v3.8.0.1

Investments - Fair Value of Derivative Instruments (Detail) - USD ($) | Sep. 30, 2017 | Dec. 31, 2016
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Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative asset not designated as hedging instrument, Unrealized Appreciation | [1] | $ 170,471,084 | $ 118,541,276 |
Derivative liability not designated as hedging instrument, Unrealized Depreciation | [1] | 183,021,726 | 76,945,784 |
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 designated as hedging instrument, Unrealized Depreciation | [1] | 18,329,321 | 2,742,526 |
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 designated as hedging instrument, Unrealized Depreciation | [1] | 1,941,640 | 1,356,620 |
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 designated as hedging instrument, Unrealized Depreciation | [1] |  | 10,309,611 |
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 designated as hedging instrument, Unrealized Depreciation | [1] | 101,763,031 | 21,567,112 |
VIX Futures Contracts [Member] | Receivables on Open Futures Contracts [Member] | ProShares VIX Mid-Term Futures ETF [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative asset not designated as hedging instrument, Unrealized Appreciation | [1] |  | 68,375 |
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 designated as hedging instrument, Unrealized Appreciation | [1] | 94,244,035 | 2,273,874 |
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 designated as hedging instrument, Unrealized Appreciation | [1] |  | 13,594,875 |
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 designated as hedging instrument, Unrealized Depreciation | [1] | 19,045,866 | 13,633,696 |
Commodity Contracts [Member] | Payable on Open Futures Contracts, Unrealized Depreciation on Swaps and/or Forward Agreements [Member] | Pro Shares UltraPro 3X Short Crude Oil ETF [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative liability not designated as hedging instrument, Unrealized Depreciation | [1] | 2,423,370 |  |
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 designated as hedging instrument, Unrealized Depreciation | [1] | 971,690 | 482,031 |
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 designated as hedging instrument, Unrealized Depreciation | [1] | 9,540 |  |
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 designated as hedging instrument, Unrealized Depreciation |  | 8,453,427 | 4,450,067 | [1]
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 designated as hedging instrument, Unrealized Depreciation | [1] | 28,248,742 | 21,003,549 |
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 designated as hedging instrument, Unrealized Appreciation | [1] | 348,521 |  |
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 designated as hedging instrument, Unrealized Appreciation |  | 2,961,605 | 3,052,546 | [1]
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 designated as hedging instrument, Unrealized Appreciation | [1] | 54,614,553 | 60,895,736 |
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 designated as hedging instrument, Unrealized Appreciation | [1] | 9,520 |  |
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 designated as hedging instrument, Unrealized Appreciation | [1] | 2,157,373 | 1,411,556 |
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 designated as hedging instrument, Unrealized Appreciation | [1] | 1,272,779 |  |
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 designated as hedging instrument, Unrealized Appreciation | [1] |  | 2,536,720 |
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 designated as hedging instrument, Unrealized Depreciation |  | 565,859 | 356,139 |
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 designated as hedging instrument, Unrealized Depreciation |  | 570,141 | 125,420 |
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 designated as hedging instrument, Unrealized Depreciation |  | 291,439 | 576,558 |
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 designated as hedging instrument, Unrealized Depreciation |  | 407,660 | 342,455 |
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 designated as hedging instrument, Unrealized Appreciation | [1] | 106,206 | 132,900 |
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 designated as hedging instrument, Unrealized Appreciation | [1] | 379,490 | 1,182,340 |
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 designated as hedging instrument, Unrealized Appreciation |  | 4,465,552 | 16,519,070 |
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 designated as hedging instrument, Unrealized Appreciation |  | 9,817,020 | 16,870,357 |
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 designated as hedging instrument, Unrealized Appreciation |  | 82,079 | 2,548 |
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 designated as hedging instrument, Unrealized Appreciation |  | $ 12,351 | $ 379 |
[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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