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PENSION AND OTHER POST-EMPLOYMENT BENEFITS (Details) - USD ($) $ in Millions | 3 Months Ended | 12 Months Ended
--- | --- | ---
Mar. 31, 2023 | Mar. 31, 2022 | Dec. 31, 2023
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Pension and OPEB prior service costs amortized out of AOCI | $ 1 | $ 1 |
Pension |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Service costs | 34 | 46 |
Interest costs | 109 | 68 |
Expected return on plan assets | (128) | (164) |
Amortization of prior service costs (credits) | 0 | 1 |
Net periodic benefit costs (credits) | 15 | (49) |
Net periodic benefit credits, net of amounts capitalized | (3) | (69) |
Expected future contributions in 2025 | 250 |  |
Pension | Forecast |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Estimated return |  |  | 8.00%
OPEB |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Service costs | 1 | 1 |
Interest costs | 5 | 3 |
Expected return on plan assets | (8) | (10) |
Amortization of prior service costs (credits) | (2) | (3) |
Net periodic benefit costs (credits) | (4) | (9) |
Net periodic benefit credits, net of amounts capitalized | $ (4) | $ (9) |

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- Definition Amount of prior service cost (credit) recognized in net periodic benefit cost (credit) of defined benefit plan. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 55 -Paragraph 17 -URI https://asc.fasb.org/extlink&oid=123450688&loc=d3e4179-114921 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (h)(5) -URI https://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 45 -Paragraph 3A -Subparagraph (b) -URI https://asc.fasb.org/extlink&oid=123453770&loc=SL108413299-114919 Reference 4: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 55 -Paragraph 18 -URI https://asc.fasb.org/extlink&oid=123450688&loc=d3e4587-114921 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 6 -Subparagraph (a)(5) -URI https://asc.fasb.org/extlink&oid=123447040&loc=d3e2709-114920 + Details
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