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PENSION AND OTHER POST-EMPLOYMENT BENEFITS - Pension Investments Measured at Fair Value (Details) - USD ($) $ in Millions | Dec. 31, 2023 | Dec. 31, 2022
--- | --- | ---
Pension |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Pension investments measured at fair value | $ 6,927 | $ 6,343
Asset Allocation | 100.00% | 100.00%
Excluded from total investments | $ (48) | $ 350
Pension | Investments Excluding in Investments at NAV |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Pension investments measured at fair value | $ 4,393 | $ 3,707
Asset Allocation | 63.00% | 58.00%
Pension | Cash and short-term securities |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Pension investments measured at fair value | $ 755 | $ 714
Asset Allocation | 11.00% | 11.00%
Pension | Public equity |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Pension investments measured at fair value | $ 1,815 | $ 2,087
Asset Allocation | 26.00% | 33.00%
Pension | Fixed income |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Pension investments measured at fair value | $ 1,784 | $ 942
Asset Allocation | 26.00% | 15.00%
Pension | Derivatives |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Pension investments measured at fair value | $ 39 |
Asset Allocation | 0.00% |
Pension | Derivatives |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Pension investments measured at fair value |  | $ (36)
Asset Allocation |  | (1.00%)
Pension | Private - equity and debt funds |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Pension investments measured at fair value | $ 1,296 | $ 1,061
Asset Allocation | 19.00% | 17.00%
Pension | Insurance-linked securities |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Pension investments measured at fair value | $ 107 | $ 159
Asset Allocation | 2.00% | 3.00%
Pension | Hedge funds |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Pension investments measured at fair value | $ 410 | $ 563
Asset Allocation | 6.00% | 9.00%
Pension | Real estate funds |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Pension investments measured at fair value | $ 721 | $ 853
Asset Allocation | 10.00% | 13.00%
Pension | Level 1 | Investments Excluding in Investments at NAV |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Pension investments measured at fair value | $ 1,813 | $ 1,833
Pension | Level 1 | Cash and short-term securities |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Pension investments measured at fair value | 0 | 0
Pension | Level 1 | Public equity |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Pension investments measured at fair value | 1,811 | 1,871
Pension | Level 1 | Fixed income |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Pension investments measured at fair value | 0 | 0
Pension | Level 1 | Derivatives |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Pension investments measured at fair value | 2 |
Pension | Level 1 | Derivatives |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Pension investments measured at fair value |  | (38)
Pension | Level 2 | Investments Excluding in Investments at NAV |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Pension investments measured at fair value | 2,580 | 1,874
Pension | Level 2 | Cash and short-term securities |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Pension investments measured at fair value | 755 | 714
Pension | Level 2 | Public equity |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Pension investments measured at fair value | 4 | 216
Pension | Level 2 | Fixed income |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Pension investments measured at fair value | 1,784 | 942
Pension | Level 2 | Derivatives |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Pension investments measured at fair value | 37 |
Pension | Level 2 | Derivatives |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Pension investments measured at fair value |  | 2
Pension | Level 3 | Investments Excluding in Investments at NAV |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Pension investments measured at fair value | 0 | 0
Pension | Level 3 | Cash and short-term securities |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Pension investments measured at fair value | 0 | 0
Pension | Level 3 | Public equity |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Pension investments measured at fair value | 0 | 0
Pension | Level 3 | Fixed income |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Pension investments measured at fair value | 0 | 0
Pension | Level 3 | Derivatives |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Pension investments measured at fair value | 0 |
Pension | Level 3 | Derivatives |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Pension investments measured at fair value |  | 0
OPEB |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Pension investments measured at fair value | $ 516 | $ 461
Asset Allocation | 100.00% | 100.00%
Excluded from total investments |  | $ (1)
OPEB | Cash and short-term securities |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Pension investments measured at fair value | $ 100 | $ 87
Asset Allocation | 19.00% | 19.00%
OPEB | Public equity |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Pension investments measured at fair value | $ 258 | $ 217
Asset Allocation | 50.00% | 47.00%
OPEB | Fixed income |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Pension investments measured at fair value | $ 158 | $ 157
Asset Allocation | 31.00% | 34.00%
OPEB | Level 1 |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Pension investments measured at fair value | $ 258 | $ 217
OPEB | Level 1 | Cash and short-term securities |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Pension investments measured at fair value | 0 | 0
OPEB | Level 1 | Public equity |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Pension investments measured at fair value | 258 | 217
OPEB | Level 1 | Fixed income |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Pension investments measured at fair value | 0 | 0
OPEB | Level 2 |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Pension investments measured at fair value | 258 | 244
OPEB | Level 2 | Cash and short-term securities |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Pension investments measured at fair value | 100 | 87
OPEB | Level 2 | Public equity |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Pension investments measured at fair value | 0 | 0
OPEB | Level 2 | Fixed income |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Pension investments measured at fair value | 158 | 157
OPEB | Level 3 |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Pension investments measured at fair value | 0 | 0
OPEB | Level 3 | Cash and short-term securities |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Pension investments measured at fair value | 0 | 0
OPEB | Level 3 | Public equity |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Pension investments measured at fair value | 0 | $ 0
OPEB | Level 3 | Fixed income |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Pension investments measured at fair value | $ 0 |

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