v2.4.0.6

Investments (Offsetting Of Financial Liabilities And Derivative Liabilities) (Detail) (USD $)	Mar. 31, 2013		Dec. 31, 2012
ProShares UltraShort DJ-UBS Commodity [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities	$ 92,919
Net Amounts of Liabilities Presented in the Statement of Financial Condition	92,919
ProShares UltraShort DJ-UBS Commodity [Member] | Swap Agreements [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities	92,919
Net Amounts of Liabilities Presented in the Statement of Financial Condition	92,919
ProShares UltraShort DJ-UBS Crude Oil [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities	12,719,387		6,586,396
Net Amounts of Liabilities Presented in the Statement of Financial Condition	12,719,387		6,586,396
ProShares UltraShort DJ-UBS Crude Oil [Member] | Swap Agreements [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities	11,368,414		5,607,060
Net Amounts of Liabilities Presented in the Statement of Financial Condition	11,368,414		5,607,060
ProShares UltraShort DJ-UBS Crude Oil [Member] | Future Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities	1,350,973	[1]	979,336	[1]
Net Amounts of Liabilities Presented in the Statement of Financial Condition	1,350,973	[1]	979,336	[1]
ProShares UltraShort DJ-UBS Natural Gas [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities
Gross Amounts Offset in the Statement of Financial Condition
Net Amounts of Liabilities Presented in the Statement of Financial Condition
ProShares UltraShort DJ-UBS Natural Gas [Member] | Future Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities		[1]
Gross Amounts Offset in the Statement of Financial Condition		[1]
Net Amounts of Liabilities Presented in the Statement of Financial Condition		[1]
ProShares UltraShort Gold [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities	3,246,282		3,980
Net Amounts of Liabilities Presented in the Statement of Financial Condition	3,246,282		3,980
ProShares UltraShort Gold [Member] | Future Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities			3,980	[1]
Net Amounts of Liabilities Presented in the Statement of Financial Condition			3,980	[1]
ProShares UltraShort Gold [Member] | Forward Agreements [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities	3,246,282
Net Amounts of Liabilities Presented in the Statement of Financial Condition	3,246,282
ProShares UltraShort Silver [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities	11,313		2,520
Net Amounts of Liabilities Presented in the Statement of Financial Condition	11,313		2,520
ProShares UltraShort Silver [Member] | Future Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities			2,520	[1]
Net Amounts of Liabilities Presented in the Statement of Financial Condition			2,520	[1]
ProShares UltraShort Silver [Member] | Forward Agreements [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities	11,313
Net Amounts of Liabilities Presented in the Statement of Financial Condition	11,313
ProShares Short Euro [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities	12,300
Net Amounts of Liabilities Presented in the Statement of Financial Condition	12,300
ProShares Short Euro [Member] | Future Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities	12,300	[1]
Net Amounts of Liabilities Presented in the Statement of Financial Condition	12,300	[1]
ProShares UltraShort Australian Dollar [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities			10,950
Gross Amounts Offset in the Statement of Financial Condition
Net Amounts of Liabilities Presented in the Statement of Financial Condition			10,950
ProShares UltraShort Australian Dollar [Member] | Future Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities		[1]	10,950	[1]
Gross Amounts Offset in the Statement of Financial Condition		[1]
Net Amounts of Liabilities Presented in the Statement of Financial Condition		[1]	10,950	[1]
ProShares UltraShort Euro [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities	1,439,211		13,398,619
Net Amounts of Liabilities Presented in the Statement of Financial Condition	1,439,211		13,398,619
ProShares UltraShort Euro [Member] | Foreign Currency Forward Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities	1,439,211		13,398,619
Net Amounts of Liabilities Presented in the Statement of Financial Condition	1,439,211		13,398,619
ProShares UltraShort Yen [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities			232,642
Gross Amounts Offset in the Statement of Financial Condition
Net Amounts of Liabilities Presented in the Statement of Financial Condition			232,642
ProShares UltraShort Yen [Member] | Foreign Currency Forward Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities			232,642
Gross Amounts Offset in the Statement of Financial Condition
Net Amounts of Liabilities Presented in the Statement of Financial Condition			232,642
ProShares Ultra DJ-UBS Commodity [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities			306,268
Gross Amounts Offset in the Statement of Financial Condition
Net Amounts of Liabilities Presented in the Statement of Financial Condition			306,268
ProShares Ultra DJ-UBS Commodity [Member] | Swap Agreements [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities			306,268
Gross Amounts Offset in the Statement of Financial Condition
Net Amounts of Liabilities Presented in the Statement of Financial Condition			306,268
ProShares Ultra DJ-UBS Crude Oil [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities
Gross Amounts Offset in the Statement of Financial Condition
Net Amounts of Liabilities Presented in the Statement of Financial Condition
ProShares Ultra DJ-UBS Crude Oil [Member] | Swap Agreements [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities
Gross Amounts Offset in the Statement of Financial Condition
Net Amounts of Liabilities Presented in the Statement of Financial Condition
ProShares Ultra DJ-UBS Crude Oil [Member] | Future Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities		[1]
Gross Amounts Offset in the Statement of Financial Condition		[1]
Net Amounts of Liabilities Presented in the Statement of Financial Condition		[1]
ProShares Ultra DJ-UBS Natural Gas [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities	834,689		4,891,783
Net Amounts of Liabilities Presented in the Statement of Financial Condition	834,689		4,891,783
ProShares Ultra DJ-UBS Natural Gas [Member] | Future Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities	834,689	[1]	4,891,783	[1]
Net Amounts of Liabilities Presented in the Statement of Financial Condition	834,689	[1]	4,891,783	[1]
ProShares Ultra Gold [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities	2,300		15,652,058
Net Amounts of Liabilities Presented in the Statement of Financial Condition	2,300		15,652,058
ProShares Ultra Gold [Member] | Future Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities	2,300	[1]
Net Amounts of Liabilities Presented in the Statement of Financial Condition	2,300	[1]
ProShares Ultra Gold [Member] | Forward Agreements [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities			15,652,058
Net Amounts of Liabilities Presented in the Statement of Financial Condition			15,652,058
ProShares Ultra Silver [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities	8,109,608		145,740,706
Net Amounts of Liabilities Presented in the Statement of Financial Condition	8,109,608		145,740,706
ProShares Ultra Silver [Member] | Future Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities	2,890	[1]
Net Amounts of Liabilities Presented in the Statement of Financial Condition	2,890	[1]
ProShares Ultra Silver [Member] | Forward Agreements [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities	8,106,718		145,740,706
Net Amounts of Liabilities Presented in the Statement of Financial Condition	8,106,718		145,740,706
ProShares Ultra Australian Dollar [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities	22,982
Net Amounts of Liabilities Presented in the Statement of Financial Condition	22,982
ProShares Ultra Australian Dollar [Member] | Future Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities	22,982	[1]
Net Amounts of Liabilities Presented in the Statement of Financial Condition	22,982	[1]
ProShares Ultra Euro [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities	137,134		2,314
Net Amounts of Liabilities Presented in the Statement of Financial Condition	137,134		2,314
ProShares Ultra Euro [Member] | Foreign Currency Forward Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities	137,134		2,314
Net Amounts of Liabilities Presented in the Statement of Financial Condition	137,134		2,314
ProShares Ultra Yen [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities	70,562		507,819
Net Amounts of Liabilities Presented in the Statement of Financial Condition	70,562		507,819
ProShares Ultra Yen [Member] | Foreign Currency Forward Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities	70,562		507,819
Net Amounts of Liabilities Presented in the Statement of Financial Condition	70,562		507,819
ProShares VIX Short-Term Futures ETF [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities	2,471,348		31,540,181
Net Amounts of Liabilities Presented in the Statement of Financial Condition	2,471,348		31,540,181
ProShares VIX Short-Term Futures ETF [Member] | Future Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities	2,471,348	[1]	31,540,181	[1]
Net Amounts of Liabilities Presented in the Statement of Financial Condition	2,471,348	[1]	31,540,181	[1]
ProShares VIX Mid-Term Futures ETF [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities			1,890,675
Gross Amounts Offset in the Statement of Financial Condition
Net Amounts of Liabilities Presented in the Statement of Financial Condition			1,890,675
ProShares VIX Mid-Term Futures ETF [Member] | Future Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities		[1]	1,890,675	[1]
Gross Amounts Offset in the Statement of Financial Condition		[1]
Net Amounts of Liabilities Presented in the Statement of Financial Condition		[1]	1,890,675	[1]
ProShares Ultra VIX Short-Term Futures ETF [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities	4,961,933		35,666,735
Net Amounts of Liabilities Presented in the Statement of Financial Condition	4,961,933		35,666,735
ProShares Ultra VIX Short-Term Futures ETF [Member] | Future Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities	4,961,933	[1]	35,666,735	[1]
Net Amounts of Liabilities Presented in the Statement of Financial Condition	4,961,933	[1]	35,666,735	[1]
ProShares Short VIX Short-Term Futures ETF [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities
Gross Amounts Offset in the Statement of Financial Condition
Net Amounts of Liabilities Presented in the Statement of Financial Condition
ProShares Short VIX Short-Term Futures ETF [Member] | Future Contracts [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities		[1]
Gross Amounts Offset in the Statement of Financial Condition		[1]
Net Amounts of Liabilities Presented in the Statement of Financial Condition		[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.

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- Definition

Fair value of derivative liability, 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.

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The amount as of the balance sheet date of the fair value of derivative liabilities that in accordance with the entity's accounting policy were offset against the right to reclaim cash collateral under a master netting arrangement.

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

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