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Fair Value Measurement - Fair Value Level 3 Rollforward Recurring Basis (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2025 | Sep. 30, 2024 | Sep. 30, 2025 | Sep. 30, 2024
Credit Risk Contract |  |  |  |
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward] |  |  |  |
Fair value at start of period | $ (29) | $ (34) | $ (29) | $ (50)
Total pre-tax realized and unrealized gains (losses) recorded in: |  |  |  |
Net income (loss) | 5 | 3 | 110 | 19
Other comprehensive income (loss) | 0 | 0 | 0 | 0
Issuances |  | (2) |  | (2)
Settlements | (2) | (1) | (107) | (1)
Fair value at end of period | (26) | (34) | (26) | (34)
Change in unrealized gains/(losses) included in earnings related to financial instruments | 3 | 1 | 3 | 9
Total pre-tax realized and unrealized gains (losses) recorded in: |  |  |  |
Issuances |  | (2) |  | (2)
FG VIEs’ Assets |  |  |  |
Fair Value Level 3 Rollforward |  |  |  |
Fair value at beginning of period | 153 |  | 147 | 174
Total pre-tax realized and unrealized gains (losses) recorded in: |  |  |  |
Net income (loss) | 7 |  | 14 | (1)
Other comprehensive income (loss) | 0 |  | 0 | 1
Purchases | 0 |  | 0 | 0
Sales | 0 |  | 0 | 0
Settlements | (6) |  | (16) | (18)
Deconsolidations | (9) |  | (9) |
Reclassifications |  |  |  | 0
Consolidations |  |  | 9 |
Transfers into Level 3 |  |  |  | 0
Transfers out of Level 3 |  |  |  | 0
Fair value at end of period | 145 | 156 | 145 | 156
Change in unrealized gains/(losses) related to financial instruments held | 6 |  | 11 | (5)
FG VIEs’ Assets | Other Comprehensive Income (Loss) |  |  |  |
Total pre-tax realized and unrealized gains (losses) recorded in: |  |  |  |
Change in unrealized gains/(losses) related to financial instruments held |  |  |  | 1
FG VIEs’ Assets | Assets of CIVs, Equity Securities |  |  |  |
Fair Value Level 3 Rollforward |  |  |  |
Fair value at beginning of period |  | 93 |  |
Total pre-tax realized and unrealized gains (losses) recorded in: |  |  |  |
Net income (loss) |  | 9 |  |
Other comprehensive income (loss) |  | 0 |  |
Purchases |  | 0 |  |
Sales |  | (3) |  |
Settlements |  | 0 |  |
Reclassifications |  | 0 |  |
Transfers out of Level 3 |  | (2) |  |
Fair value at end of period |  | 97 |  | 97
Change in unrealized gains/(losses) related to financial instruments held |  | 9 |  |
Consolidated Investment Vehicles | Assets of CIVs, Equity Securities |  |  |  |
Fair Value Level 3 Rollforward |  |  |  |
Fair value at beginning of period | 121 |  | 99 | 80
Total pre-tax realized and unrealized gains (losses) recorded in: |  |  |  |
Net income (loss) | 11 |  | 33 | 21
Other comprehensive income (loss) | 0 |  | 0 | 0
Purchases | 0 |  | 0 | 0
Sales | 0 |  | 0 | (5)
Settlements | 0 |  | 0 | 0
Deconsolidations | 0 |  | 0 |
Reclassifications |  |  |  | 0
Consolidations |  |  | 0 |
Transfers into Level 3 |  |  |  | 3
Transfers out of Level 3 |  |  |  | (2)
Fair value at end of period | 132 | 97 | 132 | 97
Change in unrealized gains/(losses) related to financial instruments held | 11 |  | 33 | 21
Consolidated Investment Vehicles | Structured Products |  |  |  |
Fair Value Level 3 Rollforward |  |  |  |
Fair value at beginning of period |  | 225 |  | 189
Total pre-tax realized and unrealized gains (losses) recorded in: |  |  |  |
Net income (loss) |  | (5) |  | (10)
Other comprehensive income (loss) |  | 0 |  | 0
Purchases |  | 25 |  | 76
Sales |  | 0 |  | (20)
Settlements |  | 0 |  | 0
Reclassifications |  | (8) |  | (8)
Transfers into Level 3 |  |  |  | 10
Transfers out of Level 3 |  | 0 |  | 0
Fair value at end of period |  | 237 |  | 237
Change in unrealized gains/(losses) related to financial instruments held |  | (1) |  | (3)
Other |  |  |  |
Fair Value Level 3 Rollforward |  |  |  |
Fair value at beginning of period | 5 | 6 | 5 | 14
Total pre-tax realized and unrealized gains (losses) recorded in: |  |  |  |
Net income (loss) | 9 | (4) | 10 | (12)
Other comprehensive income (loss) | 1 | 1 | 0 | 1
Purchases | 0 | 1 | 0 | 1
Sales | 0 | 0 | 0 | 0
Settlements | 0 | 0 | 0 | 0
Deconsolidations | 0 |  | 0 |
Reclassifications |  | 0 |  | 0
Consolidations |  |  | 0 |
Transfers into Level 3 |  |  |  | 0
Transfers out of Level 3 |  | 0 |  | 0
Fair value at end of period | 15 | 4 | 15 | 4
Change in unrealized gains/(losses) related to financial instruments held | 9 | (4) | 10 | (12)
Other | Other Comprehensive Income (Loss) |  |  |  |
Total pre-tax realized and unrealized gains (losses) recorded in: |  |  |  |
Change in unrealized gains/(losses) related to financial instruments held | 1 | (1) | 0 | 1
Financial Guaranty Variable Interest Entities |  |  |  |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |
Fair value at start of period | (161) | (393) | (164) | (554)
Total pre-tax realized and unrealized gains (losses) recorded in: |  |  |  |
Net income (loss) | (4) | (3) | (9) | 6
Other comprehensive income (loss) | 1 | (1) | 1 | (1)
Issuances |  | 0 |  | 0
Settlements | 5 | 5 | 13 | 157
Fair value at end of period | (159) | (392) | (159) | (392)
Change in unrealized gains/(losses) included in earnings related to financial instruments | (4) | (4) | (8) | 0
Change in unrealized gains/(losses) included in OCI related to financial instruments | 1 | (1) | 1 | (1)
Obligations of state and political subdivisions | Fixed-maturity securities, available-for-sale |  |  |  |
Fair Value Level 3 Rollforward |  |  |  |
Fair value at beginning of period | 10 | 7 | 10 | 6
Total pre-tax realized and unrealized gains (losses) recorded in: |  |  |  |
Net income (loss) | 0 | 0 | 2 | 0
Other comprehensive income (loss) | 0 | 0 | 0 | 2
Purchases | 0 | 0 | 0 | 0
Sales | 0 | 0 | 0 | 0
Settlements | 0 | 0 | (2) | (1)
Deconsolidations | 0 |  | 0 |
Reclassifications |  | 0 |  | 0
Consolidations |  |  | 0 |
Transfers into Level 3 |  |  |  | 0
Transfers out of Level 3 |  | 0 |  | 0
Fair value at end of period | 10 | 7 | 10 | 7
Obligations of state and political subdivisions | Fixed-maturity securities, available-for-sale | Other Comprehensive Income (Loss) |  |  |  |
Total pre-tax realized and unrealized gains (losses) recorded in: |  |  |  |
Change in unrealized gains/(losses) related to financial instruments held | 0 | 0 | 0 | 2
Corporate securities | Fixed-maturity securities, available-for-sale |  |  |  |
Fair Value Level 3 Rollforward |  |  |  |
Fair value at beginning of period | 84 |  | 0 |
Total pre-tax realized and unrealized gains (losses) recorded in: |  |  |  |
Net income (loss) | 1 |  | 1 |
Other comprehensive income (loss) | 10 |  | 20 |
Purchases | 73 |  | 147 |
Sales | 0 |  | 0 |
Settlements | 0 |  | 0 |
Deconsolidations | 0 |  | 0 |
Consolidations |  |  | 0 |
Fair value at end of period | 168 |  | 168 |
Corporate securities | Fixed-maturity securities, available-for-sale | Other Comprehensive Income (Loss) |  |  |  |
Total pre-tax realized and unrealized gains (losses) recorded in: |  |  |  |
Change in unrealized gains/(losses) related to financial instruments held | 10 |  | 20 |
RMBS | Fixed-maturity securities, available-for-sale |  |  |  |
Fair Value Level 3 Rollforward |  |  |  |
Fair value at beginning of period | 142 | 150 | 145 | 154
Total pre-tax realized and unrealized gains (losses) recorded in: |  |  |  |
Net income (loss) | 3 | 5 | 7 | 12
Other comprehensive income (loss) | 6 | 3 | 12 | 5
Purchases | 0 | 0 | 0 | 0
Sales | 0 | 0 | 0 | 0
Settlements | (6) | (6) | (19) | (19)
Deconsolidations | 0 |  | 0 |
Reclassifications |  | 0 |  | 0
Consolidations |  |  | 0 |
Transfers into Level 3 |  |  |  | 0
Transfers out of Level 3 |  | 0 |  | 0
Fair value at end of period | 145 | 152 | 145 | 152
RMBS | Fixed-maturity securities, available-for-sale | Other Comprehensive Income (Loss) |  |  |  |
Total pre-tax realized and unrealized gains (losses) recorded in: |  |  |  |
Change in unrealized gains/(losses) related to financial instruments held | 6 | 3 | 12 | 5
Asset-backed securities | Fixed-maturity securities, available-for-sale |  |  |  |
Fair Value Level 3 Rollforward |  |  |  |
Fair value at beginning of period | 977 | 795 | 1,031 | 803
Total pre-tax realized and unrealized gains (losses) recorded in: |  |  |  |
Net income (loss) | 3 | 7 | 21 | 24
Other comprehensive income (loss) | (3) | (3) | 8 | 5
Purchases | 40 | 19 | 40 | 30
Sales | 0 | 0 | (12) | 0
Settlements | (496) | (31) | (567) | (95)
Deconsolidations | 0 |  | 0 |
Reclassifications |  | 0 |  | 0
Consolidations |  |  | 0 |
Transfers into Level 3 |  |  |  | 20
Transfers out of Level 3 |  | 0 |  | 0
Fair value at end of period | 521 | 787 | 521 | 787
Asset-backed securities | Fixed-maturity securities, available-for-sale | Other Comprehensive Income (Loss) |  |  |  |
Total pre-tax realized and unrealized gains (losses) recorded in: |  |  |  |
Change in unrealized gains/(losses) related to financial instruments held | (2) | (3) | (20) | 3
Fixed-Maturity Securities, Trading | Fixed-maturity securities, available-for-sale |  |  |  |
Fair Value Level 3 Rollforward |  |  |  |
Fair value at beginning of period | 4 | 0 | 5 | 0
Total pre-tax realized and unrealized gains (losses) recorded in: |  |  |  |
Net income (loss) | 1 | 0 | 1 | 0
Other comprehensive income (loss) | 0 | 0 | 0 | 0
Purchases | 0 | 0 | 0 | 0
Sales | 0 | 0 | 0 | 0
Settlements | (1) | (2) | (2) | (2)
Deconsolidations | 0 |  | 0 |
Reclassifications |  | 8 |  | 8
Consolidations |  |  | 0 |
Transfers into Level 3 |  |  |  | 0
Transfers out of Level 3 |  | 0 |  | 0
Fair value at end of period | 4 | 6 | 4 | 6
Change in unrealized gains/(losses) related to financial instruments held | $ 0 | 0 | $ 0 | 0
Fixed-Maturity Securities, Trading | FG VIEs’ Assets |  |  |  |
Fair Value Level 3 Rollforward |  |  |  |
Fair value at beginning of period |  | 160 |  |
Total pre-tax realized and unrealized gains (losses) recorded in: |  |  |  |
Net income (loss) |  | 2 |  |
Other comprehensive income (loss) |  | 0 |  |
Purchases |  | 0 |  |
Sales |  | 0 |  |
Settlements |  | (6) |  |
Reclassifications |  | 0 |  |
Transfers out of Level 3 |  | 0 |  |
Fair value at end of period |  | 156 |  | $ 156
Change in unrealized gains/(losses) related to financial instruments held |  | $ 0 |  |

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- Definition Fair Value Measurement with Unobservable Inputs, Reconciliation, Recurring Basis Asset, Consolidations + References No definition available. + Details
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- Definition Total Pretax Realized And Unrealized Gains (Losses) Recorded As Assets [Abstract] + References No definition available. + Details
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- Definition Total Pretax Realized And Unrealized Gains (Losses) Recorded As Liabilities [Abstract] + References No definition available. + Details
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- Definition Total Pretax Realized And Unrealized Gains (Losses) Recorded As Net Derivative Asset (Liability) [Abstract] + References No definition available. + Details
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- Definition Amount of unrealized gain (loss) recognized in income from asset measured at fair value on recurring basis using unobservable input (level 3) and still held. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 101 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482078/820-10-55-101 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-3 Reference 3: http://www.xbrl.org/2003/role/exampleRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 102 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482078/820-10-55-102 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
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- Definition Amount of unrealized gain (loss) recognized in income from liability measured at fair value on recurring basis using unobservable input (level 3) and still held. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-3 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
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- Definition Amount of unrealized gain (loss) recognized in other comprehensive income (OCI) from liability measured at fair value on recurring basis using unobservable input (level 3) and still held. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-3 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
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- Definition Amount of gain (loss) recognized in income from asset measured at fair value on recurring basis using unobservable input (level 3). + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 101 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482078/820-10-55-101 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-3 Reference 3: http://www.xbrl.org/2003/role/exampleRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 102 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482078/820-10-55-102 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (c)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
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- Definition Amount of gain (loss) recognized in other comprehensive income (OCI) from asset measured at fair value on recurring basis using unobservable input (level 3). + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 101 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482078/820-10-55-101 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-3 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (c)(1a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
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- Definition Amount of transfer of financial instrument classified as an asset into level 3 of the fair value hierarchy. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2G -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2G Reference 2: http://www.xbrl.org/2003/role/exampleRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 101 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482078/820-10-55-101 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-3 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (c)(3) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
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- Definition Amount of transfer of financial instrument classified as an asset into (out of) level 3 of the fair value hierarchy. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-3 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (c)(3) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
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