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Pension Plans and Postretirement Benefits - Plan Asset Allocations by Asset Category (Detail) | Dec. 31, 2023 | Dec. 31, 2022
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United States: | Pension Plan |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Total | 100.00% | 100.00%
United States: | Pension Plan | U.S. Government Securities |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Total | 34.00% | 36.00%
United States: | Pension Plan | Commingled and Mutual Funds |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Total | 25.00% | 25.00%
United States: | Pension Plan | Real Estate |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Total | 15.00% | 16.00%
United States: | Pension Plan | Diversified Credit |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Total | 13.00% | 13.00%
United States: | Pension Plan | Fixed Income (excluding U.S. Government Securities) |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Total | 6.00% | 5.00%
United States: | Pension Plan | Partnerships with Security Holdings |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Total | 2.00% | 3.00%
United States: | Pension Plan | Other |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Total | 5.00% | 2.00%
Canada | Other Benefits |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Total | 100.00% | 100.00%
Canada | Other Benefits | Fixed Income |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Total | 61.00% | 51.00%
Canada | Other Benefits | Equity Securities and Commingled Mutual Funds |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Total | 35.00% | 29.00%
Canada | Other Benefits | Other |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Total | 4.00% | 20.00%

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- Definition Percentage of actual 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/2009/role/commonPracticeRef -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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