v2.4.1.9

Investments - Fair Value of Derivative Instruments (Detail) (USD $) | Mar. 31, 2015 | Dec. 31, 2014
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Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative asset not designated as hedging instrument, Unrealized Appreciation | $ 112,237,936 ck0001415311_DerivativeAssetNotDesignatedAsHedgingInstrumentUnrealizedAppreciation | [1] | $ 117,369,486 ck0001415311_DerivativeAssetNotDesignatedAsHedgingInstrumentUnrealizedAppreciation | [2]
Derivative liability not designated as hedging instrument, Unrealized Depreciation | 221,525,982 ck0001415311_DerivativeLiabilityNotDesignatedAsHedgingInstrumentUnrealizedDepreciation | [1] | 193,984,012 ck0001415311_DerivativeLiabilityNotDesignatedAsHedgingInstrumentUnrealizedDepreciation | [2]
Managed Futures Contracts [Member] | Payable on Open Futures Contracts [Member] | ProShares Managed Futures Strategy [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative liability not designated as hedging instrument, Unrealized Depreciation | 107,342 ck0001415311_DerivativeLiabilityNotDesignatedAsHedgingInstrumentUnrealizedDepreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_PayableOnOpenFuturesContractsMember / us-gaap_DerivativeInstrumentRiskAxis = ck0001415311_FuturesContractsMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesManagedFuturesStrategyMember | [1] | 18,504 ck0001415311_DerivativeLiabilityNotDesignatedAsHedgingInstrumentUnrealizedDepreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_PayableOnOpenFuturesContractsMember / us-gaap_DerivativeInstrumentRiskAxis = ck0001415311_FuturesContractsMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesManagedFuturesStrategyMember | [2]
Managed Futures Contracts [Member] | Receivables on Open Futures Contracts [Member] | ProShares Managed Futures Strategy [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative asset not designated as hedging instrument, Unrealized Appreciation | 190,575 ck0001415311_DerivativeAssetNotDesignatedAsHedgingInstrumentUnrealizedAppreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_ReceivablesOnOpenFuturesContractsMember / us-gaap_DerivativeInstrumentRiskAxis = ck0001415311_FuturesContractsMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesManagedFuturesStrategyMember | [1] | 122,831 ck0001415311_DerivativeAssetNotDesignatedAsHedgingInstrumentUnrealizedAppreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_ReceivablesOnOpenFuturesContractsMember / us-gaap_DerivativeInstrumentRiskAxis = ck0001415311_FuturesContractsMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesManagedFuturesStrategyMember | [2]
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 | 5,816,262 ck0001415311_DerivativeLiabilityNotDesignatedAsHedgingInstrumentUnrealizedDepreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_PayableOnOpenFuturesContractsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_FutureMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesVixShortTermFuturesEtfMember | [1] |  |
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 | 616,590 ck0001415311_DerivativeLiabilityNotDesignatedAsHedgingInstrumentUnrealizedDepreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_PayableOnOpenFuturesContractsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_FutureMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesVixMidTermFuturesEtfMember | [1] | 222,845 ck0001415311_DerivativeLiabilityNotDesignatedAsHedgingInstrumentUnrealizedDepreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_PayableOnOpenFuturesContractsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_FutureMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesVixMidTermFuturesEtfMember | [2]
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 | 1,599,750 ck0001415311_DerivativeLiabilityNotDesignatedAsHedgingInstrumentUnrealizedDepreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_PayableOnOpenFuturesContractsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_FutureMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesShortVixShortTermFuturesEtfMember |  | 16,352,149 ck0001415311_DerivativeLiabilityNotDesignatedAsHedgingInstrumentUnrealizedDepreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_PayableOnOpenFuturesContractsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_FutureMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesShortVixShortTermFuturesEtfMember | [2]
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 | 55,127,903 ck0001415311_DerivativeLiabilityNotDesignatedAsHedgingInstrumentUnrealizedDepreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_PayableOnOpenFuturesContractsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_FutureMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltraVixShortTermFuturesEtfMember |  |  |
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 | 710,151 ck0001415311_DerivativeAssetNotDesignatedAsHedgingInstrumentUnrealizedAppreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_ReceivablesOnOpenFuturesContractsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_FutureMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesVixShortTermFuturesEtfMember | [1] | 6,264,620 ck0001415311_DerivativeAssetNotDesignatedAsHedgingInstrumentUnrealizedAppreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_ReceivablesOnOpenFuturesContractsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_FutureMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesVixShortTermFuturesEtfMember | [2]
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 | 116,200 ck0001415311_DerivativeAssetNotDesignatedAsHedgingInstrumentUnrealizedAppreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_ReceivablesOnOpenFuturesContractsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_FutureMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesVixMidTermFuturesEtfMember | [1] | 483,510 ck0001415311_DerivativeAssetNotDesignatedAsHedgingInstrumentUnrealizedAppreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_ReceivablesOnOpenFuturesContractsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_FutureMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesVixMidTermFuturesEtfMember | [2]
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 | 8,591,734 ck0001415311_DerivativeAssetNotDesignatedAsHedgingInstrumentUnrealizedAppreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_ReceivablesOnOpenFuturesContractsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_FutureMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesShortVixShortTermFuturesEtfMember | [1] |  |
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 | 6,202,210 ck0001415311_DerivativeAssetNotDesignatedAsHedgingInstrumentUnrealizedAppreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_ReceivablesOnOpenFuturesContractsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_FutureMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltraVixShortTermFuturesEtfMember |  | 39,585,253 ck0001415311_DerivativeAssetNotDesignatedAsHedgingInstrumentUnrealizedAppreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_ReceivablesOnOpenFuturesContractsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_FutureMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltraVixShortTermFuturesEtfMember | [2]
Commodity Contracts [Member] | Payable on Open Futures Contracts, Unrealized Depreciation on Swap and/or Forward Agreements [Member] | ProShares UltraShort Silver [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative liability not designated as hedging instrument, Unrealized Depreciation | 3,736,183 ck0001415311_DerivativeLiabilityNotDesignatedAsHedgingInstrumentUnrealizedDepreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_PayableOnOpenFuturesContractsUnrealizedDepreciationOnSwapAndOrForwardAgreementsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_CommodityContractMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltrashortSilverMember |  | 204,570 ck0001415311_DerivativeLiabilityNotDesignatedAsHedgingInstrumentUnrealizedDepreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_PayableOnOpenFuturesContractsUnrealizedDepreciationOnSwapAndOrForwardAgreementsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_CommodityContractMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltrashortSilverMember |
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 | 3,320 ck0001415311_DerivativeLiabilityNotDesignatedAsHedgingInstrumentUnrealizedDepreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_PayableOnOpenFuturesContractsUnrealizedDepreciationOnSwapAndOrForwardAgreementsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_CommodityContractMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltraSilverMember | [1] | 12,396,680 ck0001415311_DerivativeLiabilityNotDesignatedAsHedgingInstrumentUnrealizedDepreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_PayableOnOpenFuturesContractsUnrealizedDepreciationOnSwapAndOrForwardAgreementsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_CommodityContractMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltraSilverMember | [2]
Commodity Contracts [Member] | Payable on Open Futures Contracts, Unrealized Depreciation on Swap and/or Forward Agreements [Member] | ProShares UltraShort Gold [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative liability not designated as hedging instrument, Unrealized Depreciation | 1,588,121 ck0001415311_DerivativeLiabilityNotDesignatedAsHedgingInstrumentUnrealizedDepreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_PayableOnOpenFuturesContractsUnrealizedDepreciationOnSwapAndOrForwardAgreementsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_CommodityContractMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltrashortGoldMember | [1] | 2,287,298 ck0001415311_DerivativeLiabilityNotDesignatedAsHedgingInstrumentUnrealizedDepreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_PayableOnOpenFuturesContractsUnrealizedDepreciationOnSwapAndOrForwardAgreementsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_CommodityContractMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltrashortGoldMember | [2]
Commodity Contracts [Member] | Payable on Open Futures Contracts, Unrealized Depreciation on Swap and/or Forward Agreements [Member] | ProShares Ultra Bloomberg Commodity [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative liability not designated as hedging instrument, Unrealized Depreciation | 129,433 ck0001415311_DerivativeLiabilityNotDesignatedAsHedgingInstrumentUnrealizedDepreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_PayableOnOpenFuturesContractsUnrealizedDepreciationOnSwapAndOrForwardAgreementsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_CommodityContractMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltraBloombergCommodityMember |  | 331,338 ck0001415311_DerivativeLiabilityNotDesignatedAsHedgingInstrumentUnrealizedDepreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_PayableOnOpenFuturesContractsUnrealizedDepreciationOnSwapAndOrForwardAgreementsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_CommodityContractMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltraBloombergCommodityMember |
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 | 142,337,660 ck0001415311_DerivativeLiabilityNotDesignatedAsHedgingInstrumentUnrealizedDepreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_PayableOnOpenFuturesContractsUnrealizedDepreciationOnSwapAndOrForwardAgreementsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_CommodityContractMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltraBloombergCrudeOilMember | [1] | 122,655,884 ck0001415311_DerivativeLiabilityNotDesignatedAsHedgingInstrumentUnrealizedDepreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_PayableOnOpenFuturesContractsUnrealizedDepreciationOnSwapAndOrForwardAgreementsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_CommodityContractMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltraBloombergCrudeOilMember | [2]
Commodity Contracts [Member] | Payable on Open Futures Contracts, Unrealized Depreciation on Swap and/or Forward Agreements [Member] | ProShares Ultra Bloomberg Natural Gas [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative liability not designated as hedging instrument, Unrealized Depreciation | 7,437,631 ck0001415311_DerivativeLiabilityNotDesignatedAsHedgingInstrumentUnrealizedDepreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_PayableOnOpenFuturesContractsUnrealizedDepreciationOnSwapAndOrForwardAgreementsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_CommodityContractMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltraBloombergNaturalGasMember | [1] | 34,889,283 ck0001415311_DerivativeLiabilityNotDesignatedAsHedgingInstrumentUnrealizedDepreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_PayableOnOpenFuturesContractsUnrealizedDepreciationOnSwapAndOrForwardAgreementsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_CommodityContractMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltraBloombergNaturalGasMember | [2]
Commodity Contracts [Member] | Receivables on Open Futures Contracts, Unrealized Appreciation on Swap and/ or Forwards Agreements [Member] | ProShares UltraShort Bloomberg Commodity [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative asset not designated as hedging instrument, Unrealized Appreciation | 276,625 ck0001415311_DerivativeAssetNotDesignatedAsHedgingInstrumentUnrealizedAppreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_ReceivablesOnOpenFuturesContractsUnrealizedAppreciationOnSwapAndOrForwardContractsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_CommodityContractMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltrashortBloombergCommodityMember |  | 567,259 ck0001415311_DerivativeAssetNotDesignatedAsHedgingInstrumentUnrealizedAppreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_ReceivablesOnOpenFuturesContractsUnrealizedAppreciationOnSwapAndOrForwardContractsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_CommodityContractMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltrashortBloombergCommodityMember |
Commodity Contracts [Member] | Receivables on Open Futures Contracts, Unrealized Appreciation on Swap 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 | 44,263,734 ck0001415311_DerivativeAssetNotDesignatedAsHedgingInstrumentUnrealizedAppreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_ReceivablesOnOpenFuturesContractsUnrealizedAppreciationOnSwapAndOrForwardContractsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_CommodityContractMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltrashortBloombergCrudeOilMember | [1] | 42,824,680 ck0001415311_DerivativeAssetNotDesignatedAsHedgingInstrumentUnrealizedAppreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_ReceivablesOnOpenFuturesContractsUnrealizedAppreciationOnSwapAndOrForwardContractsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_CommodityContractMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltrashortBloombergCrudeOilMember | [2]
Commodity Contracts [Member] | Receivables on Open Futures Contracts, Unrealized Appreciation on Swap 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 | 859,740 ck0001415311_DerivativeAssetNotDesignatedAsHedgingInstrumentUnrealizedAppreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_ReceivablesOnOpenFuturesContractsUnrealizedAppreciationOnSwapAndOrForwardContractsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_CommodityContractMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltrashortBloombergNaturalGasMember | [1] | 3,941,465 ck0001415311_DerivativeAssetNotDesignatedAsHedgingInstrumentUnrealizedAppreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_ReceivablesOnOpenFuturesContractsUnrealizedAppreciationOnSwapAndOrForwardContractsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_CommodityContractMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltrashortBloombergNaturalGasMember | [2]
Commodity Contracts [Member] | Receivables on Open Futures Contracts, Unrealized Appreciation on Swap and/ or Forwards Agreements [Member] | ProShares UltraShort Silver [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative asset not designated as hedging instrument, Unrealized Appreciation | 3,095 ck0001415311_DerivativeAssetNotDesignatedAsHedgingInstrumentUnrealizedAppreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_ReceivablesOnOpenFuturesContractsUnrealizedAppreciationOnSwapAndOrForwardContractsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_CommodityContractMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltrashortSilverMember | [1] | 801,083 ck0001415311_DerivativeAssetNotDesignatedAsHedgingInstrumentUnrealizedAppreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_ReceivablesOnOpenFuturesContractsUnrealizedAppreciationOnSwapAndOrForwardContractsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_CommodityContractMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltrashortSilverMember | [2]
Commodity Contracts [Member] | Receivables on Open Futures Contracts, Unrealized Appreciation on Swap and/ or Forwards Agreements [Member] | ProShares Ultra Gold [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative asset not designated as hedging instrument, Unrealized Appreciation | 1,666,988 ck0001415311_DerivativeAssetNotDesignatedAsHedgingInstrumentUnrealizedAppreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_ReceivablesOnOpenFuturesContractsUnrealizedAppreciationOnSwapAndOrForwardContractsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_CommodityContractMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltraGoldMember | [1] | 2,055,734 ck0001415311_DerivativeAssetNotDesignatedAsHedgingInstrumentUnrealizedAppreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_ReceivablesOnOpenFuturesContractsUnrealizedAppreciationOnSwapAndOrForwardContractsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_CommodityContractMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltraGoldMember | [2]
Commodity Contracts [Member] | Receivables on Open Futures Contracts, Unrealized Appreciation on Swap and/ or Forwards Agreements [Member] | ProShares Ultra Silver [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative asset not designated as hedging instrument, Unrealized Appreciation | 22,620,868 ck0001415311_DerivativeAssetNotDesignatedAsHedgingInstrumentUnrealizedAppreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_ReceivablesOnOpenFuturesContractsUnrealizedAppreciationOnSwapAndOrForwardContractsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_CommodityContractMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltraSilverMember |  |  |
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 | 2,088,667 ck0001415311_DerivativeLiabilityNotDesignatedAsHedgingInstrumentUnrealizedDepreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_UnrealizedDepreciationOnForeignCurrencyForwardContractsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_ForeignExchangeContractMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltrashortEuroMember |  | 2,256,771 ck0001415311_DerivativeLiabilityNotDesignatedAsHedgingInstrumentUnrealizedDepreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_UnrealizedDepreciationOnForeignCurrencyForwardContractsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_ForeignExchangeContractMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltrashortEuroMember |
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 | 57,733 ck0001415311_DerivativeLiabilityNotDesignatedAsHedgingInstrumentUnrealizedDepreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_UnrealizedDepreciationOnForeignCurrencyForwardContractsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_ForeignExchangeContractMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltrashortYenMember |  | 2,149,924 ck0001415311_DerivativeLiabilityNotDesignatedAsHedgingInstrumentUnrealizedDepreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_UnrealizedDepreciationOnForeignCurrencyForwardContractsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_ForeignExchangeContractMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltrashortYenMember |
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 | 780,795 ck0001415311_DerivativeLiabilityNotDesignatedAsHedgingInstrumentUnrealizedDepreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_UnrealizedDepreciationOnForeignCurrencyForwardContractsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_ForeignExchangeContractMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltraEuroMember |  | 106,292 ck0001415311_DerivativeLiabilityNotDesignatedAsHedgingInstrumentUnrealizedDepreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_UnrealizedDepreciationOnForeignCurrencyForwardContractsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_ForeignExchangeContractMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltraEuroMember |
Foreign Exchange Contracts [Member] | Unrealized Depreciation on Foreign Currency Forward Contracts and Payable on Open Futures Contracts [Member] | ProShares Ultra Australian Dollar [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative liability not designated as hedging instrument, Unrealized Depreciation | 57,414 ck0001415311_DerivativeLiabilityNotDesignatedAsHedgingInstrumentUnrealizedDepreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_UnrealizedDepreciationOnForeignCurrencyForwardContractsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_ForeignExchangeContractMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltraAustralianDollarMember | [1] | 96,825 ck0001415311_DerivativeLiabilityNotDesignatedAsHedgingInstrumentUnrealizedDepreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_UnrealizedDepreciationOnForeignCurrencyForwardContractsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_ForeignExchangeContractMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltraAustralianDollarMember | [2]
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 | 41,178 ck0001415311_DerivativeLiabilityNotDesignatedAsHedgingInstrumentUnrealizedDepreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_UnrealizedDepreciationOnForeignCurrencyForwardContractsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_ForeignExchangeContractMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltraYenMember |  | 15,649 ck0001415311_DerivativeLiabilityNotDesignatedAsHedgingInstrumentUnrealizedDepreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_UnrealizedDepreciationOnForeignCurrencyForwardContractsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_ForeignExchangeContractMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltraYenMember |
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 | 109,769 ck0001415311_DerivativeAssetNotDesignatedAsHedgingInstrumentUnrealizedAppreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_UnrealizedAppreciationOnForeignCurrencyForwardContractsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_ForeignExchangeContractMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesShortEuroMember | [1] | 385,331 ck0001415311_DerivativeAssetNotDesignatedAsHedgingInstrumentUnrealizedAppreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_UnrealizedAppreciationOnForeignCurrencyForwardContractsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_ForeignExchangeContractMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesShortEuroMember | [2]
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 | 419,850 ck0001415311_DerivativeAssetNotDesignatedAsHedgingInstrumentUnrealizedAppreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_UnrealizedAppreciationOnForeignCurrencyForwardContractsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_ForeignExchangeContractMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltrashortAustralianDollarMember | [1] | 743,481 ck0001415311_DerivativeAssetNotDesignatedAsHedgingInstrumentUnrealizedAppreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_UnrealizedAppreciationOnForeignCurrencyForwardContractsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_ForeignExchangeContractMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltrashortAustralianDollarMember | [2]
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 | 25,478,862 ck0001415311_DerivativeAssetNotDesignatedAsHedgingInstrumentUnrealizedAppreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_UnrealizedAppreciationOnForeignCurrencyForwardContractsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_ForeignExchangeContractMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltrashortEuroMember |  | 19,019,765 ck0001415311_DerivativeAssetNotDesignatedAsHedgingInstrumentUnrealizedAppreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_UnrealizedAppreciationOnForeignCurrencyForwardContractsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_ForeignExchangeContractMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltrashortEuroMember |
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 | 725,490 ck0001415311_DerivativeAssetNotDesignatedAsHedgingInstrumentUnrealizedAppreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_UnrealizedAppreciationOnForeignCurrencyForwardContractsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_ForeignExchangeContractMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltrashortYenMember |  | 571,149 ck0001415311_DerivativeAssetNotDesignatedAsHedgingInstrumentUnrealizedAppreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_UnrealizedAppreciationOnForeignCurrencyForwardContractsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_ForeignExchangeContractMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltrashortYenMember |
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 | 2,045 ck0001415311_DerivativeAssetNotDesignatedAsHedgingInstrumentUnrealizedAppreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_UnrealizedAppreciationOnForeignCurrencyForwardContractsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_ForeignExchangeContractMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltraEuroMember |  | 2,921 ck0001415311_DerivativeAssetNotDesignatedAsHedgingInstrumentUnrealizedAppreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_UnrealizedAppreciationOnForeignCurrencyForwardContractsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_ForeignExchangeContractMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltraEuroMember |
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 |  |  | $ 404 ck0001415311_DerivativeAssetNotDesignatedAsHedgingInstrumentUnrealizedAppreciation / us-gaap_BalanceSheetLocationAxis = ck0001415311_UnrealizedAppreciationOnForeignCurrencyForwardContractsMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_ForeignExchangeContractMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltraYenMember |
[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] | Includes cumulative appreciation/depreciation of futures contracts as reported in the Schedules of Investments as presented in the Form 10-K for the year ended December 31, 2014. Only current day's variation margin is reported within the Statements of Financial Condition as presented in the Form 10-K for the year ended December 31, 2014 in receivable/payable on open futures contracts.

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