v2.4.1.9
Schedule of Investments - Swap Agreements (Detail) (USD $)
 3 Months Ended
Mar. 31, 2015
ProShares UltraShort Bloomberg Commodity [Member]  
Schedule of Investments [Line Items]  
Unrealized Appreciation (Depreciation) $ 276,625us-gaap_InvestmentOwnedUnrecognizedUnrealizedAppreciationDepreciationNet
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCommodityMember		 [1]
ProShares UltraShort Bloomberg Commodity [Member] | Swap Agreement with Deutsche Bank AG Based on Bloomberg Commodity Index [Member]  
Schedule of Investments [Line Items]  
Rate Paid (Received) 0.25%ck0001415311_DerivativeRateReceivedPaidPercent
/ us-gaap_InvestmentTypeAxis
= ck0001415311_SwapAgreementWithDeutscheBankAgBasedOnBloombergCommodityIndexMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCommodityMember		 [1],[2]
Termination Date Apr. 07, 2015 [1]
Notional Amount at Value (4,602,773)ck0001415311_LongShortInvestmentOwnedUnderlyingFaceAmountAtMarketValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_SwapAgreementWithDeutscheBankAgBasedOnBloombergCommodityIndexMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCommodityMember		 [1],[3]
Unrealized Appreciation (Depreciation) 118,941us-gaap_InvestmentOwnedUnrecognizedUnrealizedAppreciationDepreciationNet
/ us-gaap_InvestmentTypeAxis
= ck0001415311_SwapAgreementWithDeutscheBankAgBasedOnBloombergCommodityIndexMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCommodityMember		 [1]
ProShares UltraShort Bloomberg Commodity [Member] | Swap Agreement with Goldman Sachs International Based on Bloomberg Commodity Index [Member]  
Schedule of Investments [Line Items]  
Rate Paid (Received) 0.25%ck0001415311_DerivativeRateReceivedPaidPercent
/ us-gaap_InvestmentTypeAxis
= ck0001415311_SwapAgreementWithGoldmanSachsInternationalBasedOnBloombergCommodityIndexMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCommodityMember		 [1],[2]
Termination Date Apr. 07, 2015 [1]
Notional Amount at Value (4,537,347)ck0001415311_LongShortInvestmentOwnedUnderlyingFaceAmountAtMarketValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_SwapAgreementWithGoldmanSachsInternationalBasedOnBloombergCommodityIndexMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCommodityMember		 [1],[3]
Unrealized Appreciation (Depreciation) 113,070us-gaap_InvestmentOwnedUnrecognizedUnrealizedAppreciationDepreciationNet
/ us-gaap_InvestmentTypeAxis
= ck0001415311_SwapAgreementWithGoldmanSachsInternationalBasedOnBloombergCommodityIndexMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCommodityMember		 [1]
ProShares UltraShort Bloomberg Commodity [Member] | Swap Agreement with UBS AG Based on Bloomberg Commodity Index [Member]  
Schedule of Investments [Line Items]  
Rate Paid (Received) 0.60%ck0001415311_DerivativeRateReceivedPaidPercent
/ us-gaap_InvestmentTypeAxis
= ck0001415311_SwapAgreementWithUbsAgBasedOnBloombergCommodityIndexMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCommodityMember		 [1],[2]
Termination Date Apr. 07, 2015 [1]
Notional Amount at Value (2,475,856)ck0001415311_LongShortInvestmentOwnedUnderlyingFaceAmountAtMarketValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_SwapAgreementWithUbsAgBasedOnBloombergCommodityIndexMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCommodityMember		 [1],[3]
Unrealized Appreciation (Depreciation) 44,614us-gaap_InvestmentOwnedUnrecognizedUnrealizedAppreciationDepreciationNet
/ us-gaap_InvestmentTypeAxis
= ck0001415311_SwapAgreementWithUbsAgBasedOnBloombergCommodityIndexMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCommodityMember		 [1]
ProShares UltraShort Bloomberg Crude Oil [Member]  
Schedule of Investments [Line Items]  
Unrealized Appreciation (Depreciation) 26,857,473us-gaap_InvestmentOwnedUnrecognizedUnrealizedAppreciationDepreciationNet
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCrudeOilMember		 [1]
ProShares UltraShort Bloomberg Crude Oil [Member] | Swap Agreement with Deutsche Bank AG Based on Bloomberg WTI Crude Oil Sub-Index [Member]  
Schedule of Investments [Line Items]  
Rate Paid (Received) 0.25%ck0001415311_DerivativeRateReceivedPaidPercent
/ us-gaap_InvestmentTypeAxis
= ck0001415311_SwapAgreementWithDeutscheBankAgBasedOnBloombergWtiCrudeOilSubIndexMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCrudeOilMember		 [1],[2]
