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Investments and Cash - Fixed Maturity Securities (Details) - USD ($) $ in Millions | Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021 | Dec. 31, 2020
--- | --- | --- | --- | ---
Investments |  |  |  |
Percent of Total | 100.00% | 100.00% |  |
Amortized Cost | $ 6,746 | $ 7,707 |  |
Allowance for Credit Losses | (77) | (65) | $ (42) | $ (78)
Gross Unrealized Gains | 55 | 65 |  |
Gross Unrealized Losses | (417) | (588) |  |
Fixed-maturity securities, available-for-sale, at fair value, net of allowance for credit loss | $ 6,307 | $ 7,119 |  |
Mortgage backed securities consisting of government-agency obligations, percent | 42.00% | 30.00% |  |
Obligations of state and political subdivisions |  |  |  |
Investments |  |  |  |
Percent of Total | 41.00% | 45.00% |  |
Amortized Cost | $ 2,733 | $ 3,509 |  |
Allowance for Credit Losses | (13) | (14) |  |
Gross Unrealized Gains | 33 | 37 |  |
Gross Unrealized Losses | (92) | (138) |  |
Fixed-maturity securities, available-for-sale, at fair value, net of allowance for credit loss | $ 2,661 | $ 3,394 |  |
U.S. government and agencies |  |  |  |
Investments |  |  |  |
Percent of Total | 1.00% | 2.00% |  |
Amortized Cost | $ 65 | $ 118 |  |
Allowance for Credit Losses | 0 | 0 |  |
Gross Unrealized Gains | 1 | 1 |  |
Gross Unrealized Losses | (6) | (8) |  |
Fixed-maturity securities, available-for-sale, at fair value, net of allowance for credit loss | $ 60 | $ 111 |  |
Corporate securities |  |  |  |
Investments |  |  |  |
Percent of Total | 34.00% | 31.00% |  |
Amortized Cost | $ 2,327 | $ 2,387 |  |
Allowance for Credit Losses | (6) | (6) |  |
Gross Unrealized Gains | 17 | 2 |  |
Gross Unrealized Losses | (197) | (299) |  |
Fixed-maturity securities, available-for-sale, at fair value, net of allowance for credit loss | $ 2,141 | $ 2,084 |  |
RMBS |  |  |  |
Investments |  |  |  |
Percent of Total | 6.00% | 5.00% |  |
Amortized Cost | $ 428 | $ 418 |  |
Allowance for Credit Losses | (21) | (19) |  |
Gross Unrealized Gains | 3 | 3 |  |
Gross Unrealized Losses | (68) | (62) |  |
Fixed-maturity securities, available-for-sale, at fair value, net of allowance for credit loss | $ 342 | $ 340 |  |
CMBS |  |  |  |
Investments |  |  |  |
Percent of Total | 2.00% | 4.00% |  |
Amortized Cost | $ 157 | $ 282 |  |
Allowance for Credit Losses | 0 | 0 |  |
Gross Unrealized Gains | 0 | 0 |  |
Gross Unrealized Losses | (6) | (11) |  |
Fixed-maturity securities, available-for-sale, at fair value, net of allowance for credit loss | $ 151 | $ 271 |  |
CLOs |  |  |  |
Investments |  |  |  |
Percent of Total | 7.00% | 6.00% |  |
Amortized Cost | $ 456 | $ 449 |  |
Allowance for Credit Losses | 0 | 0 |  |
Gross Unrealized Gains | 1 | 0 |  |
Gross Unrealized Losses | (7) | (21) |  |
Fixed-maturity securities, available-for-sale, at fair value, net of allowance for credit loss | $ 450 | $ 428 |  |
Others |  |  |  |
Investments |  |  |  |
Percent of Total | 7.00% | 5.00% |  |
Amortized Cost | $ 465 | $ 423 |  |
Allowance for Credit Losses | (37) | (26) |  |
Gross Unrealized Gains | 0 | 22 |  |
Gross Unrealized Losses | (26) | (26) |  |
Fixed-maturity securities, available-for-sale, at fair value, net of allowance for credit loss | $ 402 | $ 393 |  |
Non-U.S. government securities |  |  |  |
Investments |  |  |  |
Percent of Total | 2.00% | 2.00% |  |
Amortized Cost | $ 115 | $ 121 |  |
Allowance for Credit Losses | 0 | 0 |  |
Gross Unrealized Gains | 0 | 0 |  |
Gross Unrealized Losses | (15) | (23) |  |
Fixed-maturity securities, available-for-sale, at fair value, net of allowance for credit loss | $ 100 | $ 98 |  |

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