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v3.23.3

Reserves for Loss and Loss Expenses (Narrative) (Details) - USD ($) | 3 Months Ended | 9 Months Ended
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Sep. 30, 2023 | Jun. 30, 2023 | Mar. 31, 2023 | Sep. 30, 2023 | Sep. 30, 2022
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |
Net of loss reserves discount | $ 35,000,000 |  |  | $ 35,000,000 | $ 26,000,000
Increase (decrease) in estimates for claims |  |  |  | 12,000,000 | (20,000,000)
Adjustment expense |  |  |  | 20,000,000 | 37,000,000
Liability recognized for best estimate net of reinsurance | 354,000,000 |  |  | 354,000,000 |
Liability recognized for best estimate net of reinsurance, current accident year losses |  |  |  | 670,000 |
Unfavorable reserve development net of premium offsets |  |  | $ 24,000,000 |  |
Favorable reserve development net of premium offsets | 4,000,000 | $ 4,000,000 |  |  |
Insurance |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |
Liability recognized for best estimate net of reinsurance | 299,000,000 |  |  | 299,000,000 |
Unfavorable reserve development net of premium offsets |  |  |  | 26,000,000 | 33,000,000
Reinsurance & Monoline Excess |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |
Liability recognized for best estimate net of reinsurance | $ 55,000,000 |  |  | 55,000,000 |
Unfavorable reserve development net of premium offsets |  |  |  |  | $ 4,000,000
Favorable reserve development net of premium offsets |  |  |  | $ 6,000,000 |

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- Definition Amount, after effects of reinsurance, of expense (reversal of expense) for claims incurred in prior reporting periods and related claims settlement costs. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480081/944-40-50-3 + Details
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