CONTINGENCIES, COMMITMENTS, AND GUARANTEES - Other Matters (Details) - Mississippi Power - USD ($) $ in Millions				7 Months Ended	12 Months Ended
	Nov. 05, 2025	Nov. 04, 2025	Mar. 31, 2025	Nov. 03, 2025	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023	Jan. 13, 2026
Loss Contingencies [Line Items]
Estimate of possible loss			$ 29
Settlement agreement		$ 13
Payment of settlement	$ 2			$ 11
Subsequent Event
Loss Contingencies [Line Items]
Regulatory asset								$ 9
Kemper County energy facility assets, net
Loss Contingencies [Line Items]
Pre-tax charge to income					$ 13	$ 12	$ 17
After tax charge to income					$ 10	$ 9	$ 12