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PENSION AND POST RETIREMENT BENEFITS - Components of Accumulated Other Comprehensive Loss (Income) (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2024 | Dec. 31, 2023
Pension Benefits |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Actuarial loss (gain) on benefit obligation | $ (113) | $ 42
Actual returns on assets under (over) expected | 67 | (60)
Amortization of net actuarial gain (loss) | 1 | (3)
Amortization of prior service credits (costs) | (18) | (18)
Settlements | 2 | 4
Plan amendments | 0 | 3
OPEB |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Actuarial loss (gain) on benefit obligation | 335 | (12)
Actual returns on assets under (over) expected | (3) | (24)
Amortization of net actuarial gain (loss) | 154 | 145
Amortization of prior service credits (costs) | 15 | 17
Settlements | 0 | 0
Plan amendments | 7 | 8
Discount rates | Pension Benefits |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Actuarial loss (gain) on benefit obligation | (146) | 124
Discount rates | OPEB |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Actuarial loss (gain) on benefit obligation | (43) | 28
Demographic updates | Pension Benefits |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Actuarial loss (gain) on benefit obligation | (14) | (5)
Demographic updates | OPEB |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Actuarial loss (gain) on benefit obligation | 26 | (208)
Mortality | Pension Benefits |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Actuarial loss (gain) on benefit obligation | 0 | (2)
Mortality | OPEB |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Actuarial loss (gain) on benefit obligation | 0 | (11)
Per capita healthcare costs | Pension Benefits |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Actuarial loss (gain) on benefit obligation | 0 | 0
Per capita healthcare costs | OPEB |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Actuarial loss (gain) on benefit obligation | 179 | 33
Other | Pension Benefits |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Actuarial loss (gain) on benefit obligation | (5) | (1)
Other | OPEB |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Actuarial loss (gain) on benefit obligation | 0 | 0
Actuarial loss (gain) on benefit obligation | Pension Benefits |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Actuarial loss (gain) on benefit obligation | (165) | 116
Actuarial loss (gain) on benefit obligation | OPEB |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Actuarial loss (gain) on benefit obligation | $ 162 | $ (158)

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