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Investments - Analysis of Cost or Amortized Cost, Gross Unrealized Gains and Losses and Fair Value for Investments (Details) - USD ($) $ in Millions | Mar. 31, 2025 | Dec. 31, 2024
--- | --- | ---
Debt Securities, Available-for-sale |  |
Investments, available-for-sale, amortized cost basis | $ 17,109 | $ 17,033
Investments, Available-for-Sale, Accumulated Gross Unrealized Gain Before Tax | 96 | 78
Investments, Available-for-Sale, Accumulated Gross Unrealized Loss Before Tax | 582 | 631
Investments, Available-for-Sale | 16,623 | 16,480
Short-term investments, available-for-sale, amortized cost basis | 100 | 298
Short-term investments, available-for-sale, accumulated gross unrealized gain, before tax | 0 | 0
Short-term investments, available-for-sale, accumulated gross unrealized loss, before tax | 0 | 0
Short-Term Investments | 100 | 298
Total | 17,009 | 16,735
Gross unrealized gain | 96 | 78
Gross unrealized loss | 582 | 631
Fixed maturities, at fair value | 16,523 | 16,182
Corporate |  |
Debt Securities, Available-for-sale |  |
Total | 8,833 | 8,652
Gross unrealized gain | 78 | 61
Gross unrealized loss | 278 | 333
Fixed maturities, at fair value | 8,633 | 8,380
States, municipalities and political subdivisions |  |
Debt Securities, Available-for-sale |  |
Total | 4,973 | 4,976
Gross unrealized gain | 10 | 15
Gross unrealized loss | 291 | 270
Fixed maturities, at fair value | 4,692 | 4,721
Government-sponsored enterprises |  |
Debt Securities, Available-for-sale |  |
Total | 2,310 | 2,282
Gross unrealized gain | 3 | 1
Gross unrealized loss | 3 | 9
Fixed maturities, at fair value | 2,310 | 2,274
Asset-backed |  |
Debt Securities, Available-for-sale |  |
Total | 649 | 567
Gross unrealized gain | 5 | 1
Gross unrealized loss | 9 | 17
Fixed maturities, at fair value | 645 | 551
United States government |  |
Debt Securities, Available-for-sale |  |
Total | 217 | 228
Gross unrealized gain | 0 | 0
Gross unrealized loss | 1 | 2
Fixed maturities, at fair value | 216 | 226
Foreign government |  |
Debt Securities, Available-for-sale |  |
Total | 27 | 30
Gross unrealized gain | 0 | 0
Gross unrealized loss | 0 | 0
Fixed maturities, at fair value | $ 27 | $ 30

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