Regulatory Assets and Liabilities Disclosure

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- Definition

Residential Fixed Customer Charge Adjustment

+ References

No definition available.

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- Definition

Weather Normalization Adjustment

+ References

No definition available.

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- Definition

The amount for the individual regulatory asset as itemized in a table of regulatory assets as of the end of the period.

+ References

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- Definition

The amount for the individual regulatory liability as itemized in a table of regulatory liabilities as of the end of the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 980
-SubTopic 405
-Name Accounting Standards Codification
-Section 25
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477571/980-405-25-1

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- Definition

Remaining balance of regulatory assets for which no return on investment during recovery is provided. In some cases, a regulator may permit an enterprise to include a cost that would be charged to expense by an unregulated enterprise as an allowable cost over a period of time by amortizing that cost for rate-making purposes, but the regulator does not include the unrecovered amount in the rate base.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 980
-SubTopic 340
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478742/980-340-50-1

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-Name Accounting Standards Codification
-Topic 980
-SubTopic 340
-Section 55
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478098/980-340-55-2

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- Definition

Remaining recovery period of regulatory assets for which no return on investment during recovery period is provided, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Regulatory Matters (Narrative) (Details) - USD ($)	Dec. 31, 2025	Sep. 30, 2025	Dec. 31, 2024
Regulatory Assets and Liabilities Disclosure [Line Items]
Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided	$ 499,300,000		$ 671,300,000
COVID-19 related regulatory asset	2,499,400,000	$ 5.7	2,477,300,000
Regulatory Liabilities	1,773,400,000	$ 23.3	$ 1,581,700,000
Columbia Of Pennsylvania
Regulatory Assets and Liabilities Disclosure [Line Items]
Residential Fixed Customer Charge Adjustment	$ 20.15
Columbia Of Pennsylvania
Regulatory Assets and Liabilities Disclosure [Line Items]
Weather Normalization Adjustment	5.00%		3.00%
Minimum
Regulatory Assets and Liabilities Disclosure [Line Items]
Remaining Recovery Period of Regulatory Assets for which No Return on Investment During Recovery Period is Provided	15 years
Maximum
Regulatory Assets and Liabilities Disclosure [Line Items]
Remaining Recovery Period of Regulatory Assets for which No Return on Investment During Recovery Period is Provided	75 years
Overrecovered Gas And Fuel Costs
Regulatory Assets and Liabilities Disclosure [Line Items]
Regulatory Liabilities	$ 50,600,000		$ 21,400,000