v3.10.0.1

Investments - Fair Value of Derivative Instruments (Detail) - USD ($)		Jun. 30, 2018	Dec. 31, 2017
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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