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Employee Benefit Plans (Obligations and Funded Status) (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021
Pension Benefits |  |  |
Change in benefit obligations: |  |  |
Benefit obligations at January 1, | $ 9,298 | $ 12,182 |
Service costs | 143 | 187 | $ 215
Interest costs | 474 | 328 | 342
Plan participants’ contributions | 0 | 0 |
Plan amendments | 0 | 8 |
Net actuarial (gains) losses | 299 | (2,609) |
Acquisition, divestitures, settlements and curtailments | (35) | (45) |
Benefits paid | (636) | (630) |
Effect of foreign currency translation | (45) | (123) |
Benefit obligations at December 31, | 9,498 | 9,298 | 12,182
Change in plan assets |  |  |
Estimated fair value of plan assets at January 1, | 8,294 | 10,971 |
Actual return on plan assets | 529 | (2,095) |
Acquisition, divestitures and settlements | (35) | (38) |
Plan participants’ contributions | 0 | 0 |
Employer contributions | 140 | 152 |
Benefits paid | (636) | (630) |
Effect of foreign currency translation | (22) | (66) |
Estimated fair value of plan assets at December 31, | 8,270 | 8,294 | 10,971
Over (under) funded status at December 31, | (1,228) | (1,004) |
Amounts recognized in the consolidated balance sheets |  |  |
Other assets | 229 | 428 |
Other liabilities | (1,457) | (1,432) |
Net amount recognized | (1,228) | (1,004) |
Accumulated other comprehensive (income) loss: |  |  |
Net actuarial (gains) losses | 2,360 | 2,277 |
Prior service costs (credit) | (25) | (36) |
AOCI, before income tax | 2,335 | 2,241 |
Accumulated benefit obligation | 9,377 | 9,185 |
Other Postretirement Benefits |  |  |
Change in benefit obligations: |  |  |
Benefit obligations at January 1, | 794 | 1,138 |
Service costs | 3 | 4 | 4
Interest costs | 43 | 34 | 37
Plan participants’ contributions | 30 | 32 |
Plan amendments | 0 | 0 |
Net actuarial (gains) losses | (23) | (289) |
Acquisition, divestitures, settlements and curtailments | 0 | 0 |
Benefits paid | (86) | (125) |
Effect of foreign currency translation | 4 | 0 |
Benefit obligations at December 31, | 765 | 794 | 1,138
Change in plan assets |  |  |
Estimated fair value of plan assets at January 1, | 1,303 | 1,443 |
Actual return on plan assets | 72 | (43) |
Acquisition, divestitures and settlements | 0 | 0 |
Plan participants’ contributions | 30 | 32 |
Employer contributions | 13 | (3) |
Benefits paid | (86) | (125) |
Effect of foreign currency translation | 2 | (1) |
Estimated fair value of plan assets at December 31, | 1,334 | 1,303 | $ 1,443
Over (under) funded status at December 31, | 569 | 509 |
Amounts recognized in the consolidated balance sheets |  |  |
Other assets | 886 | 796 |
Other liabilities | (317) | (287) |
Net amount recognized | 569 | 509 |
Accumulated other comprehensive (income) loss: |  |  |
Net actuarial (gains) losses | (509) | (498) |
Prior service costs (credit) | 0 | 0 |
AOCI, before income tax | (509) | (498) |
United States Pension Plan of US Entity, Non Qualified [Member] |  |  |
Change in benefit obligations: |  |  |
Benefit obligations at January 1, | 1,000 |  |
Benefit obligations at December 31, | 1,000 | 1,000 |
Changes to financial assumptions [Member] | Pension Benefits |  |  |
Change in benefit obligations: |  |  |
Net actuarial (gains) losses | (256) | 2,600 |
Changes to financial assumptions [Member] | Other Postretirement Benefits |  |  |
Change in benefit obligations: |  |  |
Net actuarial (gains) losses | (8) | 276 |
Changes to demographic assumptions [Member] | Pension Benefits |  |  |
Change in benefit obligations: |  |  |
Net actuarial (gains) losses | 54 |  |
Changes to demographic assumptions [Member] | Other Postretirement Benefits |  |  |
Change in benefit obligations: |  |  |
Net actuarial (gains) losses | 8 |  |
Changes to Plan Experience [Member] | Pension Benefits |  |  |
Change in benefit obligations: |  |  |
Net actuarial (gains) losses | (97) | (14) |
Changes to Plan Experience [Member] | Other Postretirement Benefits |  |  |
Change in benefit obligations: |  |  |
Net actuarial (gains) losses | $ 23 | $ 13 |

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