FAIR VALUE MEASUREMENTS - Fair Value Hierarchy Levels of Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Assets:
Fixed maturity securities, available-for-sale	$ 66,259	$ 73,290
Equity securities	728	1,088
Other investments	3,380	1,304
Cash and cash equivalents	6,060	4,306
Asset derivatives	316	337
Total assets	76,743	80,325
Liabilities:
Liability derivatives	1,324	1,430
Total liabilities	1,324	1,430
Foreign currency swaps
Assets:
Asset derivatives	74	86
Liabilities:
Liability derivatives	700	507
Foreign currency forwards
Assets:
Asset derivatives	235	238
Liabilities:
Liability derivatives		504
Foreign currency options
Assets:
Asset derivatives	7	2
Liabilities:
Liability derivatives	173
Interest rate swaps
Assets:
Asset derivatives		11
Liabilities:
Liability derivatives	451	419
Government and agencies
Assets:
Fixed maturity securities, available-for-sale	18,281	22,600
Municipalities
Assets:
Fixed maturity securities, available-for-sale	2,083	2,298
Mortgage- and asset-backed securities
Assets:
Fixed maturity securities, available-for-sale	3,703	3,086
Public utilities
Assets:
Fixed maturity securities, available-for-sale	6,826	7,592
Sovereign and supranational
Assets:
Fixed maturity securities, available-for-sale	460	537
Banks/financial institutions
Assets:
Fixed maturity securities, available-for-sale	8,699	8,835
Other corporate
Assets:
Fixed maturity securities, available-for-sale	26,207	28,342
Level 1
Assets:
Fixed maturity securities, available-for-sale	17,520	21,700
Equity securities	571	840
Other investments	3,380	1,304
Cash and cash equivalents	6,060	4,306
Asset derivatives	0	0
Total assets	27,531	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	17,520	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	46,683	49,809
Equity securities	0	0
Other investments	0	0
Cash and cash equivalents	0	0
Asset derivatives	316	337
Total assets	46,999	50,146
Liabilities:
Total liabilities	1,324	1,430
Level 2 | Foreign currency swaps
Assets:
Asset derivatives	74	86
Liabilities:
Liability derivatives	700	507
Level 2 | Foreign currency forwards
Assets:
Asset derivatives	235	238
Liabilities:
Liability derivatives		504
Level 2 | Foreign currency options
Assets:
Asset derivatives	7	2
Liabilities:
Liability derivatives	173
Level 2 | Interest rate swaps
Assets:
Asset derivatives		11
Liabilities:
Liability derivatives	451	419
Level 2 | Government and agencies
Assets:
Fixed maturity securities, available-for-sale	761	900
Level 2 | Municipalities
Assets:
Fixed maturity securities, available-for-sale	2,083	2,298
Level 2 | Mortgage- and asset-backed securities
Assets:
Fixed maturity securities, available-for-sale	2,490	2,314
Level 2 | Public utilities
Assets:
Fixed maturity securities, available-for-sale	6,461	7,339
Level 2 | Sovereign and supranational
Assets:
Fixed maturity securities, available-for-sale	435	507
Level 2 | Banks/financial institutions
Assets:
Fixed maturity securities, available-for-sale	8,630	8,757
Level 2 | Other corporate
Assets:
Fixed maturity securities, available-for-sale	25,823	27,694
Level 3
Assets:
Fixed maturity securities, available-for-sale	2,056	1,781
Equity securities	157	248
Other investments	0	0
Cash and cash equivalents	0	0
Asset derivatives	0	0
Total assets	2,213	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	1,213	772
Level 3 | Public utilities
Assets:
Fixed maturity securities, available-for-sale	365	253
Level 3 | Sovereign and supranational
Assets:
Fixed maturity securities, available-for-sale	25	30
Level 3 | Banks/financial institutions
Assets:
Fixed maturity securities, available-for-sale	69	78
Level 3 | Other corporate
Assets:
Fixed maturity securities, available-for-sale	$ 384	$ 648