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Fair Value (Assets and liabilities measured at fair value on a recurring basis) (Details) - USD ($) $ in Millions | Mar. 31, 2024 | Dec. 31, 2023
--- | --- | ---
Fixed maturity securities: |  |
Fixed maturity securities | $ 40,605 | $ 40,425
Equity securities: |  |
Equity securities | 691 | 683
Short term and other | 1,820 | 2,008
Total assets | 43,116 | 43,116
Other liabilities | 0 | 1
Total liabilities | 0 | 1
Corporate and other bonds |  |
Fixed maturity securities: |  |
Fixed maturity securities | 25,237 | 25,132
States, municipalities and political subdivisions |  |
Fixed maturity securities: |  |
Fixed maturity securities | 7,288 | 7,392
Asset-backed |  |
Fixed maturity securities: |  |
Fixed maturity securities | 8,080 | 7,901
Common Stock |  |
Equity securities: |  |
Equity securities | 206 | 191
Non-redeemable preferred stock |  |
Equity securities: |  |
Equity securities | 485 | 492
Level 1 |  |
Fixed maturity securities: |  |
Fixed maturity securities | 189 | 161
Equity securities: |  |
Equity securities | 241 | 219
Short term and other | 1,801 | 1,976
Total assets | 2,231 | 2,356
Other liabilities | 0 | 0
Total liabilities | 0 | 0
Level 1 | Corporate and other bonds |  |
Fixed maturity securities: |  |
Fixed maturity securities | 189 | 161
Level 1 | States, municipalities and political subdivisions |  |
Fixed maturity securities: |  |
Fixed maturity securities | 0 | 0
Level 1 | Asset-backed |  |
Fixed maturity securities: |  |
Fixed maturity securities | 0 | 0
Level 1 | Common Stock |  |
Equity securities: |  |
Equity securities | 195 | 167
Level 1 | Non-redeemable preferred stock |  |
Equity securities: |  |
Equity securities | 46 | 52
Level 2 |  |
Fixed maturity securities: |  |
Fixed maturity securities | 38,420 | 38,274
Equity securities: |  |
Equity securities | 439 | 440
Short term and other | 19 | 32
Total assets | 38,878 | 38,746
Other liabilities | 0 | 1
Total liabilities | 0 | 1
Level 2 | Corporate and other bonds |  |
Fixed maturity securities: |  |
Fixed maturity securities | 23,966 | 23,926
Level 2 | States, municipalities and political subdivisions |  |
Fixed maturity securities: |  |
Fixed maturity securities | 7,245 | 7,348
Level 2 | Asset-backed |  |
Fixed maturity securities: |  |
Fixed maturity securities | 7,209 | 7,000
Level 2 | Common Stock |  |
Equity securities: |  |
Equity securities | 0 | 0
Level 2 | Non-redeemable preferred stock |  |
Equity securities: |  |
Equity securities | 439 | 440
Level 3 |  |
Fixed maturity securities: |  |
Fixed maturity securities | 1,996 | 1,990
Equity securities: |  |
Equity securities | 11 | 24
Short term and other | 0 | 0
Total assets | 2,007 | 2,014
Other liabilities | 0 | 0
Total liabilities | 0 | 0
Level 3 | Corporate and other bonds |  |
Fixed maturity securities: |  |
Fixed maturity securities | 1,082 | 1,045
Level 3 | States, municipalities and political subdivisions |  |
Fixed maturity securities: |  |
Fixed maturity securities | 43 | 44
Level 3 | Asset-backed |  |
Fixed maturity securities: |  |
Fixed maturity securities | 871 | 901
Level 3 | Common Stock |  |
Equity securities: |  |
Equity securities | 11 | 24
Level 3 | Non-redeemable preferred stock |  |
Equity securities: |  |
Equity securities | $ 0 | $ 0

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