Regulatory Matters - Southern Company Gas (Details) - USD ($) $ in Millions	Aug. 12, 2025	Mar. 26, 2025
Nicor Gas \| Investing In Illinois Qualifying Infrastructure Plant
Public Utilities, General Disclosures [Line Items]
Capital expenditures disallowed		$ 14
Virginia Natural Gas \| SAVE Program
Public Utilities, General Disclosures [Line Items]
Approved rate increase (decrease)	$ 40
ROE	9.85%
Equity ratio	49.35%
Requested rate increase amount	$ 63

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