Fair Value Measurements - Level 3 Rollforwards (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Purchases, Sales, Issuances and Settlements	$ 380	$ 109	$ 56	$ 115
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Purchases, Sales, Issuances and Settlements	(31)		(106)
Funds withheld payable under reinsurance treaties
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	(1,979)	(1,560)	(1,971)	(1,353)
Total Realized/Unrealized Gains (Losses) Included in Net Income (Loss)	(199)	(211)	(175)	(404)
Total Realized/Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss)	0	0	0	0
Purchases, Sales, Issuances and Settlements	23	(13)	(9)	(27)
Transfers in and/or (out of ) Level 3	0	0	0	0
Fair Value, end of period	(2,155)	(1,784)	(2,155)	(1,784)
Market risk benefit liabilities
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	(3,971)	(4,125)	(3,754)	(3,774)
Total Realized/Unrealized Gains (Losses) Included in Net Income (Loss)	720	823	213	145
Total Realized/Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss)	(63)	(267)	270	60
Purchases, Sales, Issuances and Settlements	(54)	0	(97)	0
Transfers in and/or (out of ) Level 3	0	0	0	0
Fair Value, end of period	(3,368)	(3,569)	(3,368)	(3,569)
Debt Securities \| Public utilities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period				44
Total Realized/Unrealized Gains (Losses) Included in Net Income (Loss)				0
Total Realized/Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss)				0
Purchases, Sales, Issuances and Settlements				(44)
Transfers in and/or (out of ) Level 3				0
Fair Value, end of period		0		0
Debt Securities \| Corporate securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	145	300	346	274
Total Realized/Unrealized Gains (Losses) Included in Net Income (Loss)	1	10	3	10
Total Realized/Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss)	0	(1)	2	3
Purchases, Sales, Issuances and Settlements	6	62	(184)	89
Transfers in and/or (out of ) Level 3	(18)	3	(33)	(2)
Fair Value, end of period	134	374	134	374
Debt Securities \| Other asset-backed securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	278	791	426	661
Total Realized/Unrealized Gains (Losses) Included in Net Income (Loss)	0	(52)	(17)	(52)
Total Realized/Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss)	(2)	30	(7)	28
Purchases, Sales, Issuances and Settlements	(6)	141	(54)	152
Transfers in and/or (out of ) Level 3	13	(58)	(65)	63
Fair Value, end of period	283	852	283	852
Equity securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	9	7	7	7
Total Realized/Unrealized Gains (Losses) Included in Net Income (Loss)	2	0	4	0
Total Realized/Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss)	0	0	0	0
Purchases, Sales, Issuances and Settlements	0	0	0	0
Transfers in and/or (out of ) Level 3	0	0	0	0
Fair Value, end of period	11	7	11	7
Mortgage loans
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	196	451	324	449
Total Realized/Unrealized Gains (Losses) Included in Net Income (Loss)	(3)	3	(1)	7
Total Realized/Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss)	0	0	0	0
Purchases, Sales, Issuances and Settlements	402	(61)	272	(63)
Transfers in and/or (out of ) Level 3	0	0	0	0
Fair Value, end of period	595	393	595	393
Limited partnerships
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	276	203	250	195
Total Realized/Unrealized Gains (Losses) Included in Net Income (Loss)	16	2	20	9
Total Realized/Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss)	0	0	0	0
Purchases, Sales, Issuances and Settlements	2	0	15	1
Transfers in and/or (out of ) Level 3	20	0	29	0
Fair Value, end of period	314	205	314	205
Policy loans
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	3,556	3,492	3,537	3,489
Total Realized/Unrealized Gains (Losses) Included in Net Income (Loss)	85	81	73	71
Total Realized/Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss)	0	0	0	0
Purchases, Sales, Issuances and Settlements	(24)	(33)	7	(20)
Transfers in and/or (out of ) Level 3	0	0	0	0
Fair Value, end of period	3,617	3,540	3,617	3,540
Reinsurance recoverable on market risk benefits
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	121	126	118	121
Total Realized/Unrealized Gains (Losses) Included in Net Income (Loss)	(12)	(15)	(9)	(10)
Total Realized/Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss)	0	0	0	0
Purchases, Sales, Issuances and Settlements	0	0	0	0
Transfers in and/or (out of ) Level 3	0	0	0	0
Fair Value, end of period	109	111	109	111
Market risk benefit assets
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	6,701	7,326	7,867	8,899
Total Realized/Unrealized Gains (Losses) Included in Net Income (Loss)	1,345	1,395	179	(178)
Total Realized/Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss)	0	0	0	0
Purchases, Sales, Issuances and Settlements	0	0	0	0
Transfers in and/or (out of ) Level 3	0	0	0	0
Fair Value, end of period	$ 8,046	$ 8,721	$ 8,046	$ 8,721

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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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).

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

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Amount of purchases, (sales), issuances and (settlements) of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of transfer of financial instrument classified as an asset into (out of) level 3 of the fair value hierarchy.

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Fair value of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of gain (loss) recognized in income from liability measured at fair value on recurring basis using unobservable input (level 3).

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

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Amount of transfers of financial instrument classified as a liability into (out of) level 3 of the fair value hierarchy.

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Fair value of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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