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Investments - Allowance for credit losses on fixed maturities (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2025 | Sep. 30, 2024 | Sep. 30, 2025 | Sep. 30, 2024
Allowance for Credit Losses [Roll Forward] |  |  |  |
Beginning balance | $ 15 | $ 10 | $ 34 | $ 12
Provision for expected credit losses on securities with no previous allowance | 0 | 15 | 3 | 16
Additions to previously recognized expected credit losses | 1 | 0 | 5 | 1
Reductions due to sales or redemptions | 0 | 0 | (26) | (4)
Ending balance | 16 | 25 | 16 | 25
Structured securities |  |  |  |
Allowance for Credit Losses [Roll Forward] |  |  |  |
Beginning balance | 10 | 10 | 11 | 9
Provision for expected credit losses on securities with no previous allowance | 0 | 0 | 0 | 1
Additions to previously recognized expected credit losses | 1 | 0 | 0 | 1
Reductions due to sales or redemptions | 0 | 0 | 0 | (1)
Ending balance | 11 | 10 | 11 | 10
Corporate and other |  |  |  |
Allowance for Credit Losses [Roll Forward] |  |  |  |
Beginning balance | 5 | 0 | 23 | 3
Provision for expected credit losses on securities with no previous allowance | 0 | 15 | 3 | 15
Additions to previously recognized expected credit losses | 0 | 0 | 5 | 0
Reductions due to sales or redemptions | 0 | 0 | (26) | (3)
Ending balance | $ 5 | $ 15 | $ 5 | $ 15

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- Definition Amount of allowance for credit loss on 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 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (aaa) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481800/320-10-50-2 Reference 2: 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 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 9 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479106/326-30-50-9 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 9 -Subparagraph (i) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479106/326-30-50-9 + Details
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- Definition Amount of expense for credit loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), for which no credit loss was previously recorded. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 9 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479106/326-30-50-9 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 220 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 22 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147476148/220-40-50-22 + Details
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- Definition Amount of expense (reversal of expense) for allowance for credit loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), not intended to be sold and not more likely than not will be required to sell before recovery of amortized cost basis, with previously recorded allowance. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 9 -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479106/326-30-50-9 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 220 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 22 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147476148/220-40-50-22 + Details
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- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. + References No definition available. + Details
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- Definition Amount of decrease in allowance for credit loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale) from sale. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 9 -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479106/326-30-50-9 + Details
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