XML 120 R105.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Long-Term Debt (Schedule of Consolidated Long-Term Debt (Details) - USD ($) $ in Millions | 12 Months Ended |
--- | --- | ---
Dec. 31, 2018 | Dec. 31, 2017
Debt Instrument [Line Items] |  |
Senior Notes | $ 6,831.6 | $ 7,516.9
Medium-Term Notes | 157.0 | 157.0
Capital Lease Obligations | 194.3 | 153.1
Long-term Debt, Excluding Current Maturities | 7,155.4 | 7,796.5
Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net | $ (68.5) | (71.5)
4.375% Notes due 2047 |  |
Debt Instrument [Line Items] |  |
Debt Instrument, Maturity Date | Dec. 31, 2027 |
3.68% Notes Due 2019 |  |
Debt Instrument [Line Items] |  |
Debt Instrument, Maturity Date | Oct. 31, 2022 |
NiSource Finance | 6.40% Notes Due 2018 |  |
Debt Instrument [Line Items] |  |
Senior Notes |  | 275.1
NiSource Finance | 6.80% Notes Due 2019 |  |
Debt Instrument [Line Items] |  |
Senior Notes |  | 255.1
NiSource Finance | 5.45% Notes due 2020 |  |
Debt Instrument [Line Items] |  |
Senior Notes |  | 325.1
NiSource Finance | 4.45% Notes Due 2021 |  |
Debt Instrument [Line Items] |  |
Senior Notes |  | 63.6
NiSource Finance | 6.13% Notes Due 2022 |  |
Debt Instrument [Line Items] |  |
Senior Notes |  | 180.0
NiSource Finance | 2.65% Notes Due 2022 |  |
Debt Instrument [Line Items] |  |
Senior Notes |  | 500.0
NiSource Finance | 3.85% Notes Due 2023 |  |
Debt Instrument [Line Items] |  |
Senior Notes |  | 250.0
NiSource Finance | 3.65% Notes Due 2023 |  |
Debt Instrument [Line Items] |  |
Senior Notes |  | 0.0
NiSource Finance | 5.89% Notes Due 2025 |  |
Debt Instrument [Line Items] |  |
Senior Notes |  | 265.0
NiSource Finance | 3.49% Notes due 2027 |  |
Debt Instrument [Line Items] |  |
Senior Notes |  | 1,000.0
NiSource Finance | 6.25% Notes Due 2040 |  |
Debt Instrument [Line Items] |  |
Senior Notes |  | 250.0
NiSource Finance | 5.95% Notes Due 2041 |  |
Debt Instrument [Line Items] |  |
Senior Notes |  | 400.0
NiSource Finance | 5.80% Notes Due 2042 |  |
Debt Instrument [Line Items] |  |
Senior Notes |  | 250.0
NiSource Finance | 5.25% Notes Due 2043 |  |
Debt Instrument [Line Items] |  |
Senior Notes |  | 500.0
NiSource Finance | 4.80% Notes due 2044 |  |
Debt Instrument [Line Items] |  |
Senior Notes |  | 750.0
NiSource Finance | 5.65% Notes Due 2045 |  |
Debt Instrument [Line Items] |  |
Senior Notes |  | 500.0
Nisource Capital Markets Inc | 6.78% Notes Due 2027 |  |
Debt Instrument [Line Items] |  |
Senior Notes |  | 3.0
Nisource Capital Markets Inc | 4.375% Notes due 2047 |  |
Debt Instrument [Line Items] |  |
Senior Notes |  | 1,000.0
Nisource Capital Markets Inc | 3.95% Notes Due 2048 |  |
Debt Instrument [Line Items] |  |
Senior Notes |  | 750.0
NiSource | 6.40% Notes Due 2018 |  |
Debt Instrument [Line Items] |  |
Debt Instrument, Maturity Date | Mar. 31, 2018 |
Debt, Weighted Average Interest Rate | 6.40% |
Senior Notes | $ 0.0 |
NiSource | 6.80% Notes Due 2019 |  |
Debt Instrument [Line Items] |  |
Debt Instrument, Maturity Date | Jan. 31, 2019 |
Debt, Weighted Average Interest Rate | 6.80% |
Senior Notes | $ 0.0 |
NiSource | 5.45% Notes due 2020 |  |
Debt Instrument [Line Items] |  |
Debt Instrument, Maturity Date | Sep. 30, 2020 |
Debt, Weighted Average Interest Rate | 5.45% |
Senior Notes | $ 0.0 |
NiSource | 4.45% Notes Due 2021 |  |
Debt Instrument [Line Items] |  |
Debt Instrument, Maturity Date | Dec. 31, 2021 |
Debt, Weighted Average Interest Rate | 4.45% |
Senior Notes | $ 63.6 |
NiSource | 6.13% Notes Due 2022 |  |
Debt Instrument [Line Items] |  |
Debt Instrument, Maturity Date | Mar. 31, 2022 |
Debt, Weighted Average Interest Rate | 6.13% |
Senior Notes | $ 0.0 |
NiSource | 2.65% Notes Due 2022 |  |
Debt Instrument [Line Items] |  |
Debt Instrument, Maturity Date | Nov. 30, 2022 |
Debt, Weighted Average Interest Rate | 2.65% |
Senior Notes | $ 500.0 |
NiSource | 3.85% Notes Due 2023 |  |
Debt Instrument [Line Items] |  |
Debt Instrument, Maturity Date | Feb. 28, 2023 |
Debt, Weighted Average Interest Rate | 3.85% |
Senior Notes | $ 250.0 |
NiSource | 3.65% Notes Due 2023 |  |
Debt Instrument [Line Items] |  |
Debt, Weighted Average Interest Rate | 3.65% |
Senior Notes | $ 350.0 |
NiSource | 5.89% Notes Due 2025 |  |
Debt Instrument [Line Items] |  |
Debt Instrument, Maturity Date | Nov. 30, 2025 |
Debt, Weighted Average Interest Rate | 5.89% |
Senior Notes | $ 265.0 |
NiSource | 3.49% Notes due 2027 |  |
Debt Instrument [Line Items] |  |
Debt, Weighted Average Interest Rate | 3.49% |
Senior Notes | $ 1,000.0 |
NiSource | 6.78% Notes Due 2027 |  |
Debt Instrument [Line Items] |  |
Debt, Weighted Average Interest Rate | 6.78% |
Senior Notes | $ 3.0 |
NiSource | 6.25% Notes Due 2040 |  |
Debt Instrument [Line Items] |  |
Debt Instrument, Maturity Date | Dec. 31, 2040 |
Debt, Weighted Average Interest Rate | 6.25% |
Senior Notes | $ 250.0 |
NiSource | 5.95% Notes Due 2041 |  |
Debt Instrument [Line Items] |  |
Debt Instrument, Maturity Date | Jun. 30, 2041 |
Debt, Weighted Average Interest Rate | 5.95% |
Senior Notes | $ 400.0 |
NiSource | 5.80% Notes Due 2042 |  |
Debt Instrument [Line Items] |  |
Debt Instrument, Maturity Date | Feb. 28, 2042 |
Debt, Weighted Average Interest Rate | 5.80% |
Senior Notes | $ 250.0 |
NiSource | 5.25% Notes Due 2043 |  |
Debt Instrument [Line Items] |  |
Debt Instrument, Maturity Date | Feb. 28, 2043 |
Debt, Weighted Average Interest Rate | 5.25% |
Senior Notes | $ 500.0 |
NiSource | 4.80% Notes due 2044 |  |
Debt Instrument [Line Items] |  |
Debt Instrument, Maturity Date | Feb. 29, 2044 |
Debt, Weighted Average Interest Rate | 4.80% |
Senior Notes | $ 750.0 |
NiSource | 5.65% Notes Due 2045 |  |
Debt Instrument [Line Items] |  |
Debt Instrument, Maturity Date | Feb. 28, 2045 |
Debt, Weighted Average Interest Rate | 5.65% |
Senior Notes | $ 500.0 |
NiSource | 4.375% Notes due 2047 |  |
Debt Instrument [Line Items] |  |
Debt Instrument, Maturity Date | May 31, 2047 |
Debt, Weighted Average Interest Rate | 4.38% |
Senior Notes | $ 1,000.0 |
NiSource | 3.95% Notes Due 2048 |  |
Debt Instrument [Line Items] |  |
Debt Instrument, Maturity Date | Mar. 31, 2048 |
Debt, Weighted Average Interest Rate | 3.95% |
Senior Notes | $ 750.0 |
NiSource | 7.99% Notes Due 2027 |  |
Debt Instrument [Line Items] |  |
Debt, Weighted Average Interest Rate | 7.99% |
Medium-Term Notes | $ 49.0 | 49.0
NiSource | 7.99% Notes Due 2027 | Maximum |  |
Debt Instrument [Line Items] |  |
Debt Instrument, Maturity Date | May 31, 2027 |
NiSource | 7.99% Notes Due 2027 | Minimum |  |
Debt Instrument [Line Items] |  |
Debt Instrument, Maturity Date | Apr. 30, 2022 |
NiSource | 3.95% Notes Due 2018 |  |
Debt Instrument [Line Items] |  |
Debt Instrument, Maturity Date | May 31, 2018 |
Columbia Of Massachusetts | 6.30% Notes Due 2028 |  |
Debt Instrument [Line Items] |  |
Debt, Weighted Average Interest Rate | 6.30% |
Medium-Term Notes | $ 40.0 | 40.0
Columbia Of Massachusetts | 6.30% Notes Due 2028 | Maximum |  |
Debt Instrument [Line Items] |  |
Debt Instrument, Maturity Date | Dec. 31, 2025 |
Columbia Of Massachusetts | 6.30% Notes Due 2028 | Minimum |  |
Debt Instrument [Line Items] |  |
Debt Instrument, Maturity Date | Feb. 28, 2028 |
Columbia Of Massachusetts | 5.48% notes Due 2043 |  |
Debt Instrument [Line Items] |  |
Debt, Weighted Average Interest Rate | 5.48% |
Capital Lease Obligations | $ 45.7 | 22.8
Columbia Of Massachusetts | 5.48% notes Due 2043 | Maximum |  |
Debt Instrument [Line Items] |  |
Debt Instrument, Maturity Date | Nov. 30, 2043 |
Columbia Of Massachusetts | 5.48% notes Due 2043 | Minimum |  |
Debt Instrument [Line Items] |  |
Debt Instrument, Maturity Date | Dec. 31, 2033 |
NIPSCO | 7.61% Notes Due 2027 |  |
Debt Instrument [Line Items] |  |
Debt, Weighted Average Interest Rate | 7.61% |
Medium-Term Notes | $ 68.0 | 68.0
NIPSCO | 7.61% Notes Due 2027 | Maximum |  |
Debt Instrument [Line Items] |  |
Debt Instrument, Maturity Date | Aug. 31, 2027 |
NIPSCO | 7.61% Notes Due 2027 | Minimum |  |
Debt Instrument [Line Items] |  |
Debt Instrument, Maturity Date | Aug. 31, 2022 |
NIPSCO | 3.95% Notes Due 2018 |  |
Debt Instrument [Line Items] |  |
Debt, Weighted Average Interest Rate | 3.95% |
Capital Lease Obligations | $ 0.0 | 3.8
NIPSCO | 5.85% Notes Due 2019 |  |
Debt Instrument [Line Items] |  |
Debt, Weighted Average Interest Rate | 5.85% |
Long-term Pollution Control Bond | $ 41.0 | 41.0
NIPSCO | 5.85% Notes Due 2019 | Maximum |  |
Debt Instrument [Line Items] |  |
Debt Instrument, Maturity Date | Apr. 30, 2019 |
NIPSCO | 5.85% Notes Due 2019 | Minimum |  |
Debt Instrument [Line Items] |  |
Debt Instrument, Maturity Date | Jul. 31, 2017 |
Columbia Of Ohio | 6.33% Notes Due 2038 |  |
Debt Instrument [Line Items] |  |
Debt, Weighted Average Interest Rate | 6.33% |
Capital Lease Obligations | $ 91.5 | 88.5
Columbia Of Ohio | 6.33% Notes Due 2038 | Maximum |  |
Debt Instrument [Line Items] |  |
Debt Instrument, Maturity Date | Jun. 30, 2038 |
Columbia Of Ohio | 6.33% Notes Due 2038 | Minimum |  |
Debt Instrument [Line Items] |  |
Debt Instrument, Maturity Date | Oct. 31, 2021 |
NiSource Corporate Services | 3.68% Notes Due 2019 |  |
Debt Instrument [Line Items] |  |
Debt, Weighted Average Interest Rate | 3.68% |
Capital Lease Obligations | $ 11.6 | 1.4
Columbia Of Virginia | 7.12% Notes Due 2037 |  |
Debt Instrument [Line Items] |  |
Debt, Weighted Average Interest Rate | 7.12% |
Capital Lease Obligations | $ 15.2 | 5.2
Columbia Of Virginia | 7.12% Notes Due 2037 | Maximum |  |
Debt Instrument [Line Items] |  |
Debt Instrument, Maturity Date | Dec. 31, 2037 |
Columbia Of Virginia | 7.12% Notes Due 2037 | Minimum |  |
Debt Instrument [Line Items] |  |
Debt Instrument, Maturity Date | Jul. 31, 2029 |
Columbia Of Kentucky | 3.79% Notes Due 2027 |  |
Debt Instrument [Line Items] |  |
Debt Instrument, Maturity Date | May 31, 2027 |
Debt, Weighted Average Interest Rate | 3.79% |
Capital Lease Obligations | $ 0.3 | 0.4
Columbia Of Pennsylvania | 5.42% Notes Due 2036 |  |
Debt Instrument [Line Items] |  |
Debt, Weighted Average Interest Rate | 5.42% |
Capital Lease Obligations | $ 30.0 | $ 31.0
Columbia Of Pennsylvania | 5.42% Notes Due 2036 | Maximum |  |
Debt Instrument [Line Items] |  |
Debt Instrument, Maturity Date | Jun. 30, 2036 |
Columbia Of Pennsylvania | 5.42% Notes Due 2036 | Minimum |  |
Debt Instrument [Line Items] |  |
Debt Instrument, Maturity Date | Aug. 31, 2027 |

X
- Definition Amount equal to the present value (the principal) at the beginning of the lease term of minimum lease payments during the lease term (excluding that portion of the payments representing executory costs such as insurance, maintenance, and taxes to be paid by the lessor, together with any profit thereon) net of payments or other amounts applied to the principal through the balance sheet date. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 30 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=84164817&loc=d3e45280-112737 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(16)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 + Details
Name: | us-gaap_CapitalLeaseObligations
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (b)(1) -URI http://asc.fasb.org/extlink&oid=109500613&loc=SL6031897-161870 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(16)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + 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 No definition available. + Details
Name: | us-gaap_DebtInstrumentLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(2)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (bbb)(2) -URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258 + Details
Name: | us-gaap_DebtInstrumentMaturityDate
Namespace Prefix: | us-gaap_
Data Type: | xbrli:dateItemType
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/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (b)(2) -URI http://asc.fasb.org/extlink&oid=109500613&loc=SL6031897-161870 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28555-108399 + 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: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Represents the current and noncurrent portions of a debt security issued by a state, certain agencies or authorities, a local government, or development corporation to finance the construction of air- or water-pollution control facilities or sewage or solid waste disposal facilities pursuant to federal law. The bonds are backed by the credit of the beneficiary of the financing rather than the credit of the issuer. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.16) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.16) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.20,22) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_LongtermPollutionControlBondCurrentAndNoncurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Including the current and noncurrent portions, carrying value at the balance sheet date of a financial instrument used to receive debt funding on a regular basis with original maturities ranging from 5-10 years. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(16)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 946 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.6-04(13)) -URI http://asc.fasb.org/extlink&oid=6488278&loc=d3e603758-122996 + 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 -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.16(a)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.16) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + Details
Name: | us-gaap_SeniorNotes
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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_A3.68NotesDue2022Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=nix_A6.40NotesDue2018Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=nix_A6.80NotesDue2019Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=nix_A5.45Notesdue2020Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=nix_A4.45NotesDue2021Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=nix_A6.125NotesDue2022Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=nix_A2.65NotesDue2022Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=nix_A3.85NotesDue2023Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=nix_A3.65NotesDue2023Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=nix_A5.89NotesDue2025Member
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_A6.25NotesDue2040Member
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: | dei_LegalEntityAxis=nix_NisourceCapitalMarketsIncMember
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_A3.95NotesDue2048Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=nix_A7.99NotesDue2027Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=nix_A3.95NotesDue2018Member
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: | us-gaap_LongtermDebtTypeAxis=nix_A6.30NotesDue2028Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=nix_A5.48notesDue2043Member
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_A7.61NotesDue2027Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=nix_A5.85NotesDue2019Member
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: | us-gaap_LongtermDebtTypeAxis=nix_A6.33NotesDue2038Member
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: | us-gaap_LongtermDebtTypeAxis=nix_A7.12NotesDue2037Member
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: | us-gaap_LongtermDebtTypeAxis=nix_A3.79NotesDue2027Member
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: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=nix_A5.42NotesDue2036Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |