FAIR VALUE MEASUREMENTS - Fair Value Hierarchy Levels of Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Assets:
Fixed maturity securities, available-for-sale	$ 69,801	$ 75,741
Equity securities	990	1,091
Other investments	2,288	1,532
Cash and cash equivalents	5,502	3,943
Asset derivatives	578	617
Total assets	79,159	82,924
Liabilities:
Liability derivatives	1,666	1,698
Total liabilities	1,666	1,698
Foreign currency swaps
Assets:
Asset derivatives	98	128
Liabilities:
Liability derivatives	442	390
Foreign currency forwards
Assets:
Asset derivatives	479	400
Liabilities:
Liability derivatives	588	725
Foreign currency options
Assets:
Asset derivatives	1	82
Interest rate swaps
Assets:
Asset derivatives		7
Liabilities:
Liability derivatives	636	583
Government and agencies
Assets:
Fixed maturity securities, available-for-sale	21,952	25,114
Municipalities
Assets:
Fixed maturity securities, available-for-sale	2,141	2,320
Mortgage- and asset-backed securities
Assets:
Fixed maturity securities, available-for-sale	2,996	2,146
Public utilities
Assets:
Fixed maturity securities, available-for-sale	7,250	7,666
Sovereign and supranational
Assets:
Fixed maturity securities, available-for-sale	511	834
Banks/financial institutions
Assets:
Fixed maturity securities, available-for-sale	8,341	9,299
Other corporate
Assets:
Fixed maturity securities, available-for-sale	26,610	28,362
Level 1
Assets:
Fixed maturity securities, available-for-sale	21,095	24,158
Equity securities	787	822
Other investments	2,288	1,532
Cash and cash equivalents	5,502	3,943
Asset derivatives	0	0
Total assets	29,672	30,455
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
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	21,095	24,158
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	47,102	49,805
Equity securities	0	60
Other investments	0	0
Cash and cash equivalents	0	0
Asset derivatives	578	617
Total assets	47,680	50,482
Liabilities:
Total liabilities	1,666	1,698
Level 2 | Foreign currency swaps
Assets:
Asset derivatives	98	128
Liabilities:
Liability derivatives	442	390
Level 2 | Foreign currency forwards
Assets:
Asset derivatives	479	400
Liabilities:
Liability derivatives	588	725
Level 2 | Foreign currency options
Assets:
Asset derivatives	1	82
Level 2 | Interest rate swaps
Assets:
Asset derivatives		7
Liabilities:
Liability derivatives	636	583
Level 2 | Government and agencies
Assets:
Fixed maturity securities, available-for-sale	857	956
Level 2 | Municipalities
Assets:
Fixed maturity securities, available-for-sale	2,141	2,320
Level 2 | Mortgage- and asset-backed securities
Assets:
Fixed maturity securities, available-for-sale	2,316	1,803
Level 2 | Public utilities
Assets:
Fixed maturity securities, available-for-sale	6,991	7,169
Level 2 | Sovereign and supranational
Assets:
Fixed maturity securities, available-for-sale	480	797
Level 2 | Banks/financial institutions
Assets:
Fixed maturity securities, available-for-sale	8,271	9,140
Level 2 | Other corporate
Assets:
Fixed maturity securities, available-for-sale	26,046	27,620
Level 3
Assets:
Fixed maturity securities, available-for-sale	1,604	1,778
Equity securities	203	209
Other investments	0	0
Cash and cash equivalents	0	0
Asset derivatives	0	0
Total assets	1,807	1,987
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
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	680	343
Level 3 | Public utilities
Assets:
Fixed maturity securities, available-for-sale	259	497
Level 3 | Sovereign and supranational
Assets:
Fixed maturity securities, available-for-sale	31	37
Level 3 | Banks/financial institutions
Assets:
Fixed maturity securities, available-for-sale	70	159
Level 3 | Other corporate
Assets:
Fixed maturity securities, available-for-sale	$ 564	$ 742