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Financial Guaranty Variable Interest Entities and Consolidated Investment Vehicles - Schedule of Assets and Liabilities of Consolidated Investment Vehicles (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2022 | Dec. 31, 2021
Variable Interest Entity [Line Items] |  |
Total assets | $ 16,843 | $ 18,208
Total liabilities | 11,551 | 11,708
Variable Interest Entity, Primary Beneficiary | Consolidated Investment Vehicles |  |
Variable Interest Entity [Line Items] |  |
Total liabilities | 4,625 | 4,436
Variable Interest Entity, Primary Beneficiary | CLO obligations of CFEs | Consolidated Investment Vehicles |  |
Variable Interest Entity [Line Items] |  |
Total liabilities | 4,090 | 3,665
Variable Interest Entity, Primary Beneficiary | Warehouse financing debt | Consolidated Investment Vehicles |  |
Variable Interest Entity [Line Items] |  |
Total liabilities | 313 | 126
Variable Interest Entity, Primary Beneficiary | Securities sold short, at fair value | Consolidated Investment Vehicles |  |
Variable Interest Entity [Line Items] |  |
Total liabilities | 0 | 41
Variable Interest Entity, Primary Beneficiary | Due to brokers and counterparties | Consolidated Investment Vehicles |  |
Variable Interest Entity [Line Items] |  |
Total liabilities | 112 | 570
Variable Interest Entity, Primary Beneficiary | Other liabilities | Consolidated Investment Vehicles |  |
Variable Interest Entity [Line Items] |  |
Total liabilities | 110 | 34
Variable Interest Entity, Primary Beneficiary | Consolidated Investment Vehicles |  |
Variable Interest Entity [Line Items] |  |
Total assets | 5,493 | 5,271
Variable Interest Entity, Primary Beneficiary | Consolidated Investment Vehicles | Investments in AssuredIM Funds and Other Affiliated Entities |  |
Variable Interest Entity [Line Items] |  |
Total assets | $ 392 | $ 223
Variable Interest Entity, Primary Beneficiary | Consolidated Investment Vehicles | CLO obligations of CFEs |  |
Variable Interest Entity [Line Items] |  |
CLOs, weighted average maturity | 6 years 2 months 12 days | 6 years 7 months 6 days
CLOs, weighted average interest rate | 5.30% | 1.80%
Variable Interest Entity, Primary Beneficiary | Consolidated Investment Vehicles | Warehouse financing debt |  |
Variable Interest Entity [Line Items] |  |
CLOs, weighted average maturity | 1 year 10 months 24 days | 1 year 9 months 18 days
CLOs, weighted average interest rate | 4.50% | 1.10%
Variable Interest Entity, Primary Beneficiary | Consolidated Investment Vehicles | Fund Investments | Cash and cash equivalents |  |
Variable Interest Entity [Line Items] |  |
Total assets | $ 59 | $ 64
Variable Interest Entity, Primary Beneficiary | Consolidated Investment Vehicles | Fund Investments | Due from brokers and counterparties |  |
Variable Interest Entity [Line Items] |  |
Total assets | 0 | 49
Variable Interest Entity, Primary Beneficiary | Consolidated Investment Vehicles | Fund Investments | Other |  |
Variable Interest Entity [Line Items] |  |
Total assets | 1 | 1
Variable Interest Entity, Primary Beneficiary | Consolidated Investment Vehicles | Fund Investments | Equity securities and warrants |  |
Variable Interest Entity [Line Items] |  |
Total assets | 434 | 252
Variable Interest Entity, Primary Beneficiary | Consolidated Investment Vehicles | Fund Investments | Obligations of state and political subdivisions |  |
Variable Interest Entity [Line Items] |  |
Total assets | 0 | 101
Variable Interest Entity, Primary Beneficiary | Consolidated Investment Vehicles | Fund Investments | Structured products |  |
Variable Interest Entity [Line Items] |  |
Total assets | 128 | 62
Variable Interest Entity, Primary Beneficiary | Consolidated Investment Vehicles | Fund Investments | Corporate securities |  |
Variable Interest Entity [Line Items] |  |
Total assets | 96 | 98
Variable Interest Entity, Primary Beneficiary | Consolidated Investment Vehicles | CLOs | Cash and cash equivalents |  |
Variable Interest Entity [Line Items] |  |
Total assets | 38 | 156
Variable Interest Entity, Primary Beneficiary | Consolidated Investment Vehicles | CLOs | Due from brokers and counterparties |  |
Variable Interest Entity [Line Items] |  |
Total assets | 32 | 99
Variable Interest Entity, Primary Beneficiary | Consolidated Investment Vehicles | CLOs | Loans in CLOs, FVO |  |
Variable Interest Entity [Line Items] |  |
Total assets | 4,202 | 3,913
Variable Interest Entity, Primary Beneficiary | Consolidated Investment Vehicles | CLOs | Loans in CLO warehouses, FVO |  |
Variable Interest Entity [Line Items] |  |
Total assets | 368 | 331
Variable Interest Entity, Primary Beneficiary | Consolidated Investment Vehicles | CLOs | Short-term investments |  |
Variable Interest Entity [Line Items] |  |
Total assets | 135 | 145
Voting Interest Entity | Consolidated Investment Vehicles |  |
Variable Interest Entity [Line Items] |  |
Total liabilities | 1 |
Voting Interest Entity | Consolidated Investment Vehicles | Investments |  |
Variable Interest Entity [Line Items] |  |
Total assets | $ 58 | $ 12

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