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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 | Sep. 30, 2025 | Dec. 31, 2024
--- | --- | ---
Debt Securities, Available-for-sale |  |
Investments, available-for-sale, amortized cost basis | $ 17,996 | $ 17,033
Investments, Available-for-Sale, Accumulated Gross Unrealized Gain Before Tax | 212 | 78
Investments, Available-for-Sale, Accumulated Gross Unrealized Loss Before Tax | 429 | 631
Investments, Available-for-Sale | 17,779 | 16,480
Short-term investments, available-for-sale, amortized cost basis | 149 | 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 | 149 | 298
Total | 17,847 | 16,735
Gross unrealized gain | 212 | 78
Gross unrealized loss | 429 | 631
Fixed maturities, at fair value | 17,630 | 16,182
Corporate |  |
Debt Securities, Available-for-sale |  |
Total | 9,385 | 8,652
Gross unrealized gain | 171 | 61
Gross unrealized loss | 193 | 333
Fixed maturities, at fair value | 9,363 | 8,380
States, municipalities and political subdivisions |  |
Debt Securities, Available-for-sale |  |
Total | 5,043 | 4,976
Gross unrealized gain | 24 | 15
Gross unrealized loss | 221 | 270
Fixed maturities, at fair value | 4,846 | 4,721
Government-sponsored enterprises |  |
Debt Securities, Available-for-sale |  |
Total | 2,348 | 2,282
Gross unrealized gain | 3 | 1
Gross unrealized loss | 5 | 9
Fixed maturities, at fair value | 2,346 | 2,274
Asset-backed |  |
Debt Securities, Available-for-sale |  |
Total | 776 | 567
Gross unrealized gain | 11 | 1
Gross unrealized loss | 9 | 17
Fixed maturities, at fair value | 778 | 551
United States government |  |
Debt Securities, Available-for-sale |  |
Total | 272 | 228
Gross unrealized gain | 3 | 0
Gross unrealized loss | 1 | 2
Fixed maturities, at fair value | 274 | 226
Foreign government |  |
Debt Securities, Available-for-sale |  |
Total | 23 | 30
Gross unrealized gain | 0 | 0
Gross unrealized loss | 0 | 0
Fixed maturities, at fair value | $ 23 | $ 30

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