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Contracts Accounted for as Insurance - Effect of Reinsurance on Premiums Written, Premiums Earned and Loss and LAE (Benefit) (Details) - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021
Premiums Written: |  |  |
Direct | $ 307 | $ 377 | $ 355
Assumed | 50 | (17) | 22
Ceded | (16) | 0 | 0
Net | 341 | 360 | 377
Premiums Earned: |  |  |
Direct | 319 | 469 | 385
Assumed | 28 | 28 | 32
Ceded | (3) | (3) | (3)
Net earned premiums | 344 | 494 | 414
Loss and LAE (benefit): |  |  |
Direct | 157 | 32 | (203)
Assumed | 8 | (17) | 5
Ceded | (3) | 1 | (22)
Loss and LAE (benefit) | $ 162 | $ 16 | $ (220)

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