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	9 Months Ended
Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Assets
Beginning balance	$ 2,445	$ 2,010	$ 2,708	$ 1,805
Total realized/unrealized gains (losses), Included in net income	(3)	4	(7)	12
Total realized/unrealized gains (losses), Included in OCI	(56)	(8)	(242)	(19)
Purchases	146	471	846	1,222
Settlements	(58)	(120)	(329)	(362)
Sales	(11)	(1)	(33)	(65)
Transfers into Level 3	24	0	48	177
Transfers out of Level 3	(58)	(182)	(562)	(596)
Ending balance	2,429	2,174	2,429	2,174
Equity securities, at fair value
Assets
Beginning balance	60	74	64	70
Total realized/unrealized gains (losses), Included in net income	1	4	10	6
Total realized/unrealized gains (losses), Included in OCI	0	0	0	0
Purchases	0	2	2	5
Settlements	0	(9)	(15)	(10)
Sales	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Ending balance	61	71	61	71
Short-term investments
Assets
Beginning balance	60	18	80	30
Total realized/unrealized gains (losses), Included in net income	0	0	0	0
Total realized/unrealized gains (losses), Included in OCI	0	0	0	0
Purchases	36	8	72	10
Settlements	(3)	(3)	(9)	(17)
Sales	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	(50)	0
Ending balance	93	23	93	23
Securities available-for-sale and other \| Total Fixed Maturities, AFS
Assets
Beginning balance	2,132	1,918	2,404	1,705
Total realized/unrealized gains (losses), Included in net income	0	0	(2)	6
Total realized/unrealized gains (losses), Included in OCI	(56)	(8)	(242)	(19)
Purchases	110	386	717	1,132
Settlements	(52)	(108)	(291)	(335)
Sales	(11)	(1)	(33)	(65)
Transfers into Level 3	24	0	48	177
Transfers out of Level 3	(58)	(182)	(512)	(596)
Ending balance	2,089	2,005	2,089	2,005
Securities available-for-sale and other \| ABS \| Total Fixed Maturities, AFS
Assets
Beginning balance		14	0	0
Total realized/unrealized gains (losses), Included in net income		0	0	0
Total realized/unrealized gains (losses), Included in OCI		0	0	0
Purchases		23	19	42
Settlements		0	0	0
Sales		0	0	0
Transfers into Level 3		0	0	0
Transfers out of Level 3		(14)	(19)	(19)
Ending balance	0	23	0	23
Securities available-for-sale and other \| Collateralized Loan Obligations [Member] \| Total Fixed Maturities, AFS
Assets
Beginning balance	164	375	257	360
Total realized/unrealized gains (losses), Included in net income	0	0	0	0
Total realized/unrealized gains (losses), Included in OCI	0	0	(2)	0
Purchases	31	132	113	391
Settlements	(13)	(34)	(53)	(79)
Sales	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	(27)	(119)	(160)	(318)
Ending balance	155	354	155	354
Securities available-for-sale and other \| CMBS \| Total Fixed Maturities, AFS
Assets
Beginning balance	224	86	196	77
Total realized/unrealized gains (losses), Included in net income	0	0	0	0
Total realized/unrealized gains (losses), Included in OCI	(1)	0	(16)	2
Purchases	4	29	50	68
Settlements	(7)	0	(10)	(3)
Sales	0	0	0	0
Transfers into Level 3	0	0	0	5
Transfers out of Level 3	0	(14)	0	(48)
Ending balance	220	101	220	101
Securities available-for-sale and other \| Corporate \| Total Fixed Maturities, AFS
Assets
Beginning balance	1,609	1,141	1,618	881
Total realized/unrealized gains (losses), Included in net income	(1)	0	(2)	6
Total realized/unrealized gains (losses), Included in OCI	(52)	(7)	(210)	(18)
Purchases	75	156	398	405
Settlements	(13)	(29)	(145)	(105)
Sales	(9)	(1)	(30)	(45)
Transfers into Level 3	24	0	45	172
Transfers out of Level 3	(31)	(6)	(72)	(42)
Ending balance	1,602	1,254	1,602	1,254
Securities available-for-sale and other \| Foreign government/government agencies \| Total Fixed Maturities, AFS
Assets
Beginning balance	5	0	5	6
Total realized/unrealized gains (losses), Included in net income	1	0	0	0
Total realized/unrealized gains (losses), Included in OCI	0	0	(1)	0
Purchases	0	5	0	5
Settlements	0	0	0	0
Sales	(2)	0	(3)	(6)
Transfers into Level 3	0	0	3	0
Transfers out of Level 3	0	0	0	0
Ending balance	4	5	4	5
Securities available-for-sale and other \| RMBS \| Total Fixed Maturities, AFS
Assets
Beginning balance	130	302	328	381
Total realized/unrealized gains (losses), Included in net income	0	0	0	0
Total realized/unrealized gains (losses), Included in OCI	(3)	(1)	(13)	(3)
Purchases	0	41	137	221
Settlements	(19)	(45)	(83)	(148)
Sales	0	0	0	(14)
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	(29)	(261)	(169)
Ending balance	108	268	108	268
Fair Value Option, Other Eligible Items \| Collateralized Loan Obligations [Member] \| Total Fixed Maturities, AFS
Assets
Beginning balance	193	0	160	0
Total realized/unrealized gains (losses), Included in net income	(4)	0	(15)	0
Total realized/unrealized gains (losses), Included in OCI	0	0	0	0
Purchases	0	75	55	75
Settlements	(3)	0	(14)	0
Sales	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Ending balance	$ 186	$ 75	$ 186	$ 75

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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- 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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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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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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