Background and Basis of Presentation (Details) $ in Millions	Mar. 31, 2025 USD ($)	Mar. 07, 2025 USD ($) MW	Jun. 30, 2025 registrant
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of registrants \| registrant			3
Disposal Group, Held-for-sale or Disposed of by Sale, Not Discontinued Operations \| Louisiana and Mississippi Regulated Natural Gas LDC Businesses \| CERC
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sale of disposal	$ 1,200
Alternative Energy \| Posey Solar
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Power generation capacity, megawatts \| MW		191
Consideration transferred		$ 357
Alternative Energy \| Posey Solar \| SIGECO
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Percentage of posey solar assets acquired		1