v2.4.1.9
Schedule of Investments - Short-Term U.S. Government and Agency Obligations (Detail) (USD $)
Mar. 31, 2015
ProShares VIX Short-Term Futures ETF [Member]  
Schedule of Investments [Line Items]  
Total short-term U.S. government and Value $ 131,184,020us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixShortTermFuturesEtfMember
ProShares VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.036% Due 04/16/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 5,181,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeSixPercentageDueAprilSixteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixShortTermFuturesEtfMember
Total short-term U.S. government and Value 5,180,968us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeSixPercentageDueAprilSixteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixShortTermFuturesEtfMember
ProShares VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.026% Due 04/30/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 3,973,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoSixPercentageDueAprilThirtyTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixShortTermFuturesEtfMember
Total short-term U.S. government and Value 3,972,856us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoSixPercentageDueAprilThirtyTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixShortTermFuturesEtfMember
ProShares VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.061% Due 05/14/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 4,724,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSixOnePercentageDueMayFourteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixShortTermFuturesEtfMember
Total short-term U.S. government and Value 4,723,859us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSixOnePercentageDueMayFourteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixShortTermFuturesEtfMember
ProShares VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.017% Due 05/21/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 9,229,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneSevenPercentageDueMayTwentyOneTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixShortTermFuturesEtfMember
Total short-term U.S. government and Value 9,228,680us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneSevenPercentageDueMayTwentyOneTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixShortTermFuturesEtfMember
ProShares VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.049% Due 05/28/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 18,620,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourNinePercentageDueMayTwentyEighthTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixShortTermFuturesEtfMember
Total short-term U.S. government and Value 18,619,116us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourNinePercentageDueMayTwentyEighthTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixShortTermFuturesEtfMember
ProShares VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.046% Due 06/04/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 105,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourSixPercentageDueJuneFourTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixShortTermFuturesEtfMember
Total short-term U.S. government and Value 104,996us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourSixPercentageDueJuneFourTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixShortTermFuturesEtfMember
ProShares VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.013% Due 06/11/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 3,645,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneThreePercentageDueJuneElevenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixShortTermFuturesEtfMember
Total short-term U.S. government and Value 3,644,856us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneThreePercentageDueJuneElevenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixShortTermFuturesEtfMember
ProShares VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.016% Due 06/18/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 7,018,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneSixPercentageDueJuneEighteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixShortTermFuturesEtfMember
Total short-term U.S. government and Value 7,017,772us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneSixPercentageDueJuneEighteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixShortTermFuturesEtfMember
ProShares VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.021% Due 06/25/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 8,833,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoOnePercentageDueJuneTwentyFiveTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixShortTermFuturesEtfMember
[1]
Total short-term U.S. government and Value 8,832,792us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoOnePercentageDueJuneTwentyFiveTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixShortTermFuturesEtfMember
[1]
ProShares VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.024% Due 07/02/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 12,954,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoFourPercentageDueJulyTwoTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixShortTermFuturesEtfMember
Total short-term U.S. government and Value 12,953,006us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoFourPercentageDueJulyTwoTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixShortTermFuturesEtfMember
ProShares VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.039% Due 07/09/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 3,121,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeNinePercentageDueJulyNineTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixShortTermFuturesEtfMember
Total short-term U.S. government and Value 3,120,828us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeNinePercentageDueJulyNineTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixShortTermFuturesEtfMember
ProShares VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.036% Due 07/16/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 11,521,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeSixPercentageDueJulySixteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixShortTermFuturesEtfMember
Total short-term U.S. government and Value 11,519,812us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeSixPercentageDueJulySixteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixShortTermFuturesEtfMember
ProShares VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.043% Due 07/23/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 10,365,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourThreePercentageDueJulyTwentyThreeTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixShortTermFuturesEtfMember
Total short-term U.S. government and Value 10,363,861us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourThreePercentageDueJulyTwentyThreeTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixShortTermFuturesEtfMember
ProShares VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.035% Due 07/30/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 907,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeFivePercentageDueJulyThirtyTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixShortTermFuturesEtfMember
Total short-term U.S. government and Value 906,879us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeFivePercentageDueJulyThirtyTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixShortTermFuturesEtfMember
ProShares VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.057% Due 08/06/2015 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 7,920,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFiveSevenPercentageDueAugustSixTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixShortTermFuturesEtfMember
[1]
Total short-term U.S. government and Value 7,918,463us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFiveSevenPercentageDueAugustSixTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixShortTermFuturesEtfMember
[1]
ProShares VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.050% Due 08/13/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 23,080,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFiveZeroPercentageDueAugustThirteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixShortTermFuturesEtfMember
[1]
Total short-term U.S. government and Value 23,075,276us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFiveZeroPercentageDueAugustThirteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixShortTermFuturesEtfMember
[1]
ProShares VIX Mid-Term Futures ETF [Member]  
Schedule of Investments [Line Items]  
Total short-term U.S. government and Value 27,675,412us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixMidTermFuturesEtfMember
ProShares VIX Mid-Term Futures ETF [Member] | U.S. Treasury Bills 0.036% Due 07/16/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 6,167,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeSixPercentageDueJulySixteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixMidTermFuturesEtfMember
Total short-term U.S. government and Value 6,166,364us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeSixPercentageDueJulySixteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixMidTermFuturesEtfMember
ProShares VIX Mid-Term Futures ETF [Member] | U.S. Treasury Bills 0.043% Due 04/16/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 5,374,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourThreePercentageDueAprilSixteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixMidTermFuturesEtfMember
Total short-term U.S. government and Value 5,373,967us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourThreePercentageDueAprilSixteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixMidTermFuturesEtfMember
ProShares VIX Mid-Term Futures ETF [Member] | U.S. Treasury Bills 0.036% Due 04/30/2015 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 1,593,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeSixPercentageDueAprilThirtyTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixMidTermFuturesEtfMember
Total short-term U.S. government and Value 1,592,942us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeSixPercentageDueAprilThirtyTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixMidTermFuturesEtfMember
ProShares VIX Mid-Term Futures ETF [Member] | U.S. Treasury Bills 0.031% Due 05/21/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 5,405,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeOnePercentageDueAprilTwentyOneTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixMidTermFuturesEtfMember
Total short-term U.S. government and Value 5,404,813us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeOnePercentageDueAprilTwentyOneTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixMidTermFuturesEtfMember
ProShares VIX Mid-Term Futures ETF [Member] | U.S. Treasury Bills 0.071% Due 05/28/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 851,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSevenOnePercentageDueMayTwentyEightTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixMidTermFuturesEtfMember
Total short-term U.S. government and Value 850,960us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSevenOnePercentageDueMayTwentyEightTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixMidTermFuturesEtfMember
ProShares VIX Mid-Term Futures ETF [Member] | U.S. Treasury Bills 0.087% Due 06/11/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 3,675,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroEightSevenPercentageDueJuneElevenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixMidTermFuturesEtfMember
Total short-term U.S. government and Value 3,674,855us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroEightSevenPercentageDueJuneElevenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixMidTermFuturesEtfMember
ProShares VIX Mid-Term Futures ETF [Member] | U.S. Treasury Bills 0.015% Due 06/18/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 1,773,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneFivePercentageDueJuneEighteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixMidTermFuturesEtfMember
Total short-term U.S. government and Value 1,772,942us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneFivePercentageDueJuneEighteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixMidTermFuturesEtfMember
ProShares VIX Mid-Term Futures ETF [Member] | U.S. Treasury Bills 0.030% Due 07/02/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 1,020,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeZeroPercentageDueJulySevenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixMidTermFuturesEtfMember
Total short-term U.S. government and Value 1,019,922us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeZeroPercentageDueJulySevenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixMidTermFuturesEtfMember
ProShares VIX Mid-Term Futures ETF [Member] | U.S. Treasury Bills 0.045% Due 08/06/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 1,819,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourFivePercentageDueAugustSixTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixMidTermFuturesEtfMember
[1]
Total short-term U.S. government and Value 1,818,647us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourFivePercentageDueAugustSixTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesVixMidTermFuturesEtfMember
[1]
ProShares Short VIX Short-Term Futures ETF [Member]  
Schedule of Investments [Line Items]  
Total short-term U.S. government and Value 222,919,943us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesShortVixShortTermFuturesEtfMember
ProShares Short VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.043% Due 04/16/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 6,920,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourThreePercentageDueAprilSixteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesShortVixShortTermFuturesEtfMember
Total short-term U.S. government and Value 6,919,957us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourThreePercentageDueAprilSixteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesShortVixShortTermFuturesEtfMember
ProShares Short VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.015% Due 06/18/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 19,284,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneFivePercentageDueJuneEighteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesShortVixShortTermFuturesEtfMember
Total short-term U.S. government and Value 19,283,373us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneFivePercentageDueJuneEighteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesShortVixShortTermFuturesEtfMember
ProShares Short VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.044% Due 05/14/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 12,864,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourFourPercentageDueMayFourteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesShortVixShortTermFuturesEtfMember
Total short-term U.S. government and Value 12,863,615us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourFourPercentageDueMayFourteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesShortVixShortTermFuturesEtfMember
ProShares Short VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.032% Due 05/21/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 12,226,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeTwoPercentageDueMayTwentyOneTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesShortVixShortTermFuturesEtfMember
Total short-term U.S. government and Value 12,225,576us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeTwoPercentageDueMayTwentyOneTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesShortVixShortTermFuturesEtfMember
ProShares Short VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.073% Due 05/28/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 3,786,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSevenThreePercentageDueMayTwentyEighthTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesShortVixShortTermFuturesEtfMember
Total short-term U.S. government and Value 3,785,820us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSevenThreePercentageDueMayTwentyEighthTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesShortVixShortTermFuturesEtfMember
ProShares Short VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.061% Due 06/04/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 13,984,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSixOnePercentageDueJuneFourTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesShortVixShortTermFuturesEtfMember
Total short-term U.S. government and Value 13,983,502us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSixOnePercentageDueJuneFourTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesShortVixShortTermFuturesEtfMember
ProShares Short VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.017% Due 06/11/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 4,401,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneSevenPercentageDueJuneElevenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesShortVixShortTermFuturesEtfMember
Total short-term U.S. government and Value 4,400,827us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneSevenPercentageDueJuneElevenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesShortVixShortTermFuturesEtfMember
ProShares Short VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.041% Due 06/25/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 25,966,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourOnePercentageDueJuneTwentyFiveTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesShortVixShortTermFuturesEtfMember
[1]
Total short-term U.S. government and Value 25,965,387us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourOnePercentageDueJuneTwentyFiveTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesShortVixShortTermFuturesEtfMember
[1]
ProShares Short VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.022% Due 07/02/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 43,634,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoTwoPercentageDueJulyTwoTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesShortVixShortTermFuturesEtfMember
[1]
Total short-term U.S. government and Value 43,630,653us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoTwoPercentageDueJulyTwoTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesShortVixShortTermFuturesEtfMember
[1]
ProShares Short VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.057% Due 07/19/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 16,047,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFiveSevenPercentageDueJulyNineTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesShortVixShortTermFuturesEtfMember
[1]
Total short-term U.S. government and Value 16,046,118us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFiveSevenPercentageDueJulyNineTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesShortVixShortTermFuturesEtfMember
[1]
ProShares Short VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.028% Due 07/16/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 21,796,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoEightPercentageDueJulySixteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesShortVixShortTermFuturesEtfMember
Total short-term U.S. government and Value 21,793,753us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoEightPercentageDueJulySixteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesShortVixShortTermFuturesEtfMember
ProShares Short VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.047% Due 07/23/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 4,213,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourSevenPercentageDueJulyTwentyThreeTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesShortVixShortTermFuturesEtfMember
Total short-term U.S. government and Value 4,212,537us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourSevenPercentageDueJulyTwentyThreeTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesShortVixShortTermFuturesEtfMember
ProShares Short VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.030% Due 07/30/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 20,999,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeZeroPercentageDueJulyThirtyTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesShortVixShortTermFuturesEtfMember
Total short-term U.S. government and Value 20,996,201us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeZeroPercentageDueJulyThirtyTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesShortVixShortTermFuturesEtfMember
ProShares Short VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.061% Due 08/06/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 6,164,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSixOnePercentageDueAugustSixTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesShortVixShortTermFuturesEtfMember
[1]
Total short-term U.S. government and Value 6,162,804us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSixOnePercentageDueAugustSixTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesShortVixShortTermFuturesEtfMember
[1]
ProShares Short VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.045% Due 08/13/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 10,652,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourFivePercentageDueAugustThirteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesShortVixShortTermFuturesEtfMember
[1]
Total short-term U.S. government and Value 10,649,820us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourFivePercentageDueAugustThirteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesShortVixShortTermFuturesEtfMember
[1]
ProShares Ultra VIX Short-Term Futures ETF [Member]  
Schedule of Investments [Line Items]  
Total short-term U.S. government and Value 569,900,064us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraVixShortTermFuturesEtfMember
ProShares Ultra VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.036% Due 04/16/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 212,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeSixPercentageDueAprilSixteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraVixShortTermFuturesEtfMember
Total short-term U.S. government and Value 211,999us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeSixPercentageDueAprilSixteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraVixShortTermFuturesEtfMember
ProShares Ultra VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.061% Due 05/14/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 3,104,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSixOnePercentageDueMayFourteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraVixShortTermFuturesEtfMember
Total short-term U.S. government and Value 3,103,907us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSixOnePercentageDueMayFourteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraVixShortTermFuturesEtfMember
ProShares Ultra VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.046% Due 06/04/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 27,212,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourSixPercentageDueJuneFourTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraVixShortTermFuturesEtfMember
Total short-term U.S. government and Value 27,211,031us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourSixPercentageDueJuneFourTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraVixShortTermFuturesEtfMember
ProShares Ultra VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.021% Due 06/25/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 76,304,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoOnePercentageDueJuneTwentyFiveTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraVixShortTermFuturesEtfMember
Total short-term U.S. government and Value 76,302,199us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoOnePercentageDueJuneTwentyFiveTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraVixShortTermFuturesEtfMember
ProShares Ultra VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.001% Due 04/30/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 29,754,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroZeroOnePercentageDueAprilThirtyTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraVixShortTermFuturesEtfMember
Total short-term U.S. government and Value 29,752,923us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroZeroOnePercentageDueAprilThirtyTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraVixShortTermFuturesEtfMember
ProShares Ultra VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.012% Due 05/21/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 13,489,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneTwoPercentageDueMayTwentyOneTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraVixShortTermFuturesEtfMember
Total short-term U.S. government and Value 13,488,532us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneTwoPercentageDueMayTwentyOneTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraVixShortTermFuturesEtfMember
ProShares Ultra VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.018% Due 05/28/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 75,945,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneEightPercentageDueMayTwentyEightTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraVixShortTermFuturesEtfMember
Total short-term U.S. government and Value 75,941,393us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneEightPercentageDueMayTwentyEightTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraVixShortTermFuturesEtfMember
ProShares Ultra VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.010% Due 06/11/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 10,230,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneZeroPercentageDueJuneElevenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraVixShortTermFuturesEtfMember
Total short-term U.S. government and Value 10,229,597us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneZeroPercentageDueJuneElevenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraVixShortTermFuturesEtfMember
ProShares Ultra VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.013% Due 06/18/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 8,550,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneThreePercentageDueJuneEighteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraVixShortTermFuturesEtfMember
Total short-term U.S. government and Value 8,549,722us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneThreePercentageDueJuneEighteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraVixShortTermFuturesEtfMember
ProShares Ultra VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.015% Due 07/02/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 8,100,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneFivePercentageDueJulyTwoTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraVixShortTermFuturesEtfMember
[1]
Total short-term U.S. government and Value 8,099,379us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneFivePercentageDueJulyTwoTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraVixShortTermFuturesEtfMember
[1]
ProShares Ultra VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.040% Due 07/09/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 73,985,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourZeroPercentageDueJulyNineTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraVixShortTermFuturesEtfMember
[1]
Total short-term U.S. government and Value 73,980,931us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourZeroPercentageDueJulyNineTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraVixShortTermFuturesEtfMember
[1]
ProShares Ultra VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.027% Due 07/16/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 46,270,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoSevenPercentageDueJulySixteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraVixShortTermFuturesEtfMember
[1]
Total short-term U.S. government and Value 46,265,229us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoSevenPercentageDueJulySixteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraVixShortTermFuturesEtfMember
[1]
ProShares Ultra VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.037% Due 07/23/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 15,294,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeSevenPercentageDueJulyTwentyThreeTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraVixShortTermFuturesEtfMember
Total short-term U.S. government and Value 15,292,319us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeSevenPercentageDueJulyTwentyThreeTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraVixShortTermFuturesEtfMember
ProShares Ultra VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.031% Due 07/30/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 46,862,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeOnePercentageDueJulyThirtyTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraVixShortTermFuturesEtfMember
[1]
Total short-term U.S. government and Value 46,855,753us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeOnePercentageDueJulyThirtyTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraVixShortTermFuturesEtfMember
[1]
ProShares Ultra VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.046% Due 08/06/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 66,459,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourSixPercentageDueAugustSixTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraVixShortTermFuturesEtfMember
[1]
Total short-term U.S. government and Value 66,446,107us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourSixPercentageDueAugustSixTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraVixShortTermFuturesEtfMember
[1]
ProShares Ultra VIX Short-Term Futures ETF [Member] | U.S. Treasury Bills 0.048% Due 08/13/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 68,183,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourEightPercentageDueAugustThirteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraVixShortTermFuturesEtfMember
[1]
Total short-term U.S. government and Value 68,169,043us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourEightPercentageDueAugustThirteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraVixShortTermFuturesEtfMember
[1]
ProShares UltraShort Bloomberg Commodity [Member]  
Schedule of Investments [Line Items]  
Total short-term U.S. government and Value 4,990,827us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCommodityMember
ProShares UltraShort Bloomberg Commodity [Member] | U.S. Treasury Bills 0.016% Due 06/18/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 607,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneSixPercentageDueJuneEighteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCommodityMember
Total short-term U.S. government and Value 606,980us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneSixPercentageDueJuneEighteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCommodityMember
ProShares UltraShort Bloomberg Commodity [Member] | U.S. Treasury Bills 0.087% Due 06/11/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 877,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroEightSevenPercentageDueJuneElevenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCommodityMember
[2]
Total short-term U.S. government and Value 876,965us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroEightSevenPercentageDueJuneElevenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCommodityMember
[2]
ProShares UltraShort Bloomberg Commodity [Member] | U.S. Treasury Bills 0.039% Due 04/16/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 2,131,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeNinePercentageDueAprilSixteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCommodityMember
[2]
Total short-term U.S. government and Value 2,130,987us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeNinePercentageDueAprilSixteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCommodityMember
[2]
ProShares UltraShort Bloomberg Commodity [Member] | U.S. Treasury Bills 0.050% Due 07/09/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 828,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFiveZeroPercentageDueJulyNineTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCommodityMember
[2]
Total short-term U.S. government and Value 827,955us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFiveZeroPercentageDueJulyNineTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCommodityMember
[2]
ProShares UltraShort Bloomberg Commodity [Member] | U.S. Treasury Bills 0.038% Due 07/23/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 548,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeEightPercentageDueJulyTwentyThreeTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCommodityMember
[2]
Total short-term U.S. government and Value 547,940us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeEightPercentageDueJulyTwentyThreeTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCommodityMember
[2]
ProShares UltraShort Bloomberg Crude Oil [Member]  
Schedule of Investments [Line Items]  
Total short-term U.S. government and Value 319,733,997us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCrudeOilMember
ProShares UltraShort Bloomberg Crude Oil [Member] | U.S. Treasury Bills 0.026% Due 04/30/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 29,818,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoSixPercentageDueAprilThirtyTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCrudeOilMember
Total short-term U.S. government and Value 29,816,921us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoSixPercentageDueAprilThirtyTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCrudeOilMember
ProShares UltraShort Bloomberg Crude Oil [Member] | U.S. Treasury Bills 0.041% Due 04/16/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 8,635,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourOnePercentageDueAprilSixteenTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCrudeOilMember
Total short-term U.S. government and Value 8,634,946us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourOnePercentageDueAprilSixteenTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCrudeOilMember
ProShares UltraShort Bloomberg Crude Oil [Member] | U.S. Treasury Bills 0.064% Due 05/14/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 6,795,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSixFourPercentageDueMayFourteenTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCrudeOilMember
[3]
Total short-term U.S. government and Value 6,794,797us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSixFourPercentageDueMayFourteenTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCrudeOilMember
[3]
ProShares UltraShort Bloomberg Crude Oil [Member] | U.S. Treasury Bills 0.023% Due 05/21/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 7,636,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoThreePercentageDueMayTwentyOneTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCrudeOilMember
[3]
Total short-term U.S. government and Value 7,635,735us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoThreePercentageDueMayTwentyOneTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCrudeOilMember
[3]
ProShares UltraShort Bloomberg Crude Oil [Member] | U.S. Treasury Bills 0.020% Due 05/28/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 40,758,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoZeroPercentageDueMayTwentyEightTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCrudeOilMember
Total short-term U.S. government and Value 40,756,064us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoZeroPercentageDueMayTwentyEightTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCrudeOilMember
ProShares UltraShort Bloomberg Crude Oil [Member] | U.S. Treasury Bills 0.069% Due 06/04/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 6,555,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSixNinePercentageDueJuneFourTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCrudeOilMember
Total short-term U.S. government and Value 6,554,767us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSixNinePercentageDueJuneFourTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCrudeOilMember
ProShares UltraShort Bloomberg Crude Oil [Member] | U.S. Treasury Bills 0.013% Due 06/11/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 39,293,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneThreePercentageDueJuneElevenTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCrudeOilMember
[3]
Total short-term U.S. government and Value 39,291,452us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneThreePercentageDueJuneElevenTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCrudeOilMember
[3]
ProShares UltraShort Bloomberg Crude Oil [Member] | U.S. Treasury Bills 0.002% Due 06/18/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 31,032,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroZeroTwoPercentageDueJuneEighteenTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCrudeOilMember
[3]
Total short-term U.S. government and Value 31,030,991us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroZeroTwoPercentageDueJuneEighteenTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCrudeOilMember
[3]
ProShares UltraShort Bloomberg Crude Oil [Member] | U.S. Treasury Bills 0.015% Due 06/25/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 12,887,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneFivePercentageDueJuneTwentyFiveTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCrudeOilMember
[3]
Total short-term U.S. government and Value 12,886,696us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneFivePercentageDueJuneTwentyFiveTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCrudeOilMember
[3]
ProShares UltraShort Bloomberg Crude Oil [Member] | U.S. Treasury Bills 0.023% Due 07/02/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 54,556,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoThreePercentageDueJulyTwoTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCrudeOilMember
[3]
Total short-term U.S. government and Value 54,551,815us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoThreePercentageDueJulyTwoTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCrudeOilMember
[3]
ProShares UltraShort Bloomberg Crude Oil [Member] | U.S. Treasury Bills 0.029% Due 07/16/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 13,419,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoNinePercentageDueJulySixteenTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCrudeOilMember
[3]
Total short-term U.S. government and Value 13,417,616us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoNinePercentageDueJulySixteenTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCrudeOilMember
[3]
ProShares UltraShort Bloomberg Crude Oil [Member] | U.S. Treasury Bills 0.037% Due 07/23/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 16,787,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeSevenPercentageDueJulyTwentyThreeTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCrudeOilMember
[3]
Total short-term U.S. government and Value 16,785,155us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeSevenPercentageDueJulyTwentyThreeTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCrudeOilMember
[3]
ProShares UltraShort Bloomberg Crude Oil [Member] | U.S. Treasury Bills 0.035% Due 07/30/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 6,214,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeFivePercentageDueJulyThirtyTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCrudeOilMember
[3]
Total short-term U.S. government and Value 6,213,172us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeFivePercentageDueJulyThirtyTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCrudeOilMember
[3]
ProShares UltraShort Bloomberg Crude Oil [Member] | U.S. Treasury Bills 0.050% Due 08/06/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 14,741,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFiveZeroPercentageDueAugustSixTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCrudeOilMember
[3]
Total short-term U.S. government and Value 14,738,140us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFiveZeroPercentageDueAugustSixTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCrudeOilMember
[3]
ProShares UltraShort Bloomberg Crude Oil [Member] | U.S. Treasury Bills 0.044% Due 08/13/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 30,632,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourFourPercentageDueAugustThirteenTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCrudeOilMember
[3]
Total short-term U.S. government and Value 30,625,730us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourFourPercentageDueAugustThirteenTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergCrudeOilMember
[3]
ProShares UltraShort Bloomberg Natural Gas [Member]  
Schedule of Investments [Line Items]  
Total short-term U.S. government and Value 8,979,498us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergNaturalGasMember
ProShares UltraShort Bloomberg Natural Gas [Member] | U.S. Treasury Bills 0.061% Due 05/14/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 2,097,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSixOnePercentageDueMayFourteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergNaturalGasMember
Total short-term U.S. government and Value 2,096,937us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSixOnePercentageDueMayFourteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergNaturalGasMember
ProShares UltraShort Bloomberg Natural Gas [Member] | U.S. Treasury Bills 0.016% Due 06/18/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 1,095,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneSixPercentageDueJuneEighteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergNaturalGasMember
Total short-term U.S. government and Value 1,094,964us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneSixPercentageDueJuneEighteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergNaturalGasMember
ProShares UltraShort Bloomberg Natural Gas [Member] | U.S. Treasury Bills 0.045% Due 08/13/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 735,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourFivePercentageDueAugustThirteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergNaturalGasMember
[1]
Total short-term U.S. government and Value 734,850us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourFivePercentageDueAugustThirteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergNaturalGasMember
[1]
ProShares UltraShort Bloomberg Natural Gas [Member] | U.S. Treasury Bills 0.015% Due 07/02/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 2,297,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneFivePercentageDueJulyTwoTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergNaturalGasMember
[1]
Total short-term U.S. government and Value 2,296,824us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneFivePercentageDueJulyTwoTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergNaturalGasMember
[1]
ProShares UltraShort Bloomberg Natural Gas [Member] | U.S. Treasury Bills 0.015% Due 06/25/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 225,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneFivePercentageDueJuneTwentyFiveTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergNaturalGasMember
Total short-term U.S. government and Value 224,995us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneFivePercentageDueJuneTwentyFiveTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergNaturalGasMember
ProShares UltraShort Bloomberg Natural Gas [Member] | U.S. Treasury Bills 0.042% Due 04/16/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 613,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourTwoPercentageDueAprilSixteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergNaturalGasMember
Total short-term U.S. government and Value 612,996us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourTwoPercentageDueAprilSixteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergNaturalGasMember
ProShares UltraShort Bloomberg Natural Gas [Member] | U.S. Treasury Bills 0.056% Due 04/30/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 790,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFiveSixPercentageDueAprilThirtyTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergNaturalGasMember
Total short-term U.S. government and Value 789,971us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFiveSixPercentageDueAprilThirtyTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergNaturalGasMember
ProShares UltraShort Bloomberg Natural Gas [Member] | U.S. Treasury Bills 0.044% Due 05/21/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 469,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourFourPercentageDueMayTwentyOneTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergNaturalGasMember
Total short-term U.S. government and Value 468,984us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourFourPercentageDueMayTwentyOneTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergNaturalGasMember
ProShares UltraShort Bloomberg Natural Gas [Member] | U.S. Treasury Bills 0.022% Due 06/04/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 659,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoTwoPercentageDueJuneFourTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergNaturalGasMember
Total short-term U.S. government and Value 658,977us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoTwoPercentageDueJuneFourTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortBloombergNaturalGasMember
ProShares UltraShort Gold [Member]  
Schedule of Investments [Line Items]  
Total short-term U.S. government and Value 79,438,219us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortGoldMember
ProShares UltraShort Gold [Member] | U.S. Treasury Bills 0.035% Due 07/30/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 1,191,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeFivePercentageDueJulyThirtyTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortGoldMember
Total short-term U.S. government and Value 1,190,841us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeFivePercentageDueJulyThirtyTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortGoldMember
ProShares UltraShort Gold [Member] | U.S. Treasury Bills 0.030% Due 07/02/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 9,863,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeZeroPercentageDueJulySevenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortGoldMember
[4]
Total short-term U.S. government and Value 9,862,244us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeZeroPercentageDueJulySevenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortGoldMember
[4]
ProShares UltraShort Gold [Member] | U.S. Treasury Bills 0.045% Due 08/06/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 2,915,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourFivePercentageDueAugustSixTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortGoldMember
Total short-term U.S. government and Value 2,914,435us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourFivePercentageDueAugustSixTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortGoldMember
ProShares UltraShort Gold [Member] | U.S. Treasury Bills 0.038% Due 07/23/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 2,562,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeEightPercentageDueJulyTwentyThreeTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortGoldMember
[4]
Total short-term U.S. government and Value 2,561,718us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeEightPercentageDueJulyTwentyThreeTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortGoldMember
[4]
ProShares UltraShort Gold [Member] | U.S. Treasury Bills 0.041% Due 04/16/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 2,572,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourOnePercentageDueAprilSixteenTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortGoldMember
Total short-term U.S. government and Value 2,571,984us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourOnePercentageDueAprilSixteenTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortGoldMember
ProShares UltraShort Gold [Member] | U.S. Treasury Bills 0.042% Due 04/30/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 6,386,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourTwoPercentageDueAprilThirtyTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortGoldMember
[4]
Total short-term U.S. government and Value 6,385,769us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourTwoPercentageDueAprilThirtyTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortGoldMember
[4]
ProShares UltraShort Gold [Member] | U.S. Treasury Bills 0.056% Due 05/14/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 25,151,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFiveSixPercentageDueMayFourteenTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortGoldMember
[4]
Total short-term U.S. government and Value 25,150,248us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFiveSixPercentageDueMayFourteenTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortGoldMember
[4]
ProShares UltraShort Gold [Member] | U.S. Treasury Bills 0.061% Due 05/21/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 2,641,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSixOnePercentageDueMayTwentyOneTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortGoldMember
[4]
Total short-term U.S. government and Value 2,640,908us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSixOnePercentageDueMayTwentyOneTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortGoldMember
[4]
ProShares UltraShort Gold [Member] | U.S. Treasury Bills 0.005% Due 06/11/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 530,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroZeroFivePercentageDueJuneElevenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortGoldMember
Total short-term U.S. government and Value 529,979us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroZeroFivePercentageDueJuneElevenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortGoldMember
ProShares UltraShort Gold [Member] | U.S. Treasury Bills 0.060% Due 06/18/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 996,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSixZeroPercentageDueJuneEighteenTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortGoldMember
Total short-term U.S. government and Value 995,968us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSixZeroPercentageDueJuneEighteenTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortGoldMember
ProShares UltraShort Gold [Member] | U.S. Treasury Bills 0.024% Due 07/16/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 1,661,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoFourPercentageDueJulySixteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortGoldMember
Total short-term U.S. government and Value 1,660,829us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoFourPercentageDueJulySixteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortGoldMember
ProShares UltraShort Gold [Member] | U.S. Treasury Bills 0.043% Due 08/13/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 22,978,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourThreePercentageDueAugustThirteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortGoldMember
[4]
Total short-term U.S. government and Value 22,973,296us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourThreePercentageDueAugustThirteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortGoldMember
[4]
ProShares UltraShort Silver [Member]  
Schedule of Investments [Line Items]  
Total short-term U.S. government and Value 50,001,670us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortSilverMember
ProShares UltraShort Silver [Member] | U.S. Treasury Bills 0.030% Due 07/02/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 4,494,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeZeroPercentageDueJulySevenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortSilverMember
[4]
Total short-term U.S. government and Value 4,493,655us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeZeroPercentageDueJulySevenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortSilverMember
[4]
ProShares UltraShort Silver [Member] | U.S. Treasury Bills 0.037% Due 07/23/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 3,881,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeSevenPercentageDueJulyTwentyThreeTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortSilverMember
[4]
Total short-term U.S. government and Value 3,880,574us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeSevenPercentageDueJulyTwentyThreeTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortSilverMember
[4]
ProShares UltraShort Silver [Member] | U.S. Treasury Bills 0.056% Due 05/14/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 1,504,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFiveSixPercentageDueMayFourteenTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortSilverMember
Total short-term U.S. government and Value 1,503,955us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFiveSixPercentageDueMayFourteenTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortSilverMember
ProShares UltraShort Silver [Member] | U.S. Treasury Bills 0.061% Due 05/21/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 2,355,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSixOnePercentageDueMayTwentyOneTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortSilverMember
Total short-term U.S. government and Value 2,354,918us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSixOnePercentageDueMayTwentyOneTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortSilverMember
ProShares UltraShort Silver [Member] | U.S. Treasury Bills 0.024% Due 07/16/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 3,518,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoFourPercentageDueJulySixteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortSilverMember
[4]
Total short-term U.S. government and Value 3,517,637us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoFourPercentageDueJulySixteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortSilverMember
[4]
ProShares UltraShort Silver [Member] | U.S. Treasury Bills 0.054% Due 04/30/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 7,530,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFiveFourPercentageDueAprilThirtyTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortSilverMember
[4]
Total short-term U.S. government and Value 7,529,727us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFiveFourPercentageDueAprilThirtyTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortSilverMember
[4]
ProShares UltraShort Silver [Member] | U.S. Treasury Bills 0.067% Due 06/04/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 15,634,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSixSevenPercentageDueJuneFourTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortSilverMember
[4]
Total short-term U.S. government and Value 15,633,444us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSixSevenPercentageDueJuneFourTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortSilverMember
[4]
ProShares UltraShort Silver [Member] | U.S. Treasury Bills 0.027% Due 06/18/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 5,981,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoSevenPercentageDueJuneEighteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortSilverMember
[4]
Total short-term U.S. government and Value 5,980,806us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoSevenPercentageDueJuneEighteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortSilverMember
[4]
ProShares UltraShort Silver [Member] | U.S. Treasury Bills 0.038% Due 08/13/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 5,108,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeEightPercentageDueAugustThirteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortSilverMember
[4]
Total short-term U.S. government and Value 5,106,954us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeEightPercentageDueAugustThirteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortSilverMember
[4]
ProShares Short Euro [Member]  
Schedule of Investments [Line Items]  
Total short-term U.S. government and Value 18,012,179us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesShortEuroMember
ProShares Short Euro [Member] | U.S. Treasury Bills 0.045% Due 08/13/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 679,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourFivePercentageDueAugustThirteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesShortEuroMember
Total short-term U.S. government and Value 678,861us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourFivePercentageDueAugustThirteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesShortEuroMember
ProShares Short Euro [Member] | U.S. Treasury Bills 0.050% Due 07/09/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 206,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFiveZeroPercentageDueJulyNineTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesShortEuroMember
Total short-term U.S. government and Value 205,989us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFiveZeroPercentageDueJulyNineTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesShortEuroMember
ProShares Short Euro [Member] | U.S. Treasury Bills 0.038% Due 07/23/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 404,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeEightPercentageDueJulyTwentyThreeTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesShortEuroMember
Total short-term U.S. government and Value 403,955us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeEightPercentageDueJulyTwentyThreeTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesShortEuroMember
ProShares Short Euro [Member] | U.S. Treasury Bills 0.041% Due 04/16/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 2,278,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourOnePercentageDueAprilSixteenTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesShortEuroMember
Total short-term U.S. government and Value 2,277,986us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourOnePercentageDueAprilSixteenTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesShortEuroMember
ProShares Short Euro [Member] | U.S. Treasury Bills 0.015% Due 06/25/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 4,804,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneFivePercentageDueJuneTwentyFiveTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesShortEuroMember
Total short-term U.S. government and Value 4,803,887us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneFivePercentageDueJuneTwentyFiveTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesShortEuroMember
ProShares Short Euro [Member] | U.S. Treasury Bills 0.040% Due 04/30/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 1,708,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourZeroPercentageDueAprilThirtyTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesShortEuroMember
Total short-term U.S. government and Value 1,707,938us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourZeroPercentageDueAprilThirtyTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesShortEuroMember
ProShares Short Euro [Member] | U.S. Treasury Bills 0.073% Due 06/04/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 3,375,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSevenThreePercentageDueJuneFourTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesShortEuroMember
Total short-term U.S. government and Value 3,374,880us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSevenThreePercentageDueJuneFourTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesShortEuroMember
ProShares Short Euro [Member] | U.S. Treasury Bills 0.010% Due 06/18/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 2,171,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneZeroPercentageDueJuneEighteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesShortEuroMember
Total short-term U.S. government and Value 2,170,929us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneZeroPercentageDueJuneEighteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesShortEuroMember
ProShares Short Euro [Member] | U.S. Treasury Bills 0.035% Due 07/16/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 2,388,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeFivePercentageDueJulySixteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesShortEuroMember
Total short-term U.S. government and Value 2,387,754us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeFivePercentageDueJulySixteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesShortEuroMember
ProShares UltraShort Australian Dollar [Member]  
Schedule of Investments [Line Items]  
Total short-term U.S. government and Value 16,932,493us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortAustralianDollarMember
ProShares UltraShort Australian Dollar [Member] | U.S. Treasury Bills 0.043% Due 04/16/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 756,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourThreePercentageDueAprilSixteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortAustralianDollarMember
Total short-term U.S. government and Value 755,995us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourThreePercentageDueAprilSixteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortAustralianDollarMember
ProShares UltraShort Australian Dollar [Member] | U.S. Treasury Bills 0.012% Due 05/21/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 3,305,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneTwoPercentageDueMayTwentyOneTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortAustralianDollarMember
Total short-term U.S. government and Value 3,304,885us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneTwoPercentageDueMayTwentyOneTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortAustralianDollarMember
ProShares UltraShort Australian Dollar [Member] | U.S. Treasury Bills 0.038% Due 07/23/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 199,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeEightPercentageDueJulyTwentyThreeTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortAustralianDollarMember
[1]
Total short-term U.S. government and Value 198,978us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeEightPercentageDueJulyTwentyThreeTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortAustralianDollarMember
[1]
ProShares UltraShort Australian Dollar [Member] | U.S. Treasury Bills 0.015% Due 06/25/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 11,303,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneFivePercentageDueJuneTwentyFiveTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortAustralianDollarMember
[1]
Total short-term U.S. government and Value 11,302,733us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneFivePercentageDueJuneTwentyFiveTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortAustralianDollarMember
[1]
ProShares UltraShort Australian Dollar [Member] | U.S. Treasury Bills 0.043% Due 08/13/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 121,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourThreePercentageDueAugustThirteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortAustralianDollarMember
Total short-term U.S. government and Value 120,975us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourThreePercentageDueAugustThirteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortAustralianDollarMember
ProShares UltraShort Australian Dollar [Member] | U.S. Treasury Bills 0.056% Due 04/30/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 236,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFiveSixPercentageDueAprilThirtyTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortAustralianDollarMember
Total short-term U.S. government and Value 235,992us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFiveSixPercentageDueAprilThirtyTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortAustralianDollarMember
ProShares UltraShort Australian Dollar [Member] | U.S. Treasury Bills 0.022% Due 05/28/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 409,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoTwoPercentageDueMayTwentyEightTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortAustralianDollarMember
Total short-term U.S. government and Value 408,981us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoTwoPercentageDueMayTwentyEightTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortAustralianDollarMember
ProShares UltraShort Australian Dollar [Member] | U.S. Treasury Bills 0.050% Due 07/02/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 604,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFiveZeroPercentageDueJulyTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortAustralianDollarMember
[1]
Total short-term U.S. government and Value 603,954us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFiveZeroPercentageDueJulyTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortAustralianDollarMember
[1]
ProShares UltraShort Euro [Member]  
Schedule of Investments [Line Items]  
Total short-term U.S. government and Value 549,451,431us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortEuroMember
ProShares UltraShort Euro [Member] | U.S. Treasury Bills 0.030% Due 07/30/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 22,538,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeZeroPercentageDueJulyThirtyTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortEuroMember
Total short-term U.S. government and Value 22,534,996us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeZeroPercentageDueJulyThirtyTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortEuroMember
ProShares UltraShort Euro [Member] | U.S. Treasury Bills 0.050% Due 07/09/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 25,516,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFiveZeroPercentageDueJulyNineTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortEuroMember
[5]
Total short-term U.S. government and Value 25,514,597us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFiveZeroPercentageDueJulyNineTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortEuroMember
[5]
ProShares UltraShort Euro [Member] | U.S. Treasury Bills 0.041% Due 04/16/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 2,717,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourOnePercentageDueAprilSixteenTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortEuroMember
[5]
Total short-term U.S. government and Value 2,716,983us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourOnePercentageDueAprilSixteenTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortEuroMember
[5]
ProShares UltraShort Euro [Member] | U.S. Treasury Bills 0.073% Due 06/04/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 130,454,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSevenThreePercentageDueJuneFourTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortEuroMember
[5]
Total short-term U.S. government and Value 130,449,356us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSevenThreePercentageDueJuneFourTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortEuroMember
[5]
ProShares UltraShort Euro [Member] | U.S. Treasury Bills 0.048% Due 04/30/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 51,620,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourEightPercentageDueAprilThirtyTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortEuroMember
[5]
Total short-term U.S. government and Value 51,618,131us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourEightPercentageDueAprilThirtyTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortEuroMember
[5]
ProShares UltraShort Euro [Member] | U.S. Treasury Bills 0.015% Due 05/14/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 6,567,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneFivePercentageDueMayFourteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortEuroMember
Total short-term U.S. government and Value 6,566,804us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneFivePercentageDueMayFourteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortEuroMember
ProShares UltraShort Euro [Member] | U.S. Treasury Bills 0.050% Due 05/21/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 74,042,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFiveZeroPercentageDueMayTwentyOneTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortEuroMember
Total short-term U.S. government and Value 74,039,431us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFiveZeroPercentageDueMayTwentyOneTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortEuroMember
ProShares UltraShort Euro [Member] | U.S. Treasury Bills 0.070% Due 05/28/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 6,919,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSevenZeroPercentageDueMayTwentyEightTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortEuroMember
Total short-term U.S. government and Value 6,918,671us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSevenZeroPercentageDueMayTwentyEightTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortEuroMember
