v2.4.0.6
STATEMENTS OF FINANCIAL CONDITION (Parenthetical) (USD $)
Mar. 31, 2013
Dec. 31, 2012
ProShares UltraShort DJ-UBS Commodity [Member]
   
Short-term U.S. government and agency obligations, cost $ 3,062,693 $ 2,803,598
ProShares UltraShort DJ-UBS Crude Oil [Member]
   
Short-term U.S. government and agency obligations, cost 145,470,481 87,042,320
ProShares UltraShort DJ-UBS Natural Gas [Member]
   
Short-term U.S. government and agency obligations, cost 21,192,907 10,042,198
ProShares UltraShort Gold [Member]
   
Short-term U.S. government and agency obligations, cost 108,154,807 88,573,928
ProShares UltraShort Silver [Member]
   
Short-term U.S. government and agency obligations, cost 105,343,764 86,199,868
ProShares Short Euro [Member]
   
Short-term U.S. government and agency obligations, cost 3,371,937 3,409,716
ProShares UltraShort Australian Dollar [Member]
   
Short-term U.S. government and agency obligations, cost 3,329,947 3,302,725
ProShares UltraShort Euro [Member]
   
Short-term U.S. government and agency obligations, cost 507,177,936 553,417,216
ProShares UltraShort Yen [Member]
   
Short-term U.S. government and agency obligations, cost 463,610,208 362,731,936
ProShares Ultra DJ-UBS Commodity [Member]
   
Short-term U.S. government and agency obligations, cost 3,350,591 6,240,818
ProShares Ultra DJ-UBS Crude Oil [Member]
   
Short-term U.S. government and agency obligations, cost 303,993,548 437,644,628
ProShares Ultra DJ-UBS Natural Gas [Member]
   
Short-term U.S. government and agency obligations, cost 53,700,121 64,312,441
ProShares Ultra Gold [Member]
   
Short-term U.S. government and agency obligations, cost 307,376,479 350,608,755
ProShares Ultra Silver [Member]
   
Short-term U.S. government and agency obligations, cost 754,938,086 891,006,493
ProShares Ultra Australian Dollar [Member]
   
Short-term U.S. government and agency obligations, cost 3,676,855 3,570,687
ProShares Ultra Euro [Member]
   
Short-term U.S. government and agency obligations, cost 4,478,870 4,546,872
ProShares Ultra Yen [Member]
   
Short-term U.S. government and agency obligations, cost 3,534,876 4,587,701
ProShares VIX Short-Term Futures ETF [Member]
   
Short-term U.S. government and agency obligations, cost 152,933,255 144,057,296
ProShares VIX Mid-Term Futures ETF [Member]
   
Short-term U.S. government and agency obligations, cost 49,700,662 79,927,870
ProShares Ultra VIX Short-Term Futures ETF [Member]
   
Short-term U.S. government and agency obligations, cost 118,784,627 97,445,279
ProShares Short VIX Short-Term Futures ETF [Member]
   
Short-term U.S. government and agency obligations, cost 45,829,953 53,683,800
ProShares Trust II [Member]
   
Short-term U.S. government and agency obligations, cost $ 3,163,012,603 $ 3,335,156,145