Investments - Fair Value of Derivative Instruments (Detail) - USD ($)		Dec. 31, 2016	Dec. 31, 2015
Derivative Instruments, Gain (Loss) [Line Items]
Derivative asset not designated as hedging instrument, Unrealized Appreciation	[1]	$ 118,541,276	$ 46,547,274	[2]
Derivative liability not designated as hedging instrument, Unrealized Depreciation	[1]	76,945,784	162,860,301	[2]
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]	1,356,620	354,365
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	58,830
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]	2,742,526	1,078,625
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]	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	10,005
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]		10,805,245
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 designated as hedging instrument, Unrealized Appreciation	[1]	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	11,894,466
Commodity Contracts [Member] | Payable on Open Futures Contracts, Unrealized Depreciation on Swap and/or Forward Agreements [Member] | ProShares Ultra Gold [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative liability not designated as hedging instrument, Unrealized Depreciation	[1]	4,450,067	2,255,795
Commodity Contracts [Member] | Payable on Open Futures Contracts, Unrealized Depreciation on Swap and/or Forward Agreements [Member] | ProShares Ultra Bloomberg Crude Oil [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative liability not designated as hedging instrument, Unrealized Depreciation	[1]		90,105,903
Commodity Contracts [Member] | Payable on Open Futures Contracts, Unrealized Depreciation on Swap 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]	482,031	2,471,164
Commodity Contracts [Member] | Payable on Open Futures Contracts, Unrealized Depreciation on Swap 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]	21,003,549	22,570,131
Commodity Contracts [Member] | Payable on Open Futures Contracts, Unrealized Depreciation on Swap 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]	13,633,696
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]	1,411,556	4,784,249
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]	60,895,736
Commodity Contracts [Member] | Receivables on Open Futures Contracts, Unrealized Appreciation on Swaps and/ or Forwards Agreements [Member] | ProShares UltraShort Bloomberg Crude Oil [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative asset not designated as hedging instrument, Unrealized Appreciation	[1]		8,877,169
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	6,312,879
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	[1]	3,052,546	1,814,162
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		356,139	28,710,336
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		125,420	14,829,179
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		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		342,455	5,703
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 designated as hedging instrument, Unrealized Depreciation	[1]		420,270
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		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		16,870,357	933,727
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		2,548	604,920
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		379	267,014
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]	132,900	$ 243,438
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]	$ 1,182,340

[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.

[2] Amounts exclude the activity of: ProShares Managed Futures Strategy which liquidated on March 30, 2016, ProShares UltraShort Bloomberg Commodity and ProShares Ultra Bloomberg Commodity which liquidated on September 1, 2016.