FAIR VALUE MEASUREMENTS - Fair Value Hierarchy Levels of Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Assets:
Available for sale, fixed maturity securities	$ 96,288	$ 91,262
Equity securities	660	802
Other investments	892	628
Cash and cash equivalents	4,148	4,896
Asset derivatives	472	482
Total assets	102,460	98,070
Liabilities:
Liability derivatives	723	586
Total liabilities	723	586
Foreign currency swaps
Assets:
Asset derivatives	155	241
Liabilities:
Liability derivatives	273	204
Foreign currency forwards
Assets:
Asset derivatives	269	238
Liabilities:
Liability derivatives	427	377
Foreign currency options
Assets:
Asset derivatives	27
Liabilities:
Liability derivatives	23	5
Interest rate swaps
Assets:
Asset derivatives	21	3
Government and agencies
Assets:
Available for sale, fixed maturity securities	36,978	36,400
Municipalities
Assets:
Available for sale, fixed maturity securities	2,440	1,847
Mortgage- and asset-backed securities
Assets:
Available for sale, fixed maturity securities	497	410
Public utilities
Assets:
Available for sale, fixed maturity securities	9,192	6,780
Sovereign and supranational
Assets:
Available for sale, fixed maturity securities	1,609	1,042
Banks/financial institutions
Assets:
Available for sale, fixed maturity securities	10,378	10,287
Other corporate
Assets:
Available for sale, fixed maturity securities	35,194	34,496
Level 1
Assets:
Available for sale, fixed maturity securities	35,469	34,878
Equity securities	509	642
Other investments	892	628
Cash and cash equivalents	4,148	4,896
Asset derivatives	0	0
Total assets	41,018	41,044
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
Liabilities:
Liability derivatives	0	0
Level 1 \| Interest rate swaps
Assets:
Asset derivatives	0	0
Level 1 \| Government and agencies
Assets:
Available for sale, fixed maturity securities	35,469	34,878
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	60,065	55,697
Equity securities	69	80
Other investments	0	0
Cash and cash equivalents	0	0
Asset derivatives	383	313
Total assets	60,517	56,090
Liabilities:
Total liabilities	488	460
Level 2 \| Foreign currency swaps
Assets:
Asset derivatives	66	72
Liabilities:
Liability derivatives	38	78
Level 2 \| Foreign currency forwards
Assets:
Asset derivatives	269	238
Liabilities:
Liability derivatives	427	377
Level 2 \| Foreign currency options
Assets:
Asset derivatives	27
Liabilities:
Liability derivatives	23	5
Level 2 \| Interest rate swaps
Assets:
Asset derivatives	21	3
Level 2 \| Government and agencies
Assets:
Available for sale, fixed maturity securities	1,509	1,522
Level 2 \| Municipalities
Assets:
Available for sale, fixed maturity securities	2,440	1,847
Level 2 \| Mortgage- and asset-backed securities
Assets:
Available for sale, fixed maturity securities	309	232
Level 2 \| Public utilities
Assets:
Available for sale, fixed maturity securities	8,894	6,556
Level 2 \| Sovereign and supranational
Assets:
Available for sale, fixed maturity securities	1,609	1,042
Level 2 \| Banks/financial institutions
Assets:
Available for sale, fixed maturity securities	10,355	10,264
Level 2 \| Other corporate
Assets:
Available for sale, fixed maturity securities	34,949	34,234
Level 3
Assets:
Available for sale, fixed maturity securities	754	687
Equity securities	82	80
Other investments	0	0
Cash and cash equivalents	0	0
Asset derivatives	89	169
Total assets	925	936
Liabilities:
Total liabilities	235	126
Level 3 \| Foreign currency swaps
Assets:
Asset derivatives	89	169
Liabilities:
Liability derivatives	235	126
Level 3 \| Foreign currency forwards
Assets:
Asset derivatives	0	0
Liabilities:
Liability derivatives	0	0
Level 3 \| Foreign currency options
Assets:
Asset derivatives	0
Liabilities:
Liability derivatives	0	0
Level 3 \| Interest rate swaps
Assets:
Asset 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	188	178
Level 3 \| Public utilities
Assets:
Available for sale, fixed maturity securities	298	224
Level 3 \| Sovereign and supranational
Assets:
Available for sale, fixed maturity securities	0	0
Level 3 \| Banks/financial institutions
Assets:
Available for sale, fixed maturity securities	23	23
Level 3 \| Other corporate
Assets:
Available for sale, fixed maturity securities	$ 245	$ 262

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Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Fair value of financial and nonfinancial obligations.

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