Schedule of Investments - Futures Contracts Purchased (Parenthetical) (Detail) - Futures Contracts Purchased [Member] - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
ProShares VIX Short-Term Futures ETF [Member]
Schedule of Investments [Line Items]
Cash collateral pledged to cover margin requirements	$ 17,235,855	$ 5,888,545
ProShares VIX Mid-Term Futures ETF [Member]
Schedule of Investments [Line Items]
Cash collateral pledged to cover margin requirements	1,052,615	980,750
ProShares Ultra VIX Short-Term Futures ETF [Member]
Schedule of Investments [Line Items]
Cash collateral pledged to cover margin requirements	71,363,625	62,348,600
ProShares Ultra Bloomberg Crude Oil [Member]
Schedule of Investments [Line Items]
Cash collateral pledged to cover margin requirements	20,609,600	47,571,810
ProShares Ultra Bloomberg Natural Gas [Member]
Schedule of Investments [Line Items]
Cash collateral pledged to cover margin requirements	7,612,770	7,595,280
ProShares Ultra Gold [Member]
Schedule of Investments [Line Items]
Cash collateral pledged to cover margin requirements	13,200	8,250
ProShares Ultra Silver [Member]
Schedule of Investments [Line Items]
Cash collateral pledged to cover margin requirements	$ 14,300	$ 17,160