v2.4.1.9

Significant Accounting Policies - Cut-off Times and Times of Calculation of Funds' Final Net Asset Value for Creation and Redemption of Fund Shares (Detail)	3 Months Ended
	Mar. 31, 2015
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	March 31
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	March 31
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	March 31
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	March 31
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	March 31
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	March 31
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	March 31
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	March 31
ProShares UltraShort Bloomberg Commodity [Member]
Net Asset Value [Line Items]
Create/Redeem Cut-off	10:45 a.m.
NAV Calculation Time	2:30 p.m.
NAV Calculation Date	March 31
ProShares Ultra Bloomberg Commodity [Member]
Net Asset Value [Line Items]
Create/Redeem Cut-off	10:45 a.m.
NAV Calculation Time	2:30 p.m.
NAV Calculation Date	March 31
ProShares Managed Futures Strategy [Member]
Net Asset Value [Line Items]
Create/Redeem Cut-off	10:45 a.m.
NAV Calculation Time	3:00 p.m.
NAV Calculation Date	March 31
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	March 31
ProShares Ultra 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	March 31
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	March 31
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	March 31
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	March 31
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	March 31
ProShares Ultra Yen [Member]
Net Asset Value [Line Items]
Create/Redeem Cut-off	2:00 p.m.
NAV Calculation Time	4:15 p.m.
NAV Calculation Date	March 31
ProShares 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	March 31
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	March 31
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	March 31
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	March 31

X

- Definition

Create or redeem cut off.

+ References

No definition available.

+ Details

Name:	ck0001415311_CreateOrRedeemCutoff
Namespace Prefix:	ck0001415311_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Net asset value calculation date.

+ References

No definition available.

+ Details

Name:	ck0001415311_NetAssetValueCalculationDate
Namespace Prefix:	ck0001415311_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Net asset value calculation time.

+ References

No definition available.

+ Details

Name:	ck0001415311_NetAssetValueCalculationTime
Namespace Prefix:	ck0001415311_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	ck0001415311_NetAssetValueLineItems
Namespace Prefix:	ck0001415311_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=ck0001415311_ProsharesManagedFuturesStrategyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

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_ProsharesUltraAustralianDollarMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=ck0001415311_ProsharesUltraBloombergCommodityMember
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_ProsharesUltrashortAustralianDollarMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=ck0001415311_ProsharesUltrashortBloombergCommodityMember
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_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_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: