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Investments in fixed maturity securities (Detail) - USD ($) $ in Millions | Jun. 30, 2025 | Dec. 31, 2024
--- | --- | ---
Summary of Investment Holdings [Line Items] |  |
Amortized cost of fixed maturity securities | $ 14,776 | $ 15,214
Unrealized gains on fixed maturity securities | 336 | 257
Unrealized losses on fixed maturity securities | (28) | (107)
Fair value of fixed maturity securities | 15,084 | 15,364
U.S. Treasury, U.S. government corporations and agencies [Member] |  |
Summary of Investment Holdings [Line Items] |  |
Amortized cost of fixed maturity securities | 3,845 | 4,447
Unrealized gains on fixed maturity securities | 13 | 16
Unrealized losses on fixed maturity securities | (1) | (4)
Fair value of fixed maturity securities | 3,857 | 4,459
Foreign governments [Member] |  |
Summary of Investment Holdings [Line Items] |  |
Amortized cost of fixed maturity securities | 9,674 | 9,443
Unrealized gains on fixed maturity securities | 86 | 16
Unrealized losses on fixed maturity securities | (24) | (97)
Fair value of fixed maturity securities | 9,736 | 9,362
Corporate and Other [Member] |  |
Summary of Investment Holdings [Line Items] |  |
Amortized cost of fixed maturity securities | 1,257 | 1,324
Unrealized gains on fixed maturity securities | 237 | 225
Unrealized losses on fixed maturity securities | (3) | (6)
Fair value of fixed maturity securities | $ 1,491 | $ 1,543

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- Definition Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(1)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481800/320-10-50-2 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 30 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479130/326-30-45-1 + Details
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