Name:	energy12_CapitalContributionandPartnersEquityDetailsLineItems
Namespace Prefix:	energy12_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Distribution withholding tax to limited partner per common unit.

No definition available.

Name:	energy12_DistributionWithholdingTaxToLimitedPartnerPerCommonUnit
Namespace Prefix:	energy12_
Data Type:	dtr:perShareItemType
Balance Type:	na
Period Type:	duration

The maximum contingent incentive fee percentage paid in cash to the managing dealer on gross proceeds of Units sold.

No definition available.

Name:	energy12_ManagingDealerMaximumContingenIncentiveFeeOnGrossProceedsPercentage
Namespace Prefix:	energy12_
Data Type:	dtr:percentItemType
Balance Type:	na
Period Type:	duration

The maximum contingent incentive fee due to the managing dealer on gross proceeds of Units sold related to occurrence of an event triggering a payout.

No definition available.

Name:	energy12_ManagingDealerMaximumContingentIncentiveFeeOnGrossProceeds
Namespace Prefix:	energy12_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

The selling commission percentage paid to the managing dealer on gross proceeds of Units sold.

No definition available.

Name:	energy12_ManagingDealerSellingCommissionsPercentage
Namespace Prefix:	energy12_
Data Type:	dtr:percentItemType
Balance Type:	na
Period Type:	duration

Description of the units sold during the year of each class of partners' capital account. Units represent shares of ownership of the general, limited, and preferred partners.

No definition available.

Name:	energy12_PartnersCapitalAccountDescriptionOfUnitsSold1
Namespace Prefix:	energy12_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

The amount of partners' capital to be returned upon the Company's completion of its minimum offering.

No definition available.

Name:	energy12_PartnersCapitalAccountReturnOfContributionUponMinimumOffering
Namespace Prefix:	energy12_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

The cash inflow from the issuance of common limited partners units during the period, net of offering costs.

No definition available.

Name:	energy12_ProceedsNetOfOfferingCostsFromIssuanceOfCommonLimitedPartnersUnits
Namespace Prefix:	energy12_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Total inclusive of distributions as well as withholding tax payments per common unit.

No definition available.

Name:	energy12_TotalInclusiveOfDistributionsAsWellAsWithholdingTaxPaymentsPerCommonUnit
Namespace Prefix:	energy12_
Data Type:	dtr:perShareItemType
Balance Type:	na
Period Type:	duration

Amount of cash distribution paid to unit-holder of limited partnership (LP).

Name:	us-gaap_DistributionMadeToLimitedPartnerCashDistributionsPaid
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Per unit of ownership amount of cash distributions paid to unit-holder of a limited partnership (LP).

Name:	us-gaap_DistributionMadeToLimitedPartnerDistributionsPaidPerUnit
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	duration

Total contributions made by each class of partners (i.e., general, limited and preferred partners).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480008/505-10-S99-1

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 4.F)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480008/505-10-S99-1

Name:	us-gaap_PartnersCapitalAccountContributions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Total units issued during the year due to the sale of units. All partners include general, limited and preferred partners.

Name:	us-gaap_PartnersCapitalAccountUnitsSaleOfUnits
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

The cash inflow from the issuance of common limited partners units during the period.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 45
-Paragraph 14
-Subparagraph (a)
-SubTopic 10
-Topic 230
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-14

Name:	us-gaap_ProceedsFromIssuanceOfCommonLimitedPartnersUnits
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	energy12_EquityTransactionAxis=energy12_BestEffortsOfferingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_TaxPeriodAxis=us-gaap_TaxYear2021Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_TaxPeriodAxis=us-gaap_TaxYear2022Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_TaxPeriodAxis=us-gaap_TaxYear2023Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_TaxPeriodAxis=us-gaap_TaxYear2024Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: