v2.4.0.6
Investments (Financial Liabilities, Derivative Liabilities, And Collateral Pledged By Counterparty) (Detail) (USD $)
Mar. 31, 2013
Dec. 31, 2012
ProShares UltraShort DJ-UBS Commodity [Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition $ 92,919  
Financial Instruments (92,919)  
ProShares UltraShort DJ-UBS Commodity [Member] | Goldman Sachs International (Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition 64,434  
Financial Instruments (64,434)  
ProShares UltraShort DJ-UBS Commodity [Member] | UBS AG [Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition 28,485  
Financial Instruments (28,485)  
ProShares UltraShort DJ-UBS Crude Oil [Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition 12,719,387 6,586,396
Financial Instruments (11,368,414) (5,607,060)
Cash Collateral Pledged (1,350,973) (979,336)
ProShares UltraShort DJ-UBS Crude Oil [Member] | Goldman Sachs International (Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition 6,252,210 1,880,292
Financial Instruments (6,252,210) (1,880,292)
ProShares UltraShort DJ-UBS Crude Oil [Member] | UBS AG [Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition 3,986,152 1,996,402
Financial Instruments (3,986,152) (1,996,402)
ProShares UltraShort DJ-UBS Crude Oil [Member] | Goldman Sachs & Co.Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition 1,350,973 979,336
Cash Collateral Pledged (1,350,973) (979,336)
ProShares UltraShort DJ-UBS Crude Oil [Member] | Societe Generale S.A. [Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition 1,130,052 1,730,366
Financial Instruments (1,130,052) (1,730,366)
ProShares UltraShort DJ-UBS Natural Gas [Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition     
Financial Instruments     
Cash Collateral Pledged     
Net Amount     
ProShares UltraShort Gold [Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition 3,246,282 3,980
Financial Instruments (3,246,282)  
Cash Collateral Pledged   (3,980)
ProShares UltraShort Gold [Member] | Goldman Sachs International (Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition 589,404  
Financial Instruments (589,404)  
ProShares UltraShort Gold [Member] | UBS AG [Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition 444,201  
Financial Instruments (444,201)  
ProShares UltraShort Gold [Member] | Goldman Sachs & Co.Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition   3,980
Cash Collateral Pledged   (3,980)
ProShares UltraShort Gold [Member] | Societe Generale S.A. [Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition 460,599  
Financial Instruments (460,599)  
ProShares UltraShort Gold [Member] | Deutsche Bank AG [Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition 1,752,078  
Financial Instruments (1,752,078)  
ProShares UltraShort Silver [Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition 11,313 2,520
Financial Instruments (11,313)  
Cash Collateral Pledged   (2,520)
ProShares UltraShort Silver [Member] | UBS AG [Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition 11,313  
Financial Instruments (11,313)  
ProShares UltraShort Silver [Member] | Goldman Sachs & Co.Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition   2,520
Cash Collateral Pledged   (2,520)
ProShares Short Euro [Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition 12,300  
Cash Collateral Pledged (12,300)  
ProShares Short Euro [Member] | RBC Capital Markets [Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition 12,300  
Cash Collateral Pledged (12,300)  
ProShares UltraShort Australian Dollar [Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition    10,950
Financial Instruments     
Cash Collateral Pledged    (10,950)
Net Amount     
ProShares UltraShort Australian Dollar [Member] | RBC Capital Markets [Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition   10,950
Cash Collateral Pledged   (10,950)
ProShares UltraShort Euro [Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition 1,439,211 13,398,619
Financial Instruments (1,439,211) (13,398,619)
ProShares UltraShort Euro [Member] | Goldman Sachs International (Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition 930,513 6,048,832
Financial Instruments (930,513) (6,048,832)
ProShares UltraShort Euro [Member] | UBS AG [Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition 508,698 7,349,787
Financial Instruments (508,698) (7,349,787)
ProShares UltraShort Yen [Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition    232,642
Financial Instruments    (232,642)
Cash Collateral Pledged     
Net Amount     
ProShares UltraShort Yen [Member] | UBS AG [Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition   232,642
Financial Instruments   (232,642)
ProShares Ultra DJ-UBS Commodity [Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition    306,268
Financial Instruments    (306,268)
Cash Collateral Pledged     
Net Amount     
ProShares Ultra DJ-UBS Commodity [Member] | Goldman Sachs International (Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition   198,117
Financial Instruments   (198,117)
ProShares Ultra DJ-UBS Commodity [Member] | UBS AG [Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition   108,151
Financial Instruments   (108,151)
ProShares Ultra DJ-UBS Crude Oil [Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition     
Financial Instruments     
Cash Collateral Pledged     
Net Amount     
ProShares Ultra DJ-UBS Natural Gas [Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition 834,689 4,891,783
Cash Collateral Pledged (834,689) (4,891,783)
ProShares Ultra DJ-UBS Natural Gas [Member] | Goldman Sachs & Co.Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition 834,689 4,891,783
Cash Collateral Pledged (834,689) (4,891,783)
ProShares Ultra Gold [Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition 2,300 15,652,058
Financial Instruments   (15,652,058)
Cash Collateral Pledged (2,300)  
ProShares Ultra Gold [Member] | Goldman Sachs International (Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition   3,678,367
Financial Instruments   (3,678,367)
ProShares Ultra Gold [Member] | UBS AG [Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition   3,634,829
Financial Instruments   (3,634,829)
ProShares Ultra Gold [Member] | Goldman Sachs & Co.Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition 2,300  
Cash Collateral Pledged (2,300)  
ProShares Ultra Gold [Member] | Societe Generale S.A. [Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition   3,715,989
Financial Instruments   (3,715,989)
ProShares Ultra Gold [Member] | Deutsche Bank AG [Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition   4,622,873
Financial Instruments   (4,622,873)
ProShares Ultra Silver [Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition 8,109,608 145,740,706
Financial Instruments (8,106,718) (143,623,808)
Cash Collateral Pledged (2,890)  
Net Amount   2,116,898
ProShares Ultra Silver [Member] | Goldman Sachs International (Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition 1,237,902 34,491,042
Financial Instruments (1,237,902) (34,491,042)
ProShares Ultra Silver [Member] | UBS AG [Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition 1,005,386 31,574,331
Financial Instruments (1,005,386) (31,574,331)
ProShares Ultra Silver [Member] | Goldman Sachs & Co.Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition 2,890  
Cash Collateral Pledged (2,890)  
ProShares Ultra Silver [Member] | Societe Generale S.A. [Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition 1,056,353 34,802,217
Financial Instruments (1,056,353) (34,802,217)
ProShares Ultra Silver [Member] | Deutsche Bank AG [Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition 4,807,077 44,873,116
Financial Instruments (4,807,077) (42,756,218)
Net Amount   2,116,898
ProShares Ultra Australian Dollar [Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition 22,982  
Cash Collateral Pledged (22,982)  
ProShares Ultra Australian Dollar [Member] | RBC Capital Markets [Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition 22,982  
Cash Collateral Pledged (22,982)  
ProShares Ultra Euro [Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition 137,134 2,314
Financial Instruments (137,134) (2,314)
ProShares Ultra Euro [Member] | Goldman Sachs International (Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition 63,478 635
Financial Instruments (63,478) (635)
ProShares Ultra Euro [Member] | UBS AG [Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition 73,656 1,679
Financial Instruments (73,656) (1,679)
ProShares Ultra Yen [Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition 70,562 507,819
Financial Instruments (70,562) (410,046)
Net Amount   97,773
ProShares Ultra Yen [Member] | Goldman Sachs International (Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition 22,860 231,047
Financial Instruments (22,860) (231,047)
ProShares Ultra Yen [Member] | UBS AG [Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition 47,702 276,772
Financial Instruments (47,702) (178,999)
Net Amount   97,773
ProShares VIX Short-Term Futures ETF [Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition 2,471,348 31,540,181
Cash Collateral Pledged (2,471,348) (31,540,181)
ProShares VIX Short-Term Futures ETF [Member] | RBC Capital Markets [Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition 2,471,348 31,540,181
Cash Collateral Pledged (2,471,348) (31,540,181)
ProShares VIX Mid-Term Futures ETF [Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition    1,890,675
Financial Instruments     
Cash Collateral Pledged    (1,890,675)
Net Amount     
ProShares VIX Mid-Term Futures ETF [Member] | RBC Capital Markets [Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition   1,890,675
Cash Collateral Pledged   (1,890,675)
ProShares Ultra VIX Short-Term Futures ETF [Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition 4,961,933 35,666,735
Cash Collateral Pledged (4,961,933) (35,666,735)
ProShares Ultra VIX Short-Term Futures ETF [Member] | RBC Capital Markets [Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition 4,961,933 35,666,735
Cash Collateral Pledged (4,961,933) (35,666,735)
ProShares Short VIX Short-Term Futures ETF [Member]
   
Derivative [Line Items]    
Net Amounts of Liabilities Presented in the Statement of Financial Condition     
Financial Instruments     
Cash Collateral Pledged     
Net Amount