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v3.23.1

Expected Loss to be Paid (Recovered) - Additional Information (Details) $ in Millions | 3 Months Ended | 12 Months Ended |
--- | --- | --- | ---
Mar. 31, 2023 USD ($) scenario Payment Curve | Mar. 31, 2022 USD ($) | Dec. 31, 2022 USD ($) scenario | Dec. 31, 2021 USD ($)
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
Period of insured credit performance of guaranteed obligations (in some cases over) | 30 years |  |  |
Discount factor (as a percent) | 3.75% |  | 4.08% |
Net Expected Loss to be Paid (Recovered) | $ 517 | $ 432 | $ 522 | $ 411
Loss and LAE Reserve paid | 3 | 13 |  |
Expected LAE to be paid | 9 |  | 11 |
Net par outstanding | 236,383 |  | 233,258 |
Net economic loss development (benefit) | $ 11 | (44) |  |
Additional loss recovery assumption, recovery period | 5 years |  |  |
First Lien |  |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
Effect of recovery | $ 1 |  |  |
Second Lien |  |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
Effect of recovery | 1 |  |  |
Public finance |  |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
Net Expected Loss to be Paid (Recovered) | 393 | 191 | 412 | 209
Net par outstanding | 226,746 |  | 224,099 |
Net economic loss development (benefit) | 5 | (50) |  |
Other structured finance |  |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
Net Expected Loss to be Paid (Recovered) | 42 | 46 | 44 | 52
Net par outstanding | 7,727 |  | 7,203 |
Net economic loss development (benefit) | 1 | (1) |  |
BIG |  |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
Net par outstanding | 5,882 |  | 5,892 |
BIG | Public finance |  |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
Net par outstanding | 4,794 |  | 4,777 |
BIG | Other structured finance |  |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
Net par outstanding | 100 |  | $ 105 |
BIG | Student Loan |  |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
Net par outstanding | 46 |  |  |
BIG | Life insurance transactions |  |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
Net par outstanding | $ 40 |  |  |
United States |  |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
Net expected loss to be paid after recoveries for representations and warranties, percent | 97.60% |  | 98.50% |
United States | Public finance |  |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
Net Expected Loss to be Paid (Recovered) | $ 380 | 181 | $ 403 | 197
Net par outstanding | 180,837 |  | 179,636 |
Net economic loss development (benefit) | 1 | (48) |  |
United States | RMBS |  |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
Net Expected Loss to be Paid (Recovered) | 82 | 195 | 66 | $ 150
Net par outstanding | 1,910 |  | $ 1,956 |
Net economic loss development (benefit) | 5 | 7 |  |
United States | RMBS | First Lien |  |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
Net economic loss development (benefit) | $ 0 | $ 18 |  |
Number of delinquent payments | Payment | 2 |  |  |
Projected loss assumptions, CDR, plateau rate, projection period | 36 months |  |  |
Projected loss assumptions, final CPR, period for voluntary prepayments to continue | 12 months |  |  |
Intermediate conditional default rate (as a percent) | 5.00% |  |  |
Number of scenarios weighted in estimating expected losses | scenario | 5 |  | 5 |
United States | RMBS | First Lien | Pessimistic Scenario |  |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
Percent of deferred loan balances to be recovered | 10.00% |  |  |
United States | RMBS | First Lien | Optimistic Scenario |  |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
Percent of deferred loan balances to be recovered | 50.00% |  |  |
United States | RMBS | First Lien | Base Scenario |  |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
Percent of deferred loan balances to be recovered | 20.00% | 20.00% |  |
United States | RMBS | First Lien | Base Scenario |  |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
Projected loss assumptions, CDR, plateau rate, projection period | 36 months |  |  |
Period from plateau to intermediate conditional default rate (in months) | 12 months |  |  |
Final conditional default rate as a percentage of plateau conditional default rate | 5.00% |  |  |
Projected loss assumptions, final CPR, period for voluntary prepayments to continue | 1 year |  |  |
Default from delinquentor rate, term | 36 months |  |  |
Performing or projected to reperform, projection period | 36 months |  |  |
Projected loss assumptions, loss severity, subsequent period | 18 months |  |  |
Estimated loss severity rate, one through six months (as a percent) | 18 months |  |  |
Loss severity (as a percent) | 40.00% |  |  |
Projected loss assumptions, period to reach final loss severity rate | 2 years 6 months |  |  |
Final CPR | 15.00% |  |  |
United States | RMBS | First Lien | More Stressful Environment |  |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
Period from plateau to intermediate conditional default rate (in months) | 16 months |  |  |
Projected loss assumptions, period to reach final loss severity rate | 9 years |  |  |
Percent of deferred loan balances to be recovered | 10.00% |  |  |
Projected loss assumptions, increase (decrease) in expected loss to be paid, net | $ 23 |  |  |
United States | RMBS | First Lien | Least Stressful Environment |  |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
Projected loss assumptions, CDR, plateau rate, projection period | 30 months |  |  |
Period from plateau to intermediate conditional default rate (in months) | 8 months |  |  |
Percent of deferred loan balances to be recovered | 50.00% |  |  |
Projected loss assumptions, increase (decrease) in expected loss to be paid, net | $ (33) |  |  |
Decrease in the plateau period used to calculate potential change in loss estimate (in months) | 6 months |  |  |
United States | RMBS | Second Lien |  |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
Net economic loss development (benefit) | $ 5 | $ (11) |  |
Projected loss assumptions, period of consistent conditional default rate | 36 months |  |  |
Period of conditional default rate downward trend | 1 year |  |  |
Percent of original period of consistent conditional default rate | 5.00% |  |  |
Loss recovery assumption (as a percent) | 2.00% |  | 2.00% |
Number of conditional default rate curves modeled in estimating losses | Curve | 5 |  |  |
Liquidation rate | 30.00% |  |  |
United States | RMBS | Second Lien | Pessimistic Scenario |  |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
Percent of deferred loan balances to be recovered | 10.00% |  |  |
United States | RMBS | Second Lien | Optimistic Scenario |  |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
Percent of deferred loan balances to be recovered | 50.00% |  |  |
United States | RMBS | Second Lien | Home Equity Line of Credit and Closed-end Mortgage |  |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
Final CPR | 15.00% |  |  |
United States | RMBS | Second Lien | More Stressful Environment |  |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
Projected loss assumptions, CDR, plateau rate, projection period | 42 months |  |  |
Period from plateau to intermediate conditional default rate (in months) | 16 months |  |  |
Stress period (in months) | 58 months |  |  |
Increase in conditional default rate ramp down period | 4 months |  |  |
United States | RMBS | Second Lien | More Stressful Environment | Home Equity Line of Credit |  |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
Change in estimate for increased conditional default rate plateau period | $ (65) |  |  |
United States | RMBS | Second Lien | Least Stressful Environment |  |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
Stress period (in months) | 38 months |  |  |
Period of constant conditional default rate (in months) | 30 months |  |  |
Decreased conditional default rate ramp down period | 8 months |  |  |
Change in estimate for decreased prepayment rate, Percent | 10.00% |  |  |
United States | RMBS | Second Lien | Least Stressful Environment | Home Equity Line of Credit |  |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
Change in estimate for decreased conditional default rate ramp down period | $ 66 |  |  |
United States | Home Equity Line of Credit |  |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
Initial period for which borrower can pay only interest payments | 10 years |  |  |
United States | Home Equity Line of Credit Insured |  |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
Initial period for which borrower can pay only interest payments | 15 years |  |  |
United States | BIG | Public finance |  |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
Net par outstanding | $ 3,804 |  | $ 3,796 |
United States | BIG | RMBS |  |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
Net par outstanding | 988 |  | 1,010 |
Puerto Rico |  |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
Net par outstanding | 1,351 |  | 1,361 |
Puerto Rico | BIG |  |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
Net par outstanding | $ 1,400 |  | $ 1,400 |
Minimum |  |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
Risk free discount rate | 3.44% |  | 3.82% |
Maximum |  |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
Risk free discount rate | 4.87% |  | 4.69% |

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