v3.8.0.1

Investments - Fair Value of Derivative Instruments (Detail) - USD ($)		Sep. 30, 2017	Dec. 31, 2016
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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