Investments - Analysis of Cost or Amortized Cost, Gross Unrealized Gains and Losses and Fair Value for Investments (Detail) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Debt Securities, Available-for-sale
Total	$ 12,812	$ 12,230
Gross unrealized gain	37	808
Gross unrealized loss	1,115	16
Fixed maturities, at fair value	11,734	13,022
Corporate
Debt Securities, Available-for-sale
Total	7,307	7,043
Gross unrealized gain	33	467
Gross unrealized loss	661	13
Fixed maturities, at fair value	6,679	7,497
States, municipalities and political subdivisions
Debt Securities, Available-for-sale
Total	4,911	4,768
Gross unrealized gain	4	330
Gross unrealized loss	433	3
Fixed maturities, at fair value	4,482	5,095
Commercial mortgage-backed
Debt Securities, Available-for-sale
Total	253	264
Gross unrealized gain	0	9
Gross unrealized loss	13	0
Fixed maturities, at fair value	240	273
United States government
Debt Securities, Available-for-sale
Total	193	121
Gross unrealized gain	0	2
Gross unrealized loss	5	0
Fixed maturities, at fair value	188	123
Government-sponsored enterprises
Debt Securities, Available-for-sale
Total	122	8
Gross unrealized gain	0	0
Gross unrealized loss	3	0
Fixed maturities, at fair value	119	8
Foreign government
Debt Securities, Available-for-sale
Total	26	26
Gross unrealized gain	0	0
Gross unrealized loss	0	0
Fixed maturities, at fair value	26	26
Debt Securities
Debt Securities, Available-for-sale
Gross unrealized loss	1,115	16
Debt Securities \| Corporate
Debt Securities, Available-for-sale
Gross unrealized loss	661	13
Debt Securities \| States, municipalities and political subdivisions
Debt Securities, Available-for-sale
Gross unrealized loss	433	3
Debt Securities \| Commercial mortgage-backed
Debt Securities, Available-for-sale
Gross unrealized loss	13	0
Debt Securities \| United States government
Debt Securities, Available-for-sale
Gross unrealized loss	5	0
Debt Securities \| Government-sponsored enterprises
Debt Securities, Available-for-sale
Gross unrealized loss	3	0
Debt Securities \| Foreign government
Debt Securities, Available-for-sale
Gross unrealized loss	$ 0	$ 0

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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-Publisher FASB
-Name Accounting Standards Codification
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Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126970911&loc=d3e27161-111563

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI https://asc.fasb.org/extlink&oid=124258926&loc=SL82898722-210454

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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