Termination Date Apr. 07, 2015 [1]
Notional Amount at Value (137,750,775)ck0001415311_LongShortInvestmentOwnedUnderlyingFaceAmountAtMarketValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_SwapAgreementWithDeutscheBankAgBasedOnBloombergWtiCrudeOilSubIndexMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCrudeOilMember		 [1],[3]
Unrealized Appreciation (Depreciation) 9,502,897us-gaap_InvestmentOwnedUnrecognizedUnrealizedAppreciationDepreciationNet
/ us-gaap_InvestmentTypeAxis
= ck0001415311_SwapAgreementWithDeutscheBankAgBasedOnBloombergWtiCrudeOilSubIndexMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCrudeOilMember		 [1]
ProShares UltraShort Bloomberg Crude Oil [Member] | Swap Agreement with Goldman Sachs International Based on Bloomberg WTI Crude Oil Sub-Index [Member]  
Schedule of Investments [Line Items]  
Rate Paid (Received) 0.25%ck0001415311_DerivativeRateReceivedPaidPercent
/ us-gaap_InvestmentTypeAxis
= ck0001415311_SwapAgreementWithGoldmanSachsInternationalBasedOnBloombergWtiCrudeOilSubIndexMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCrudeOilMember		 [1],[2]
Termination Date Apr. 07, 2015 [1]
Notional Amount at Value (126,651,917)ck0001415311_LongShortInvestmentOwnedUnderlyingFaceAmountAtMarketValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_SwapAgreementWithGoldmanSachsInternationalBasedOnBloombergWtiCrudeOilSubIndexMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCrudeOilMember		 [1],[3]
Unrealized Appreciation (Depreciation) 7,090,832us-gaap_InvestmentOwnedUnrecognizedUnrealizedAppreciationDepreciationNet
/ us-gaap_InvestmentTypeAxis
= ck0001415311_SwapAgreementWithGoldmanSachsInternationalBasedOnBloombergWtiCrudeOilSubIndexMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCrudeOilMember		 [1]
ProShares UltraShort Bloomberg Crude Oil [Member] | Swap Agreement with Societe Generale S.A. Based on Bloomberg WTI Crude Oil Sub-Index [Member]  
Schedule of Investments [Line Items]  
Rate Paid (Received) 0.25%ck0001415311_DerivativeRateReceivedPaidPercent
/ us-gaap_InvestmentTypeAxis
= ck0001415311_SwapAgreementWithSocieteGeneraleSaBasedOnBloombergWtiCrudeOilSubIndexMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCrudeOilMember		 [1],[2]
Termination Date Apr. 07, 2015 [1]
Notional Amount at Value (35,138,342)ck0001415311_LongShortInvestmentOwnedUnderlyingFaceAmountAtMarketValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_SwapAgreementWithSocieteGeneraleSaBasedOnBloombergWtiCrudeOilSubIndexMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCrudeOilMember		 [1],[3]
Unrealized Appreciation (Depreciation) 2,850,353us-gaap_InvestmentOwnedUnrecognizedUnrealizedAppreciationDepreciationNet
/ us-gaap_InvestmentTypeAxis
= ck0001415311_SwapAgreementWithSocieteGeneraleSaBasedOnBloombergWtiCrudeOilSubIndexMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCrudeOilMember		 [1]
ProShares UltraShort Bloomberg Crude Oil [Member] | Swap Agreement with UBS AG Based on Bloomberg WTI Crude Oil Sub-Index [Member]  
Schedule of Investments [Line Items]  
Rate Paid (Received) 0.25%ck0001415311_DerivativeRateReceivedPaidPercent
/ us-gaap_InvestmentTypeAxis
= ck0001415311_SwapAgreementWithUbsAgBasedOnBloombergWtiCrudeOilSubIndexMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCrudeOilMember		 [1],[2]
Termination Date Apr. 07, 2015 [1]
Notional Amount at Value (125,826,188)ck0001415311_LongShortInvestmentOwnedUnderlyingFaceAmountAtMarketValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_SwapAgreementWithUbsAgBasedOnBloombergWtiCrudeOilSubIndexMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCrudeOilMember		 [1],[3]
Unrealized Appreciation (Depreciation) 7,413,391us-gaap_InvestmentOwnedUnrecognizedUnrealizedAppreciationDepreciationNet
/ us-gaap_InvestmentTypeAxis
= ck0001415311_SwapAgreementWithUbsAgBasedOnBloombergWtiCrudeOilSubIndexMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCrudeOilMember		 [1]
ProShares Ultra Bloomberg Commodity [Member]  
Schedule of Investments [Line Items]  
Unrealized Appreciation (Depreciation) (129,433)us-gaap_InvestmentOwnedUnrecognizedUnrealizedAppreciationDepreciationNet
