v3.21.1

Significant Accounting Policies - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2021
Minimum [Member] | Matching VIX Funds [Member]
Significant Accounting Policies [Line Items]
Percentage of brokerage commissions exceed variable create/redeem fees	0.02%

X

- Definition

Percentage of brokerage commissions exceed variable create/redeem fees.

+ References

No definition available.

+ Details

Name:	ck0001415311_PercentageOfBrokerageCommissionsExceedVariableCreateOrRedeemFees
Namespace Prefix:	ck0001415311_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Significant accounting policies.

+ References

No definition available.

+ Details

Name:	ck0001415311_SignificantAccountingPoliciesLineItems
Namespace Prefix:	ck0001415311_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=ck0001415311_MatchingVIXFundsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: