v3.21.1

Significant Accounting Policies - Valuation of Investments using Fair Value Hierarchy (Detail) - USD ($)		Mar. 31, 2021	Dec. 31, 2020
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure		$ 1,840,450,492	$ 1,238,455,454
ProShares Short Euro [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure		1,033,901	(44,626)
ProShares Short VIX Short-Term Futures ETF [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure		142,469,135	78,348,422
ProShares Ultra Bloomberg Crude Oil [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure		887,776,906	382,804,628
ProShares Ultra Bloomberg Natural Gas [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure		22,699,048	36,500,610
ProShares Ultra Euro [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure		777,569	88,736
ProShares Ultra Gold [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure		93,552,448	82,787,321
ProShares Ultra Silver [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure		376,163,013	338,936,867
ProShares Ultra VIX Short-Term Futures ETF [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure		44,056,924	196,446,496
ProShares Ultra Yen [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure		310,984	67,087
ProShares UltraShort Australian Dollar [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure		67,102	(138,950)
ProShares UltraShort Bloomberg Crude Oil [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure		25,998,903	(14,636,813)
ProShares UltraShort Bloomberg Natural Gas [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure		60,271,658	10,379,171
ProShares UltraShort Euro [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure		21,254,229	8,863,157
ProShares UltraShort Gold [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure		12,353,275	(465,658)
ProShares UltraShort Silver [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure		19,047,747	(3,417,637)
ProShares UltraShort Yen [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure		16,835,557	(564,966)
ProShares VIX Mid-Term Futures ETF [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure		22,588,865	43,866,116
ProShares VIX Short-Term Futures ETF [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure		93,193,228	78,635,493
Level I - Quoted Prices [Member] | Short-Term U.S. Government and Agencies [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure		2,026,935,650	1,034,986,384
Level I - Quoted Prices [Member] | Futures Contracts [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure	[1]	(128,740,966)	128,370,172
Level I - Quoted Prices [Member] | ProShares Short Euro [Member] | Short-Term U.S. Government and Agencies [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure		999,973
Level I - Quoted Prices [Member] | ProShares Short Euro [Member] | Futures Contracts [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure	[1]	33,928	(44,626)
Level I - Quoted Prices [Member] | ProShares Short VIX Short-Term Futures ETF [Member] | Short-Term U.S. Government and Agencies [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure		91,998,460	69,999,639
Level I - Quoted Prices [Member] | ProShares Short VIX Short-Term Futures ETF [Member] | Futures Contracts [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure	[1]	50,470,675	8,348,783
Level I - Quoted Prices [Member] | ProShares Ultra Bloomberg Crude Oil [Member] | Short-Term U.S. Government and Agencies [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure		689,976,589	219,998,394
Level I - Quoted Prices [Member] | ProShares Ultra Bloomberg Crude Oil [Member] | Futures Contracts [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure	[1]	238,548,911	144,564,039
Level I - Quoted Prices [Member] | ProShares Ultra Bloomberg Natural Gas [Member] | Short-Term U.S. Government and Agencies [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure		33,999,110	29,999,889
Level I - Quoted Prices [Member] | ProShares Ultra Bloomberg Natural Gas [Member] | Futures Contracts [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure	[1]	(11,300,062)	6,500,721
Level I - Quoted Prices [Member] | ProShares Ultra Euro [Member] | Short-Term U.S. Government and Agencies [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure		999,973
Level I - Quoted Prices [Member] | ProShares Ultra Gold [Member] | Short-Term U.S. Government and Agencies [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure		86,998,893	74,999,467
Level I - Quoted Prices [Member] | ProShares Ultra Gold [Member] | Futures Contracts [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure	[1]	393,125	2,646,874
Level I - Quoted Prices [Member] | ProShares Ultra Silver [Member] | Short-Term U.S. Government and Agencies [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure		419,985,837	244,993,989
Level I - Quoted Prices [Member] | ProShares Ultra Silver [Member] | Futures Contracts [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure	[1]	(15,401,821)	37,190,212
Level I - Quoted Prices [Member] | ProShares Ultra VIX Short-Term Futures ETF [Member] | Short-Term U.S. Government and Agencies [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure		376,985,173	244,995,969
Level I - Quoted Prices [Member] | ProShares Ultra VIX Short-Term Futures ETF [Member] | Futures Contracts [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure	[1]	(332,928,249)	(48,524,666)
Level I - Quoted Prices [Member] | ProShares Ultra Yen [Member] | Short-Term U.S. Government and Agencies [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure		499,986
Level I - Quoted Prices [Member] | ProShares UltraShort Australian Dollar [Member] | Futures Contracts [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure	[1]	67,102	(138,950)
Level I - Quoted Prices [Member] | ProShares UltraShort Bloomberg Crude Oil [Member] | Short-Term U.S. Government and Agencies [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure		34,999,082
Level I - Quoted Prices [Member] | ProShares UltraShort Bloomberg Crude Oil [Member] | Futures Contracts [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure	[1]	(9,000,179)	(14,636,813)
Level I - Quoted Prices [Member] | ProShares UltraShort Bloomberg Natural Gas [Member] | Short-Term U.S. Government and Agencies [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure		43,998,801	9,999,861
Level I - Quoted Prices [Member] | ProShares UltraShort Bloomberg Natural Gas [Member] | Futures Contracts [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure	[1]	16,272,857	379,310
Level I - Quoted Prices [Member] | ProShares UltraShort Euro [Member] | Short-Term U.S. Government and Agencies [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure		17,999,536	9,999,861
Level I - Quoted Prices [Member] | ProShares UltraShort Gold [Member] | Short-Term U.S. Government and Agencies [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure		12,999,597
Level I - Quoted Prices [Member] | ProShares UltraShort Gold [Member] | Futures Contracts [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure	[1]	39,145	(196,930)
Level I - Quoted Prices [Member] | ProShares UltraShort Silver [Member] | Short-Term U.S. Government and Agencies [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure		14,999,620
Level I - Quoted Prices [Member] | ProShares UltraShort Silver [Member] | Futures Contracts [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure	[1]	3,276,894	(220,076)
Level I - Quoted Prices [Member] | ProShares UltraShort Yen [Member] | Short-Term U.S. Government and Agencies [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure		14,499,635
Level I - Quoted Prices [Member] | ProShares VIX Mid-Term Futures ETF [Member] | Short-Term U.S. Government and Agencies [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure		31,999,153	44,999,732
Level I - Quoted Prices [Member] | ProShares VIX Mid-Term Futures ETF [Member] | Futures Contracts [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure	[1]	(9,410,288)	(1,133,616)
Level I - Quoted Prices [Member] | ProShares VIX Short-Term Futures ETF [Member] | Short-Term U.S. Government and Agencies [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure		152,996,232	84,999,583
Level I - Quoted Prices [Member] | ProShares VIX Short-Term Futures ETF [Member] | Futures Contracts [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure	[1]	(59,803,004)	(6,364,090)
Level II - Other Significant Observable Inputs [Member] | Foreign Currency Forward Contracts [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure		5,179,209	(1,545,847)
Level II - Other Significant Observable Inputs [Member] | Swap Agreements [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure		(62,923,401)	76,644,745
Level II - Other Significant Observable Inputs [Member] | ProShares Ultra Bloomberg Crude Oil [Member] | Swap Agreements [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure		(40,748,594)	18,242,195
Level II - Other Significant Observable Inputs [Member] | ProShares Ultra Euro [Member] | Foreign Currency Forward Contracts [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure		(222,404)	88,736
Level II - Other Significant Observable Inputs [Member] | ProShares Ultra Gold [Member] | Swap Agreements [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure		6,160,430	5,140,980
Level II - Other Significant Observable Inputs [Member] | ProShares Ultra Silver [Member] | Swap Agreements [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure		(28,421,003)	56,752,666
Level II - Other Significant Observable Inputs [Member] | ProShares Ultra VIX Short-Term Futures ETF [Member] | Swap Agreements [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure			(24,807)
Level II - Other Significant Observable Inputs [Member] | ProShares Ultra Yen [Member] | Foreign Currency Forward Contracts [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure		(189,002)	67,087
Level II - Other Significant Observable Inputs [Member] | ProShares UltraShort Euro [Member] | Foreign Currency Forward Contracts [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure		3,254,693	(1,136,704)
Level II - Other Significant Observable Inputs [Member] | ProShares UltraShort Gold [Member] | Swap Agreements [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure		(685,467)	(268,728)
Level II - Other Significant Observable Inputs [Member] | ProShares UltraShort Silver [Member] | Swap Agreements [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure		771,233	(3,197,561)
Level II - Other Significant Observable Inputs [Member] | ProShares UltraShort Yen [Member] | Foreign Currency Forward Contracts [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, fair value disclosure		$ 2,335,922	$ (564,966)
[1] Includes cumulative appreciation (depreciation) of futures contracts as reported in the Schedule of Investments. Only current day’s variation margin is reported within the Statements of Financial Condition in receivable/payable on open futures.

X

- Definition

Fair value of investment other than investment in equity security, investment in debt security and equity method investment. Includes, but is not limited to, investment in certain entities that calculate net asset value per share. Example includes, but is not limited to, investment in hedge fund, venture capital fund, private equity fund, and real estate partnership or fund.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 6A
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=SL6742756-110258

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 35
-Paragraph 54B
-URI http://asc.fasb.org/extlink&oid=117332851&loc=SL7495116-110257

+ Details

Name:	us-gaap_AlternativeInvestment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=ck0001415311_ProsharesShortEuroMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=ck0001415311_ProsharesShortVixShortTermFuturesEtfMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=ck0001415311_ProsharesUltraBloombergCrudeOilMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=ck0001415311_ProsharesUltraBloombergNaturalGasMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=ck0001415311_ProsharesUltraEuroMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=ck0001415311_ProsharesUltraGoldMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=ck0001415311_ProsharesUltraSilverMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=ck0001415311_ProsharesUltraVixShortTermFuturesEtfMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=ck0001415311_ProsharesUltraYenMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=ck0001415311_ProsharesUltraShortAustralianDollarMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=ck0001415311_ProsharesUltraShortBloombergCrudeOilMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=ck0001415311_ProsharesUltraShortBloombergNaturalGasMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=ck0001415311_ProsharesUltraShortEuroMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=ck0001415311_ProsharesUltraShortGoldMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=ck0001415311_ProsharesUltraShortSilverMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=ck0001415311_ProsharesUltraShortYenMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=ck0001415311_ProsharesVixMidTermFuturesEtfMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=ck0001415311_ProsharesVixShortTermFuturesEtfMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_InvestmentTypeAxis=us-gaap_USTreasuryAndGovernmentShorttermDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_InvestmentTypeAxis=us-gaap_FutureMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_InvestmentTypeAxis=us-gaap_ForeignExchangeForwardMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_InvestmentTypeAxis=us-gaap_SwapMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: