Fair Value Measurements - Fair Value Recurring Basis, Unobservable Input (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022
Assets
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Net realized gains (losses)	Net realized gains (losses)
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Asset, Gain (Loss), Statement of Other Comprehensive Income or Comprehensive Income [Extensible Enumeration]	OCI, net of tax	OCI, net of tax
Significant Unobservable Inputs (Level 3) \| Fair Value, Measurements, Recurring
Assets
Beginning balance	$ 2,483	$ 2,708
Total realized/unrealized gains (losses), Included in net income	(9)	(14)
Total realized/unrealized gains (losses), Included in OCI	74	(205)
Purchases	737	1,215
Settlements	(521)	(591)
Sales	(16)	(47)
Transfers into Level 3	71	48
Transfers out of Level 3	(332)	(631)
Ending balance	2,487	2,483
Significant Unobservable Inputs (Level 3) \| Fair Value, Measurements, Recurring \| Equity Securities [Member]
Assets
Beginning balance	61	64
Total realized/unrealized gains (losses), Included in net income	(1)	11
Total realized/unrealized gains (losses), Included in OCI	0	0
Purchases	1	2
Settlements	(3)	(16)
Sales	0	0
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Ending balance	58	61
Significant Unobservable Inputs (Level 3) \| Fair Value, Measurements, Recurring \| Short-term Investments [Member]
Assets
Beginning balance	193	80
Total realized/unrealized gains (losses), Included in net income	0	0
Total realized/unrealized gains (losses), Included in OCI	0	0
Purchases	48	284
Settlements	(216)	(121)
Sales	0	0
Transfers into Level 3	0	0
Transfers out of Level 3	0	(50)
Ending balance	25	193
Significant Unobservable Inputs (Level 3) \| Fair Value, Measurements, Recurring \| Securities available-for-sale and other \| Total fixed maturities
Assets
Beginning balance	2,051	2,404
Total realized/unrealized gains (losses), Included in net income	(7)	(1)
Total realized/unrealized gains (losses), Included in OCI	74	(205)
Purchases	688	874
Settlements	(292)	(441)
Sales	(16)	(47)
Transfers into Level 3	71	48
Transfers out of Level 3	(332)	(581)
Ending balance	2,237	2,051
Significant Unobservable Inputs (Level 3) \| Fair Value, Measurements, Recurring \| Securities available-for-sale and other \| ABS \| Total fixed maturities
Assets
Beginning balance	30	0
Total realized/unrealized gains (losses), Included in net income	0	0
Total realized/unrealized gains (losses), Included in OCI	0	0
Purchases	82	49
Settlements	0	0
Sales	0	0
Transfers into Level 3	0	0
Transfers out of Level 3	(112)	(19)
Ending balance	0	30
Significant Unobservable Inputs (Level 3) \| Fair Value, Measurements, Recurring \| Securities available-for-sale and other \| CLO \| Total fixed maturities
Assets
Beginning balance	115	257
Total realized/unrealized gains (losses), Included in net income	0	0
Total realized/unrealized gains (losses), Included in OCI	0	(2)
Purchases	102	113
Settlements	(49)	(62)
Sales	0	0
Transfers into Level 3	0	0
Transfers out of Level 3	(55)	(191)
Ending balance	113	115
Significant Unobservable Inputs (Level 3) \| Fair Value, Measurements, Recurring \| Securities available-for-sale and other \| CMBS \| Total fixed maturities
Assets
Beginning balance	222	196
Total realized/unrealized gains (losses), Included in net income	(2)	0
Total realized/unrealized gains (losses), Included in OCI	3	(15)
Purchases	6	51
Settlements	(18)	(10)
Sales	(5)	0
Transfers into Level 3	21	0
Transfers out of Level 3	0	0
Ending balance	227	222
Significant Unobservable Inputs (Level 3) \| Fair Value, Measurements, Recurring \| Securities available-for-sale and other \| Corporate \| Total fixed maturities
Assets
Beginning balance	1,589	1,618
Total realized/unrealized gains (losses), Included in net income	(5)	0
Total realized/unrealized gains (losses), Included in OCI	71	(174)
Purchases	458	524
Settlements	(196)	(274)
Sales	(11)	(40)
Transfers into Level 3	50	45
Transfers out of Level 3	(95)	(110)
Ending balance	1,861	1,589
Significant Unobservable Inputs (Level 3) \| Fair Value, Measurements, Recurring \| Securities available-for-sale and other \| Foreign government/government agencies \| Total fixed maturities
Assets
Beginning balance	0	5
Total realized/unrealized gains (losses), Included in net income		(1)
Total realized/unrealized gains (losses), Included in OCI		0
Purchases		0
Settlements		0
Sales		(7)
Transfers into Level 3		3
Transfers out of Level 3		0
Ending balance		0
Significant Unobservable Inputs (Level 3) \| Fair Value, Measurements, Recurring \| Securities available-for-sale and other \| Residential mortgage-backed securities ("RMBS") \| Total fixed maturities
Assets
Beginning balance	95	328
Total realized/unrealized gains (losses), Included in net income	0	0
Total realized/unrealized gains (losses), Included in OCI	0	(14)
Purchases	40	137
Settlements	(29)	(95)
Sales	0	0
Transfers into Level 3	0	0
Transfers out of Level 3	(70)	(261)
Ending balance	36	95
Significant Unobservable Inputs (Level 3) \| Fair Value, Measurements, Recurring \| Fair Value Option, Other Eligible Items \| CLO \| Total fixed maturities
Assets
Beginning balance	178	160
Total realized/unrealized gains (losses), Included in net income	(1)	(24)
Total realized/unrealized gains (losses), Included in OCI	0	0
Purchases	0	55
Settlements	(10)	(13)
Sales	0	0
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Ending balance	$ 167	$ 178

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).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
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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).

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition

Amount of purchases 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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- Definition

Amount of sale 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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- Definition

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

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-Topic 820
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-Name Accounting Standards Codification
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Amount of transfers of financial instrument classified as an asset 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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- Definition

Indicates line item in statement in which net income is reported that includes gain (loss) from asset measured at fair value using unobservable input (level 3).

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