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Outstanding Exposure - Financial Guaranty Portfolio by Internal Rating (Details) - USD ($) $ in Millions | Dec. 31, 2024 | Dec. 31, 2023
--- | --- | ---
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | $ 261,552 | $ 249,153
% of total net par outstanding | 100.00% | 100.00%
AAA |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | $ 3,081 | $ 3,504
% of total net par outstanding | 1.20% | 1.40%
AA |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | $ 25,962 | $ 25,868
% of total net par outstanding | 9.90% | 10.40%
A |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | $ 127,617 | $ 118,123
% of total net par outstanding | 48.80% | 47.40%
BBB |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | $ 94,710 | $ 96,221
% of total net par outstanding | 36.20% | 38.60%
BIG |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | $ 10,182 | $ 5,437
% of total net par outstanding | 3.90% | 2.20%
U.S. |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | $ 209,628 |
Non U.S. |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | 51,924 |
Public finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | 250,375 | $ 239,296
Public finance | BIG |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | 9,286 | 4,402
Public finance | U.S. |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | $ 201,175 | $ 190,289
% of total net par outstanding | 100.00% | 100.00%
Public finance | U.S. | AAA |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | $ 25 | $ 110
% of total net par outstanding | 0.00% | 0.10%
Public finance | U.S. | AA |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | $ 17,664 | $ 17,883
% of total net par outstanding | 8.80% | 9.40%
Public finance | U.S. | A |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | $ 111,502 | $ 102,945
% of total net par outstanding | 55.50% | 54.10%
Public finance | U.S. | BBB |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | $ 69,096 | $ 66,080
% of total net par outstanding | 34.30% | 34.70%
Public finance | U.S. | BIG |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | $ 2,888 | $ 3,271
% of total net par outstanding | 1.40% | 1.70%
Public finance | Non U.S. |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | $ 49,200 | $ 49,007
% of total net par outstanding | 100.00% | 100.00%
Public finance | Non U.S. | AAA |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | $ 2,074 | $ 2,062
% of total net par outstanding | 4.20% | 4.20%
Public finance | Non U.S. | AA |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | $ 2,854 | $ 3,379
% of total net par outstanding | 5.80% | 6.90%
Public finance | Non U.S. | A |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | $ 13,046 | $ 12,968
% of total net par outstanding | 26.50% | 26.50%
Public finance | Non U.S. | BBB |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | $ 24,828 | $ 29,467
% of total net par outstanding | 50.50% | 60.10%
Public finance | Non U.S. | BIG |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | $ 6,398 | $ 1,131
% of total net par outstanding | 13.00% | 2.30%
Structured finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | $ 11,177 | $ 9,857
Structured finance | BIG |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | 896 | 1,035
Structured finance | U.S. |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | $ 8,453 | $ 8,632
% of total net par outstanding | 100.00% | 100.00%
Structured finance | U.S. | AAA |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | $ 512 | $ 867
% of total net par outstanding | 6.10% | 10.00%
Structured finance | U.S. | AA |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | $ 5,386 | $ 4,517
% of total net par outstanding | 63.70% | 52.30%
Structured finance | U.S. | A |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | $ 952 | $ 1,639
% of total net par outstanding | 11.30% | 19.00%
Structured finance | U.S. | BBB |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | $ 707 | $ 574
% of total net par outstanding | 8.30% | 6.70%
Structured finance | U.S. | BIG |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | $ 896 | $ 1,035
% of total net par outstanding | 10.60% | 12.00%
Structured finance | Non U.S. |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | $ 2,724 | $ 1,225
% of total net par outstanding | 100.00% | 100.00%
Structured finance | Non U.S. | AAA |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | $ 470 | $ 465
% of total net par outstanding | 17.30% | 38.00%
Structured finance | Non U.S. | AA |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | $ 58 | $ 89
% of total net par outstanding | 2.10% | 7.30%
Structured finance | Non U.S. | A |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | $ 2,117 | $ 571
% of total net par outstanding | 77.70% | 46.60%
Structured finance | Non U.S. | BBB |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | $ 79 | $ 100
% of total net par outstanding | 2.90% | 8.10%
Structured finance | Non U.S. | BIG |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | $ 0 | $ 0
% of total net par outstanding | 0.00% | 0.00%

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