v2.4.0.8

Investments - Offsetting of Financial Assets and Liabilities (Detail) (USD $)	Jun. 30, 2014	Dec. 31, 2013
ProShares UltraShort Bloomberg Commodity [Member] | Swap Agreements [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets presented in the Statement of Financial Conditions	$ 0	$ 0
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	0	0
Gross Amounts of Recognized Liabilities presented in the Statement of Financial Conditions	49,719	27,665
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	49,719	27,665
ProShares UltraShort Bloomberg Crude Oil [Member] | Swap Agreements [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets presented in the Statement of Financial Conditions	0	0
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	0	0
Gross Amounts of Recognized Liabilities presented in the Statement of Financial Conditions	16,105,152	2,332,900
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	16,105,152	2,332,900
ProShares UltraShort Bloomberg Crude Oil [Member] | VIX Futures Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets presented in the Statement of Financial Conditions	778,232	1,503,943
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	778,232	1,503,943
Gross Amounts of Recognized Liabilities presented in the Statement of Financial Conditions	0	0
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	0	0
ProShares UltraShort Bloomberg Natural Gas [Member] | VIX Futures Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets presented in the Statement of Financial Conditions	0	1,520,548
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	0	1,520,548
Gross Amounts of Recognized Liabilities presented in the Statement of Financial Conditions	730,316	0
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	730,316	0
ProShares UltraShort Gold [Member] | VIX Futures Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets presented in the Statement of Financial Conditions	0	300
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	0	300
Gross Amounts of Recognized Liabilities presented in the Statement of Financial Conditions	1,000	0
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	1,000	0
ProShares UltraShort Gold [Member] | Forward Agreements [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets presented in the Statement of Financial Conditions	0	5,633,053
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	0	5,633,053
Gross Amounts of Recognized Liabilities presented in the Statement of Financial Conditions	10,583,508	0
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	10,583,508	0
ProShares UltraShort Silver [Member] | VIX Futures Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets presented in the Statement of Financial Conditions	780	2,450
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	780	2,450
Gross Amounts of Recognized Liabilities presented in the Statement of Financial Conditions	0	0
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	0	0
ProShares UltraShort Silver [Member] | Forward Agreements [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets presented in the Statement of Financial Conditions	0	0
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	0	0
Gross Amounts of Recognized Liabilities presented in the Statement of Financial Conditions	10,563,213	2,227,857
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	10,563,213	2,227,857
ProShares Short Euro [Member] | VIX Futures Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets presented in the Statement of Financial Conditions	0	9,100
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	0	9,100
Gross Amounts of Recognized Liabilities presented in the Statement of Financial Conditions	49,240	0
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	49,240	0
ProShares UltraShort Australian Dollar [Member] | VIX Futures Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets presented in the Statement of Financial Conditions	0	0
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	0	0
Gross Amounts of Recognized Liabilities presented in the Statement of Financial Conditions	17,160	86,166
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	17,160	86,166
ProShares UltraShort Euro [Member] | Foreign Currency Forward Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets presented in the Statement of Financial Conditions	327,971	151,351
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	327,971	151,351
Gross Amounts of Recognized Liabilities presented in the Statement of Financial Conditions	5,915,312	13,899,858
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	5,915,312	13,899,858
ProShares UltraShort Yen [Member] | Foreign Currency Forward Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets presented in the Statement of Financial Conditions	480,205	31,317,568
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	480,205	31,317,568
Gross Amounts of Recognized Liabilities presented in the Statement of Financial Conditions	10,127,815	1,930,884
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	10,127,815	1,930,884
ProShares Ultra Bloomberg Commodity [Member] | Swap Agreements [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets presented in the Statement of Financial Conditions	14,121	15,078
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	14,121	15,078
Gross Amounts of Recognized Liabilities presented in the Statement of Financial Conditions	5,077	0
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	5,077	0
ProShares Ultra Bloomberg Crude Oil [Member] | Swap Agreements [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets presented in the Statement of Financial Conditions	4,111,030	1,957,893
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	4,111,030	1,957,893
Gross Amounts of Recognized Liabilities presented in the Statement of Financial Conditions	0	0
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	0	0
ProShares Ultra Bloomberg Crude Oil [Member] | VIX Futures Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets presented in the Statement of Financial Conditions	0	0
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	0	0
Gross Amounts of Recognized Liabilities presented in the Statement of Financial Conditions	313,787	997,210
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	313,787	997,210
ProShares Ultra Bloomberg Natural Gas [Member] | VIX Futures Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets presented in the Statement of Financial Conditions	111,842	0
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	111,842	0
Gross Amounts of Recognized Liabilities presented in the Statement of Financial Conditions	0	5,628,532
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	0	5,628,532
ProShares Ultra Gold [Member] | VIX Futures Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets presented in the Statement of Financial Conditions	0	0
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	0	0
Gross Amounts of Recognized Liabilities presented in the Statement of Financial Conditions	120	300
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	120	300
ProShares Ultra Gold [Member] | Forward Agreements [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets presented in the Statement of Financial Conditions	13,227,915	0
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	13,227,915	0
Gross Amounts of Recognized Liabilities presented in the Statement of Financial Conditions	0	6,812,974
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	0	6,812,974
ProShares Ultra Silver [Member] | VIX Futures Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets presented in the Statement of Financial Conditions	0	0
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	0	0
Gross Amounts of Recognized Liabilities presented in the Statement of Financial Conditions	575	2,450
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	575	2,450
ProShares Ultra Silver [Member] | Forward Agreements [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets presented in the Statement of Financial Conditions	86,902,211	0
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	86,902,211	0
Gross Amounts of Recognized Liabilities presented in the Statement of Financial Conditions	0	2,492,880
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	0	2,492,880
ProShares Ultra Australian Dollar [Member] | VIX Futures Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets presented in the Statement of Financial Conditions	3,080	10,650
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	3,080	10,650
Gross Amounts of Recognized Liabilities presented in the Statement of Financial Conditions	0	0
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	0	0
ProShares Ultra Euro [Member] | Foreign Currency Forward Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets presented in the Statement of Financial Conditions	31,105	120,908
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	31,105	120,908
Gross Amounts of Recognized Liabilities presented in the Statement of Financial Conditions	378	19,946
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	378	19,946
ProShares Ultra Yen [Member] | Foreign Currency Forward Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets presented in the Statement of Financial Conditions	76,915	4,052
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	76,915	4,052
Gross Amounts of Recognized Liabilities presented in the Statement of Financial Conditions	24,196	163,361
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	24,196	163,361
ProShares VIX Short-Term Futures ETF [Member] | VIX Futures Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets presented in the Statement of Financial Conditions	0	3,179,017
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	0	3,179,017
Gross Amounts of Recognized Liabilities presented in the Statement of Financial Conditions	1,041,667	0
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	1,041,667	0
ProShares VIX Mid-Term Futures ETF [Member] | VIX Futures Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets presented in the Statement of Financial Conditions	0	100,734
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	0	100,734
Gross Amounts of Recognized Liabilities presented in the Statement of Financial Conditions	522,035	0
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	522,035	0
ProShares Ultra VIX Short-Term Futures ETF [Member] | VIX Futures Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets presented in the Statement of Financial Conditions	0	0
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	0	0
Gross Amounts of Recognized Liabilities presented in the Statement of Financial Conditions	5,702,682	3,356,803
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	5,702,682	3,356,803
ProShares Short VIX Short-Term Futures ETF [Member] | VIX Futures Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets presented in the Statement of Financial Conditions	0	603,833
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	0	603,833
Gross Amounts of Recognized Liabilities presented in the Statement of Financial Conditions	14,181	0
Gross Amounts Offset in the Statement of Financial Conditions	0	0
Net Amount	$ 14,181	$ 0

