares Ultra Yen [Member] |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Derivative liability not accounted as hedging instrument, Unrealized Depreciation |  | 24,570 | 34,824
Foreign Exchange Contracts [Member] | Unrealized Depreciation on Foreign Currency Forward Contracts and Payable on Open Futures Contracts [Member] | ProShares UltraShort Australian Dollar [Member] |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Derivative liability not accounted as hedging instrument, Unrealized Depreciation | [1] |  | 893,220
Foreign Exchange Contracts [Member] | Unrealized Depreciation on Foreign Currency Forward Contracts and Payable on Open Futures Contracts [Member] | ProShares UltraShort Euro [Member] |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Derivative liability not accounted as hedging instrument, Unrealized Depreciation |  |  | 6,793,571
Foreign Exchange Contracts [Member] | Unrealized Depreciation on Foreign Currency Forward Contracts and Payable on Open Futures Contracts [Member] | ProShares UltraShort Yen [Member] |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Derivative liability not accounted as hedging instrument, Unrealized Depreciation |  | 57,960 | 41,734
Foreign Exchange Contracts [Member] | Unrealized Appreciation on Foreign Currency Forward Contracts and Receivables on Open Futures Contracts [Member] | ProShares Short Euro [Member] |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Derivative asset not accounted as hedging instrument, Unrealized Appreciation | [1] | 87,213 |
Foreign Exchange Contracts [Member] | Unrealized Appreciation on Foreign Currency Forward Contracts and Receivables on Open Futures Contracts [Member] | ProShares Ultra Euro [Member] |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Derivative asset not accounted as hedging instrument, Unrealized Appreciation |  |  | 321,609
Foreign Exchange Contracts [Member] | Unrealized Appreciation on Foreign Currency Forward Contracts and Receivables on Open Futures Contracts [Member] | ProShares Ultra Yen [Member] |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Derivative asset not accounted as hedging instrument, Unrealized Appreciation |  | 311 |
Foreign Exchange Contracts [Member] | Unrealized Appreciation on Foreign Currency Forward Contracts and Receivables on Open Futures Contracts [Member] | ProShares UltraShort Australian Dollar [Member] |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Derivative asset not accounted as hedging instrument, Unrealized Appreciation | [1] | 391,770 |
Foreign Exchange Contracts [Member] | Unrealized Appreciation on Foreign Currency Forward Contracts and Receivables on Open Futures Contracts [Member] | ProShares UltraShort Euro [Member] |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Derivative asset not accounted as hedging instrument, Unrealized Appreciation |  | 3,399,950 | 449,302
Foreign Exchange Contracts [Member] | Unrealized Appreciation on Foreign Currency Forward Contracts and Receivables on Open Futures Contracts [Member] | ProShares UltraShort Yen [Member] |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Derivative asset not accounted as hedging instrument, Unrealized Appreciation |  | $ 751,278 | $ 1,568,997
[1] | Includes cumulative appreciation/depreciation of futures contracts as reported in the Schedules of Investments. Only current day's variation margin is reported within the Statements of Financial Condition in receivable/payable on open futures contracts.

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