v3.10.0.1

Schedule of Investments - Futures Contracts Sold (Detail)

6 Months Ended

Jun. 30, 2018

USD ($)

Contract

ProShares UltraPro 3X Short Crude Oil ETF [Member] | Futures Contracts Sold [Member] | WTI Crude Oil NYMEX, Expires September 2018 [Member]

Schedule of Investments [Line Items]

Number of Contracts | Contract

899

Notional Amount at Value

$ 65,141,540

Unrealized Appreciation (Depreciation)

$ (5,442,454)

ProShares UltraShort Australian Dollar [Member] | Futures Contracts Sold [Member] | Australian Dollar Fx Currency Futures - CME, expires September 2018 [Member]

Schedule of Investments [Line Items]

Number of Contracts | Contract

205

Notional Amount at Value

$ 15,165,900

Unrealized Appreciation (Depreciation)

391,770

ProShares Short VIX Short-Term Futures ETF [Member] | Futures Contracts Sold [Member]

Schedule of Investments [Line Items]

Unrealized Appreciation (Depreciation)

$ (22,528,398)

ProShares Short VIX Short-Term Futures ETF [Member] | Futures Contracts Sold [Member] | VIX Futures - CBOE, expires July 2018 [Member]

Schedule of Investments [Line Items]

Number of Contracts | Contract

9,451

Notional Amount at Value

$ 151,452,275

Unrealized Appreciation (Depreciation)

$ (18,305,380)

ProShares Short VIX Short-Term Futures ETF [Member] | Futures Contracts Sold [Member] | VIX Futures - CBOE, expires August 2018 [Member]

Schedule of Investments [Line Items]

Number of Contracts | Contract

6,868

Notional Amount at Value

$ 112,463,500

Unrealized Appreciation (Depreciation)

$ (4,223,018)

ProShares Short Euro [Member] | Futures Contracts Sold [Member] | Euro Fx Currency Futures-CME expires September 2018 [Member]

Schedule of Investments [Line Items]

Number of Contracts | Contract

57

Notional Amount at Value

$ 8,362,256

Unrealized Appreciation (Depreciation)

87,213

ProShares UltraShort Bloomberg Crude Oil [Member]

Schedule of Investments [Line Items]

Unrealized Appreciation (Depreciation)

$ (33,768,200)

^[1]

ProShares UltraShort Bloomberg Crude Oil [Member] | Futures Contracts Sold [Member] | WTI Crude Oil NYMEX, Expires September 2018 [Member]

Schedule of Investments [Line Items]

Number of Contracts | Contract

1,028

Notional Amount at Value

$ 74,488,880

Unrealized Appreciation (Depreciation)

$ (7,161,949)

ProShares UltraShort Bloomberg Natural Gas [Member] | Futures Contracts Sold [Member] | Natural Gas - NYMEX, expires September 2018 [Member]

Schedule of Investments [Line Items]

Number of Contracts | Contract

465

Notional Amount at Value

$ 13,489,650

Unrealized Appreciation (Depreciation)

6,272

ProShares UltraShort Gold [Member]

Schedule of Investments [Line Items]

Unrealized Appreciation (Depreciation)

$ 2,276,610

^[2]

ProShares UltraShort Gold [Member] | Futures Contracts Sold [Member] | Gold Futures - COMEX, expires August 2018 [Member]

Schedule of Investments [Line Items]

Number of Contracts | Contract

2

Notional Amount at Value

$ 250,900

Unrealized Appreciation (Depreciation)

15,080

ProShares UltraShort Silver [Member]

Schedule of Investments [Line Items]

Unrealized Appreciation (Depreciation)

$ 1,452,785

^[2]

ProShares UltraShort Silver [Member] | Futures Contracts Sold [Member] | Silver Futures - COMEX, expires September 2018 [Member]

Schedule of Investments [Line Items]

Number of Contracts | Contract

2

Notional Amount at Value

$ 161,980

Unrealized Appreciation (Depreciation)

$ 7,970

[1]	Total Return Swap Agreements
[2]	The positions and counterparties herein are as of June 30, 2018. The Funds continually evaluate different counterparties for their transactions and counterparties are subject to change. New counterparties can be added at any time.

X

- Definition

Long (Short) Investment Owned Underlying Face Amount at Market Value

+ References

No definition available.

+ Details

Name:	ck0001415311_LongShortInvestmentOwnedUnderlyingFaceAmountAtMarketValue
Namespace Prefix:	ck0001415311_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Number of contracts.

+ References

No definition available.

+ Details

Name:	ck0001415311_NumberOfContracts
Namespace Prefix:	ck0001415311_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

+ Details

Name:	invest_DerivativeNotionalAmount
Namespace Prefix:	invest_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

X

- Definition

The number of derivative instruments of a particular group held by the entity.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5579245-113959

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5580258-113959

+ Details

Name:	us-gaap_DerivativeNumberOfInstrumentsHeld
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

X

- Definition

This element represents the net excess or deficiency of the fair value of an investment (security, contract) over or under its cost (face amount, notional amount), respectively, which excess value or deficiency has not been recognized in earnings of the entity.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 320
-Section S99
-Paragraph 22
-URI http://asc.fasb.org/extlink&oid=50485924&loc=SL6090603-123010

+ Details

Name:	us-gaap_InvestmentOwnedUnrecognizedUnrealizedAppreciationDepreciationNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_ScheduleOfInvestmentsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=ck0001415311_ProsharesUltraProThreeXShortCrudeOilEtfMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=ck0001415311_FuturesContractsSoldMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_InvestmentTypeAxis=ck0001415311_WtiCrudeOilNymexExpiresSeptemberTwoThousandAndEighteenMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=ck0001415311_ProsharesUltraShortAustralianDollarMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_InvestmentTypeAxis=ck0001415311_AustralianDollarFxCurrencyFuturesCmeExpiresSeptemberTwoThousandEighteenMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=ck0001415311_ProsharesShortVixShortTermFuturesEtfMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_InvestmentTypeAxis=ck0001415311_VixFuturesCboeExpiresJulyTwoThousandAndEighteenMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_InvestmentTypeAxis=ck0001415311_VIXFuturesCBOEExpiresAugustTwoThousandAndEighteenMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=ck0001415311_ProsharesShortEuroMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_InvestmentTypeAxis=ck0001415311_EuroFxCurrencyFuturesCmeExpiresSeptemberTwoThousandEighteenMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=ck0001415311_ProsharesUltraShortBloombergCrudeOilMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=ck0001415311_ProsharesUltraShortBloombergNaturalGasMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_InvestmentTypeAxis=ck0001415311_NaturalGasNymexExpiresSeptemberTwoThousandAndEighteenMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=ck0001415311_ProsharesUltraShortGoldMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_InvestmentTypeAxis=ck0001415311_GoldFuturesComexExpiresJuneTwoThousandEighteenMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=ck0001415311_ProsharesUltraShortSilverMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_InvestmentTypeAxis=ck0001415311_SilverFuturesComexExpiresSeptemberTwoThousandAndEighteenMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: