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Pension and Other Postretirement Benefit Plans - Narrative (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2024 | Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Employer contributions to defined contribution savings plans |  | $ 199 | $ 175 | $ 158
Pension Benefits |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Accumulated benefit obligation |  | $ 19,100 | $ 17,200 |
Percentage of Company's pension investments categorized as level 3 assets |  | 4.00% | 4.00% |
Pension Benefits | Level 3 |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Fair value of plan assets |  | $ 788 | $ 765 |
Other Postretirement Benefits |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Fair value of plan assets |  | 1,045 | 947 | $ 1,292
Expected contributions to the pension plans and other postretirement benefit plans during next fiscal year |  | 65 |  |
Other Postretirement Benefits | Level 3 |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Fair value of plan assets |  | $ 0 | $ 0 |
United States |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Expected annual standard deviation in returns of the target portfolio which reflects both the equity allocation and the diversification benefits among the asset classes in which the portfolio invests |  | 11.00% |  |
Expected rate of return on plan assets |  | 7.00% | 6.70% | 6.70%
United States | Forecast | Subsequent Event |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Expected rate of return on plan assets | 7.75% |  |  |
United States | U.S. equities | Minimum |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Target allocation |  | 25.00% |  |
United States | U.S. equities | Maximum |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Target allocation |  | 40.00% |  |
United States | International equities | Minimum |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Target allocation |  | 10.00% |  |
United States | International equities | Maximum |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Target allocation |  | 20.00% |  |
United States | Fixed Income Investments | Minimum |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Target allocation |  | 35.00% |  |
United States | Fixed Income Investments | Maximum |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Target allocation |  | 45.00% |  |
United States | Cash And Other Investments | Maximum |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Target allocation |  | 8.00% |  |
United States | Pension Benefits |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Accumulated benefit obligation |  | $ 10,300 | $ 9,700 |
Fair value of plan assets |  | 9,804 | 9,094 | $ 13,067
Expected contributions to the pension plans and other postretirement benefit plans during next fiscal year |  | 260 |  |
United States | Pension Benefits | Level 3 |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Fair value of plan assets |  | 3 | 4 | 6
International | Pension Benefits |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Fair value of plan assets |  | 9,562 | $ 8,473 | $ 12,195
Expected contributions to the pension plans and other postretirement benefit plans during next fiscal year |  | $ 190 |  |
Expected rate of return on plan assets |  | 5.00% | 3.70% | 3.80%
International | Pension Benefits | Level 3 |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Fair value of plan assets |  | $ 785 | $ 761 | $ 937

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