XML 18 R61.htm IDEA: XBRL DOCUMENT v3.20.1

Regulatory Matters (Rate Case Action) (Details) - USD ($) $ in Millions	Apr. 24, 2020	Oct. 31, 2018
NIPSCO - Electric
Rate Case Action [Line Items]
Public Utilities, Requested Rate Increase (Decrease), Amount		$ 21.4
Public Utilities, Approved Rate Increase (Decrease), Amount		$ (53.5)
Subsequent Event | Columbia Of Pennsylvania [Member]
Rate Case Action [Line Items]
Public Utilities, Requested Rate Increase (Decrease), Amount	$ 100.4

X

- Definition

[Line Items] for Rate Case Action [Table]

+ References

No definition available.

+ Details

Name:	nix_RateCaseActionLineItems
Namespace Prefix:	nix_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- 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

X

- Definition

Amount of public utility's requested rate increase (decrease) with regulatory agency.

+ References

No definition available.

+ Details

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

X

- Details

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

X

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
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: