v2.4.1.9

Schedule of Investments - Futures Contracts Sold (Parenthetical) (Detail) (Futures Contracts Sold [Member], USD $)	3 Months Ended
	Mar. 31, 2015
ProShares Managed Futures Strategy [Member]
Schedule of Investments [Line Items]
Cash collateral pledged to cover margin requirements	$ 269,253ck0001415311_CashCollateralPledgedToCoverMarginRequirements / us-gaap_DerivativeInstrumentRiskAxis = ck0001415311_FuturesContractsSoldMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesManagedFuturesStrategyMember
ProShares Short VIX Short-Term Futures ETF [Member]
Schedule of Investments [Line Items]
Cash collateral pledged to cover margin requirements	55,500,260ck0001415311_CashCollateralPledgedToCoverMarginRequirements / us-gaap_DerivativeInstrumentRiskAxis = ck0001415311_FuturesContractsSoldMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesShortVixShortTermFuturesEtfMember
ProShares UltraShort Bloomberg Crude Oil [Member]
Schedule of Investments [Line Items]
Cash collateral pledged to cover margin requirements	20,594,295ck0001415311_CashCollateralPledgedToCoverMarginRequirements / us-gaap_DerivativeInstrumentRiskAxis = ck0001415311_FuturesContractsSoldMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltrashortBloombergCrudeOilMember
ProShares UltraShort Bloomberg Natural Gas [Member]
Schedule of Investments [Line Items]
Cash collateral pledged to cover margin requirements	1,708,036ck0001415311_CashCollateralPledgedToCoverMarginRequirements / us-gaap_DerivativeInstrumentRiskAxis = ck0001415311_FuturesContractsSoldMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltrashortBloombergNaturalGasMember
ProShares UltraShort Gold [Member]
Schedule of Investments [Line Items]
Cash collateral pledged to cover margin requirements	8,800ck0001415311_CashCollateralPledgedToCoverMarginRequirements / us-gaap_DerivativeInstrumentRiskAxis = ck0001415311_FuturesContractsSoldMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltrashortGoldMember
ProShares UltraShort Silver [Member]
Schedule of Investments [Line Items]
Cash collateral pledged to cover margin requirements	16,940ck0001415311_CashCollateralPledgedToCoverMarginRequirements / us-gaap_DerivativeInstrumentRiskAxis = ck0001415311_FuturesContractsSoldMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltrashortSilverMember
ProShares Short Euro [Member]
Schedule of Investments [Line Items]
Cash collateral pledged to cover margin requirements	511,500ck0001415311_CashCollateralPledgedToCoverMarginRequirements / us-gaap_DerivativeInstrumentRiskAxis = ck0001415311_FuturesContractsSoldMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesShortEuroMember
ProShares UltraShort Australian Dollar [Member]
Schedule of Investments [Line Items]
Cash collateral pledged to cover margin requirements	$ 382,125ck0001415311_CashCollateralPledgedToCoverMarginRequirements / us-gaap_DerivativeInstrumentRiskAxis = ck0001415311_FuturesContractsSoldMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltrashortAustralianDollarMember

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