ProShares UltraShort Euro [Member] | U.S. Treasury Bills 0.090% Due 06/11/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 38,365,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroNineZeroPercentageDueJuneElevenTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortEuroMember
[5]
Total short-term U.S. government and Value 38,363,488us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroNineZeroPercentageDueJuneElevenTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortEuroMember
[5]
ProShares UltraShort Euro [Member] | U.S. Treasury Bills 0.025% Due 07/16/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 84,059,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoFivePercentageDueJulySixteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortEuroMember
Total short-term U.S. government and Value 84,050,333us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoFivePercentageDueJulySixteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortEuroMember
ProShares UltraShort Euro [Member] | U.S. Treasury Bills 0.041% Due 07/23/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 51,595,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourOnePercentageDueJulyTwentyThreeTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortEuroMember
[5]
Total short-term U.S. government and Value 51,589,330us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourOnePercentageDueJulyTwentyThreeTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortEuroMember
[5]
ProShares UltraShort Euro [Member] | U.S. Treasury Bills 0.040% Due 08/06/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 55,100,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourZeroPercentageDueAugustSixTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortEuroMember
[5]
Total short-term U.S. government and Value 55,089,311us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourZeroPercentageDueAugustSixTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortEuroMember
[5]
ProShares UltraShort Yen [Member]  
Schedule of Investments [Line Items]  
Total short-term U.S. government and Value 444,090,783us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortYenMember
ProShares UltraShort Yen [Member] | U.S. Treasury Bills 0.045% Due 08/13/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 19,736,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourFivePercentageDueAugustThirteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortYenMember
[5]
Total short-term U.S. government and Value 19,731,960us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourFivePercentageDueAugustThirteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortYenMember
[5]
ProShares UltraShort Yen [Member] | U.S. Treasury Bills 0.041% Due 04/16/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 81,110,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourOnePercentageDueAprilSixteenTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortYenMember
Total short-term U.S. government and Value 81,109,497us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourOnePercentageDueAprilSixteenTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortYenMember
ProShares UltraShort Yen [Member] | U.S. Treasury Bills 0.056% Due 04/30/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 17,961,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFiveSixPercentageDueAprilThirtyTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortYenMember
[5]
Total short-term U.S. government and Value 17,960,350us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFiveSixPercentageDueAprilThirtyTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortYenMember
[5]
ProShares UltraShort Yen [Member] | U.S. Treasury Bills 0.063% Due 05/14/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 1,002,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSixThreePercentageDueMayFourteenTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortYenMember
Total short-term U.S. government and Value 1,001,970us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSixThreePercentageDueMayFourteenTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortYenMember
ProShares UltraShort Yen [Member] | U.S. Treasury Bills 0.070% Due 05/21/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 9,923,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSevenZeroPercentageDueMayTwentyOneTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortYenMember
[5]
Total short-term U.S. government and Value 9,922,656us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSevenZeroPercentageDueMayTwentyOneTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortYenMember
[5]
ProShares UltraShort Yen [Member] | U.S. Treasury Bills 0.087% Due 06/11/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 31,920,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroEightSevenPercentageDueJuneElevenTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortYenMember
[5]
Total short-term U.S. government and Value 31,918,742us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroEightSevenPercentageDueJuneElevenTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortYenMember
[5]
ProShares UltraShort Yen [Member] | U.S. Treasury Bills 0.026% Due 06/25/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 17,106,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoSixPercentageDueJuneTwentyFiveTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortYenMember
[5]
Total short-term U.S. government and Value 17,105,596us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoSixPercentageDueJuneTwentyFiveTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortYenMember
[5]
ProShares UltraShort Yen [Member] | U.S. Treasury Bills 0.030% due 07/02/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 5,564,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeZeroPercentageDueJulyTwoTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortYenMember
[5]
Total short-term U.S. government and Value 5,563,573us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeZeroPercentageDueJulyTwoTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortYenMember
[5]
ProShares UltraShort Yen [Member] | U.S. Treasury Bills 0.040% Due 07/23/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 62,192,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourZeroPercentageDueJulyTwentyThreeTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortYenMember
Total short-term U.S. government and Value 62,185,165us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourZeroPercentageDueJulyTwentyThreeTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortYenMember
ProShares UltraShort Yen [Member] | U.S. Treasury Bills 0.034% Due 07/30/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 174,813,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeFourPercentageDueJulyThirtyTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortYenMember
[5]
Total short-term U.S. government and Value 174,789,698us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeFourPercentageDueJulyThirtyTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortYenMember
[5]
ProShares UltraShort Yen [Member] | U.S. Treasury Bills 0.070% Due 08/06/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 22,806,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSevenZeroPercentageDueAugustSixTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortYenMember
Total short-term U.S. government and Value 22,801,576us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSevenZeroPercentageDueAugustSixTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltrashortYenMember
ProShares Ultra Bloomberg Commodity [Member]  
Schedule of Investments [Line Items]  
Total short-term U.S. government and Value 2,242,809us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCommodityMember
ProShares Ultra Bloomberg Commodity [Member] | U.S. Treasury Bills 0.036% Due 07/16/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 308,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeSixPercentageDueJulySixteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCommodityMember
Total short-term U.S. government and Value 307,968us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeSixPercentageDueJulySixteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCommodityMember
ProShares Ultra Bloomberg Commodity [Member] | U.S. Treasury Bills 0.060% Due 06/18/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 903,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSixZeroPercentageDueJuneEighteenTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCommodityMember
[2]
Total short-term U.S. government and Value 902,971us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSixZeroPercentageDueJuneEighteenTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCommodityMember
[2]
ProShares Ultra Bloomberg Commodity [Member] | U.S. Treasury Bills 0.043% Due 08/13/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 549,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourThreePercentageDueAugustThirteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCommodityMember
Total short-term U.S. government and Value 548,888us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourThreePercentageDueAugustThirteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCommodityMember
ProShares Ultra Bloomberg Commodity [Member] | U.S. Treasury Bills 0.047% Due 04/30/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 483,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourSevenPercentageDueAprilThirtyTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCommodityMember
[2]
Total short-term U.S. government and Value 482,982us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourSevenPercentageDueAprilThirtyTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCommodityMember
[2]
ProShares Ultra Bloomberg Crude Oil [Member]  
Schedule of Investments [Line Items]  
Total short-term U.S. government and Value 1,066,114,169us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCrudeOilMember
ProShares Ultra Bloomberg Crude Oil [Member] | U.S. Treasury Bills 0.061% Due 05/14/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 15,454,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSixOnePercentageDueMayFourteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCrudeOilMember
Total short-term U.S. government and Value 15,453,538us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSixOnePercentageDueMayFourteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCrudeOilMember
ProShares Ultra Bloomberg Crude Oil [Member] | U.S. Treasury Bills 0.036% Due 07/16/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 78,958,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeSixPercentageDueJulySixteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCrudeOilMember
[3]
Total short-term U.S. government and Value 78,949,859us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeSixPercentageDueJulySixteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCrudeOilMember
[3]
ProShares Ultra Bloomberg Crude Oil [Member] | U.S. Treasury Bills 0.048% Due 08/13/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 20,506,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourEightPercentageDueAugustThirteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCrudeOilMember
[3]
Total short-term U.S. government and Value 20,501,802us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourEightPercentageDueAugustThirteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCrudeOilMember
[3]
ProShares Ultra Bloomberg Crude Oil [Member] | U.S. Treasury Bills 0.038% Due 04/16/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 19,702,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeEightPercentageDueAprilSixteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCrudeOilMember
Total short-term U.S. government and Value 19,701,878us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeEightPercentageDueAprilSixteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCrudeOilMember
ProShares Ultra Bloomberg Crude Oil [Member] | U.S. Treasury Bills 0.035% Due 04/30/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 49,089,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeFivePercentageDueAprilThirtyTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCrudeOilMember
Total short-term U.S. government and Value 49,087,223us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeFivePercentageDueAprilThirtyTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCrudeOilMember
ProShares Ultra Bloomberg Crude Oil [Member] | U.S. Treasury Bills 0.027% Due 05/21/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 107,478,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoSevenPercentageDueMayTwentyOneTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCrudeOilMember
[3]
Total short-term U.S. government and Value 107,474,271us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoSevenPercentageDueMayTwentyOneTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCrudeOilMember
[3]
ProShares Ultra Bloomberg Crude Oil [Member] | U.S. Treasury Bills 0.023% Due 05/28/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 10,311,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoThreePercentageDueMayTwentyEightTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCrudeOilMember
[3]
Total short-term U.S. government and Value 10,310,510us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoThreePercentageDueMayTwentyEightTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCrudeOilMember
[3]
ProShares Ultra Bloomberg Crude Oil [Member] | U.S. Treasury Bills 0.027% Due 06/04/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 154,348,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoSevenPercentageDueJuneFourTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCrudeOilMember
Total short-term U.S. government and Value 154,342,505us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoSevenPercentageDueJuneFourTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCrudeOilMember
ProShares Ultra Bloomberg Crude Oil [Member] | U.S. Treasury Bills 0.007% Due 06/11/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 32,535,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroZeroSevenPercentageDueJuneElevenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCrudeOilMember
Total short-term U.S. government and Value 32,533,718us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroZeroSevenPercentageDueJuneElevenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCrudeOilMember
ProShares Ultra Bloomberg Crude Oil [Member] | U.S. Treasury Bills 0.028% Due 06/18/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 163,086,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoEightPercentageDueJuneEighteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCrudeOilMember
[3]
Total short-term U.S. government and Value 163,080,700us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoEightPercentageDueJuneEighteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCrudeOilMember
[3]
ProShares Ultra Bloomberg Crude Oil [Member] | U.S. Treasury Bills 0.045% Due 06/25/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 63,939,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourFivePercentageDueJuneTwentyFiveTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCrudeOilMember
[3]
Total short-term U.S. government and Value 63,937,491us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourFivePercentageDueJuneTwentyFiveTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCrudeOilMember
[3]
ProShares Ultra Bloomberg Crude Oil [Member] | U.S. Treasury Bills 0.027% Due 07/02/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 4,114,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoSevenPercentageDueJulyTwoTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCrudeOilMember
[3]
Total short-term U.S. government and Value 4,113,685us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoSevenPercentageDueJulyTwoTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCrudeOilMember
[3]
ProShares Ultra Bloomberg Crude Oil [Member] | U.S. Treasury Bills 0.034% Due 07/09/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 49,453,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeFourPercentageDueJulyNineTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCrudeOilMember
[3]
Total short-term U.S. government and Value 49,450,280us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeFourPercentageDueJulyNineTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCrudeOilMember
[3]
ProShares Ultra Bloomberg Crude Oil [Member] | U.S. Treasury Bills 0.030% Due 07/23/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 94,595,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeZeroPercentageDueJulyTwentyThreeTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCrudeOilMember
[3]
Total short-term U.S. government and Value 94,584,604us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeZeroPercentageDueJulyTwentyThreeTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCrudeOilMember
[3]
ProShares Ultra Bloomberg Crude Oil [Member] | U.S. Treasury Bills 0.029% Due 07/30/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 105,672,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoNinePercentageDueJulyThirtyTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCrudeOilMember
[3]
Total short-term U.S. government and Value 105,657,914us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoNinePercentageDueJulyThirtyTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCrudeOilMember
[3]
ProShares Ultra Bloomberg Crude Oil [Member] | U.S. Treasury Bills 0.051% Due 08/06/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 96,953,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFiveOnePercentageDueAugustSixTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCrudeOilMember
[3]
Total short-term U.S. government and Value 96,934,191us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFiveOnePercentageDueAugustSixTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergCrudeOilMember
[3]
ProShares Ultra Bloomberg Natural Gas [Member]  
Schedule of Investments [Line Items]  
Total short-term U.S. government and Value 57,169,841us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergNaturalGasMember
ProShares Ultra Bloomberg Natural Gas [Member] | U.S. Treasury Bills 0.046% Due 06/04/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 910,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourSixPercentageDueJuneFourTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergNaturalGasMember
Total short-term U.S. government and Value 909,968us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourSixPercentageDueJuneFourTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergNaturalGasMember
ProShares Ultra Bloomberg Natural Gas [Member] | U.S. Treasury Bills 0.045% Due 08/06/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 4,885,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourFivePercentageDueAugustSixTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergNaturalGasMember
[1]
Total short-term U.S. government and Value 4,884,052us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourFivePercentageDueAugustSixTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergNaturalGasMember
[1]
ProShares Ultra Bloomberg Natural Gas [Member] | U.S. Treasury Bills 0.028% Due 07/16/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 6,392,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoEightPercentageDueJulySixteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergNaturalGasMember
[1]
Total short-term U.S. government and Value 6,391,341us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoEightPercentageDueJulySixteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergNaturalGasMember
[1]
ProShares Ultra Bloomberg Natural Gas [Member] | U.S. Treasury Bills 0.047% Due 07/23/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 3,623,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourSevenPercentageDueJulyTwentyThreeTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergNaturalGasMember
[1]
Total short-term U.S. government and Value 3,622,602us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourSevenPercentageDueJulyTwentyThreeTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergNaturalGasMember
[1]
ProShares Ultra Bloomberg Natural Gas [Member] | U.S. Treasury Bills 0.040% Due 04/30/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 10,407,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourZeroPercentageDueAprilThirtyTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergNaturalGasMember
Total short-term U.S. government and Value 10,406,623us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourZeroPercentageDueAprilThirtyTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergNaturalGasMember
ProShares Ultra Bloomberg Natural Gas [Member] | U.S. Treasury Bills 0.063% Due 05/14/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 2,130,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSixThreePercentageDueMayFourteenTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergNaturalGasMember
Total short-term U.S. government and Value 2,129,936us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSixThreePercentageDueMayFourteenTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergNaturalGasMember
ProShares Ultra Bloomberg Natural Gas [Member] | U.S. Treasury Bills 0.026% Due 06/25/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 2,447,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoSixPercentageDueJuneTwentyFiveTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergNaturalGasMember
Total short-term U.S. government and Value 2,446,942us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoSixPercentageDueJuneTwentyFiveTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergNaturalGasMember
ProShares Ultra Bloomberg Natural Gas [Member] | U.S. Treasury Bills 0.052% Due 05/28/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 5,377,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFiveTwoPercentageDueMayTwentyEightThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergNaturalGasMember
Total short-term U.S. government and Value 5,376,745us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFiveTwoPercentageDueMayTwentyEightThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergNaturalGasMember
ProShares Ultra Bloomberg Natural Gas [Member] | U.S. Treasury Bills 0.026% Due 06/18/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 11,308,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoSixPercentageDueJuneEighteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergNaturalGasMember
Total short-term U.S. government and Value 11,307,632us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoSixPercentageDueJuneEighteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergNaturalGasMember
ProShares Ultra Bloomberg Natural Gas [Member] | U.S. Treasury Bills 0.047% Due 07/02/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 1,672,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourSevenPercentageDueJulyTwoTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergNaturalGasMember
Total short-term U.S. government and Value 1,671,872us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourSevenPercentageDueJulyTwoTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergNaturalGasMember
ProShares Ultra Bloomberg Natural Gas [Member] | U.S. Treasury Bills 0.042% Due 07/09/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 5,146,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourTwoPercentageDueJulyNineTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergNaturalGasMember
Total short-term U.S. government and Value 5,145,717us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourTwoPercentageDueJulyNineTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergNaturalGasMember
ProShares Ultra Bloomberg Natural Gas [Member] | U.S. Treasury Bills 0.039% Due 08/13/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 2,877,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeNinePercentageDueAugustThirteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergNaturalGasMember
[1]
Total short-term U.S. government and Value 2,876,411us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeNinePercentageDueAugustThirteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraBloombergNaturalGasMember
[1]
ProShares Ultra Gold [Member]  
Schedule of Investments [Line Items]  
Total short-term U.S. government and Value 94,234,586us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraGoldMember
ProShares Ultra Gold [Member] | U.S. Treasury Bills 0.042% Due 04/30/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 13,896,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourTwoPercentageDueAprilThirtyTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraGoldMember
[4]
Total short-term U.S. government and Value 13,895,497us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourTwoPercentageDueAprilThirtyTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraGoldMember
[4]
ProShares Ultra Gold [Member] | U.S. Treasury Bills 0.038% Due 08/13/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 17,169,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeEightPercentageDueAugustThirteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraGoldMember
[4]
Total short-term U.S. government and Value 17,165,485us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeEightPercentageDueAugustThirteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraGoldMember
[4]
ProShares Ultra Gold [Member] | U.S. Treasury Bills 0.050% Due 05/21/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 5,376,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFiveZeroPercentageDueMayTwentyOneTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraGoldMember
Total short-term U.S. government and Value 5,375,813us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFiveZeroPercentageDueMayTwentyOneTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraGoldMember
ProShares Ultra Gold [Member] | U.S. Treasury Bills 0.058% Due 05/14/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 24,874,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFiveEightPercentageDueMayFourteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraGoldMember
[4]
Total short-term U.S. government and Value 24,873,256us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFiveEightPercentageDueMayFourteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraGoldMember
[4]
ProShares Ultra Gold [Member] | U.S. Treasury Bills 0.078% Due 06/04/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 11,782,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSevenEightPercentageDueJuneFourTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraGoldMember
[4]
Total short-term U.S. government and Value 11,781,581us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSevenEightPercentageDueJuneFourTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraGoldMember
[4]
ProShares Ultra Gold [Member] | U.S. Treasury Bills 0.058% Due 06/18/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 13,020,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFiveEightPercentageDueJuneEighteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraGoldMember
[4]
Total short-term U.S. government and Value 13,019,577us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFiveEightPercentageDueJuneEighteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraGoldMember
[4]
ProShares Ultra Gold [Member] | U.S. Treasury Bills 0.037% Due 07/02/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 8,124,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeSevenPercentageDueJulyTwoTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraGoldMember
[4]
Total short-term U.S. government and Value 8,123,377us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeSevenPercentageDueJulyTwoTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraGoldMember
[4]
ProShares Ultra Silver [Member]  
