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Pension Plans and Other Postretirement Benefits - Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income (Detail) - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2024 | Dec. 31, 2023
Defined Benefit Plan Disclosure [Line Items] |  |
Net gain | $ (305) | $ (125)
Amortization of prior service credit | 2 | 2
Amortization of actuarial gain | 5 | 5
Settlement gain | 12 |
Total recognized in other comprehensive income, pre-tax | (286) | (118)
Pension Plans |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Net gain | (298) | (120)
Amortization of prior service credit | 0 | 0
Amortization of actuarial gain | 2 | 2
Settlement gain | 12 |
Total recognized in other comprehensive income, pre-tax | (284) | (118)
Other Postretirement Benefit Plans |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Net gain | (7) | (5)
Amortization of prior service credit | 2 | 2
Amortization of actuarial gain | 3 | 3
Settlement gain | 0 |
Total recognized in other comprehensive income, pre-tax | $ (2) | $ 0

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- Definition Other Comprehensive Income (Loss), Defined Benefit Plan, Settlement, Reclassification Adjustment from AOCI, Before Tax + References No definition available. + Details
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- Definition Amount, before tax, after reclassification adjustment, of increase (decrease) in accumulated other comprehensive income from gain (loss) of defined benefit plan. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 220 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 11 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482790/220-10-45-11 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (i) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 220 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 10A -Subparagraph (i) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482790/220-10-45-10A + Details
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