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Outstanding Exposure - Components of BIG Net Par Outstanding (Details) - USD ($) $ in Millions | Dec. 31, 2022 | Dec. 31, 2021
--- | --- | ---
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | $ 233,258 | $ 236,392
Public finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | 224,099 | 227,164
Other structured finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | 7,203 | 6,837
Structured finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | 9,159 | 9,228
U.S. |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | 187,864 |
U.S. | Public finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | 179,636 | 177,219
U.S. | RMBS |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | 1,956 | 2,391
U.S. | Structured finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | 8,228 | 8,374
Non U.S. |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | 45,394 |
Non U.S. | Public finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | 44,463 | 49,945
Non U.S. | Structured finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | 931 | 854
BIG |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | 5,892 | 7,356
BIG | Public finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | 4,777 | 5,972
BIG | Other structured finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | 105 | 119
BIG | Structured finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | 1,115 | 1,384
BIG | U.S. | Public finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | 3,796 | 5,372
BIG | U.S. | RMBS |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | 1,010 | 1,265
BIG | U.S. | Structured finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | 1,115 | 1,384
BIG | Non U.S. | Public finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | 981 | 600
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 | 3,363 | 2,443
BIG | BIG 1 | Public finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | 3,345 | 2,321
BIG | BIG 1 | Other structured finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | 0 | 1
BIG | BIG 1 | Structured finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | 18 | 122
BIG | BIG 1 | U.S. | Public finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | 2,364 | 1,765
BIG | BIG 1 | U.S. | RMBS |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | 18 | 121
BIG | BIG 1 | Non U.S. | Public finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | 981 | 556
BIG | BIG 2 |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | 181 | 181
BIG | BIG 2 | Public finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | 108 | 116
BIG | BIG 2 | Other structured finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | 34 | 41
BIG | BIG 2 | Structured finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | 73 | 65
BIG | BIG 2 | U.S. | Public finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | 108 | 116
BIG | BIG 2 | U.S. | RMBS |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | 39 | 24
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 | 2,348 | 4,732
BIG | BIG 3 | Public finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | 1,324 | 3,535
BIG | BIG 3 | Other structured finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | 71 | 77
BIG | BIG 3 | Structured finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | 1,024 | 1,197
BIG | BIG 3 | U.S. | Public finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | 1,324 | 3,491
BIG | BIG 3 | U.S. | RMBS |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | 953 | 1,120
BIG | BIG 3 | Non U.S. | Public finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net Par Outstanding | $ 0 | $ 44

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