Schedule of Investments [Line Items]  
Total short-term U.S. government and Value 294,501,633us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraSilverMember
ProShares Ultra Silver [Member] | U.S. Treasury Bills 0.041% Due 04/16/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 16,066,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourOnePercentageDueAprilSixteenTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraSilverMember
[4]
Total short-term U.S. government and Value 16,065,900us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourOnePercentageDueAprilSixteenTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraSilverMember
[4]
ProShares Ultra Silver [Member] | U.S. Treasury Bills 0.064% Due 05/14/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 27,423,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSixFourPercentageDueMayFourteenTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraSilverMember
[4]
Total short-term U.S. government and Value 27,422,180us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSixFourPercentageDueMayFourteenTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraSilverMember
[4]
ProShares Ultra Silver [Member] | U.S. Treasury Bills 0.090% Due 06/11/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 43,631,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroNineZeroPercentageDueJuneElevenTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraSilverMember
Total short-term U.S. government and Value 43,629,281us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroNineZeroPercentageDueJuneElevenTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraSilverMember
ProShares Ultra Silver [Member] | U.S. Treasury Bills 0.047% Due 04/30/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 6,604,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourSevenPercentageDueAprilThirtyTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraSilverMember
Total short-term U.S. government and Value 6,603,761us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourSevenPercentageDueAprilThirtyTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraSilverMember
ProShares Ultra Silver [Member] | U.S. Treasury Bills 0.039% Due 08/13/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 39,592,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeNinePercentageDueAugustThirteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraSilverMember
[4]
Total short-term U.S. government and Value 39,583,896us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeNinePercentageDueAugustThirteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraSilverMember
[4]
ProShares Ultra Silver [Member] | U.S. Treasury Bills 0.078% Due 06/04/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 4,277,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSevenEightPercentageDueJuneFourTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraSilverMember
[4]
Total short-term U.S. government and Value 4,276,848us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSevenEightPercentageDueJuneFourTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraSilverMember
[4]
ProShares Ultra Silver [Member] | U.S. Treasury Bills 0.004% Due 05/21/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 5,723,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroZeroFourPercentageDueMayTwentyOneTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraSilverMember
Total short-term U.S. government and Value 5,722,801us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroZeroFourPercentageDueMayTwentyOneTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraSilverMember
ProShares Ultra Silver [Member] | U.S. Treasury Bills 0.015% Due 05/28/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 849,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneFivePercentageDueMayTwentyEightTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraSilverMember
Total short-term U.S. government and Value 848,960us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneFivePercentageDueMayTwentyEightTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraSilverMember
ProShares Ultra Silver [Member] | U.S. Treasury Bills 0.045% Due 06/18/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 5,482,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourFivePercentageDueJuneEighteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraSilverMember
Total short-term U.S. government and Value 5,481,822us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourFivePercentageDueJuneEighteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraSilverMember
ProShares Ultra Silver [Member] | U.S. Treasury Bills 0.038% Due 07/02/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 45,162,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeEightPercentageDueJulyTwoTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraSilverMember
[4]
Total short-term U.S. government and Value 45,158,536us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeEightPercentageDueJulyTwoTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraSilverMember
[4]
ProShares Ultra Silver [Member] | U.S. Treasury Bills 0.020% Due 07/16/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 7,015,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoZeroPercentageDueJulySixteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraSilverMember
Total short-term U.S. government and Value 7,014,277us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroTwoZeroPercentageDueJulySixteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraSilverMember
ProShares Ultra Silver [Member] | U.S. Treasury Bills 0.035% Due 07/23/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 4,248,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeFivePercentageDueJulyTwentyThreeTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraSilverMember
Total short-term U.S. government and Value 4,247,533us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeFivePercentageDueJulyTwentyThreeTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraSilverMember
ProShares Ultra Silver [Member] | U.S. Treasury Bills 0.066% Due 08/06/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 88,463,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSixSixPercentageDueAugustSixTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraSilverMember
[4]
Total short-term U.S. government and Value 88,445,838us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroSixSixPercentageDueAugustSixTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraSilverMember
[4]
ProShares Ultra Australian Dollar [Member]  
Schedule of Investments [Line Items]  
Total short-term U.S. government and Value 2,201,920us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraAustralianDollarMember
ProShares Ultra Australian Dollar [Member] | U.S. Treasury Bills 0.040% Due 04/30/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 2,202,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourZeroPercentageDueAprilThirtyTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraAustralianDollarMember
Total short-term U.S. government and Value 2,201,920us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourZeroPercentageDueAprilThirtyTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraAustralianDollarMember
ProShares Ultra Euro [Member]  
Schedule of Investments [Line Items]  
Total short-term U.S. government and Value 15,242,869us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraEuroMember
ProShares Ultra Euro [Member] | U.S. Treasury Bills 0.036% Due 04/16/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 242,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeSixPercentageDueAprilSixteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraEuroMember
Total short-term U.S. government and Value 241,999us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeSixPercentageDueAprilSixteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraEuroMember
ProShares Ultra Euro [Member] | U.S. Treasury Bills 0.016% Due 06/18/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 1,575,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneSixPercentageDueJuneEighteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraEuroMember
Total short-term U.S. government and Value 1,574,949us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneSixPercentageDueJuneEighteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraEuroMember
ProShares Ultra Euro [Member] | U.S. Treasury Bills 0.036% Due 07/16/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 1,656,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeSixPercentageDueJulySixteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraEuroMember
Total short-term U.S. government and Value 1,655,829us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeSixPercentageDueJulySixteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraEuroMember
ProShares Ultra Euro [Member] | U.S. Treasury Bills 0.015% Due 06/25/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 1,129,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneFivePercentageDueJuneTwentyFiveTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraEuroMember
Total short-term U.S. government and Value 1,128,973us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneFivePercentageDueJuneTwentyFiveTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraEuroMember
ProShares Ultra Euro [Member] | U.S. Treasury Bills 0.015% Due 05/28/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 1,743,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneFivePercentageDueMayTwentyEightTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraEuroMember
Total short-term U.S. government and Value 1,742,917us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneFivePercentageDueMayTwentyEightTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraEuroMember
ProShares Ultra Euro [Member] | U.S. Treasury Bills 0.034% Due 04/30/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 911,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeFourPercentageDueAprilThirtyTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraEuroMember
[5]
Total short-term U.S. government and Value 910,967us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeFourPercentageDueAprilThirtyTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraEuroMember
[5]
ProShares Ultra Euro [Member] | U.S. Treasury Bills 0.035% Due 05/21/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 1,000,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeFivePercentageDueMayTwentyOneTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraEuroMember
Total short-term U.S. government and Value 999,965us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeFivePercentageDueMayTwentyOneTwoThousandFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraEuroMember
ProShares Ultra Euro [Member] | U.S. Treasury Bills 0.041% Due 07/02/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 1,136,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourOnePercentageDueJulyTwoTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraEuroMember
[5]
Total short-term U.S. government and Value 1,135,913us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourOnePercentageDueJulyTwoTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraEuroMember
[5]
ProShares Ultra Euro [Member] | U.S. Treasury Bills 0.034% Due 07/23/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 5,852,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeFourPercentageDueJulyTwentyThreeTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraEuroMember
[5]
Total short-term U.S. government and Value 5,851,357us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroThreeFourPercentageDueJulyTwentyThreeTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraEuroMember
[5]
ProShares Ultra Yen [Member]  
Schedule of Investments [Line Items]  
Total short-term U.S. government and Value 5,210,191us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraYenMember
ProShares Ultra Yen [Member] | U.S. Treasury Bills 0.043% Due 08/13/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 3,694,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourThreePercentageDueAugustThirteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraYenMember
[5]
Total short-term U.S. government and Value 3,693,244us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourThreePercentageDueAugustThirteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraYenMember
[5]
ProShares Ultra Yen [Member] | U.S. Treasury Bills 0.010% Due 06/18/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 586,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneZeroPercentageDueJuneEighteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraYenMember
[5]
Total short-term U.S. government and Value 585,981us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroOneZeroPercentageDueJuneEighteenTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraYenMember
[5]
ProShares Ultra Yen [Member] | U.S. Treasury Bills 0.047% Due 04/30/15 [Member]  
Schedule of Investments [Line Items]  
Principal Amount 931,000us-gaap_InvestmentOwnedBalancePrincipalAmount
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourSevenPercentageDueAprilThirtyTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraYenMember
[5]
Total short-term U.S. government and Value $ 930,966us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
/ us-gaap_InvestmentTypeAxis
= ck0001415311_UsTreasuryBillsZeroPointZeroFourSevenPercentageDueAprilThirtyTwoThousandAndFifteenMember
/ us-gaap_StatementBusinessSegmentsAxis
= ck0001415311_ProsharesUltraYenMember
[5]
[1] All or partial amount pledged as collateral for futures contracts.
[2] All or partial amount pledged as collateral for swap agreements.
[3] All or partial amount pledged as collateral for swap agreements and/or futures contracts.
[4] All or partial amount pledged as collateral for forward agreements and/or futures contracts.
[5] All or partial amount segregated as collateral for foreign currency forward contracts.