FAIR VALUE MEASUREMENTS - Changes in Investments and Derivatives Carried at Fair Value Classified as Level 3 (Detail) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	$ 1,140	$ 690	$ 1,021	$ 810
Net investment gains (losses) included in earnings	(107)	(20)	(79)	(205)
Unrealized gains (losses) included in other comprehensive income (loss)	22	0	(28)	(29)
Purchases	70	31	174	116
Issuances	17	0	17	0
Sales	(23)	(1)	(23)	(1)
Settlements	(24)	(5)	(27)	(5)
Transfers into Level 3	0	15	55	24
Transfers out of Level 3	0	(15)	(15)	(15)
Balance, end of period	1,095	695	1,095	695
Change in unrealized gains (losses) still held	(120)	(20)	(101)	(205)
Foreign currency swaps
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Balance, beginning of period	(80)	(146)	(98)	43
Net investment gains (losses) included in earnings	(120)	(20)	(101)	(205)
Unrealized gains or losses included in other comprehensive income (loss)	0	(2)	(1)	(6)
Purchases	0	0	0	0
Issuances	0	0	0	0
Sales	0	0	0	0
Settlements	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Balance, end of period	(200)	(168)	(200)	(168)
Changes in unrealized gain (losses) still held	(120)	(20)	(101)	(205)
Fixed maturity securities \| Mortgage- and asset-backed securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	204	188	224	178
Net investment gains (losses) included in earnings	0	0	0	0
Unrealized gains (losses) included in other comprehensive income (loss)	0	1	(15)	2
Purchases	54	0	64	0
Issuances	0	0	0	0
Sales	0	0	0	0
Settlements	0	(1)	0	(1)
Transfers into Level 3	0	0	0	9
Transfers out of Level 3	0	0	(15)	0
Balance, end of period	258	188	258	188
Change in unrealized gains (losses) still held	0	0	0	0
Fixed maturity securities \| Public utilities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	479	298	422	224
Net investment gains (losses) included in earnings	0	0	0	0
Unrealized gains (losses) included in other comprehensive income (loss)	8	0	(10)	(9)
Purchases	0	13	78	96
Issuances	0	0	0	0
Sales	0	0	0	0
Settlements	(7)	(4)	(10)	(4)
Transfers into Level 3	0	15	0	15
Transfers out of Level 3	0	0	0	0
Balance, end of period	480	322	480	322
Change in unrealized gains (losses) still held	0	0	0	0
Fixed maturity securities \| Sovereign and supranational
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	68		48
Net investment gains (losses) included in earnings	0		0
Unrealized gains (losses) included in other comprehensive income (loss)	0		(3)
Purchases	0		0
Issuances	0		0
Sales	(23)		(23)
Settlements	0		0
Transfers into Level 3	0		23
Transfers out of Level 3	0		0
Balance, end of period	45		45
Change in unrealized gains (losses) still held	0		0
Fixed maturity securities \| Banks/financial institutions
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	28	23	24	23
Net investment gains (losses) included in earnings	0	0	0	0
Unrealized gains (losses) included in other comprehensive income (loss)	0	0	(1)	0
Purchases	10	1	15	1
Issuances	0	0	0	0
Sales	0	0	0	0
Settlements	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Balance, end of period	38	24	38	24
Change in unrealized gains (losses) still held	0	0	0	0
Fixed maturity securities \| Other corporate
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	319	245	299	262
Net investment gains (losses) included in earnings	0	0	0	0
Unrealized gains (losses) included in other comprehensive income (loss)	14	1	2	(16)
Purchases	0	12	0	12
Issuances	0	0	0	0
Sales	0	0	0	0
Settlements	(17)	0	(17)	0
Transfers into Level 3	0	0	32	0
Transfers out of Level 3	0	(15)	0	(15)
Balance, end of period	316	243	316	243
Change in unrealized gains (losses) still held	0	0	0	0
Equity securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	122	82	102	80
Net investment gains (losses) included in earnings	13	0	22	0
Unrealized gains (losses) included in other comprehensive income (loss)	0	0	0	0
Purchases	6	5	17	7
Issuances	17	0	17	0
Sales	0	(1)	0	(1)
Settlements	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Balance, end of period	158	86	158	86
Change in unrealized gains (losses) still held	$ 0	$ 0	$ 0	$ 0

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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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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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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Amount of issuances 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 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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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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Amount of unrealized gain (loss) recognized in income for derivative asset (liability) after deduction of derivative liability (asset), measured at fair value using unobservable input (level 3) and still held.

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

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

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Amount of issuances of financial instrument classified as a derivative asset (liability) after deduction of derivative liability (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 purchases of financial instrument classified as a derivative asset (liability) after deduction of derivative liability (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 sales of financial instrument classified as a derivative asset (liability) after deduction of derivative liability (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 settlements of financial instrument classified as a derivative asset (liability) after deduction of derivative 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 transfers of financial instrument classified as a derivative asset (liability) after deduction of derivative liability (asset) into level 3 of the fair value hierarchy.

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Amount of transfers of financial instrument classified as derivative asset (liability) after deduction of derivative liability (asset) out of level 3 of the fair value hierarchy.

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Fair value of financial instrument classified as derivative asset (liability) after deduction of derivative liability (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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