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Pension and Other Postretirement Benefits - Narrative (Details) - USD ($) $ in Millions | 1 Months Ended | 3 Months Ended | 9 Months Ended
--- | --- | --- | ---
Jun. 30, 2023 | Sep. 30, 2023 | Sep. 30, 2022 | Sep. 30, 2023 | Sep. 30, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Decrease in obligation, pension benefits | $ 19 |  |  |  |
Pension plan settlements |  | $ (2) | $ (3) | $ (5) | $ (7)
Contributions and payments |  | 9 | 18 | 28 | 43
Pension benefits |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Benefit obligation |  | 2 |  | 5 |
Pension plan settlements |  | (2) | (3) | (5) | (7)
Pension benefits | US |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Pension plan settlements |  |  |  |  | (7)
Pension benefits | Canada |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Decrease in obligation, pension benefits |  | 12 |  | $ 12 |
Pension plan settlements |  | $ (2) |  |  |
Pension benefits | United States and Canada |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Pension plan settlements |  |  | $ (3) |  | $ (7)

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- Definition Amount of gain (loss) recognized in net periodic benefit (cost) credit from irrevocable action relieving primary responsibility for benefit obligation and eliminating risk related to obligation and assets used to effect settlement. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 3A -Publisher FASB -URI https://asc.fasb.org//1943274/2147480535/715-20-45-3A Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (h)(7) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a)(7) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-6 + Details
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- Definition Amount of (increase) decrease to benefit obligation of defined benefit plan from irrevocable action relieving primary responsibility for benefit obligation and eliminating risk for obligation and assets used to effect settlement. Includes, but is not limited to, lump-sum cash payment to participant in exchange for right to receive specified benefits, purchase of nonparticipating annuity contract and change from remeasurement. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (a)(10) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 + Details
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