Significant Accounting Policies - Cut-off Times and Times of Calculation of Funds' Final Net Asset Value for Creation and Redemption of Fund Shares (Detail)	12 Months Ended
	Dec. 31, 2016
ProShares UltraShort Silver [Member]
Net Asset Value [Line Items]
Create/Redeem Cut-off	6:30 a.m.
NAV Calculation Time	7:00 a.m.
NAV Calculation Date	December 30
ProShares Ultra Silver [Member]
Net Asset Value [Line Items]
Create/Redeem Cut-off	6:30 a.m.
NAV Calculation Time	7:00 a.m.
NAV Calculation Date	December 30
ProShares UltraShort Gold [Member]
Net Asset Value [Line Items]
Create/Redeem Cut-off	9:30 a.m.
NAV Calculation Time	10:00 a.m.
NAV Calculation Date	December 30
ProShares Ultra Gold [Member]
Net Asset Value [Line Items]
Create/Redeem Cut-off	9:30 a.m.
NAV Calculation Time	10:00 a.m.
NAV Calculation Date	December 30
ProShares UltraShort Bloomberg Crude Oil [Member]
Net Asset Value [Line Items]
Create/Redeem Cut-off	2:00 p.m.
NAV Calculation Time	2:30 p.m.
NAV Calculation Date	December 30
ProShares Ultra Bloomberg Crude Oil [Member]
Net Asset Value [Line Items]
Create/Redeem Cut-off	2:00 p.m.
NAV Calculation Time	2:30 p.m.
NAV Calculation Date	December 30
ProShares UltraShort Bloomberg Natural Gas [Member]
Net Asset Value [Line Items]
Create/Redeem Cut-off	2:00 p.m.
NAV Calculation Time	2:30 p.m.
NAV Calculation Date	December 30
ProShares Ultra Bloomberg Natural Gas [Member]
Net Asset Value [Line Items]
Create/Redeem Cut-off	2:00 p.m.
NAV Calculation Time	2:30 p.m.
NAV Calculation Date	December 30
ProShares UltraShort Australian Dollar [Member]
Net Asset Value [Line Items]
Create/Redeem Cut-off	3:00 p.m.
NAV Calculation Time	4:00 p.m.
NAV Calculation Date	December 30
ProShares Short Euro [Member]
Net Asset Value [Line Items]
Create/Redeem Cut-off	3:00 p.m.
NAV Calculation Time	4:00 p.m.
NAV Calculation Date	December 30
ProShares UltraShort Euro [Member]
Net Asset Value [Line Items]
Create/Redeem Cut-off	3:00 p.m.
NAV Calculation Time	4:00 p.m.
NAV Calculation Date	December 30
ProShares Ultra Euro [Member]
Net Asset Value [Line Items]
Create/Redeem Cut-off	3:00 p.m.
NAV Calculation Time	4:00 p.m.
NAV Calculation Date	December 30
ProShares UltraShort Yen [Member]
Net Asset Value [Line Items]
Create/Redeem Cut-off	3:00 p.m.
NAV Calculation Time	4:00 p.m.
NAV Calculation Date	December 30
ProShares Ultra Yen [Member]
Net Asset Value [Line Items]
Create/Redeem Cut-off	3:00 p.m.
NAV Calculation Time	4:00 p.m.
NAV Calculation Date	December 30
ProShares Short VIX Short-Term Futures ETF [Member]
Net Asset Value [Line Items]
Create/Redeem Cut-off	2:00 p.m.
NAV Calculation Time	4:15 p.m.
NAV Calculation Date	December 30
ProShares Ultra VIX Short-Term Futures ETF [Member]
Net Asset Value [Line Items]
Create/Redeem Cut-off	2:00 p.m.
NAV Calculation Time	4:15 p.m.
NAV Calculation Date	December 30
ProShares VIX Mid-Term Futures ETF [Member]
Net Asset Value [Line Items]
Create/Redeem Cut-off	2:00 p.m.
NAV Calculation Time	4:15 p.m.
NAV Calculation Date	December 30