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCommodityMember		 [1]
ProShares Ultra Bloomberg Commodity [Member] | Swap Agreement with Deutsche Bank AG Based on Bloomberg Commodity Index [Member]  
Schedule of Investments [Line Items]  
Rate Paid (Received) 0.25%ck0001415311_DerivativeRateReceivedPaidPercent
/ us-gaap_InvestmentTypeAxis
= ck0001415311_SwapAgreementWithDeutscheBankAgBasedOnBloombergCommodityIndexMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCommodityMember		 [1],[2]
Termination Date Apr. 07, 2015 [1]
Notional Amount at Value 1,972,023ck0001415311_LongShortInvestmentOwnedUnderlyingFaceAmountAtMarketValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_SwapAgreementWithDeutscheBankAgBasedOnBloombergCommodityIndexMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCommodityMember		 [1],[3]
Unrealized Appreciation (Depreciation) (54,521)us-gaap_InvestmentOwnedUnrecognizedUnrealizedAppreciationDepreciationNet
/ us-gaap_InvestmentTypeAxis
= ck0001415311_SwapAgreementWithDeutscheBankAgBasedOnBloombergCommodityIndexMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCommodityMember		 [1]
ProShares Ultra Bloomberg Commodity [Member] | Swap Agreement with Goldman Sachs International Based on Bloomberg Commodity Index [Member]  
Schedule of Investments [Line Items]  
Rate Paid (Received) 0.25%ck0001415311_DerivativeRateReceivedPaidPercent
/ us-gaap_InvestmentTypeAxis
= ck0001415311_SwapAgreementWithGoldmanSachsInternationalBasedOnBloombergCommodityIndexMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCommodityMember		 [1],[2]
Termination Date Apr. 07, 2015 [1]
Notional Amount at Value 1,999,276ck0001415311_LongShortInvestmentOwnedUnderlyingFaceAmountAtMarketValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_SwapAgreementWithGoldmanSachsInternationalBasedOnBloombergCommodityIndexMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCommodityMember		 [1],[3]
Unrealized Appreciation (Depreciation) (55,872)us-gaap_InvestmentOwnedUnrecognizedUnrealizedAppreciationDepreciationNet
/ us-gaap_InvestmentTypeAxis
= ck0001415311_SwapAgreementWithGoldmanSachsInternationalBasedOnBloombergCommodityIndexMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCommodityMember		 [1]
ProShares Ultra Bloomberg Commodity [Member] | Swap Agreement with UBS AG Based on Bloomberg Commodity Index [Member]  
Schedule of Investments [Line Items]  
Rate Paid (Received) 0.60%ck0001415311_DerivativeRateReceivedPaidPercent
/ us-gaap_InvestmentTypeAxis
= ck0001415311_SwapAgreementWithUbsAgBasedOnBloombergCommodityIndexMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCommodityMember		 [1],[2]
Termination Date Apr. 07, 2015 [1]
Notional Amount at Value 603,138ck0001415311_LongShortInvestmentOwnedUnderlyingFaceAmountAtMarketValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_SwapAgreementWithUbsAgBasedOnBloombergCommodityIndexMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCommodityMember		 [1],[3]
Unrealized Appreciation (Depreciation) (19,040)us-gaap_InvestmentOwnedUnrecognizedUnrealizedAppreciationDepreciationNet
/ us-gaap_InvestmentTypeAxis
= ck0001415311_SwapAgreementWithUbsAgBasedOnBloombergCommodityIndexMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCommodityMember		 [1]
ProShares Ultra Bloomberg Crude Oil [Member]  
Schedule of Investments [Line Items]  
Unrealized Appreciation (Depreciation) (78,474,219)us-gaap_InvestmentOwnedUnrecognizedUnrealizedAppreciationDepreciationNet
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCrudeOilMember		 [1]
ProShares Ultra Bloomberg Crude Oil [Member] | Swap Agreement with Deutsche Bank AG Based on Bloomberg WTI Crude Oil Sub-Index [Member]  
Schedule of Investments [Line Items]  
Rate Paid (Received) 0.25%ck0001415311_DerivativeRateReceivedPaidPercent
/ us-gaap_InvestmentTypeAxis
= ck0001415311_SwapAgreementWithDeutscheBankAgBasedOnBloombergWtiCrudeOilSubIndexMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCrudeOilMember		 [1],[2]
Termination Date Apr. 07, 2015 [1]
Notional Amount at Value 406,797,888ck0001415311_LongShortInvestmentOwnedUnderlyingFaceAmountAtMarketValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_SwapAgreementWithDeutscheBankAgBasedOnBloombergWtiCrudeOilSubIndexMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCrudeOilMember		 [1],[3]
