Fair Value Measurements - Fair Value Recurring Basis, Unobservable Input (Details) - Fair Value, Measurements, Recurring - Significant Unobservable Inputs (Level 3) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2023	Mar. 31, 2022
Assets
Beginning balance	$ 2,483	$ 2,708
Total realized/unrealized gains (losses), Included in net income	(8)	7
Total realized/unrealized gains (losses), Included in OCI	26	(71)
Purchases	148	339
Settlements	(69)	(146)
Sales	(7)	(8)
Transfers into Level 3	37	0
Transfers out of Level 3	(73)	(277)
Ending balance	2,537	2,552
Equity securities, at fair value
Assets
Beginning balance	61	64
Total realized/unrealized gains (losses), Included in net income	(1)	7
Total realized/unrealized gains (losses), Included in OCI	0	0
Purchases	1	0
Settlements	(1)	(14)
Sales	0	0
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Ending balance	60	57
Short-term investments
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	1	4
Settlements	(7)	(2)
Sales	0	0
Transfers into Level 3	0	0
Transfers out of Level 3	0	(50)
Ending balance	187	32
Securities available-for-sale and other \| Total Fixed Maturities, AFS
Assets
Beginning balance	2,051	2,404
Total realized/unrealized gains (losses), Included in net income	1	(2)
Total realized/unrealized gains (losses), Included in OCI	26	(71)
Purchases	146	315
Settlements	(63)	(122)
Sales	(7)	(8)
Transfers into Level 3	37	0
Transfers out of Level 3	(73)	(227)
Ending balance	2,118	2,289
Securities available-for-sale and other \| ABS \| Total Fixed Maturities, AFS
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	36	19
Settlements	0	0
Sales	0	0
Transfers into Level 3	0	0
Transfers out of Level 3	(30)	0
Ending balance	36	19
Securities available-for-sale and other \| Collateralized Loan Obligations [Member] \| Total Fixed Maturities, AFS
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	(1)
Purchases	40	54
Settlements	(4)	(17)
Sales	0	0
Transfers into Level 3	0	0
Transfers out of Level 3	0	(79)
Ending balance	151	214
Securities available-for-sale and other \| CMBS \| Total Fixed Maturities, AFS
Assets
Beginning balance	222	196
Total realized/unrealized gains (losses), Included in net income	0	0
Total realized/unrealized gains (losses), Included in OCI	(5)	(5)
Purchases	4	46
Settlements	0	(1)
Sales	0	0
Transfers into Level 3	10	0
Transfers out of Level 3	0	0
Ending balance	231	236
Securities available-for-sale and other \| Corporate \| Total Fixed Maturities, AFS
Assets
Beginning balance	1,589	1,618
Total realized/unrealized gains (losses), Included in net income	1	(2)
Total realized/unrealized gains (losses), Included in OCI	31	(59)
Purchases	66	59
Settlements	(51)	(70)
Sales	(7)	(7)
Transfers into Level 3	27	0
Transfers out of Level 3	(13)	(24)
Ending balance	1,643	1,515
Securities available-for-sale and other \| Foreign government/government agencies \| Total Fixed Maturities, AFS
Assets
Beginning balance		5
Total realized/unrealized gains (losses), Included in net income		0
Total realized/unrealized gains (losses), Included in OCI		0
Purchases		0
Settlements		0
Sales		(1)
Transfers into Level 3		0
Transfers out of Level 3		0
Ending balance		4
Securities available-for-sale and other \| RMBS \| Total Fixed Maturities, AFS
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	(6)
Purchases	0	137
Settlements	(8)	(34)
Sales	0	0
Transfers into Level 3	0	0
Transfers out of Level 3	(30)	(124)
Ending balance	57	301
Fair Value Option, Other Eligible Items \| Collateralized Loan Obligations [Member] \| Total Fixed Maturities, AFS
Assets
Beginning balance	178	160
Total realized/unrealized gains (losses), Included in net income	(8)	2
Total realized/unrealized gains (losses), Included in OCI	0	0
Purchases	0	20
Settlements	2	(8)
Sales	0	0
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Ending balance	$ 172	$ 174

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
-Publisher FASB
-Name Accounting Standards Codification
-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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- 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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Amount of settlement 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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-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
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- Definition

Amount of transfers of financial instrument classified as an asset out of level 3 of the fair value hierarchy.

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- Definition

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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