Subsequent Events - Per Share Operating Performance (Detail) (USD $)	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
ProShares Ultra VIX Short-Term Futures ETF [Member]
Financial Highlights [Line Items]
Net asset value, beginning balance	$ 25.0918	$ 67.0841
Net investment income (loss)	$ (0.0811)	$ (0.2919)
Net realized and unrealized gain (loss)	$ (9.8209)	$ (6.4957)
Change in net asset value from operations	$ (9.9020)	$ (6.7876)
Net asset value, ending balance	$ 15.1898	$ 60.2965
Market value per share, beginning balance	$ 25.15	$ 67.12
Market value per share, ending balance	$ 15.05	$ 59.91
Shares outstanding	45,670,099		14,020,099
Net income (loss) per weighted-average share	$ (8.93)	$ (2.53)
Weighted-average shares outstanding	25,266,210	3,714,601
ProShares Ultra Bloomberg Commodity [Member]
Financial Highlights [Line Items]
Net asset value, beginning balance	$ 13.0337	$ 19.4317
Net investment income (loss)	$ (0.0276)	$ (0.0464)
Net realized and unrealized gain (loss)	$ (1.5924)	$ 2.7213
Change in net asset value from operations	$ (1.6200)	$ 2.6749
Net asset value, ending balance	$ 11.4137	$ 22.1066
Market value per share, beginning balance	$ 12.86	$ 19.13
Market value per share, ending balance	$ 11.70	$ 21.51
Shares outstanding	200,014		200,014
Net income (loss) per weighted-average share	$ (1.62)	$ 2.67
Weighted-average shares outstanding	200,014	150,014
ProShares Ultra Bloomberg Crude Oil [Member]
Financial Highlights [Line Items]
Net asset value, beginning balance	$ 10.1480	$ 32.0899
Net investment income (loss)	$ (0.0184)	$ (0.0712)
Net realized and unrealized gain (loss)	$ (3.3046)	$ 2.6074
Change in net asset value from operations	$ (3.3230)	$ 2.5362
Net asset value, ending balance	$ 6.8250	$ 34.6261
Market value per share, beginning balance	$ 10.37	$ 32.22
Market value per share, ending balance	$ 6.79	$ 34.56
Shares outstanding	147,199,170		44,399,170
Net income (loss) per weighted-average share	$ (1.95)	$ 4.56
Weighted-average shares outstanding	100,201,948	4,680,281
ProShares Ultra Bloomberg Natural Gas [Member]
Financial Highlights [Line Items]
Net asset value, beginning balance	$ 15.4123	$ 38.8383
Net investment income (loss)	$ (0.0387)	$ (0.1183)
Net realized and unrealized gain (loss)	$ (3.9570)	$ 6.4173
Change in net asset value from operations	$ (3.9957)	$ 6.2990
Net asset value, ending balance	$ 11.4166	$ 45.1373
Market value per share, beginning balance	$ 15.78	$ 39.28
Market value per share, ending balance	$ 11.39	$ 45.32
Shares outstanding	5,369,941		4,569,941
Net income (loss) per weighted-average share	$ (3.48)	$ 18.61
Weighted-average shares outstanding	5,346,608	993,830
ProShares Ultra Yen [Member]
Financial Highlights [Line Items]
Net asset value, beginning balance	$ 14.1189	$ 18.6318
Net investment income (loss)	$ (0.0321)	$ (0.0428)
Net realized and unrealized gain (loss)	$ (0.0871)	$ 0.7168
Change in net asset value from operations	$ (0.1192)	$ 0.6740
Net asset value, ending balance	$ 13.9997	$ 19.3058
Market value per share, beginning balance	$ 14.12	$ 18.61
Market value per share, ending balance	$ 13.99	$ 19.29
Shares outstanding	400,014		150,014
Net income (loss) per weighted-average share	$ (0.41)	$ 0.67
Weighted-average shares outstanding	283,347	150,014
Pro Forma [Member] \| ProShares Ultra VIX Short-Term Futures ETF [Member]
Financial Highlights [Line Items]
Net asset value, beginning balance	$ 125.4591	$ 335.4203
Net investment income (loss)	$ (0.4056)	$ (1.4595)
Net realized and unrealized gain (loss)	$ (49.1045)	$ (32.4784)
Change in net asset value from operations	$ (49.5101)	$ (33.9379)
Net asset value, ending balance	$ 75.9490	$ 301.4824
Market value per share, beginning balance	$ 125.75	$ 335.60
Market value per share, ending balance	$ 75.25	$ 299.55
Shares outstanding	9,134,020		2,804,020
Net income (loss) per weighted-average share	$ (44.65)	$ (13.89)
Weighted-average shares outstanding	5,053,242	742,920
Pro Forma [Member] \| ProShares Ultra Bloomberg Commodity [Member]
Financial Highlights [Line Items]
Net asset value, beginning balance	$ 52.1342	$ 77.7259
Net investment income (loss)	$ (0.1104)	$ (0.1855)
Net realized and unrealized gain (loss)	$ (6.3693)	$ 10.8849
Change in net asset value from operations	$ (6.4797)	$ 10.6994
Net asset value, ending balance	$ 45.6545	$ 88.4253
Market value per share, beginning balance	$ 51.44	$ 76.52
Market value per share, ending balance	$ 46.80	$ 86.04
Shares outstanding	50,004		50,004
Net income (loss) per weighted-average share	$ (6.48)	$ 10.70
Weighted-average shares outstanding	50,004	37,504
Pro Forma [Member] \| ProShares Ultra Bloomberg Crude Oil [Member]
Financial Highlights [Line Items]
Net asset value, beginning balance	$ 50.7400	$ 160.4495
Net investment income (loss)	$ (0.0920)	$ (0.3562)
Net realized and unrealized gain (loss)	$ (16.5231)	$ 13.0370
Change in net asset value from operations	$ (16.6151)	$ 12.6808
Net asset value, ending balance	$ 34.1249	$ 173.1303
Market value per share, beginning balance	$ 51.85	$ 161.10
Market value per share, ending balance	$ 33.95	$ 172.80
Shares outstanding	29,439,834		8,879,834
Net income (loss) per weighted-average share	$ (9.74)	$ 22.80
Weighted-average shares outstanding	20,040,390	936,056
Pro Forma [Member] \| ProShares Ultra Bloomberg Natural Gas [Member]
Financial Highlights [Line Items]
Net asset value, beginning balance	$ 61.6491	$ 155.3534
Net investment income (loss)	$ (0.1548)	$ (0.4732)
Net realized and unrealized gain (loss)	$ (15.8280)	$ 25.6692
Change in net asset value from operations	$ (15.9828)	$ 25.1960
Net asset value, ending balance	$ 45.6663	$ 180.5494
Market value per share, beginning balance	$ 63.12	$ 157.12
Market value per share, ending balance	$ 45.56	$ 181.28
Shares outstanding	1,342,485		1,142,485
Net income (loss) per weighted-average share	$ (13.91)	$ 74.42
Weighted-average shares outstanding	1,336,652	248,458
Pro Forma [Member] \| ProShares Ultra Yen [Member]
Financial Highlights [Line Items]
Net asset value, beginning balance	$ 56.4747	$ 74.5261
Net investment income (loss)	$ (0.1283)	$ (0.1712)
Net realized and unrealized gain (loss)	$ (0.3478)	$ 2.8673
Change in net asset value from operations	$ (0.4761)	$ 2.6961
Net asset value, ending balance	$ 55.9986	$ 77.2222
Market value per share, beginning balance	$ 56.48	$ 74.44
Market value per share, ending balance	$ 55.96	$ 77.16
Shares outstanding	100,004		37,504
Net income (loss) per weighted-average share	$ (1.64)	$ 2.70
Weighted-average shares outstanding	70,837	37,504