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Outstanding Exposure - Components of BIG Net Par Outstanding (Details) - USD ($) $ in Millions | Jun. 30, 2024 | Dec. 31, 2023
--- | --- | ---
Schedule of Insured Financial Obligations [Line Items] |  |
Net | $ 254,396 | $ 249,153
Public finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | 244,176 | 239,296
Other structured finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | 8,635 | 8,083
Structured finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | 10,220 | 9,857
BIG |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | 5,502 | 5,437
BIG | Public finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | 4,575 | 4,402
BIG | Other structured finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | 82 | 94
BIG | Structured finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | 927 | 1,035
BIG | BIG 1 |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | 2,170 | 2,410
BIG | BIG 1 | Public finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | 2,154 | 2,388
BIG | BIG 1 | Other structured finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | 0 | 0
BIG | BIG 1 | Structured finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | 16 | 22
BIG | BIG 2 |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | 1,529 | 989
BIG | BIG 2 | Public finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | 1,477 | 926
BIG | BIG 2 | Other structured finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | 23 | 27
BIG | BIG 2 | Structured finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | 52 | 63
BIG | BIG 3 |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | 1,803 | 2,038
BIG | BIG 3 | Public finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | 944 | 1,088
BIG | BIG 3 | Other structured finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | 59 | 67
BIG | BIG 3 | Structured finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | 859 | 950
United States | Public finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | 194,593 | 190,289
United States | RMBS |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | 1,585 | 1,774
United States | Structured finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | 8,759 | 8,632
United States | BIG | Public finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | 3,490 | 3,271
United States | BIG | RMBS |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | 845 | 941
United States | BIG | Structured finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | 927 | 1,035
United States | BIG | BIG 1 | Public finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | 1,594 | 1,257
United States | BIG | BIG 1 | RMBS |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | 16 | 22
United States | BIG | BIG 2 | Public finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | 952 | 926
United States | BIG | BIG 2 | RMBS |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | 29 | 36
United States | BIG | BIG 3 | Public finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | 944 | 1,088
United States | BIG | BIG 3 | RMBS |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | 800 | 883
Non-U.S. public finance | Public finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | 49,583 | 49,007
Non-U.S. public finance | Structured finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | 1,461 | 1,225
Non-U.S. public finance | BIG | Public finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | 1,085 | 1,131
Non-U.S. public finance | BIG | Structured finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | 0 | 0
Non-U.S. public finance | BIG | BIG 1 | Public finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | 560 | 1,131
Non-U.S. public finance | BIG | BIG 2 | Public finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | 525 | 0
Non-U.S. public finance | BIG | BIG 3 | Public finance |  |
Schedule of Insured Financial Obligations [Line Items] |  |
Net | $ 0 | $ 0

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