Fair Value Measurements (Details) - Changes in Level 3 - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2022	Dec. 31, 2021
Changes in Level 3 fair value category [Roll Forward]
Level 3 fair value category, beginning balance	$ 596	$ 201
Level 3 fair value category, total realized and unrealized investment gains (losses) reported in net realized investment gains (losses)	$ 36	$ 5
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Net realized investment gains (losses)	Net realized investment gains (losses)
Level 3 fair value category, total unrealized investment gains (losses) reported in increases in other comprehensive income (loss)	$ (13)	$ (3)
Level 3 fair value category purchases	233	534
Level 3 fair value category sales	(1)	0
Level 3 fair value category settlements/maturities	(57)	(48)
Gross transfers into Level 3	3	0
Gross transfers out of Level 3	(122)	(93)
Level 3 fair value category, ending balance	675	596
Amount of total realized investment gains (losses) for the period included in the consolidated statement of income attributable to changes in the fair value of assets still held at the reporting date	$ 34	$ 6
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Net realized investment gains (losses)	Net realized investment gains (losses)
Fixed maturities [Member]
Changes in Level 3 fair value category [Roll Forward]
Level 3 fair value category, beginning balance	$ 248	$ 166
Level 3 fair value category, total realized and unrealized investment gains (losses) reported in net realized investment gains (losses)	1	(1)
Level 3 fair value category, total unrealized investment gains (losses) reported in increases in other comprehensive income (loss)	(13)	(3)
Level 3 fair value category purchases	226	227
Level 3 fair value category sales	0	0
Level 3 fair value category settlements/maturities	(55)	(48)
Gross transfers into Level 3	0	0
Gross transfers out of Level 3	(104)	(93)
Level 3 fair value category, ending balance	303	248
Amount of total realized investment gains (losses) for the period included in the consolidated statement of income attributable to changes in the fair value of assets still held at the reporting date	0	0
Equity securities [Member]
Changes in Level 3 fair value category [Roll Forward]
Level 3 fair value category, beginning balance	343	31
Level 3 fair value category, total realized and unrealized investment gains (losses) reported in net realized investment gains (losses)	33	5
Level 3 fair value category, total unrealized investment gains (losses) reported in increases in other comprehensive income (loss)	0	0
Level 3 fair value category purchases	7	307
Level 3 fair value category sales	0	0
Level 3 fair value category settlements/maturities	0	0
Gross transfers into Level 3	3	0
Gross transfers out of Level 3	(15)	0
Level 3 fair value category, ending balance	371	343
Amount of total realized investment gains (losses) for the period included in the consolidated statement of income attributable to changes in the fair value of assets still held at the reporting date	33	5
Other investments [Member]
Changes in Level 3 fair value category [Roll Forward]
Level 3 fair value category, beginning balance	5	4
Level 3 fair value category, total realized and unrealized investment gains (losses) reported in net realized investment gains (losses)	2	1
Level 3 fair value category, total unrealized investment gains (losses) reported in increases in other comprehensive income (loss)	0	0
Level 3 fair value category purchases	0	0
Level 3 fair value category sales	(1)	0
Level 3 fair value category settlements/maturities	(2)	0
Gross transfers into Level 3	0	0
Gross transfers out of Level 3	(3)	0
Level 3 fair value category, ending balance	1	5
Amount of total realized investment gains (losses) for the period included in the consolidated statement of income attributable to changes in the fair value of assets still held at the reporting date	$ 1	$ 1

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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
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-Section 50
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Amount of unrealized gain (loss) recognized in income from asset measured at fair value on recurring basis using unobservable input (level 3) and still held.

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