Long-Term Debt (Narrative) (Details) |
Aug. 18, 2026
USD ($)
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May 26, 2026
USD ($)
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Sep. 30, 2026
USD ($)
MW
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May 18, 2026
USD ($)
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Dec. 31, 2025
USD ($)
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| Standby Letters of Credit | |||||
| Debt Instrument [Line Items] | |||||
| Revolving credit facility interest rate of 2.13% at March 31, 2020 | $ 98,400,000 | $ 119,000,000.0 | |||
| Rosewater | |||||
| Debt Instrument [Line Items] | |||||
| Nameplate Capacity | MW | 102 | ||||
| Senior Notes | NiSource | |||||
| Debt Instrument [Line Items] | |||||
| Senior Notes | $ 500,000,000.0 | $ 750,000,000.0 | |||
| Debt, Weighted Average Interest Rate | 4.75% | ||||
| Proceeds from Debt, Net of Issuance Costs | $ 1,236,000,000 | ||||
| Unsecured Debt | NiSource | |||||
| Debt Instrument [Line Items] | |||||
| Debt, Weighted Average Interest Rate | 5.30% | ||||
| Junior Notes | NiSource | |||||
| Debt Instrument [Line Items] | |||||
| Senior Notes | $ 750,000,000 | ||||
| Debt, Weighted Average Interest Rate | 6.25% | ||||
| Proceeds from Debt, Net of Issuance Costs | $ 740,100,000 | ||||
| 6.25% Notes due 2057 | NiSource | |||||
| Debt Instrument [Line Items] | |||||
| Debt Instrument, Basis Spread on Variable Rate | 1.93% |
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- Definition Nameplate Capacity No definition available.
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- Definition Percentage points added to the reference rate to compute the variable rate on the debt instrument. No definition available.
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- 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. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Weighted average interest rate of debt outstanding. No definition available.
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- Definition The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition The cash inflow from additional borrowings, net of cash paid to third parties in connection with debt origination. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Including the current and noncurrent portions, carrying value as of the balance sheet date of Notes with the highest claim on the assets of the issuer in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle if longer). Senior note holders are paid off in full before any payments are made to junior note holders. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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