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Outstanding Exposure - Components of BIG Net Par Outstanding (Details) - USD ($) $ in Millions | Dec. 31, 2023 | Aug. 31, 2023 | Dec. 31, 2022
--- | --- | --- | ---
Schedule of Insured Financial Obligations [Line Items] |  |  |
Net Par Outstanding | $ 249,153 | $ 108 | $ 233,258
Public finance |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Net Par Outstanding | 239,296 |  | 224,099
Other structured finance |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Net Par Outstanding | 8,083 |  | 7,203
Structured finance |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Net Par Outstanding | 9,857 |  | 9,159
U.S. |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Net Par Outstanding | 198,921 |  |
U.S. | Public finance |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Net Par Outstanding | 190,289 |  | 179,636
U.S. | RMBS |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Net Par Outstanding | 1,774 |  | 1,956
U.S. | Structured finance |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Net Par Outstanding | 8,632 |  | 8,228
Non U.S. |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Net Par Outstanding | 50,232 |  |
Non U.S. | Public finance |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Net Par Outstanding | 49,007 |  | 44,463
Non U.S. | Structured finance |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Net Par Outstanding | 1,225 |  | 931
BIG |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Net Par Outstanding | 5,437 |  | 5,892
BIG | Public finance |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Net Par Outstanding | 4,402 |  | 4,777
BIG | Other structured finance |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Net Par Outstanding | 94 |  | 105
BIG | Structured finance |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Net Par Outstanding | 1,035 |  | 1,115
BIG | U.S. | Public finance |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Net Par Outstanding | 3,271 |  | 3,796
BIG | U.S. | RMBS |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Net Par Outstanding | 941 |  | 1,010
BIG | U.S. | Structured finance |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Net Par Outstanding | 1,035 |  | 1,115
BIG | Non U.S. | Public finance |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Net Par Outstanding | 1,131 |  | 981
BIG | Non U.S. | Structured finance |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Net Par Outstanding | 0 |  | 0
BIG | BIG 1 |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Net Par Outstanding | 2,410 |  | 3,363
BIG | BIG 1 | Public finance |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Net Par Outstanding | 2,388 |  | 3,345
BIG | BIG 1 | Other structured finance |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Net Par Outstanding | 0 |  | 0
BIG | BIG 1 | Structured finance |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Net Par Outstanding | 22 |  | 18
BIG | BIG 1 | U.S. | Public finance |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Net Par Outstanding | 1,257 |  | 2,364
BIG | BIG 1 | U.S. | RMBS |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Net Par Outstanding | 22 |  | 18
BIG | BIG 1 | Non U.S. | Public finance |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Net Par Outstanding | 1,131 |  | 981
BIG | BIG 2 |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Net Par Outstanding | 989 |  | 181
BIG | BIG 2 | Public finance |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Net Par Outstanding | 926 |  | 108
BIG | BIG 2 | Other structured finance |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Net Par Outstanding | 27 |  | 34
BIG | BIG 2 | Structured finance |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Net Par Outstanding | 63 |  | 73
BIG | BIG 2 | U.S. | Public finance |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Net Par Outstanding | 926 |  | 108
BIG | BIG 2 | U.S. | RMBS |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Net Par Outstanding | 36 |  | 39
BIG | BIG 2 | Non U.S. | Public finance |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Net Par Outstanding | 0 |  | 0
BIG | BIG 3 |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Net Par Outstanding | 2,038 |  | 2,348
BIG | BIG 3 | Public finance |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Net Par Outstanding | 1,088 |  | 1,324
BIG | BIG 3 | Other structured finance |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Net Par Outstanding | 67 |  | 71
BIG | BIG 3 | Structured finance |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Net Par Outstanding | 950 |  | 1,024
BIG | BIG 3 | U.S. | Public finance |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Net Par Outstanding | 1,088 |  | 1,324
BIG | BIG 3 | U.S. | RMBS |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Net Par Outstanding | 883 |  | 953
BIG | BIG 3 | Non U.S. | Public finance |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Net Par Outstanding | $ 0 |  | $ 0

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