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FAIR VALUE MEASUREMENTS - Fixed Income Securities Held in Nuclear Trusts (Details) - Spent Nuclear Fuel and Decommissioning Trusts $ in Millions | Jun. 30, 2025 USD ($)
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Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |
Within 1 year | $ 350.0
After 1 year through 5 years | 635.8
After 5 years through 10 years | 231.2
After 10 years | 356.4
Total | 1,573.4
I&M |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |
Within 1 year | 350.0
After 1 year through 5 years | 635.8
After 5 years through 10 years | 231.2
After 10 years | 356.4
Total | $ 1,573.4

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