Fair Value Measurements - Schedule of Portion of Gains (Losses) Included in Net Income or Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2026	Mar. 31, 2025
Funds withheld payable under reinsurance treaties
Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Line Items]
Included in Net Income	$ 24	$ (193)
Included in OCI	0	0
Market risk benefit liabilities
Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Line Items]
Included in Net Income	(507)	(678)
Included in OCI	333	327
Debt Securities \| Corporate securities
Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Line Items]
Included in Net Income	2	0
Included in OCI	(4)	4
Debt Securities \| Other asset-backed securities
Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Line Items]
Included in Net Income	(20)	0
Included in OCI	(1)	(3)
Equity securities
Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Line Items]
Included in Net Income	2	0
Included in OCI	0	0
Mortgage loans
Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Line Items]
Included in Net Income	2	4
Included in OCI	0	0
Limited partnerships
Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Line Items]
Included in Net Income	4	7
Included in OCI	0	0
Policy loans
Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Line Items]
Included in Net Income	(12)	(10)
Included in OCI	0	0
Reinsurance recoverable on market risk benefits
Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Line Items]
Included in Net Income	3	5
Included in OCI	0	0
Market risk benefit assets
Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Line Items]
Included in Net Income	(1,166)	(1,573)
Included in OCI	$ 0	$ 0

Amount of unrealized gain (loss) recognized in other comprehensive income (OCI) from asset (liability) measured at fair value on recurring basis using unobservable input (level 3) and still held.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-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

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: 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 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
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-Publisher FASB
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Amount of unrealized gain (loss) recognized in income for derivative asset (liability) after deduction of derivative liability (asset), measured at fair value 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
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2

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