The expense recognized in the current period that allocates the cost of nonproduction tangible assets over their useful lives.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 45
-Paragraph 28
-Subparagraph (b)
-SubTopic 10
-Topic 230
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-28

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482099/360-10-50-1

Name:	us-gaap_DepreciationNonproduction
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Regulatory Matters (Narrative) (Details) $ in Millions	3 Months Ended		6 Months Ended
Regulatory Matters (Narrative) (Details) $ in Millions	Jun. 30, 2024 USD ($) MW	Jun. 30, 2023 USD ($)	Jun. 30, 2024 USD ($) MW	Jun. 30, 2023 USD ($)
Public Utilities, General Disclosures [Line Items]
Depreciation, Nonproduction \| $	$ 13.1	$ 13.7	$ 16.6	$ 9.3
Rosewater
Public Utilities, General Disclosures [Line Items]
Nameplate Capacity	102		102
NIPSCO
Public Utilities, General Disclosures [Line Items]
Nameplate Capacity	400		400