Public Utilities Amount of System Safety and Integrity Rider Moved to Base Rates

No definition available.

Name:	bkh_PublicUtilitiesAmountOfSystemSafetyAndIntegrityRiderMovedToBaseRates
Namespace Prefix:	bkh_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Public Utilities - Length of Electric Distribution Lines to Receive Infrastructure Investments

+ References

No definition available.

+ Details

Name:	bkh_PublicUtilitiesLengthOfElectricDistributionLinesToReceiveInfrastructureInvestments
Namespace Prefix:	bkh_
Data Type:	dtr-types:lengthItemType
Balance Type:	na
Period Type:	instant

- Definition

Public Utilities - Length of Electric Transmission Lines to Receive Infrastructure Investments

+ References

No definition available.

+ Details

Name:	bkh_PublicUtilitiesLengthOfElectricTransmissionLinesToReceiveInfrastructureInvestments
Namespace Prefix:	bkh_
Data Type:	dtr-types:lengthItemType
Balance Type:	na
Period Type:	instant

- Definition

Public Utilities - Length of Natural Gas Pipeline to Receive Infrastructure Investments

+ References

No definition available.

+ Details

Name:	bkh_PublicUtilitiesLengthOfNaturalGasPipelineToReceiveInfrastructureInvestments
Namespace Prefix:	bkh_
Data Type:	dtr-types:lengthItemType
Balance Type:	na
Period Type:	instant

- Definition

Weighted Average Cost of Capital

+ References

No definition available.

+ Details

Name:	bkh_WeightedAverageCostOfCapital
Namespace Prefix:	bkh_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of public utility's approved debt to capital, including debt and equity.

+ References

No definition available.

+ Details

Name:	us-gaap_PublicUtilitiesApprovedDebtCapitalStructurePercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of public utility's approved equity to capital, including debt and equity.

+ References

No definition available.

+ Details

Name:	us-gaap_PublicUtilitiesApprovedEquityCapitalStructurePercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of public utility's approved rate increase (decrease) by regulatory agency.

+ References

No definition available.

+ Details

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

- Definition

Percentage of public utility's approved return on equity.

+ References

No definition available.

+ Details

Name:	us-gaap_PublicUtilitiesApprovedReturnOnEquityPercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

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

- Definition

Percentage of public utility's requested debt to capital, including debt and equity.

+ References

No definition available.

+ Details

Name:	us-gaap_PublicUtilitiesRequestedDebtCapitalStructurePercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of public utility's requested equity to capital, including debt and equity.

+ References

No definition available.

+ Details

Name:	us-gaap_PublicUtilitiesRequestedEquityCapitalStructurePercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount for the individual regulatory liability as itemized in a table of regulatory liabilities as of the end of the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 980
-SubTopic 405
-Name Accounting Standards Codification
-Section 25
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477571/980-405-25-1

+ Details

Name:	us-gaap_RegulatoryLiabilities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_RegulatoryAgencyAxis=bkh_ColoradoPublicUtilitiesCommissionCPUCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=bkh_BlackHillsEnergyColoradoElectricMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

Name:	us-gaap_PublicUtilitiesRegulatoryProceedingAxis=bkh_RateReviewFiledwiththeRegulatoryAgencyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RegulatoryAgencyAxis=bkh_IowaUtilitiesCommissionIUCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=bkh_BlackHillsEnergyIowaGasMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RegulatoryAgencyAxis=bkh_KansasCorporationCommissionKCCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=bkh_BlackHillsEnergyKansasGasMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ProductOrServiceAxis=bkh_GSRSRiderRevenueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RegulatoryAgencyAxis=bkh_NebraskaPublcServiceCommissionNPSCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=bkh_BlackHillsEnergyNebraskaGasMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_PublicUtilitiesRegulatoryProceedingAxis=bkh_SettlementReachedWithAllIntervenorsForAGeneralRateIncreaseSubjectToNpscApprovalMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Regulatory Matters: Gas Utilities Regulatory Activity (Details) $ in Millions						3 Months Ended
	Oct. 07, 2025 USD ($)	Jul. 24, 2025 USD ($)	May 06, 2025 USD ($)	May 05, 2025 USD ($)	Mar. 17, 2025 USD ($)	Dec. 31, 2024 USD ($)	Sep. 30, 2025 USD ($)	May 01, 2025 mi	Feb. 03, 2025 mi	Jun. 14, 2024 mi	May 01, 2024 mi
Public Utilities, General Disclosures [Line Items]
Regulatory liability						$ 568.7	$ 576.6
Colorado Public Utilities Commission (CPUC) \| Black Hills Energy - Colorado Electric
Public Utilities, General Disclosures [Line Items]
Weighted average cost of capital					6.90%
Public Utilities, Approved Rate Increase (Decrease), Amount			$ 17.5	$ 17.0	$ 17.0
Colorado Public Utilities Commission (CPUC) \| Black Hills Energy - Colorado Electric \| Minimum
Public Utilities, General Disclosures [Line Items]
Public Utilities, Approved Equity Capital Structure, Percentage					47.00%
Public Utilities, Approved Debt Capital Structure, Percentage					51.00%
Public Utilities, Approved Return on Equity, Percentage					9.30%
Colorado Public Utilities Commission (CPUC) \| Black Hills Energy - Colorado Electric \| Maximum
Public Utilities, General Disclosures [Line Items]
Public Utilities, Approved Equity Capital Structure, Percentage					49.00%
Public Utilities, Approved Debt Capital Structure, Percentage					53.00%
Public Utilities, Approved Return on Equity, Percentage					9.50%
Colorado Public Utilities Commission (CPUC) \| Black Hills Energy - Colorado Electric \| Rate Review Filed with the Regulatory Agency
Public Utilities, General Disclosures [Line Items]
Public Utilities - Length of Electric Distribution Lines to Receive Infrastructure Investments \| mi										3,200
Public Utilities - Length of Electric Transmission Lines to Receive Infrastructure Investments \| mi										600
Iowa Utilities Commission (IUC) \| Black Hills Energy - Iowa Gas
Public Utilities, General Disclosures [Line Items]
Weighted average cost of capital						7.20%
Public Utilities, Approved Rate Increase (Decrease), Amount						$ 15.0
Iowa Utilities Commission (IUC) \| Black Hills Energy - Iowa Gas \| Rate Review Filed with the Regulatory Agency
Public Utilities, General Disclosures [Line Items]
Public Utilities - Length of Natural Gas Pipeline to Receive Infrastructure Investments \| mi											5,000
Kansas Corporation Commission (KCC) \| Black Hills Energy, Kansas Gas
Public Utilities, General Disclosures [Line Items]
Public Utilities, Approved Rate Increase (Decrease), Amount		$ 10.8
Kansas Corporation Commission (KCC) \| Black Hills Energy, Kansas Gas \| GSRS Rider Revenue
Public Utilities, General Disclosures [Line Items]
Public Utilities Amount of System Safety and Integrity Rider Moved to Base Rates		$ 4.4
Kansas Corporation Commission (KCC) \| Black Hills Energy, Kansas Gas \| Rate Review Filed with the Regulatory Agency
Public Utilities, General Disclosures [Line Items]
Public Utilities - Length of Natural Gas Pipeline to Receive Infrastructure Investments \| mi									4,765
Nebraska Publc Service Commission (NPSC) \| Black Hills Energy - Nebraska Gas \| Rate Review Filed with the Regulatory Agency
Public Utilities, General Disclosures [Line Items]
Public Utilities - Length of Natural Gas Pipeline to Receive Infrastructure Investments \| mi								12,900
Subsequent Event \| Nebraska Publc Service Commission (NPSC) \| Black Hills Energy - Nebraska Gas \| Settlement reached with all intervenors for a general rate increase, subject to NPSC approval [Member]
Public Utilities, General Disclosures [Line Items]
Public utilities, requested equity capital structure, percentage	51.00%
Public utilities, requested debt capital structure, percentage	49.00%
Public Utilities, Approved Return on Equity, Percentage	9.85%
Public Utilities, Approved Rate Increase (Decrease), Amount	$ 23.9