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Outstanding Exposure - Geographic Distribution of Net Par Outstanding (Details) $ in Millions | Dec. 31, 2023 USD ($) risk | Aug. 31, 2023 USD ($) | Dec. 31, 2022 USD ($)
--- | --- | --- | ---
Schedule of Insured Financial Obligations [Line Items] |  |  |
Number of Risks | risk | 7,754 |  |
Total net par outstanding | $ 249,153 | $ 108 | $ 233,258
Percent of Total Net Par Outstanding | 100.00% |  |
U.S. |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Number of Risks | risk | 7,415 |  |
Total net par outstanding | $ 198,921 |  |
Percent of Total Net Par Outstanding | 79.80% |  |
Non U.S. |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Number of Risks | risk | 339 |  |
Total net par outstanding | $ 50,232 |  |
Percent of Total Net Par Outstanding | 20.20% |  |
U.K. |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Number of Risks | risk | 271 |  |
Total net par outstanding | $ 39,394 |  |
Percent of Total Net Par Outstanding | 15.80% |  |
Canada |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Number of Risks | risk | 5 |  |
Total net par outstanding | $ 1,696 |  |
Percent of Total Net Par Outstanding | 0.70% |  |
Spain |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Number of Risks | risk | 9 |  |
Total net par outstanding | $ 1,649 |  |
Percent of Total Net Par Outstanding | 0.70% |  |
France |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Number of Risks | risk | 7 |  |
Total net par outstanding | $ 1,565 |  |
Percent of Total Net Par Outstanding | 0.60% |  |
Australia |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Number of Risks | risk | 6 |  |
Total net par outstanding | $ 1,518 |  |
Percent of Total Net Par Outstanding | 0.60% |  |
Other |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Number of Risks | risk | 41 |  |
Total net par outstanding | $ 4,410 |  |
Percent of Total Net Par Outstanding | 1.80% |  |
Public finance |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Total net par outstanding | $ 239,296 |  | 224,099
Public finance | U.S. |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Number of Risks | risk | 7,056 |  |
Total net par outstanding | $ 190,289 |  | 179,636
Percent of Total Net Par Outstanding | 76.30% |  |
Public finance | California |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Number of Risks | risk | 1,213 |  |
Total net par outstanding | $ 36,200 |  |
Percent of Total Net Par Outstanding | 14.50% |  |
Public finance | Texas |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Number of Risks | risk | 1,077 |  |
Total net par outstanding | $ 22,783 |  |
Percent of Total Net Par Outstanding | 9.10% |  |
Public finance | New York |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Number of Risks | risk | 774 |  |
Total net par outstanding | $ 17,751 |  |
Percent of Total Net Par Outstanding | 7.10% |  |
Public finance | Pennsylvania |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Number of Risks | risk | 534 |  |
Total net par outstanding | $ 16,941 |  |
Percent of Total Net Par Outstanding | 6.80% |  |
Public finance | Illinois |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Number of Risks | risk | 485 |  |
Total net par outstanding | $ 12,953 |  |
Percent of Total Net Par Outstanding | 5.20% |  |
Public finance | New Jersey |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Number of Risks | risk | 256 |  |
Total net par outstanding | $ 9,255 |  |
Percent of Total Net Par Outstanding | 3.70% |  |
Public finance | Florida |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Number of Risks | risk | 214 |  |
Total net par outstanding | $ 8,586 |  |
Percent of Total Net Par Outstanding | 3.50% |  |
Public finance | Michigan |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Number of Risks | risk | 231 |  |
Total net par outstanding | $ 5,533 |  |
Percent of Total Net Par Outstanding | 2.20% |  |
Public finance | Louisiana |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Number of Risks | risk | 132 |  |
Total net par outstanding | $ 4,758 |  |
Percent of Total Net Par Outstanding | 1.90% |  |
Public finance | Alabama |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Number of Risks | risk | 243 |  |
Total net par outstanding | $ 3,819 |  |
Percent of Total Net Par Outstanding | 1.50% |  |
Public finance | Other |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Number of Risks | risk | 1,897 |  |
Total net par outstanding | $ 51,710 |  |
Percent of Total Net Par Outstanding | 20.80% |  |
Public finance | Non U.S. |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Total net par outstanding | $ 49,007 |  | 44,463
Structured finance |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Total net par outstanding | $ 9,857 |  | 9,159
Structured finance | U.S. |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Number of Risks | risk | 359 |  |
Total net par outstanding | $ 8,632 |  | 8,228
Percent of Total Net Par Outstanding | 3.50% |  |
Structured finance | Non U.S. |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Total net par outstanding | $ 1,225 |  | $ 931

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