v2.4.1.9

Schedule of Investments - Futures Contracts Purchased (Parenthetical) (Detail) (Futures Contracts Purchased [Member], USD $)	3 Months Ended
	Mar. 31, 2015
ProShares VIX Short-Term Futures ETF [Member]
Schedule of Investments [Line Items]
Cash collateral pledged to cover margin requirements	$ 11,020,165ck0001415311_CashCollateralPledgedToCoverMarginRequirements / us-gaap_DerivativeInstrumentRiskAxis = ck0001415311_FuturesContractsPurchasedMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesVixShortTermFuturesEtfMember
ProShares VIX Mid-Term Futures ETF [Member]
Schedule of Investments [Line Items]
Cash collateral pledged to cover margin requirements	2,134,050ck0001415311_CashCollateralPledgedToCoverMarginRequirements / us-gaap_DerivativeInstrumentRiskAxis = ck0001415311_FuturesContractsPurchasedMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesVixMidTermFuturesEtfMember
ProShares Ultra VIX Short-Term Futures ETF [Member]
Schedule of Investments [Line Items]
Cash collateral pledged to cover margin requirements	73,653,370ck0001415311_CashCollateralPledgedToCoverMarginRequirements / us-gaap_DerivativeInstrumentRiskAxis = ck0001415311_FuturesContractsPurchasedMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltraVixShortTermFuturesEtfMember
ProShares Ultra Bloomberg Crude Oil [Member]
Schedule of Investments [Line Items]
Cash collateral pledged to cover margin requirements	13,420,311ck0001415311_CashCollateralPledgedToCoverMarginRequirements / us-gaap_DerivativeInstrumentRiskAxis = ck0001415311_FuturesContractsPurchasedMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltraBloombergCrudeOilMember
ProShares Ultra Bloomberg Natural Gas [Member]
Schedule of Investments [Line Items]
Cash collateral pledged to cover margin requirements	3,842,480ck0001415311_CashCollateralPledgedToCoverMarginRequirements / us-gaap_DerivativeInstrumentRiskAxis = ck0001415311_FuturesContractsPurchasedMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltraBloombergNaturalGasMember
ProShares Ultra Gold [Member]
Schedule of Investments [Line Items]
Cash collateral pledged to cover margin requirements	8,800ck0001415311_CashCollateralPledgedToCoverMarginRequirements / us-gaap_DerivativeInstrumentRiskAxis = ck0001415311_FuturesContractsPurchasedMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltraGoldMember
ProShares Ultra Silver [Member]
Schedule of Investments [Line Items]
Cash collateral pledged to cover margin requirements	16,940ck0001415311_CashCollateralPledgedToCoverMarginRequirements / us-gaap_DerivativeInstrumentRiskAxis = ck0001415311_FuturesContractsPurchasedMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltraSilverMember
ProShares Ultra Australian Dollar [Member]
Schedule of Investments [Line Items]
Cash collateral pledged to cover margin requirements	$ 152,460ck0001415311_CashCollateralPledgedToCoverMarginRequirements / us-gaap_DerivativeInstrumentRiskAxis = ck0001415311_FuturesContractsPurchasedMember / us-gaap_StatementBusinessSegmentsAxis = ck0001415311_ProsharesUltraAustralianDollarMember

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