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Schedule IV - Reinsurance (Details) - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2025 | Dec. 31, 2024 | Dec. 31, 2023
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items] |  |  |  |
Gross Amount |  | $ 10,250 | $ 10,056 | $ 9,652
Ceded to other Companies |  | (6,402) | (5,779) | (4,935)
Assumed From Other Companies |  | 12,628 | 11,455 | 8,751
Net Amount |  | $ 16,476 | $ 15,732 | $ 13,468
Percentage of Amount Assumed to Net |  | 76.60% | 72.80% | 65.00%
Operating segments | Insurance |  |  |  |
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items] |  |  |  |
Gross Amount |  | $ 8,268 | $ 7,970 | $ 7,865
Ceded to other Companies | [1],[2] | (2,637) | (2,179) | (2,049)
Assumed From Other Companies | [1] | 2,167 | 1,083 | 46
Net Amount |  | $ 7,798 | $ 6,874 | $ 5,862
Percentage of Amount Assumed to Net |  | 27.80% | 15.80% | 0.80%
Operating segments | Reinsurance |  |  |  |
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items] |  |  |  |
Gross Amount |  | $ 895 | $ 956 | $ 626
Ceded to other Companies | [1],[2] | (3,531) | (3,366) | (2,559)
Assumed From Other Companies | [1] | 10,254 | 10,156 | 8,487
Net Amount |  | $ 7,618 | $ 7,746 | $ 6,554
Percentage of Amount Assumed to Net |  | 134.60% | 131.10% | 129.50%
Operating segments | Mortgage |  |  |  |
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items] |  |  |  |
Gross Amount |  | $ 1,087 | $ 1,130 | $ 1,161
Ceded to other Companies | [1],[2] | (245) | (239) | (335)
Assumed From Other Companies | [1] | 218 | 221 | 226
Net Amount |  | $ 1,060 | $ 1,112 | $ 1,052
Percentage of Amount Assumed to Net |  | 20.60% | 19.90% | 21.50%
[1] | Certain amounts included in the gross premiums written of each segment are related to intersegment transactions and are included in the gross premiums written of each segment. Accordingly, the sum of gross premiums written for each segment does not agree to the total gross premiums written as shown in the table above due to the elimination of intersegment transactions in the total.
[2] | Certain assumed and ceded amounts related to intersegment transactions are included in individual segment results. Accordingly, the sum of such transactions for each segment does not agree to the total due to eliminations.

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