v2.4.0.6

Investments (Offsetting Of Financial Assets And Derivative Assets) (Detail) (USD $)	Mar. 31, 2013		Dec. 31, 2012
ProShares UltraShort DJ-UBS Commodity [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets			$ 148,502
Gross Amounts Offset in the Statement of Financial Condition
Net Amounts of Assets Presented in the Statement of Financial Condition			148,502
ProShares UltraShort DJ-UBS Commodity [Member] | Swap Agreements [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets			148,502
Gross Amounts Offset in the Statement of Financial Condition
Net Amounts of Assets Presented in the Statement of Financial Condition			148,502
ProShares UltraShort DJ-UBS Crude Oil [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets
Gross Amounts Offset in the Statement of Financial Condition
Net Amounts of Assets Presented in the Statement of Financial Condition
ProShares UltraShort DJ-UBS Crude Oil [Member] | Swap Agreements [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets
Gross Amounts Offset in the Statement of Financial Condition
Net Amounts of Assets Presented in the Statement of Financial Condition
ProShares UltraShort DJ-UBS Crude Oil [Member] | Future Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets		[1]
Gross Amounts Offset in the Statement of Financial Condition		[1]
Net Amounts of Assets Presented in the Statement of Financial Condition		[1]
ProShares UltraShort DJ-UBS Natural Gas [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets	442,358		632,777
Net Amounts of Assets Presented in the Statement of Financial Condition	442,358		632,777
ProShares UltraShort DJ-UBS Natural Gas [Member] | Future Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets	442,358	[1]	632,777	[1]
Net Amounts of Assets Presented in the Statement of Financial Condition	442,358	[1]	632,777	[1]
ProShares UltraShort Gold [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets	2,300		3,729,856
Net Amounts of Assets Presented in the Statement of Financial Condition	2,300		3,729,856
ProShares UltraShort Gold [Member] | Future Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets	2,300	[1]
Net Amounts of Assets Presented in the Statement of Financial Condition	2,300	[1]
ProShares UltraShort Gold [Member] | Forward Agreements [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets			3,729,856
Net Amounts of Assets Presented in the Statement of Financial Condition			3,729,856
ProShares UltraShort Silver [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets	269,491		19,307,685
Net Amounts of Assets Presented in the Statement of Financial Condition	269,491		19,307,685
ProShares UltraShort Silver [Member] | Future Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets	2,890	[1]
Net Amounts of Assets Presented in the Statement of Financial Condition	2,890	[1]
ProShares UltraShort Silver [Member] | Forward Agreements [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets	266,601		19,307,685
Net Amounts of Assets Presented in the Statement of Financial Condition	266,601		19,307,685
ProShares Short Euro [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets			6,612
Gross Amounts Offset in the Statement of Financial Condition
Net Amounts of Assets Presented in the Statement of Financial Condition			6,612
ProShares Short Euro [Member] | Future Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets		[1]	6,612	[1]
Gross Amounts Offset in the Statement of Financial Condition		[1]
Net Amounts of Assets Presented in the Statement of Financial Condition		[1]	6,612	[1]
ProShares UltraShort Australian Dollar [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets	21,300
Net Amounts of Assets Presented in the Statement of Financial Condition	21,300
ProShares UltraShort Australian Dollar [Member] | Future Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets	21,300	[1]
Net Amounts of Assets Presented in the Statement of Financial Condition	21,300	[1]
ProShares UltraShort Euro [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets	15,104,660		251,047
Net Amounts of Assets Presented in the Statement of Financial Condition	15,104,660		251,047
ProShares UltraShort Euro [Member] | Foreign Currency Forward Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets	15,104,660		251,047
Net Amounts of Assets Presented in the Statement of Financial Condition	15,104,660		251,047
ProShares UltraShort Yen [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets	2,732,626		38,346,817
Net Amounts of Assets Presented in the Statement of Financial Condition	2,732,626		38,346,817
ProShares UltraShort Yen [Member] | Foreign Currency Forward Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets	2,732,626		38,346,817
Net Amounts of Assets Presented in the Statement of Financial Condition	2,732,626		38,346,817
ProShares Ultra DJ-UBS Commodity [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets	115,047
Net Amounts of Assets Presented in the Statement of Financial Condition	115,047
ProShares Ultra DJ-UBS Commodity [Member] | Swap Agreements [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets	115,047
Net Amounts of Assets Presented in the Statement of Financial Condition	115,047
ProShares Ultra DJ-UBS Crude Oil [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets	27,579,874		36,764,035
Net Amounts of Assets Presented in the Statement of Financial Condition	27,579,874		36,764,035
ProShares Ultra DJ-UBS Crude Oil [Member] | Swap Agreements [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets	25,193,571		33,333,620
Net Amounts of Assets Presented in the Statement of Financial Condition	25,193,571		33,333,620
ProShares Ultra DJ-UBS Crude Oil [Member] | Future Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets	2,386,303	[1]	3,430,415	[1]
Net Amounts of Assets Presented in the Statement of Financial Condition	2,386,303	[1]	3,430,415	[1]
ProShares Ultra DJ-UBS Natural Gas [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets
Gross Amounts Offset in the Statement of Financial Condition
Net Amounts of Assets Presented in the Statement of Financial Condition
ProShares Ultra DJ-UBS Natural Gas [Member] | Future Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets		[1]
Gross Amounts Offset in the Statement of Financial Condition		[1]
Net Amounts of Assets Presented in the Statement of Financial Condition		[1]
ProShares Ultra Gold [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets	9,222,440		3,980
Net Amounts of Assets Presented in the Statement of Financial Condition	9,222,440		3,980
ProShares Ultra Gold [Member] | Future Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets			3,980	[1]
Net Amounts of Assets Presented in the Statement of Financial Condition			3,980	[1]
ProShares Ultra Gold [Member] | Forward Agreements [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets	9,222,440
Net Amounts of Assets Presented in the Statement of Financial Condition	9,222,440
ProShares Ultra Silver [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets			2,520
Gross Amounts Offset in the Statement of Financial Condition
Net Amounts of Assets Presented in the Statement of Financial Condition			2,520
ProShares Ultra Silver [Member] | Future Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets		[1]	2,520	[1]
Gross Amounts Offset in the Statement of Financial Condition		[1]
Net Amounts of Assets Presented in the Statement of Financial Condition		[1]	2,520	[1]
ProShares Ultra Silver [Member] | Forward Agreements [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets
Gross Amounts Offset in the Statement of Financial Condition
Net Amounts of Assets Presented in the Statement of Financial Condition
ProShares Ultra Australian Dollar [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets			12,000
Gross Amounts Offset in the Statement of Financial Condition
Net Amounts of Assets Presented in the Statement of Financial Condition			12,000
ProShares Ultra Australian Dollar [Member] | Future Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets		[1]	12,000	[1]
Gross Amounts Offset in the Statement of Financial Condition		[1]
Net Amounts of Assets Presented in the Statement of Financial Condition		[1]	12,000	[1]
ProShares Ultra Euro [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets	3,138		89,473
Net Amounts of Assets Presented in the Statement of Financial Condition	3,138		89,473
ProShares Ultra Euro [Member] | Foreign Currency Forward Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets	3,138		89,473
Net Amounts of Assets Presented in the Statement of Financial Condition	3,138		89,473
ProShares Ultra Yen [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets			13,523
Gross Amounts Offset in the Statement of Financial Condition
Net Amounts of Assets Presented in the Statement of Financial Condition			13,523
ProShares Ultra Yen [Member] | Foreign Currency Forward Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets			13,523
Gross Amounts Offset in the Statement of Financial Condition
Net Amounts of Assets Presented in the Statement of Financial Condition			13,523
ProShares VIX Short-Term Futures ETF [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets
Gross Amounts Offset in the Statement of Financial Condition
Net Amounts of Assets Presented in the Statement of Financial Condition
ProShares VIX Short-Term Futures ETF [Member] | Future Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets		[1]
Gross Amounts Offset in the Statement of Financial Condition		[1]
Net Amounts of Assets Presented in the Statement of Financial Condition		[1]
ProShares VIX Mid-Term Futures ETF [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets	211,350
Net Amounts of Assets Presented in the Statement of Financial Condition	211,350
ProShares VIX Mid-Term Futures ETF [Member] | Future Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets	211,350	[1]
Net Amounts of Assets Presented in the Statement of Financial Condition	211,350	[1]
ProShares Ultra VIX Short-Term Futures ETF [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets			301,351
Gross Amounts Offset in the Statement of Financial Condition
Net Amounts of Assets Presented in the Statement of Financial Condition			301,351
ProShares Ultra VIX Short-Term Futures ETF [Member] | Swap Agreements [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets			301,351
Net Amounts of Assets Presented in the Statement of Financial Condition			301,351
ProShares Ultra VIX Short-Term Futures ETF [Member] | Future Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets		[1]
Gross Amounts Offset in the Statement of Financial Condition		[1]
Net Amounts of Assets Presented in the Statement of Financial Condition		[1]
ProShares Short VIX Short-Term Futures ETF [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets	472,022		5,524,721
Net Amounts of Assets Presented in the Statement of Financial Condition	472,022		5,524,721
ProShares Short VIX Short-Term Futures ETF [Member] | Future Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets	472,022	[1]	5,524,721	[1]
Net Amounts of Assets Presented in the Statement of Financial Condition	$ 472,022	[1]	$ 5,524,721	[1]
[1] Current day's variation margin is reported within the Statements of Financial Condition in receivable/payable on open futures contracts; Cumulative appreciation/depreciation is reported in the Schedule of Investments.

X

- Definition

Fair values as of the balance sheet date of all assets resulting from contracts that meet the criteria of being accounted for as derivative instruments, net of the effects of master netting arrangements.

+ References

Reference 1: 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 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FIN39-1

-Paragraph 10A, 10B

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.



Reference 3: 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=7491637&loc=d3e13433-108611



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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 4, 17

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.



Reference 5: 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 6: 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=7491637&loc=d3e13495-108611

+ Details

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

X

- Definition

Fair value of derivative asset, presented on a gross basis even when the derivative instrument is subject to master netting arrangements and qualifies for net presentation in the statement of financial position.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 205G

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.



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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 44C

-Subparagraph a

-Clause 1

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.



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

The amount as of the balance sheet date of the fair value of derivative assets that in accordance with the entity's accounting policy was offset against an obligation to return cash collateral under a master netting arrangement.

+ References

Reference 1: 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



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

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FIN39-1

-Paragraph 10B

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

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

X

- Details

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