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Outstanding Exposure - Financial Guaranty Portfolio by Internal Rating (Details) - USD ($) $ in Millions | Sep. 30, 2024 | Dec. 31, 2023
--- | --- | ---
Schedule of Insured Financial Obligations [Line Items] |  |
Net | $ 258,196 | $ 249,153
% of total net par outstanding | 100.00% | 100.00%
AAA |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | $ 3,286 | $ 3,504
% of total net par outstanding | 1.30% | 1.40%
AA |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | $ 26,545 | $ 25,868
% of total net par outstanding | 10.30% | 10.40%
A |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | $ 123,011 | $ 118,123
% of total net par outstanding | 47.60% | 47.40%
BBB |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | $ 94,704 | $ 96,221
% of total net par outstanding | 36.70% | 38.60%
BIG |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | $ 10,650 | $ 5,437
% of total net par outstanding | 4.10% | 2.20%
Public finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | $ 247,920 | $ 239,296
Public finance | United States |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | $ 195,837 | $ 190,289
% of total net par outstanding | 100.00% | 100.00%
Public finance | Non-U.S. public finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | $ 52,083 | $ 49,007
% of total net par outstanding | 100.00% | 100.00%
Public finance | AAA | United States |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | $ 26 | $ 110
% of total net par outstanding | 0.00% | 0.10%
Public finance | AAA | Non-U.S. public finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | $ 2,143 | $ 2,062
% of total net par outstanding | 4.10% | 4.20%
Public finance | AA | United States |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | $ 17,823 | $ 17,883
% of total net par outstanding | 9.10% | 9.40%
Public finance | AA | Non-U.S. public finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | $ 3,010 | $ 3,379
% of total net par outstanding | 5.80% | 6.90%
Public finance | A | United States |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | $ 107,205 | $ 102,945
% of total net par outstanding | 54.70% | 54.10%
Public finance | A | Non-U.S. public finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | $ 13,961 | $ 12,968
% of total net par outstanding | 26.80% | 26.50%
Public finance | BBB | United States |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | $ 67,651 | $ 66,080
% of total net par outstanding | 34.60% | 34.70%
Public finance | BBB | Non-U.S. public finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | $ 26,362 | $ 29,467
% of total net par outstanding | 50.60% | 60.10%
Public finance | BIG |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | $ 9,739 | $ 4,402
Public finance | BIG | United States |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | $ 3,132 | $ 3,271
% of total net par outstanding | 1.60% | 1.70%
Public finance | BIG | Non-U.S. public finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | $ 6,607 | $ 1,131
% of total net par outstanding | 12.70% | 2.30%
Structured finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | $ 10,276 | $ 9,857
Structured finance | United States |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | $ 8,717 | $ 8,632
% of total net par outstanding | 100.00% | 100.00%
Structured finance | Non-U.S. public finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | $ 1,559 | $ 1,225
% of total net par outstanding | 100.00% | 100.00%
Structured finance | AAA | United States |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | $ 657 | $ 867
% of total net par outstanding | 7.50% | 10.00%
Structured finance | AAA | Non-U.S. public finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | $ 460 | $ 465
% of total net par outstanding | 29.50% | 38.00%
Structured finance | AA | United States |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | $ 5,602 | $ 4,517
% of total net par outstanding | 64.30% | 52.30%
Structured finance | AA | Non-U.S. public finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | $ 110 | $ 89
% of total net par outstanding | 7.10% | 7.30%
Structured finance | A | United States |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | $ 945 | $ 1,639
% of total net par outstanding | 10.80% | 19.00%
Structured finance | A | Non-U.S. public finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | $ 900 | $ 571
% of total net par outstanding | 57.70% | 46.60%
Structured finance | BBB | United States |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | $ 602 | $ 574
% of total net par outstanding | 6.90% | 6.70%
Structured finance | BBB | Non-U.S. public finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | $ 89 | $ 100
% of total net par outstanding | 5.70% | 8.10%
Structured finance | BIG |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | $ 911 | $ 1,035
Structured finance | BIG | United States |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | $ 911 | $ 1,035
% of total net par outstanding | 10.50% | 12.00%
Structured finance | BIG | Non-U.S. public finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | $ 0 | $ 0
% of total net par outstanding | 0.00% | 0.00%

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