XML 71 R60.htm IDEA: XBRL DOCUMENT
v3.21.2

Regulatory Matters (Schedule of COVID-19 Regulatory Impact) (Details) $ in Millions | Jun. 30, 2021 USD ($)
--- | ---
Incremental O&M - COVID | Columbia Of Ohio |
Regulated Operations |
Regulatory Assets | $ 2.1
Incremental Bad Debt - COVID | Columbia Of Pennsylvania |
Regulated Operations |
Regulatory Assets | 7.1
Incremental O&M and Bad Debt - COVID | NIPSCO |
Regulated Operations |
Regulatory Assets | 6.2
Incremental O&M and Bad Debt - COVID | Columbia Of Virginia |
Regulated Operations |
Regulatory Assets | 1.2
Incremental O&M and Bad Debt - COVID | Columbia Of Maryland |
Regulated Operations |
Regulatory Assets | $ 0.9

X
- Definition Regulated Operations + References No definition available. + Details
Name: | nix_RegulatedOperationsLineItems
Namespace Prefix: | nix_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount for the individual regulatory asset as itemized in a table of regulatory assets as of the end of the period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 980 -SubTopic 340 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6499975&loc=d3e44250-110382 + Details
Name: | us-gaap_RegulatoryAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_RegulatoryAssetAxis=nix_IncrementalOMCOVIDMember
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_RegulatoryAssetAxis=nix_IncrementalBadDebtCOVIDMember
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_RegulatoryAssetAxis=nix_IncrementalOMAndBadDebtCOVIDMember
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: | dei_LegalEntityAxis=nix_ColumbiaOfVirginiaMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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