v2.4.0.8
Significant Accounting Policies - Valuation of Investments (Detail) (USD $)
3 Months Ended 12 Months Ended
Mar. 31, 2014
Dec. 31, 2013
Significant Accounting Policies [Line Items]    
Level III portfolio investments $ 0 $ 0
ProShares UltraShort DJ-UBS Commodity [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 2,589,002 3,426,225
ProShares UltraShort DJ-UBS Crude Oil [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 281,301,351 244,018,950
ProShares UltraShort DJ-UBS Natural Gas [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 61,232,570 19,317,013
ProShares UltraShort Gold [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 114,389,278 154,635,902
ProShares UltraShort Silver [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 74,936,760 112,612,409
ProShares Short Euro [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 6,275,157 7,868,825
ProShares UltraShort Australian Dollar [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 18,005,588 25,116,112
ProShares UltraShort Euro [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 410,586,544 424,098,652
ProShares UltraShort Yen [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 405,582,924 587,983,948
ProShares Ultra DJ-UBS Commodity [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 2,296,768 2,831,766
ProShares Ultra DJ-UBS Crude Oil [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 115,123,255 140,020,164
ProShares Ultra DJ-UBS Natural Gas [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 16,426,567 55,264,472
ProShares Ultra Gold [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 136,312,320 134,053,416
ProShares Ultra Silver [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 472,557,491 465,361,896
ProShares Ultra Australian Dollar [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 2,968,877 2,598,219
ProShares Ultra Euro [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 2,328,721 2,556,825
ProShares Ultra Yen [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 2,430,622 2,769,247
ProShares VIX Short-Term Futures ETF [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 89,123,845 190,983,697
ProShares VIX Mid-Term Futures ETF [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 46,688,561 41,143,544
ProShares Ultra VIX Short-Term Futures ETF [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 144,151,681 85,523,576
ProShares Short VIX Short-Term Futures ETF [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 177,573,312 113,675,977
Total Trust [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 2,582,881,194 2,815,860,835
Level I - Quoted Prices [Member] | ProShares UltraShort DJ-UBS Commodity [Member] | Short-Term U.S. Government and Agencies [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 2,486,733 3,453,890
Level I - Quoted Prices [Member] | ProShares UltraShort DJ-UBS Crude Oil [Member] | Short-Term U.S. Government and Agencies [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 288,258,596 247,584,623
Level I - Quoted Prices [Member] | ProShares UltraShort DJ-UBS Crude Oil [Member] | VIX Futures Contracts [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure (6,264,314) (1,232,773)
Level I - Quoted Prices [Member] | ProShares UltraShort DJ-UBS Natural Gas [Member] | Short-Term U.S. Government and Agencies [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 56,753,250 18,274,713
Level I - Quoted Prices [Member] | ProShares UltraShort DJ-UBS Natural Gas [Member] | VIX Futures Contracts [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 4,479,320 1,042,300
Level I - Quoted Prices [Member] | ProShares UltraShort Gold [Member] | Short-Term U.S. Government and Agencies [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 105,840,656 148,988,329
Level I - Quoted Prices [Member] | ProShares UltraShort Gold [Member] | VIX Futures Contracts [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 16,860 14,520
Level I - Quoted Prices [Member] | ProShares UltraShort Silver [Member] | Short-Term U.S. Government and Agencies [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 67,188,850 114,826,066
Level I - Quoted Prices [Member] | ProShares UltraShort Silver [Member] | VIX Futures Contracts [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 5,330 14,200
Level I - Quoted Prices [Member] | ProShares Short Euro [Member] | Short-Term U.S. Government and Agencies [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 6,227,257 7,902,056
Level I - Quoted Prices [Member] | ProShares Short Euro [Member] | VIX Futures Contracts [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 47,900 (33,231)
Level I - Quoted Prices [Member] | ProShares UltraShort Australian Dollar [Member] | Short-Term U.S. Government and Agencies [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 19,227,467 24,198,507
Level I - Quoted Prices [Member] | ProShares UltraShort Australian Dollar [Member] | VIX Futures Contracts [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure (1,221,879) 917,605
Level I - Quoted Prices [Member] | ProShares UltraShort Euro [Member] | Short-Term U.S. Government and Agencies [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 414,310,854 437,847,159
Level I - Quoted Prices [Member] | ProShares UltraShort Yen [Member] | Short-Term U.S. Government and Agencies [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 400,736,540 558,597,264
Level I - Quoted Prices [Member] | ProShares Ultra DJ-UBS Commodity [Member] | Short-Term U.S. Government and Agencies [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 2,410,896 2,816,688
Level I - Quoted Prices [Member] | ProShares Ultra DJ-UBS Crude Oil [Member] | Short-Term U.S. Government and Agencies [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 112,053,990 137,435,610
Level I - Quoted Prices [Member] | ProShares Ultra DJ-UBS Crude Oil [Member] | VIX Futures Contracts [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 2,109,314 626,661
Level I - Quoted Prices [Member] | ProShares Ultra DJ-UBS Natural Gas [Member] | Short-Term U.S. Government and Agencies [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 18,277,978 58,921,011
Level I - Quoted Prices [Member] | ProShares Ultra DJ-UBS Natural Gas [Member] | VIX Futures Contracts [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure (1,851,411) (3,656,539)
Level I - Quoted Prices [Member] | ProShares Ultra Gold [Member] | Short-Term U.S. Government and Agencies [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 148,339,252 140,880,950
Level I - Quoted Prices [Member] | ProShares Ultra Gold [Member] | VIX Futures Contracts [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure (16,860) (14,560)
Level I - Quoted Prices [Member] | ProShares Ultra Silver [Member] | Short-Term U.S. Government and Agencies [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 530,701,182 467,868,976
Level I - Quoted Prices [Member] | ProShares Ultra Silver [Member] | VIX Futures Contracts [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure (5,330) (14,200)
Level I - Quoted Prices [Member] | ProShares Ultra Australian Dollar [Member] | Short-Term U.S. Government and Agencies [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 2,775,892 2,716,439
Level I - Quoted Prices [Member] | ProShares Ultra Australian Dollar [Member] | VIX Futures Contracts [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 192,985 (118,220)
Level I - Quoted Prices [Member] | ProShares Ultra Euro [Member] | Short-Term U.S. Government and Agencies [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 2,307,737 2,455,863
Level I - Quoted Prices [Member] | ProShares Ultra Yen [Member] | Short-Term U.S. Government and Agencies [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 2,471,851 2,928,556
Level I - Quoted Prices [Member] | ProShares VIX Short-Term Futures ETF [Member] | Short-Term U.S. Government and Agencies [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 94,150,810 207,636,383
Level I - Quoted Prices [Member] | ProShares VIX Short-Term Futures ETF [Member] | VIX Futures Contracts [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure (5,026,965) (16,652,686)
Level I - Quoted Prices [Member] | ProShares VIX Mid-Term Futures ETF [Member] | Short-Term U.S. Government and Agencies [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 48,695,771 46,040,233
Level I - Quoted Prices [Member] | ProShares VIX Mid-Term Futures ETF [Member] | VIX Futures Contracts [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure (2,007,210) (4,896,689)
Level I - Quoted Prices [Member] | ProShares Ultra VIX Short-Term Futures ETF [Member] | Short-Term U.S. Government and Agencies [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 173,853,508 109,533,487
Level I - Quoted Prices [Member] | ProShares Ultra VIX Short-Term Futures ETF [Member] | VIX Futures Contracts [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure (29,701,827) (24,009,911)
Level I - Quoted Prices [Member] | ProShares Short VIX Short-Term Futures ETF [Member] | Short-Term U.S. Government and Agencies [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 169,490,113 105,559,022
Level I - Quoted Prices [Member] | ProShares Short VIX Short-Term Futures ETF [Member] | VIX Futures Contracts [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 8,083,199 8,116,955
Level I - Quoted Prices [Member] | Total Trust [Member] | Short-Term U.S. Government and Agencies [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 2,666,559,183 2,846,465,825
Level I - Quoted Prices [Member] | Total Trust [Member] | VIX Futures Contracts [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure (31,160,888) (39,896,568)
Level II - Other Significant Observable Inputs [Member] | ProShares UltraShort DJ-UBS Commodity [Member] | Swap Agreements [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 102,269 (27,665)
Level II - Other Significant Observable Inputs [Member] | ProShares UltraShort DJ-UBS Crude Oil [Member] | Swap Agreements [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure (692,931) (2,332,900)
Level II - Other Significant Observable Inputs [Member] | ProShares UltraShort Gold [Member] | Forward Agreements [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 8,531,762 5,633,053
Level II - Other Significant Observable Inputs [Member] | ProShares UltraShort Silver [Member] | Forward Agreements [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 7,742,580 (2,227,857)
Level II - Other Significant Observable Inputs [Member] | ProShares UltraShort Euro [Member] | Foreign Currency Forward Contracts [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure (3,724,310) (13,748,507)
Level II - Other Significant Observable Inputs [Member] | ProShares UltraShort Yen [Member] | Foreign Currency Forward Contracts [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 4,846,384 29,386,684
Level II - Other Significant Observable Inputs [Member] | ProShares Ultra DJ-UBS Commodity [Member] | Swap Agreements [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure (114,128) 15,078
Level II - Other Significant Observable Inputs [Member] | ProShares Ultra DJ-UBS Crude Oil [Member] | Swap Agreements [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 959,951 1,957,893
Level II - Other Significant Observable Inputs [Member] | ProShares Ultra Gold [Member] | Forward Agreements [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure (12,010,072) (6,812,974)
Level II - Other Significant Observable Inputs [Member] | ProShares Ultra Silver [Member] | Forward Agreements [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure (58,138,361) (2,492,880)
Level II - Other Significant Observable Inputs [Member] | ProShares Ultra Euro [Member] | Foreign Currency Forward Contracts [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 20,984 100,962
Level II - Other Significant Observable Inputs [Member] | ProShares Ultra Yen [Member] | Foreign Currency Forward Contracts [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure (41,229) (159,309)
Level II - Other Significant Observable Inputs [Member] | Total Trust [Member] | Forward Agreements [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure (53,874,091) (5,900,658)
Level II - Other Significant Observable Inputs [Member] | Total Trust [Member] | Foreign Currency Forward Contracts [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure 1,101,829 15,579,830
Level II - Other Significant Observable Inputs [Member] | Total Trust [Member] | Swap Agreements [Member]
   
Significant Accounting Policies [Line Items]    
Investments, fair value disclosure $ 255,161 $ (387,594)