v2.4.0.6

Investments (Fair Value of Derivative Instruments) (Detail) (USD $) | Mar. 31, 2013 | Dec. 31, 2012
--- | --- | ---
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative asset not designated as hedging instrument, Unrealized Appreciation | $ 70,881,000 | [1] | $ 124,994,834 | [1]
Derivative liability not designated as hedging instrument, Unrealized Depreciation | 57,067,666 | [1] | 197,488,010 | [1]
Commodity Contracts [Member] | Payable On Open Futures Contracts, Unrealized Depreciation On Swap And/ Or Forward Agreements [Member] | ProShares UltraShort DJ-UBS Commodity [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative liability not designated as hedging instrument, Unrealized Depreciation | 92,919 |  |  |
Commodity Contracts [Member] | Payable On Open Futures Contracts, Unrealized Depreciation On Swap And/ Or Forward Agreements [Member] | ProShares UltraShort DJ-UBS Crude Oil [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative liability not designated as hedging instrument, Unrealized Depreciation | 11,368,414 |  | 9,636,781 | [1]
Commodity Contracts [Member] | Payable On Open Futures Contracts, Unrealized Depreciation On Swap And/ Or Forward Agreements [Member] | ProShares UltraShort DJ-UBS Natural Gas [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative liability not designated as hedging instrument, Unrealized Depreciation | 3,496,753 | [1] |  |
Commodity Contracts [Member] | Payable On Open Futures Contracts, Unrealized Depreciation On Swap And/ Or Forward Agreements [Member] | ProShares UltraShort Gold [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative liability not designated as hedging instrument, Unrealized Depreciation | 3,247,692 | [1] |  |
Commodity Contracts [Member] | Payable On Open Futures Contracts, Unrealized Depreciation On Swap And/ Or Forward Agreements [Member] | ProShares UltraShort Silver [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative liability not designated as hedging instrument, Unrealized Depreciation | 11,313 |  |  |
Commodity Contracts [Member] | Payable On Open Futures Contracts, Unrealized Depreciation On Swap And/ Or Forward Agreements [Member] | ProShares Ultra Silver [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative liability not designated as hedging instrument, Unrealized Depreciation | 8,134,488 | [1] | 145,780,726 | [1]
Commodity Contracts [Member] | Payable On Open Futures Contracts, Unrealized Depreciation On Swap And/ Or Forward Agreements [Member] | ProShares Ultra DJ-UBS Commodity [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative liability not designated as hedging instrument, Unrealized Depreciation |  |  | 306,268 |
Commodity Contracts [Member] | Payable On Open Futures Contracts, Unrealized Depreciation On Swap And/ Or Forward Agreements [Member] | ProShares Ultra DJ-UBS Natural Gas [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative liability not designated as hedging instrument, Unrealized Depreciation |  |  | 3,816,950 | [1]
Commodity Contracts [Member] | Payable On Open Futures Contracts, Unrealized Depreciation On Swap And/ Or Forward Agreements [Member] | ProShares Ultra Gold [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative liability not designated as hedging instrument, Unrealized Depreciation |  |  | 15,667,298 | [1]
Commodity Contracts [Member] | Receivables On Open Futures Contracts, Unrealized Appreciation On Swap And/ Or Forwards Agreements [Member] | ProShares UltraShort DJ-UBS Commodity [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative asset not designated as hedging instrument, Unrealized Appreciation |  |  | 148,502 |
Commodity Contracts [Member] | Receivables On Open Futures Contracts, Unrealized Appreciation On Swap And/ Or Forwards Agreements [Member] | ProShares UltraShort DJ-UBS Crude Oil [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative asset not designated as hedging instrument, Unrealized Appreciation | 231,524 | [1] |  |
Commodity Contracts [Member] | Receivables On Open Futures Contracts, Unrealized Appreciation On Swap And/ Or Forwards Agreements [Member] | ProShares UltraShort DJ-UBS Natural Gas [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative asset not designated as hedging instrument, Unrealized Appreciation |  |  | 409,135 | [1]
Commodity Contracts [Member] | Receivables On Open Futures Contracts, Unrealized Appreciation On Swap And/ Or Forwards Agreements [Member] | ProShares UltraShort Gold [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative asset not designated as hedging instrument, Unrealized Appreciation |  |  | 3,745,096 | [1]
Commodity Contracts [Member] | Receivables On Open Futures Contracts, Unrealized Appreciation On Swap And/ Or Forwards Agreements [Member] | ProShares UltraShort Silver [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative asset not designated as hedging instrument, Unrealized Appreciation | 294,121 | [1] | 19,347,705 | [1]
Commodity Contracts [Member] | Receivables On Open Futures Contracts, Unrealized Appreciation On Swap And/ Or Forwards Agreements [Member] | ProShares Ultra DJ-UBS Commodity [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative asset not designated as hedging instrument, Unrealized Appreciation | 115,047 |  |  |
Commodity Contracts [Member] | Receivables On Open Futures Contracts, Unrealized Appreciation On Swap And/ Or Forwards Agreements [Member] | ProShares Ultra DJ-UBS Natural Gas [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative asset not designated as hedging instrument, Unrealized Appreciation | 14,044,618 | [1] |  |
Commodity Contracts [Member] | Receivables On Open Futures Contracts, Unrealized Appreciation On Swap And/ Or Forwards Agreements [Member] | ProShares Ultra Gold [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative asset not designated as hedging instrument, Unrealized Appreciation | 9,223,820 | [1] |  |
Commodity Contracts [Member] | Receivables On Open Futures Contracts, Unrealized Appreciation On Swap And/ Or Forwards Agreements [Member] | ProShares Ultra DJ-UBS Crude Oil [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative asset not designated as hedging instrument, Unrealized Appreciation | 26,556,087 | [1] | 55,294,030 | [1]
Foreign Exchange Contracts [Member] | Unrealized Depreciation On Foreign Currency Forward Contracts And Payable On Open Futures Contracts [Member] | ProShares UltraShort Australian Dollar [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative liability not designated as hedging instrument, Unrealized Depreciation | 109,570 | [1] |  |
Foreign Exchange Contracts [Member] | Unrealized Depreciation On Foreign Currency Forward Contracts And Payable On Open Futures Contracts [Member] | ProShares UltraShort Euro [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative liability not designated as hedging instrument, Unrealized Depreciation | 1,439,211 |  | 13,398,619 |
Foreign Exchange Contracts [Member] | Unrealized Depreciation On Foreign Currency Forward Contracts And Payable On Open Futures Contracts [Member] | ProShares Ultra Euro [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative liability not designated as hedging instrument, Unrealized Depreciation | 137,134 |  | 2,314 |
Foreign Exchange Contracts [Member] | Unrealized Depreciation On Foreign Currency Forward Contracts And Payable On Open Futures Contracts [Member] | ProShares Ultra Yen [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative liability not designated as hedging instrument, Unrealized Depreciation | 70,562 |  | 507,819 |
Foreign Exchange Contracts [Member] | Unrealized Depreciation On Foreign Currency Forward Contracts And Payable On Open Futures Contracts [Member] | ProShares Short Euro [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative liability not designated as hedging instrument, Unrealized Depreciation |  |  | 55,056 | [1]
Foreign Exchange Contracts [Member] | Unrealized Depreciation On Foreign Currency Forward Contracts And Payable On Open Futures Contracts [Member] | ProShares UltraShort Yen [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative liability not designated as hedging instrument, Unrealized Depreciation |  |  | 232,642 |
Foreign Exchange Contracts [Member] | Unrealized Depreciation On Foreign Currency Forward Contracts And Payable On Open Futures Contracts [Member] | ProShares Ultra Australian Dollar [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative liability not designated as hedging instrument, Unrealized Depreciation |  |  | 99,030 | [1]
Foreign Exchange Contracts [Member] | Unrealized Appreciation On Foreign Currency Forward Contracts And Receivables On Open Futures Contracts [Member] | ProShares UltraShort Australian Dollar [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative asset not designated as hedging instrument, Unrealized Appreciation |  |  | 85,590 | [1]
Foreign Exchange Contracts [Member] | Unrealized Appreciation On Foreign Currency Forward Contracts And Receivables On Open Futures Contracts [Member] | ProShares UltraShort Euro [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative asset not designated as hedging instrument, Unrealized Appreciation | 15,104,660 |  | 251,047 |
Foreign Exchange Contracts [Member] | Unrealized Appreciation On Foreign Currency Forward Contracts And Receivables On Open Futures Contracts [Member] | ProShares Ultra Euro [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative asset not designated as hedging instrument, Unrealized Appreciation | 3,138 |  | 89,473 |
Foreign Exchange Contracts [Member] | Unrealized Appreciation On Foreign Currency Forward Contracts And Receivables On Open Futures Contracts [Member] | ProShares Ultra Yen [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative asset not designated as hedging instrument, Unrealized Appreciation |  |  | 13,523 |
Foreign Exchange Contracts [Member] | Unrealized Appreciation On Foreign Currency Forward Contracts And Receivables On Open Futures Contracts [Member] | ProShares Short Euro [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative asset not designated as hedging instrument, Unrealized Appreciation | 61,713 | [1] |  |
Foreign Exchange Contracts [Member] | Unrealized Appreciation On Foreign Currency Forward Contracts And Receivables On Open Futures Contracts [Member] | ProShares UltraShort Yen [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative asset not designated as hedging instrument, Unrealized Appreciation | 2,732,626 |  | 38,346,817 |
Foreign Exchange Contracts [Member] | Unrealized Appreciation On Foreign Currency Forward Contracts And Receivables On Open Futures Contracts [Member] | ProShares Ultra Australian Dollar [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative asset not designated as hedging instrument, Unrealized Appreciation | 124,930 | [1] |  |
VIX Futures Contracts [Member] | Payable On Open Futures Contracts, Unrealized Depreciation On Swap And/ Or Forwards Agreement [Member] | ProShares VIX Short-Term Futures ETF [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative liability not designated as hedging instrument, Unrealized Depreciation | 8,346,060 | [1] | 2,590,243 | [1]
VIX Futures Contracts [Member] | Payable On Open Futures Contracts, Unrealized Depreciation On Swap And/ Or Forwards Agreement [Member] | ProShares VIX Mid-Term Futures ETF [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative liability not designated as hedging instrument, Unrealized Depreciation | 1,876,429 | [1] | 1,703,570 | [1]
VIX Futures Contracts [Member] | Payable On Open Futures Contracts, Unrealized Depreciation On Swap And/ Or Forwards Agreement [Member] | ProShares Ultra VIX Short-Term Futures ETF [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative liability not designated as hedging instrument, Unrealized Depreciation | 18,737,121 | [1] | 1,676,460 | [1]
VIX Futures Contracts [Member] | Payable On Open Futures Contracts, Unrealized Depreciation On Swap And/ Or Forwards Agreement [Member] | ProShares Short VIX Short-Term Futures ETF [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative liability not designated as hedging instrument, Unrealized Depreciation |  |  | 2,014,234 | [1]
VIX Futures Contracts [Member] | Receivables On Open Futures Contracts, Unrealized Appreciation On Swap And/ Or Forwards Agreements [Member] | ProShares VIX Short-Term Futures ETF [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative asset not designated as hedging instrument, Unrealized Appreciation |  |  | 2,368,824 | [1]
VIX Futures Contracts [Member] | Receivables On Open Futures Contracts, Unrealized Appreciation On Swap And/ Or Forwards Agreements [Member] | ProShares VIX Mid-Term Futures ETF [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative asset not designated as hedging instrument, Unrealized Appreciation |  |  | 233,160 | [1]
VIX Futures Contracts [Member] | Receivables On Open Futures Contracts, Unrealized Appreciation On Swap And/ Or Forwards Agreements [Member] | ProShares Ultra VIX Short-Term Futures ETF [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative asset not designated as hedging instrument, Unrealized Appreciation |  |  | 4,034,873 | [1]
VIX Futures Contracts [Member] | Receivables On Open Futures Contracts, Unrealized Appreciation On Swap And/ Or Forwards Agreements [Member] | ProShares Short VIX Short-Term Futures ETF [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative asset not designated as hedging instrument, Unrealized Appreciation | $ 2,388,716 | [1] | $ 627,059 | [1]
[1] | Includes cumulative appreciation/depreciation of futures contracts as reported in the Schedules of Investments. Only current day's variation margin is reported within the Statements of Financial Condition in receivable/payable on open futures contracts.

X
- Definition Derivative Asset Not Designated as Hedging Instrument, Unrealized Appreciation + References No definition available. + Details
Name: | ck0001415311_DerivativeAssetNotDesignatedAsHedgingInstrumentUnrealizedAppreciation
Namespace Prefix: | ck0001415311_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Derivative Liability Not Designated as Hedging Instrument, Unrealized Depreciation + References No definition available. + Details
Name: | ck0001415311_DerivativeLiabilityNotDesignatedAsHedgingInstrumentUnrealizedDepreciation
Namespace Prefix: | ck0001415311_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_DerivativeInstrumentsGainLossLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration