FAIR VALUE MEASUREMENTS - Fair Value Hierarchy Levels of Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Assets:
Fixed maturity securities, available-for-sale	$ 72,292	$ 73,290
Equity securities	808	1,088
Other investments	3,533	1,304
Cash and cash equivalents	5,612	4,306
Asset derivatives	199	337
Total assets	82,444	80,325
Liabilities:
Liability derivatives	921	1,430
Total liabilities	921	1,430
Foreign currency swaps
Assets:
Asset derivatives	60	86
Liabilities:
Liability derivatives	623	507
Foreign currency forwards
Assets:
Asset derivatives	63	238
Liabilities:
Liability derivatives	35	504
Foreign currency options
Assets:
Asset derivatives	57	2
Liabilities:
Liability derivatives	24
Interest rate swaps
Assets:
Asset derivatives	19	11
Liabilities:
Liability derivatives	239	419
Government and agencies
Assets:
Fixed maturity securities, available-for-sale	20,941	22,600
Municipalities
Assets:
Fixed maturity securities, available-for-sale	2,230	2,298
Mortgage- and asset-backed securities
Assets:
Fixed maturity securities, available-for-sale	3,730	3,086
Public utilities
Assets:
Fixed maturity securities, available-for-sale	7,474	7,592
Sovereign and supranational
Assets:
Fixed maturity securities, available-for-sale	494	537
Banks/financial institutions
Assets:
Fixed maturity securities, available-for-sale	9,760	8,835
Other corporate
Assets:
Fixed maturity securities, available-for-sale	27,663	28,342
Level 1
Assets:
Fixed maturity securities, available-for-sale	20,089	21,700
Equity securities	647	840
Other investments	3,533	1,304
Cash and cash equivalents	5,612	4,306
Asset derivatives	0	0
Total assets	29,881	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	0
Level 1 | Foreign currency options
Assets:
Asset derivatives	0	0
Liabilities:
Liability derivatives	0
Level 1 | Interest rate swaps
Assets:
Asset derivatives	0	0
Liabilities:
Liability derivatives	0	0
Level 1 | Government and agencies
Assets:
Fixed maturity securities, available-for-sale	20,089	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	50,012	49,809
Equity securities	0	0
Other investments	0	0
Cash and cash equivalents	0	0
Asset derivatives	199	337
Total assets	50,211	50,146
Liabilities:
Total liabilities	921	1,430
Level 2 | Foreign currency swaps
Assets:
Asset derivatives	60	86
Liabilities:
Liability derivatives	623	507
Level 2 | Foreign currency forwards
Assets:
Asset derivatives	63	238
Liabilities:
Liability derivatives	35	504
Level 2 | Foreign currency options
Assets:
Asset derivatives	57	2
Liabilities:
Liability derivatives	24
Level 2 | Interest rate swaps
Assets:
Asset derivatives	19	11
Liabilities:
Liability derivatives	239	419
Level 2 | Government and agencies
Assets:
Fixed maturity securities, available-for-sale	852	900
Level 2 | Municipalities
Assets:
Fixed maturity securities, available-for-sale	2,230	2,298
Level 2 | Mortgage- and asset-backed securities
Assets:
Fixed maturity securities, available-for-sale	2,521	2,314
Level 2 | Public utilities
Assets:
Fixed maturity securities, available-for-sale	6,904	7,339
Level 2 | Sovereign and supranational
Assets:
Fixed maturity securities, available-for-sale	466	507
Level 2 | Banks/financial institutions
Assets:
Fixed maturity securities, available-for-sale	9,750	8,757
Level 2 | Other corporate
Assets:
Fixed maturity securities, available-for-sale	27,289	27,694
Level 3
Assets:
Fixed maturity securities, available-for-sale	2,191	1,781
Equity securities	161	248
Other investments	0	0
Cash and cash equivalents	0	0
Asset derivatives	0	0
Total assets	2,352	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	0
Level 3 | Foreign currency options
Assets:
Asset derivatives	0	0
Liabilities:
Liability derivatives	0
Level 3 | Interest rate swaps
Assets:
Asset derivatives	0	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	1,209	772
Level 3 | Public utilities
Assets:
Fixed maturity securities, available-for-sale	570	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	10	78
Level 3 | Other corporate
Assets:
Fixed maturity securities, available-for-sale	$ 374	$ 648