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Pensions And Other Postretirement Benefits - Contributions and Plan Amendments (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Defined Contribution Plan [Abstract] |  |  |
Employer contributions to defined contribution plans | $ 537 | $ 617 | $ 650
Pension Plan |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Years of service | 30 years |  |
Employer contributions | $ 615 | 1,700 | 1,230
Pension Plan | U.S. |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Employer contributions | 83 | 76 | 77
Pension Plan | U.S. | Nonqualified Plan |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Estimated contributions in next fiscal year | $ 70 |  |
Pension Plan | U.S. | Qualified Plan |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Period of time for which there are no mandatory contributions for qualified plans | 5 years |  |
Mandatory contributions over the next five years | $ 0 |  |
Pension Plan | Non-U.S. |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Employer contributions | 532 | 1,624 | 1,153
Estimated contributions in next fiscal year | 500 |  |
Pension Plan | Canada and United Kingdom |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Mandatory contributions over the next five years | 368 |  |
Other Postretirement Benefits Plan |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Employer contributions | 370 | 369 |
Other Postretirement Benefits Plan | U.S. |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Employer contributions | $ 326 | 325 | $ 323
Pension Plan and Other Postretirement Benefits Plan | U.S. |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Remeasurement decrease due to mortality assumptions |  | $ 264 |

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- Definition For U.S. and Canadian hourly employees hired prior to specified dates, represents the required number of years of service, before normal retirement age, to be eligible for supplemental benefits. + References No definition available. + Details
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- Definition Period of time for which there are no significant mandatory funding requirements for the qualified defined benefit plan. + References No definition available. + Details
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- Definition Amount of gain (loss) related to change in benefit obligation resulting from changes in mortality assumptions. + References No definition available. + Details
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