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Fair Value Measurements - Changes in balances of Level 3 financial assets carried at fair value (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2024 | Dec. 31, 2023 | Dec. 31, 2022
Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward] |  |  |
Financial assets, beginning balance | $ 1,230 | $ 1,102 | $ 926
Total realized/unrealized gains (losses) included in Net earnings | 76 | 7 | 24
Total realized/unrealized gains (losses) included in other comprehensive income (loss) | 9 | 11 | (53)
Purchases and issuances | 368 | 270 | 338
Sales and settlements | (189) | (109) | (117)
Transfer into Level 3 | 9 | 46 | 72
Transfer out of Level 3 | (407) | (97) | (88)
Financial assets, ending balance | $ 1,096 | 1,230 | 1,102
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] | Realized gains (losses) on securities |  |
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Asset, Gain (Loss), Statement of Other Comprehensive Income or Comprehensive Income [Extensible Enumeration] | OCI, Debt Securities, Available-for-Sale, Unrealized Holding Gain (Loss), before Adjustment, after Tax |  |
Fixed maturities |  |  |
Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward] |  |  |
Financial assets, beginning balance | $ 736 | 664 | 600
Total realized/unrealized gains (losses) included in Net earnings | 14 | (4) | 0
Total realized/unrealized gains (losses) included in other comprehensive income (loss) | 14 | 11 | (53)
Purchases and issuances | 164 | 147 | 223
Sales and settlements | (132) | (70) | (93)
Transfer into Level 3 | 9 | 46 | 68
Transfer out of Level 3 | (37) | (58) | (81)
Financial assets, ending balance | 768 | 736 | 664
U.S. government agency |  |  |
Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward] |  |  |
Financial assets, beginning balance | 0 | 0 | 0
Total realized/unrealized gains (losses) included in Net earnings | 0 | 0 | 0
Total realized/unrealized gains (losses) included in other comprehensive income (loss) | 0 | 0 | 0
Purchases and issuances | 0 | 0 | 0
Sales and settlements | 0 | 0 | 0
Transfer into Level 3 | 0 | 0 | 0
Transfer out of Level 3 | 0 | 0 | 0
Financial assets, ending balance | 0 | 0 | 0
State and municipal |  |  |
Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward] |  |  |
Financial assets, beginning balance | 2 | 5 | 41
Total realized/unrealized gains (losses) included in Net earnings | 0 | 0 | 0
Total realized/unrealized gains (losses) included in other comprehensive income (loss) | 0 | 0 | (3)
Purchases and issuances | 0 | 0 | 0
Sales and settlements | (1) | (1) | (1)
Transfer into Level 3 | 0 | 1 | 4
Transfer out of Level 3 | 0 | (3) | (36)
Financial assets, ending balance | 1 | 2 | 5
Residential MBS |  |  |
Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward] |  |  |
Financial assets, beginning balance | 2 | 9 | 14
Total realized/unrealized gains (losses) included in Net earnings | 0 | 1 | 0
Total realized/unrealized gains (losses) included in other comprehensive income (loss) | 0 | (1) | (1)
Purchases and issuances | 0 | 0 | 0
Sales and settlements | 0 | (3) | (1)
Transfer into Level 3 | 0 | 5 | 7
Transfer out of Level 3 | (1) | (9) | (10)
Financial assets, ending balance | 1 | 2 | 9
Commercial MBS |  |  |
Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward] |  |  |
Financial assets, beginning balance | 0 | 0 | 0
Total realized/unrealized gains (losses) included in Net earnings | 0 | 0 | 0
Total realized/unrealized gains (losses) included in other comprehensive income (loss) | 0 | 0 | 0
Purchases and issuances | 0 | 0 | 0
Sales and settlements | 0 | 0 | 0
Transfer into Level 3 | 0 | 0 | 0
Transfer out of Level 3 | 0 | 0 | 0
Financial assets, ending balance | 0 | 0 | 0
Collateralized loan obligations |  |  |
Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward] |  |  |
Financial assets, beginning balance | 1 | 2 | 0
Total realized/unrealized gains (losses) included in Net earnings | (1) | (2) | 0
Total realized/unrealized gains (losses) included in other comprehensive income (loss) | 0 | 1 | 0
Purchases and issuances | 0 | 0 | 0
Sales and settlements | 0 | 0 | 0
Transfer into Level 3 | 0 | 1 | 2
Transfer out of Level 3 | 0 | (1) | 0
Financial assets, ending balance | 0 | 1 | 2
Other asset-backed securities |  |  |
Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward] |  |  |
Financial assets, beginning balance | 351 | 329 | 278
Total realized/unrealized gains (losses) included in Net earnings | (1) | 1 | 1
Total realized/unrealized gains (losses) included in other comprehensive income (loss) | 8 | 6 | (27)
Purchases and issuances | 59 | 55 | 94
Sales and settlements | (100) | (39) | (52)
Transfer into Level 3 | 5 | 31 | 35
Transfer out of Level 3 | (26) | (32) | 0
Financial assets, ending balance | 296 | 351 | 329
Corporate and other |  |  |
Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward] |  |  |
Financial assets, beginning balance | 380 | 319 | 267
Total realized/unrealized gains (losses) included in Net earnings | 16 | (4) | (1)
Total realized/unrealized gains (losses) included in other comprehensive income (loss) | 6 | 5 | (22)
Purchases and issuances | 105 | 92 | 129
Sales and settlements | (31) | (27) | (39)
Transfer into Level 3 | 4 | 8 | 20
Transfer out of Level 3 | (10) | (13) | (35)
Financial assets, ending balance | 470 | 380 | 319
Trading fixed maturities |  |  |
Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward] |  |  |
Financial assets, beginning balance | 0 |  |
Total realized/unrealized gains (losses) included in Net earnings | 2 |  |
Total realized/unrealized gains (losses) included in other comprehensive income (loss) | 0 |  |
Purchases and issuances | 24 |  |
Sales and settlements | 0 |  |
Transfer into Level 3 | 0 |  |
Transfer out of Level 3 | 0 |  |
Financial assets, ending balance | 26 | 0 |
Equity securities |  |  |
Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward] |  |  |
Financial assets, beginning balance | 485 | 427 | 313
Total realized/unrealized gains (losses) included in Net earnings | 60 | 15 | 29
Total realized/unrealized gains (losses) included in other comprehensive income (loss) | 0 | 0 | 0
Purchases and issuances | 174 | 121 | 112
Sales and settlements | (57) | (39) | (24)
Transfer into Level 3 | 0 | 0 | 4
Transfer out of Level 3 | (370) | (39) | (7)
Financial assets, ending balance | 292 | 485 | 427
Assets of MIE |  |  |
Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward] |  |  |
Financial assets, beginning balance | 9 | 11 | 13
Total realized/unrealized gains (losses) included in Net earnings | 0 | (4) | (5)
Total realized/unrealized gains (losses) included in other comprehensive income (loss) | (5) | 0 | 0
Purchases and issuances | 6 | 2 | 3
Sales and settlements | 0 | 0 | 0
Transfer into Level 3 | 0 | 0 | 0
Transfer out of Level 3 | 0 | 0 | 0
Financial assets, ending balance | $ 10 | $ 9 | $ 11

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- Definition Amount of gain (loss) recognized in income from asset measured at fair value on recurring basis using unobservable input (level 3). + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 101 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482078/820-10-55-101 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-3 Reference 3: http://www.xbrl.org/2003/role/exampleRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 102 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482078/820-10-55-102 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (c)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
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- Definition Amount of sale of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 101 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482078/820-10-55-101 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-3 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (c)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
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- Definition Amount of transfer of financial instrument classified as an asset into level 3 of the fair value hierarchy. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 101 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482078/820-10-55-101 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-3 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (c)(3) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
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