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Benefit Plans and Other Postretirement Benefits, Postretirement Health Care Benefits (Details) $ in Millions | 12 Months Ended |
--- | --- | ---
Dec. 31, 2023 USD ($) | Dec. 31, 2022 USD ($)
Postretirement Health Care Benefits [Abstract] |  |
Estimated costs of health plan subsidies - VRP | $ 34 |
Estimated cost of other medical benefits - VRP |  | $ 5
Other Postretirement Benefits Plan [Member] |  |
Postretirement Health Care Benefits [Abstract] |  |
Target pension asset allocations (as a percent) | 100.00% | 100.00%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate, VRP | 0.0550 |
Defined Benefit Plan, Health Care Cost Trend Rate Assumed and Ultimate Trend Assumption, VRP | 0.0700 |
Pension Plan [Member] |  |
Postretirement Health Care Benefits [Abstract] |  |
Target pension asset allocations (as a percent) | 100.00% | 100.00%
Equity Securities | Other Postretirement Benefits Plan [Member] |  |
Postretirement Health Care Benefits [Abstract] |  |
Target pension asset allocations (as a percent) | 9.00% | 16.00%
Equity Securities | Pension Plan [Member] |  |
Postretirement Health Care Benefits [Abstract] |  |
Target pension asset allocations (as a percent) | 31.00% | 33.00%
Long-duration fixed income and interest rate swap securities | Other Postretirement Benefits Plan [Member] |  |
Postretirement Health Care Benefits [Abstract] |  |
Target pension asset allocations (as a percent) | 0.00% | 0.00%
Long-duration fixed income and interest rate swap securities | Pension Plan [Member] |  |
Postretirement Health Care Benefits [Abstract] |  |
Target pension asset allocations (as a percent) | 38.00% | 38.00%
Short-to-intermediate fixed income securities | Other Postretirement Benefits Plan [Member] |  |
Postretirement Health Care Benefits [Abstract] |  |
Target pension asset allocations (as a percent) | 77.00% | 71.00%
Short-to-intermediate fixed income securities | Pension Plan [Member] |  |
Postretirement Health Care Benefits [Abstract] |  |
Target pension asset allocations (as a percent) | 9.00% | 9.00%
Alternative investments | Other Postretirement Benefits Plan [Member] |  |
Postretirement Health Care Benefits [Abstract] |  |
Target pension asset allocations (as a percent) | 13.00% | 12.00%
Alternative investments | Pension Plan [Member] |  |
Postretirement Health Care Benefits [Abstract] |  |
Target pension asset allocations (as a percent) | 20.00% | 18.00%
Cash | Other Postretirement Benefits Plan [Member] |  |
Postretirement Health Care Benefits [Abstract] |  |
Target pension asset allocations (as a percent) | 1.00% | 1.00%
Cash | Pension Plan [Member] |  |
Postretirement Health Care Benefits [Abstract] |  |
Target pension asset allocations (as a percent) | 2.00% | 2.00%

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- Definition Percentage of target investment allocation to total plan assets. Includes, but is not limited to, percentage on weighted-average basis if more than one plan. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 17 -Publisher FASB -URI https://asc.fasb.org//1943274/2147480482/715-20-55-17 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d)(i) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 + Details
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- Definition Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate, VRP + References No definition available. + Details
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- Definition Defined Benefit Plan, Health Care Cost Trend Rate Assumed and Ultimate Trend Assumption, VRP + References No definition available. + Details
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