Unrealized Appreciation (Depreciation) (24,270,565)us-gaap_InvestmentOwnedUnrecognizedUnrealizedAppreciationDepreciationNet
/ us-gaap_InvestmentTypeAxis
= ck0001415311_SwapAgreementWithDeutscheBankAgBasedOnBloombergWtiCrudeOilSubIndexMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCrudeOilMember		 [1]
ProShares Ultra Bloomberg Crude Oil [Member] | Swap Agreement with Goldman Sachs International Based on Bloomberg WTI Crude Oil Sub-Index [Member]  
Schedule of Investments [Line Items]  
Rate Paid (Received) 0.25%ck0001415311_DerivativeRateReceivedPaidPercent
/ us-gaap_InvestmentTypeAxis
= ck0001415311_SwapAgreementWithGoldmanSachsInternationalBasedOnBloombergWtiCrudeOilSubIndexMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCrudeOilMember		 [1],[2]
Termination Date Apr. 07, 2015 [1]
Notional Amount at Value 417,976,514ck0001415311_LongShortInvestmentOwnedUnderlyingFaceAmountAtMarketValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_SwapAgreementWithGoldmanSachsInternationalBasedOnBloombergWtiCrudeOilSubIndexMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCrudeOilMember		 [1],[3]
Unrealized Appreciation (Depreciation) (24,277,344)us-gaap_InvestmentOwnedUnrecognizedUnrealizedAppreciationDepreciationNet
/ us-gaap_InvestmentTypeAxis
= ck0001415311_SwapAgreementWithGoldmanSachsInternationalBasedOnBloombergWtiCrudeOilSubIndexMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCrudeOilMember		 [1]
ProShares Ultra Bloomberg Crude Oil [Member] | Swap Agreement with Societe Generale S.A. Based on Bloomberg WTI Crude Oil Sub-Index [Member]  
Schedule of Investments [Line Items]  
Rate Paid (Received) 0.25%ck0001415311_DerivativeRateReceivedPaidPercent
/ us-gaap_InvestmentTypeAxis
= ck0001415311_SwapAgreementWithSocieteGeneraleSaBasedOnBloombergWtiCrudeOilSubIndexMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCrudeOilMember		 [1],[2]
Termination Date Apr. 07, 2015 [1]
Notional Amount at Value 123,097,457ck0001415311_LongShortInvestmentOwnedUnderlyingFaceAmountAtMarketValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_SwapAgreementWithSocieteGeneraleSaBasedOnBloombergWtiCrudeOilSubIndexMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCrudeOilMember		 [1],[3]
Unrealized Appreciation (Depreciation) (8,155,514)us-gaap_InvestmentOwnedUnrecognizedUnrealizedAppreciationDepreciationNet
/ us-gaap_InvestmentTypeAxis
= ck0001415311_SwapAgreementWithSocieteGeneraleSaBasedOnBloombergWtiCrudeOilSubIndexMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCrudeOilMember		 [1]
ProShares Ultra Bloomberg Crude Oil [Member] | Swap Agreement with UBS AG Based on Bloomberg WTI Crude Oil Sub-Index [Member]  
Schedule of Investments [Line Items]  
Rate Paid (Received) 0.25%ck0001415311_DerivativeRateReceivedPaidPercent
/ us-gaap_InvestmentTypeAxis
= ck0001415311_SwapAgreementWithUbsAgBasedOnBloombergWtiCrudeOilSubIndexMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCrudeOilMember		 [1],[2]
Termination Date Apr. 07, 2015 [1]
Notional Amount at Value 403,481,056ck0001415311_LongShortInvestmentOwnedUnderlyingFaceAmountAtMarketValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_SwapAgreementWithUbsAgBasedOnBloombergWtiCrudeOilSubIndexMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCrudeOilMember		 [1],[3]
Unrealized Appreciation (Depreciation) $ (21,770,796)us-gaap_InvestmentOwnedUnrecognizedUnrealizedAppreciationDepreciationNet
/ us-gaap_InvestmentTypeAxis
= ck0001415311_SwapAgreementWithUbsAgBasedOnBloombergWtiCrudeOilSubIndexMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCrudeOilMember		 [1]
[1] The positions and counterparties herein are as of March 31, 2015. The Funds continually evaluate different counterparties for their transactions and counterparties are subject to change. New counterparties can be added at anytime.
[2] Reflects the floating financing rate, as of March 31, 2015, on the notional amount of the swap agreement paid to the counterparty or received from the counterparty, excluding any commissions.
[3] For swap agreements, a positive amount represents "long" exposure to the benchmark index. A negative amount represents "short" exposure to the benchmark index.