FAIR VALUE MEASUREMENTS - Fair Value Hierarchy Levels of Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Assets:
Available for sale, fixed maturity securities	$ 89,965	$ 98,696
Equity securities	1,415	1,603
Other investments	1,747	1,726
Cash and cash equivalents	4,275	5,051
Asset derivatives	1,126	936
Total assets	98,528	108,012
Liabilities:
Liability derivatives	1,460	1,619
Total liabilities	1,460	1,619
Foreign currency swaps
Assets:
Asset derivatives	141	137
Liabilities:
Liability derivatives	432	427
Foreign currency forwards
Assets:
Asset derivatives	977	791
Liabilities:
Liability derivatives	812	1,138
Foreign currency options
Assets:
Asset derivatives	8	8
Interest rate swaps
Liabilities:
Liability derivatives	216	54
Government and agencies
Assets:
Available for sale, fixed maturity securities	30,712	33,820
Municipalities
Assets:
Available for sale, fixed maturity securities	2,776	3,036
Mortgage- and asset-backed securities
Assets:
Available for sale, fixed maturity securities	1,366	1,246
Public utilities
Assets:
Available for sale, fixed maturity securities	9,189	10,051
Sovereign and supranational
Assets:
Available for sale, fixed maturity securities	1,035	1,115
Banks/financial institutions
Assets:
Available for sale, fixed maturity securities	10,686	11,591
Other corporate
Assets:
Available for sale, fixed maturity securities	34,201	37,837
Level 1
Assets:
Available for sale, fixed maturity securities	29,547	32,532
Equity securities	1,166	1,340
Other investments	1,747	1,726
Cash and cash equivalents	4,275	5,051
Asset derivatives	0	0
Total assets	36,735	40,649
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
Liabilities:
Liability derivatives	0	0
Level 1 \| Government and agencies
Assets:
Available for sale, fixed maturity securities	29,547	32,532
Level 1 \| Municipalities
Assets:
Available for sale, fixed maturity securities	0	0
Level 1 \| Mortgage- and asset-backed securities
Assets:
Available for sale, fixed maturity securities	0	0
Level 1 \| Public utilities
Assets:
Available for sale, fixed maturity securities	0	0
Level 1 \| Sovereign and supranational
Assets:
Available for sale, fixed maturity securities	0	0
Level 1 \| Banks/financial institutions
Assets:
Available for sale, fixed maturity securities	0	0
Level 1 \| Other corporate
Assets:
Available for sale, fixed maturity securities	0	0
Level 2
Assets:
Available for sale, fixed maturity securities	59,124	64,866
Equity securities	83	90
Other investments	0	0
Cash and cash equivalents	0	0
Asset derivatives	1,126	936
Total assets	60,333	65,892
Liabilities:
Total liabilities	1,460	1,619
Level 2 \| Foreign currency swaps
Assets:
Asset derivatives	141	137
Liabilities:
Liability derivatives	432	427
Level 2 \| Foreign currency forwards
Assets:
Asset derivatives	977	791
Liabilities:
Liability derivatives	812	1,138
Level 2 \| Foreign currency options
Assets:
Asset derivatives	8	8
Level 2 \| Interest rate swaps
Liabilities:
Liability derivatives	216	54
Level 2 \| Government and agencies
Assets:
Available for sale, fixed maturity securities	1,165	1,288
Level 2 \| Municipalities
Assets:
Available for sale, fixed maturity securities	2,776	3,036
Level 2 \| Mortgage- and asset-backed securities
Assets:
Available for sale, fixed maturity securities	1,048	955
Level 2 \| Public utilities
Assets:
Available for sale, fixed maturity securities	8,604	9,558
Level 2 \| Sovereign and supranational
Assets:
Available for sale, fixed maturity securities	994	1,072
Level 2 \| Banks/financial institutions
Assets:
Available for sale, fixed maturity securities	10,626	11,546
Level 2 \| Other corporate
Assets:
Available for sale, fixed maturity securities	33,911	37,411
Level 3
Assets:
Available for sale, fixed maturity securities	1,294	1,298
Equity securities	166	173
Other investments	0	0
Cash and cash equivalents	0	0
Asset derivatives	0	0
Total assets	1,460	1,471
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
Liabilities:
Liability derivatives	0	0
Level 3 \| Government and agencies
Assets:
Available for sale, fixed maturity securities	0	0
Level 3 \| Municipalities
Assets:
Available for sale, fixed maturity securities	0	0
Level 3 \| Mortgage- and asset-backed securities
Assets:
Available for sale, fixed maturity securities	318	291
Level 3 \| Public utilities
Assets:
Available for sale, fixed maturity securities	585	493
Level 3 \| Sovereign and supranational
Assets:
Available for sale, fixed maturity securities	41	43
Level 3 \| Banks/financial institutions
Assets:
Available for sale, fixed maturity securities	60	45
Level 3 \| Other corporate
Assets:
Available for sale, fixed maturity securities	$ 290	$ 426

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