Liabilities Measured at Fair Value on Recurring Basis and Utilized Significant Unobservable (Level 3) Inputs to Determine Fair Value (Detail) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	$ 191	$ 199	$ 189	$ 217
Total realized and unrealized (gains) losses included in net (income)	10	9	18	6
Total realized and unrealized (gains) losses included in OCI	13	0	13	0
Purchases	0	0	0	0
Sales	0	0	0	0
Issuances	3	2	7	7
Settlements	(8)	(11)	(17)	(30)
Transfer into Level 3	0	0	0	0
Transfer out of Level 3	0	(1)	(1)	(2)
Ending balance	209	198	209	198
Total (gains) losses included in net (income) attributable to liabilities still held	10	6	18	3
Total (gains) losses included in OCI attributable to liabilities still held	13	0	13	0
Derivative liabilities
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	13	0	9	0
Total realized and unrealized (gains) losses included in net (income)	7	3	11	3
Total realized and unrealized (gains) losses included in OCI	13	0	13	0
Purchases	0	0	0	0
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	0	0	0	0
Transfer into Level 3	0	0	0	0
Transfer out of Level 3	0	0	0	0
Ending balance	33	3	33	3
Total (gains) losses included in net (income) attributable to liabilities still held	7	0	11	0
Total (gains) losses included in OCI attributable to liabilities still held	13	0	13	0
Forward bond purchase commitments \| Derivative liabilities
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	13	0	9	0
Total realized and unrealized (gains) losses included in net (income)	7	3	11	3
Total realized and unrealized (gains) losses included in OCI	13	0	13	0
Purchases	0	0	0	0
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	0	0	0	0
Transfer into Level 3	0	0	0	0
Transfer out of Level 3	0	0	0	0
Ending balance	33	3	33	3
Total (gains) losses included in net (income) attributable to liabilities still held	7	0	11	0
Total (gains) losses included in OCI attributable to liabilities still held	13	0	13	0
Policyholder account balances
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	178	199	180	217
Total realized and unrealized (gains) losses included in net (income)	3	6	7	3
Total realized and unrealized (gains) losses included in OCI	0	0	0	0
Purchases	0	0	0	0
Sales	0	0	0	0
Issuances	3	2	7	7
Settlements	(8)	(11)	(17)	(30)
Transfer into Level 3	0	0	0	0
Transfer out of Level 3	0	(1)	(1)	(2)
Ending balance	176	195	176	195
Total (gains) losses included in net (income) attributable to liabilities still held	3	6	7	3
Total (gains) losses included in OCI attributable to liabilities still held	0	0	0	0
Policyholder account balances \| Fixed indexed annuity embedded derivatives
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	163	184	165	202
Total realized and unrealized (gains) losses included in net (income)	5	8	13	10
Total realized and unrealized (gains) losses included in OCI	0	0	0	0
Purchases	0	0	0	0
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	(8)	(11)	(17)	(30)
Transfer into Level 3	0	0	0	0
Transfer out of Level 3	0	(1)	(1)	(2)
Ending balance	160	180	160	180
Total (gains) losses included in net (income) attributable to liabilities still held	5	8	13	10
Total (gains) losses included in OCI attributable to liabilities still held	0	0	0	0
Policyholder account balances \| Indexed universal life embedded derivatives
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	15	15	15	15
Total realized and unrealized (gains) losses included in net (income)	(2)	(2)	(6)	(7)
Total realized and unrealized (gains) losses included in OCI	0	0	0	0
Purchases	0	0	0	0
Sales	0	0	0	0
Issuances	3	2	7	7
Settlements	0	0	0	0
Transfer into Level 3	0	0	0	0
Transfer out of Level 3	0	0	0	0
Ending balance	16	15	16	15
Total (gains) losses included in net (income) attributable to liabilities still held	(2)	(2)	(6)	(7)
Total (gains) losses included in OCI attributable to liabilities still held	$ 0	$ 0	$ 0	$ 0

Amount of unrealized gain (loss) recognized in income from liability measured at fair value on recurring basis using unobservable input (level 3) and still held.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482106/820-10-50-2

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Amount of unrealized gain (loss) recognized in other comprehensive income (OCI) from liability measured at fair value on recurring basis using unobservable input (level 3) and still held.

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Amount of transfers of financial instrument classified as a liability into level 3 of the fair value hierarchy.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(3)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482106/820-10-50-2

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Amount of transfers of financial instrument classified as a liability out of level 3 of the fair value hierarchy.

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Amount of gain (loss) recognized in income from liability measured at fair value on recurring basis using unobservable input (level 3).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482106/820-10-50-2

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Amount of gain (loss) recognized in other comprehensive income (OCI) from liability measured at fair value on recurring basis using unobservable input (level 3).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482106/820-10-50-2

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Amount of issuances of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
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-SubTopic 10
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Amount of purchases of financial instrument classified as a liability 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 sales of financial instrument classified as a liability 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 settlements of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Fair value of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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