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Summary of Significant Accounting Policies (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2024 | Dec. 31, 2023 | Dec. 31, 2022
Accounting Policies [Abstract] |  |  |
Unbilled Audit Premiums | $ 19 | $ 19 | $ 25
Weighted average shares held in grantor trust | 17,659,297 |  |
Indefinite-lived Intangible Assets [Line Items] |  |  |
Basic weighted average number of shares outstanding (in shares) | 399,734 | 406,500 | 415,278
Deposit contracts, liabilities | $ 29 | $ 31 |
Depreciation | 55 | 51 | $ 52
Interest payments | 138 | 114 | 138
Income taxes paid | 410 | 332 | $ 295
Other Assets |  |  |
Indefinite-lived Intangible Assets [Line Items] |  |  |
Intangible assets, net (excluding goodwill) | $ 97 | $ 119 |

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