XML 95 R77.htm IDEA: XBRL DOCUMENT
v3.25.0.1

Long-Term Debt (Schedule of Consolidated Long-Term Debt (Details) - USD ($) $ in Millions | Dec. 31, 2024 | Sep. 09, 2024 | Jun. 24, 2024 | May 16, 2024 | Mar. 14, 2024 | Dec. 31, 2023 | Jun. 08, 2023
--- | --- | --- | --- | --- | --- | --- | ---
Debt Instrument [Line Items] |  |  |  |  |  |  |
Medium-Term Notes | $ 102.0 |  |  |  |  | $ 102.0 |
Finance Lease, Liability | 246.2 |  |  |  |  | 205.4 |
Senior Notes | 12,103.0 |  |  |  |  | 10,853.0 |
Junior Subordinated Notes | 1,000.0 |  |  |  |  | 0.0 |
Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net | (95.5) |  |  |  |  | (81.1) |
Long-Term Debt, Current Maturities | (1,281.2) |  |  |  |  | (23.8) |
Long-term Debt, Excluding Current Maturities | 13,355.7 |  |  |  |  | 11,079.3 |
Long-term Debt and Lease Obligation | $ 12,074.5 |  |  |  |  | 11,055.5 |
NiSource |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Senior Notes |  |  |  |  |  |  | $ 450.0
NiSource | 0.95% Notes Due 2025 |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Debt, Weighted Average Interest Rate | 0.95% |  |  |  |  |  |
Senior Notes | $ 1,250.0 |  |  |  |  | 1,250.0 |
NiSource | 3.49% Notes due 2027 |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Debt, Weighted Average Interest Rate | 3.49% |  |  |  |  |  |
Senior Notes | $ 1,000.0 |  |  |  |  | 1,000.0 |
NiSource | 6.78% Notes Due 2027 |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Debt, Weighted Average Interest Rate | 6.78% |  |  |  |  |  |
Senior Notes | $ 3.0 |  |  |  |  | 3.0 |
NiSource | 2.95% Notes Due 2029 |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Debt, Weighted Average Interest Rate | 2.95% |  |  |  |  |  |
Senior Notes | $ 750.0 |  |  |  |  | 750.0 |
NiSource | 3.60% Notes Due 2030 |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Debt, Weighted Average Interest Rate | 3.60% |  |  |  |  |  |
Senior Notes | $ 1,000.0 |  |  |  |  | 1,000.0 |
NiSource | 1.70% Notes Due 2031 |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Debt, Weighted Average Interest Rate | 1.70% |  |  |  |  |  |
Senior Notes | $ 750.0 |  |  |  |  | 750.0 |
NiSource | 6.25% Notes Due 2040 |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Debt, Weighted Average Interest Rate | 6.25% |  |  |  |  |  |
Senior Notes | $ 152.6 |  |  |  |  | 152.6 |
NiSource | 5.95% Notes Due 2041 |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Debt, Weighted Average Interest Rate | 5.95% |  |  |  |  |  |
Senior Notes | $ 347.4 |  |  |  |  | 347.4 |
NiSource | 5.80% Notes Due 2042 |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Debt, Weighted Average Interest Rate | 5.80% |  |  |  |  |  |
Senior Notes | $ 250.0 |  |  |  |  | 250.0 |
NiSource | 5.25% Notes Due 2043 |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Debt, Weighted Average Interest Rate | 5.25% |  |  |  |  |  |
Senior Notes | $ 500.0 |  |  |  |  | 500.0 |
NiSource | 4.80% Notes due 2044 |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Debt, Weighted Average Interest Rate | 4.80% |  |  |  |  |  |
Senior Notes | $ 750.0 |  |  |  |  | 750.0 |
NiSource | 5.65% Notes Due 2045 |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Debt, Weighted Average Interest Rate | 5.65% |  |  |  |  |  |
Senior Notes | $ 500.0 |  |  |  |  | 500.0 |
NiSource | 4.375% Notes due 2047 |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Debt, Weighted Average Interest Rate | 4.375% |  |  |  |  |  |
Senior Notes | $ 1,000.0 |  |  |  |  | 1,000.0 |
NiSource | 3.95% Notes Due 2048 |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Debt, Weighted Average Interest Rate | 3.95% |  |  |  |  |  |
Senior Notes | $ 750.0 |  |  |  |  | 750.0 |
NiSource | Medium-Term Note |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Debt, Weighted Average Interest Rate | 7.99% |  |  |  |  |  |
Medium-Term Notes | $ 29.0 |  |  |  |  | 29.0 |
NiSource | 5.00% Notes Due 2052 |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Debt, Weighted Average Interest Rate | 5.00% |  |  |  |  |  |
Senior Notes | $ 350.0 |  |  |  |  | 350.0 |
NiSource | 5.25% Notes Due 2028 |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Debt, Weighted Average Interest Rate | 5.25% |  |  |  |  |  |
Senior Notes | $ 1,050.0 |  |  |  |  | 1,050.0 |
NiSource | 5.40% Notes Due 2033 |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Debt, Weighted Average Interest Rate | 5.40% |  |  |  |  |  |
Senior Notes | $ 450.0 |  |  |  |  | 450.0 |
NiSource | 5.20% Notes Due 2029 |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Debt, Weighted Average Interest Rate | 5.20% |  | 5.20% |  |  |  |
Senior Notes | $ 600.0 |  | $ 600.0 |  |  | 0.0 |
NiSource | 5.35% Notes Due 2034 |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Debt, Weighted Average Interest Rate | 5.35% |  |  |  | 5.35% |  |
Senior Notes | $ 650.0 |  |  |  | $ 650.0 | 0.0 |
NiSource | 6.95% Notes due 2054 |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Debt, Weighted Average Interest Rate | 6.95% |  |  | 6.95% |  |  |
Junior Subordinated Notes | $ 500.0 |  |  | $ 500.0 |  | 0.0 |
NiSource | 6.375% Notes due 2054 |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Debt, Weighted Average Interest Rate | 6.375% | 6.375% |  |  |  |  |
Junior Subordinated Notes | $ 500.0 | $ 500.0 |  |  |  | 0.0 |
Columbia Of Massachusetts | Medium-Term Note |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Debt, Weighted Average Interest Rate | 6.373% |  |  |  |  |  |
Medium-Term Notes | $ 15.0 |  |  |  |  | 15.0 |
NIPSCO | Medium-Term Note |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Debt, Weighted Average Interest Rate | 7.644% |  |  |  |  |  |
Medium-Term Notes | $ 58.0 |  |  |  |  | 58.0 |
NIPSCO | Finance Leases |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Debt, Weighted Average Interest Rate | 5.25% |  |  |  |  |  |
Finance Lease, Liability | $ 124.3 |  |  |  |  | 61.2 |
Columbia Of Ohio | Finance Leases |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Debt, Weighted Average Interest Rate | 6.15% |  |  |  |  |  |
Finance Lease, Liability | $ 85.6 |  |  |  |  | 90.3 |
NiSource Corporate Services | Finance Leases |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Debt, Weighted Average Interest Rate | 3.47% |  |  |  |  |  |
Finance Lease, Liability | $ 14.6 |  |  |  |  | 30.5 |
Columbia Of Virginia | Finance Leases |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Debt, Weighted Average Interest Rate | 6.19% |  |  |  |  |  |
Finance Lease, Liability | $ 15.2 |  |  |  |  | 16.1 |
Columbia Of Kentucky | Finance Leases |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Debt, Weighted Average Interest Rate | 5.36% |  |  |  |  |  |
Finance Lease, Liability | $ 0.1 |  |  |  |  | 0.2 |
Columbia Of Pennsylvania | Finance Leases |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Debt, Weighted Average Interest Rate | 4.47% |  |  |  |  |  |
Finance Lease, Liability | $ 6.4 |  |  |  |  | $ 7.1 |

X
- Definition Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)) -SubTopic 10 -Topic 210 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 942 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Subparagraph (b)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-4 + Details
Name: | us-gaap_DebtInstrumentCarryingAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- 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 Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 835 -SubTopic 30 -Name Accounting Standards Codification -Section 55 -Paragraph 8 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482949/835-30-55-8 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 235 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08(f)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480678/235-10-S99-1 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 235 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 3 -Subparagraph (SX 210.12-04(a)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480678/235-10-S99-3 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1B -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B Reference 5: http://www.xbrl.org/2003/role/exampleRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 69B -Publisher FASB -URI https://asc.fasb.org/1943274/2147481568/470-20-55-69B Reference 6: http://www.xbrl.org/2003/role/exampleRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 69C -Publisher FASB -URI https://asc.fasb.org/1943274/2147481568/470-20-55-69C Reference 7: http://www.xbrl.org/2003/role/exampleRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 69E -Publisher FASB -URI https://asc.fasb.org/1943274/2147481568/470-20-55-69E Reference 8: http://www.xbrl.org/2003/role/exampleRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 69F -Publisher FASB -URI https://asc.fasb.org/1943274/2147481568/470-20-55-69F Reference 9: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1B -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B Reference 10: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1B -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B Reference 11: http://www.xbrl.org/2003/role/exampleRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1B -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B Reference 12: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1B -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B Reference 13: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1B -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B Reference 14: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1B -Subparagraph (h) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B Reference 15: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1D -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-1D Reference 16: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1D -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-1D Reference 17: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1D -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-1D Reference 18: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1E -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-1E Reference 19: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1E -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-1E Reference 20: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1E -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-1E Reference 21: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1F -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-1F Reference 22: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1F -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-1F Reference 23: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1F -Subparagraph (b)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-1F Reference 24: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1F -Subparagraph (b)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-1F Reference 25: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1I -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-1I Reference 26: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 835 -SubTopic 30 -Name Accounting Standards Codification -Section 45 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482925/835-30-45-2 Reference 27: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 835 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482900/835-30-50-1 + Details
Name: | us-gaap_DebtInstrumentLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of unamortized debt discount (premium) and debt issuance costs. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 835 -SubTopic 30 -Name Accounting Standards Codification -Section 55 -Paragraph 8 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482949/835-30-55-8 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 69B -Publisher FASB -URI https://asc.fasb.org/1943274/2147481568/470-20-55-69B Reference 3: http://www.xbrl.org/2003/role/exampleRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 69C -Publisher FASB -URI https://asc.fasb.org/1943274/2147481568/470-20-55-69C Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1D -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-1D Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 835 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482900/835-30-50-1 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Topic 835 -SubTopic 30 -Name Accounting Standards Codification -Section 45 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482925/835-30-45-2 Reference 7: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Subparagraph (b)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-4 Reference 8: http://www.xbrl.org/2003/role/disclosureRef -Topic 835 -SubTopic 30 -Name Accounting Standards Codification -Section 45 -Paragraph 1A -Publisher FASB -URI https://asc.fasb.org/1943274/2147482925/835-30-45-1A + Details
Name: | us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Weighted average interest rate of debt outstanding. + References No definition available. + Details
Name: | us-gaap_DebtWeightedAverageInterestRate
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Present value of lessee's discounted obligation for lease payments from finance lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 842 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org/1943274/2147478964/842-20-50-6 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 842 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479041/842-20-45-1 + Details
Name: | us-gaap_FinanceLeaseLiability
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Including the current and noncurrent portions, carrying value as of the balance sheet date of long-term debt (with maturities initially due after one year or beyond the operating cycle if longer) identified as Junior Subordinated Notes, which have a lower priority than senior instruments. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)) -SubTopic 10 -Topic 210 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 942 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 944 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(16)(a)(2)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1 + Details
Name: | us-gaap_JuniorSubordinatedNotes
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of long-term debt and lease obligation, classified as noncurrent. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)) -SubTopic 10 -Topic 210 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(16)(a)(2)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1 + Details
Name: | us-gaap_LongTermDebtAndCapitalLeaseObligations
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount, after deduction of unamortized premium (discount) and debt issuance cost, of long-term debt classified as current. Excludes lease obligation. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(20)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 + Details
Name: | us-gaap_LongTermDebtCurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of debt instrument classified as medium-term. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)) -SubTopic 10 -Topic 210 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 942 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 944 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(16)(a)(2)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1 + Details
Name: | us-gaap_MediumTermNotes
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- 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. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 942 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 944 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(16)(a)(2)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1 + Details
Name: | us-gaap_SeniorNotes
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | dei_LegalEntityAxis=nix_NiSourceMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=nix_A095NotesDue2025Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=nix_A3.49Notesdue2027Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=nix_A6.78NotesDue2027Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=nix_A2.95NotesDue2029Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=nix_A3.60NotesDue2030Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=nix_A170NotesDue2031Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=nix_A6.25NotesDue2040Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=nix_A5.95NotesDue2041Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=nix_A5.80NotesDue2042Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=nix_A5.25NotesDue2043Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=nix_A4.80Notesdue2044Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=nix_A5.65NotesDue2045Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=nix_A4.375Notesdue2047Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=nix_A3.95NotesDue2048Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=us-gaap_MediumTermNotesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=nix_A500NotesDue2052Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=nix_A5.25NotesDue2028Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=nix_A5.40NotesDue2033Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=nix_A5.20NotesDue2029Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=nix_A5.35NotesDue2034Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=nix_A6.95NotesDue2054Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=nix_A6.375NotesDue2054Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=nix_ColumbiaOfMassachusettsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=nix_NIPSCOMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=nix_FinanceLeasesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=nix_ColumbiaOfOhioMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=nix_NiSourceCorporateServicesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=nix_ColumbiaOfVirginiaMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=nix_ColumbiaOfKentuckyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=nix_ColumbiaOfPennsylvaniaMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |