Summary of Significant Accounting Policies Nature of Operations (Details) customer in Millions	Dec. 31, 2024 customer
ATC
Product Information
Equity method investment, ownership interest (as a percent)	60.00%
ATC Holdco
Product Information
Equity method investment, ownership interest (as a percent)	75.00%
Electric
Product Information
Number of customers	1.7
Natural gas
Product Information
Number of customers	3.0

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 323
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481687/323-10-50-3

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Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant