FAIR VALUE MEASUREMENTS - Narrative (Details) - Spent Nuclear Fuel and Decommissioning Trusts - USD ($) $ in Millions	Sep. 30, 2025	Dec. 31, 2024
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Adjusted cost of debt securities	$ 1,700	$ 1,500
Adjusted cost of equity securities	536	549
I&M
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Adjusted cost of debt securities	1,700	1,500
Adjusted cost of equity securities	$ 536	$ 549

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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