FAIR VALUE MEASUREMENTS - Fair Value Hierarchy Levels of Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Assets:
Fixed maturity securities, available-for-sale	$ 70,130	$ 73,290
Equity securities	762	1,088
Other investments	3,341	1,304
Cash and cash equivalents	5,098	4,306
Asset derivatives	$ 321	$ 337
Derivative Asset, Statement of Financial Position [Extensible Enumeration]	Other	Other
Total assets	$ 79,652	$ 80,325
Liabilities:
Liability derivatives	1,135	1,430
Total liabilities	1,135	1,430
Foreign currency swaps
Assets:
Asset derivatives	81	86
Liabilities:
Liability derivatives	583	507
Foreign currency forwards
Assets:
Asset derivatives	202	238
Liabilities:
Liability derivatives		504
Foreign currency options
Assets:
Asset derivatives	38	2
Liabilities:
Liability derivatives	69
Interest rate swaps
Assets:
Asset derivatives		11
Liabilities:
Liability derivatives	483	419
Government and agencies
Assets:
Fixed maturity securities, available-for-sale	20,814	22,600
Municipalities
Assets:
Fixed maturity securities, available-for-sale	2,210	2,298
Mortgage- and asset-backed securities
Assets:
Fixed maturity securities, available-for-sale	3,385	3,086
Public utilities
Assets:
Fixed maturity securities, available-for-sale	7,313	7,592
Sovereign and supranational
Assets:
Fixed maturity securities, available-for-sale	490	537
Banks/financial institutions
Assets:
Fixed maturity securities, available-for-sale	8,899	8,835
Other corporate
Assets:
Fixed maturity securities, available-for-sale	27,019	28,342
Level 1
Assets:
Fixed maturity securities, available-for-sale	19,976	21,700
Equity securities	603	840
Other investments	3,341	1,304
Cash and cash equivalents	5,098	4,306
Asset derivatives	0	0
Total assets	29,018	28,150
Liabilities:
Total liabilities	0	0
Level 1 | Foreign currency swaps
Assets:
Asset derivatives	0	0
Liabilities:
Liability derivatives	0	0
Level 1 | Foreign currency forwards
Assets:
Asset derivatives	0	0
Liabilities:
Liability derivatives		0
Level 1 | Foreign currency options
Assets:
Asset derivatives	0	0
Liabilities:
Liability derivatives	0
Level 1 | Interest rate swaps
Assets:
Asset derivatives		0
Liabilities:
Liability derivatives	0	0
Level 1 | Government and agencies
Assets:
Fixed maturity securities, available-for-sale	19,976	21,700
Level 1 | Municipalities
Assets:
Fixed maturity securities, available-for-sale	0	0
Level 1 | Mortgage- and asset-backed securities
Assets:
Fixed maturity securities, available-for-sale	0	0
Level 1 | Public utilities
Assets:
Fixed maturity securities, available-for-sale	0	0
Level 1 | Sovereign and supranational
Assets:
Fixed maturity securities, available-for-sale	0	0
Level 1 | Banks/financial institutions
Assets:
Fixed maturity securities, available-for-sale	0	0
Level 1 | Other corporate
Assets:
Fixed maturity securities, available-for-sale	0	0
Level 2
Assets:
Fixed maturity securities, available-for-sale	48,236	49,809
Equity securities	0	0
Other investments	0	0
Cash and cash equivalents	0	0
Asset derivatives	321	337
Total assets	48,557	50,146
Liabilities:
Total liabilities	1,135	1,430
Level 2 | Foreign currency swaps
Assets:
Asset derivatives	81	86
Liabilities:
Liability derivatives	583	507
Level 2 | Foreign currency forwards
Assets:
Asset derivatives	202	238
Liabilities:
Liability derivatives		504
Level 2 | Foreign currency options
Assets:
Asset derivatives	38	2
Liabilities:
Liability derivatives	69
Level 2 | Interest rate swaps
Assets:
Asset derivatives		11
Liabilities:
Liability derivatives	483	419
Level 2 | Government and agencies
Assets:
Fixed maturity securities, available-for-sale	838	900
Level 2 | Municipalities
Assets:
Fixed maturity securities, available-for-sale	2,210	2,298
Level 2 | Mortgage- and asset-backed securities
Assets:
Fixed maturity securities, available-for-sale	2,526	2,314
Level 2 | Public utilities
Assets:
Fixed maturity securities, available-for-sale	6,806	7,339
Level 2 | Sovereign and supranational
Assets:
Fixed maturity securities, available-for-sale	462	507
Level 2 | Banks/financial institutions
Assets:
Fixed maturity securities, available-for-sale	8,825	8,757
Level 2 | Other corporate
Assets:
Fixed maturity securities, available-for-sale	26,569	27,694
Level 3
Assets:
Fixed maturity securities, available-for-sale	1,918	1,781
Equity securities	159	248
Other investments	0	0
Cash and cash equivalents	0	0
Asset derivatives	0	0
Total assets	2,077	2,029
Liabilities:
Total liabilities	0	0
Level 3 | Foreign currency swaps
Assets:
Asset derivatives	0	0
Liabilities:
Liability derivatives	0	0
Level 3 | Foreign currency forwards
Assets:
Asset derivatives	0	0
Liabilities:
Liability derivatives		0
Level 3 | Foreign currency options
Assets:
Asset derivatives	0	0
Liabilities:
Liability derivatives	0
Level 3 | Interest rate swaps
Assets:
Asset derivatives		0
Liabilities:
Liability derivatives	0	0
Level 3 | Government and agencies
Assets:
Fixed maturity securities, available-for-sale	0	0
Level 3 | Municipalities
Assets:
Fixed maturity securities, available-for-sale	0	0
Level 3 | Mortgage- and asset-backed securities
Assets:
Fixed maturity securities, available-for-sale	859	772
Level 3 | Public utilities
Assets:
Fixed maturity securities, available-for-sale	507	253
Level 3 | Sovereign and supranational
Assets:
Fixed maturity securities, available-for-sale	28	30
Level 3 | Banks/financial institutions
Assets:
Fixed maturity securities, available-for-sale	74	78
Level 3 | Other corporate
Assets:
Fixed maturity securities, available-for-sale	$ 450	$ 648