X

- Definition

Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 10

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=28364263&loc=d3e13433-108611



Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 45

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958



Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 15

-URI http://asc.fasb.org/extlink&oid=28364263&loc=d3e13495-108611



Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 50

-Paragraph 3

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=20225523&loc=SL20225862-175312



Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 45

-Paragraph 6

-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41271-113958



Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 55

-Paragraph 10

-URI http://asc.fasb.org/extlink&oid=28370219&loc=SL20226008-175313

+ Details

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

X

- Definition

Fair value before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 55

-Paragraph 7

-URI http://asc.fasb.org/extlink&oid=28370219&loc=SL20226000-175313



Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 50

-Paragraph 3

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=20225523&loc=SL20225862-175312



Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4B

-Subparagraph (a),(c)

-URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5624163-113959

+ Details

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

X

- Definition

Fair value of financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset offset against an obligation to return collateral. Includes assets not subject to a master netting arrangement and not elected to be offset.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 50

-Paragraph 3

-Subparagraph (e)

-URI http://asc.fasb.org/extlink&oid=20225523&loc=SL20225862-175312



Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 55

-Paragraph 13

-URI http://asc.fasb.org/extlink&oid=28370219&loc=SL20226016-175313



Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 8

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=7476318&loc=d3e41678-113959

+ Details

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

X

- Definition

Fair value before effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 55

-Paragraph 7

-URI http://asc.fasb.org/extlink&oid=28370219&loc=SL20226000-175313



Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 50

-Paragraph 3

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=20225523&loc=SL20225862-175312



Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4B

-Subparagraph (a),(c)

-URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5624163-113959

+ Details

Name:	us-gaap_DerivativeFairValueOfDerivativeLiability
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Fair value of financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset offset against the right to receive collateral. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 50

-Paragraph 3

-Subparagraph (e)

-URI http://asc.fasb.org/extlink&oid=20225523&loc=SL20225862-175312



Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 55

-Paragraph 13

-URI http://asc.fasb.org/extlink&oid=28370219&loc=SL20226016-175313



Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 8

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=7476318&loc=d3e41678-113959

+ Details

Name:	us-gaap_DerivativeFairValueOfDerivativeLiabilityAmountOffsetAgainstCollateral
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 10

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=28364263&loc=d3e13433-108611



Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 45

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958



Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 15

-URI http://asc.fasb.org/extlink&oid=28364263&loc=d3e13495-108611



Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 50

-Paragraph 3

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=20225523&loc=SL20225862-175312



Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 45

-Paragraph 6

-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41271-113958



Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 55

-Paragraph 10

-URI http://asc.fasb.org/extlink&oid=28370219&loc=SL20226008-175313

+ Details

Name:	us-gaap_DerivativeLiabilities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Details

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