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v3.23.1

Fair Value Measurement - Narrative (Details) $ in Millions | 3 Months Ended | 12 Months Ended
--- | --- | ---
Mar. 31, 2023 USD ($) Security Trust | Dec. 31, 2022 USD ($)
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Repurchase agreement liability | $ 36 | $ 35
Financial guaranty variable interest entities' assets | $ 413 | 413
Assured IM |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Obligation to purchase debt | 0.05 |
AGC And AGM |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Number of custodial trusts | Trust | 4 |
Share value, amount | $ 200 |
Maximum amount | 50 |
Fair Value Measured at Net Asset Value Per Share | Fund investments: | Equity securities and warrants | Consolidated Investment Vehicles |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Financial guaranty variable interest entities' assets | 5 | 5
Recurring | Consolidated Investment Vehicles |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Financial guaranty variable interest entities' assets | 5,062 | 5,231
Recurring | Fund investments: | Equity securities and warrants | Consolidated Investment Vehicles |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Financial guaranty variable interest entities' assets | $ 334 | 302
Recurring | Level 3 |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Number of fixed maturity securities valued using model processes | Security | 190 |
Recurring | Level 3 | Consolidated Investment Vehicles |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Financial guaranty variable interest entities' assets | $ 439 | $ 439
Recurring | Level 3 | CDR | Total | Minimum |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Conditional prepayment rate | 2.59% | 2.78%
Recurring | Level 3 | CDR | Total | Maximum |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Conditional prepayment rate | 5.06% | 5.08%
Recurring | Level 3 | Fund investments: | Equity securities and warrants | Consolidated Investment Vehicles |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Financial guaranty variable interest entities' assets | $ 329 | $ 297

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- Definition Amount to be repaid to the counterparty to the repurchase agreement when the carrying amount (or market value, if higher than the carrying amount) of securities or other assets sold under the repurchase agreement exceeds 10 percent of total assets. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08(m)(1)(ii)(A)(ii)) -URI https://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08(m)(1)(i)) -URI https://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690 + Details
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