FAIR VALUE MEASUREMENTS (Details - Changes in Level 3 Recurring Fair Value Measurements) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Fair value assets and liabilities measured on recurring basis, unobservable input reconciliation calculation
Fair Value Beginning of Period, assets	$ 31,578	$ 30,958
Net Realized and Unrealized Gains (Losses) Included in Income, assets	338	(105)
Other Comprehensive Income (Loss), assets	(178)	(2,296)
Purchases, Sales, Issuances and Settlements, Net, assets	(552)	(819)
Gross Transfers In, assets	779	1,932
Gross Transfers Out, assets	(667)	(597)
Reclassification of Held for Sale, assets	0	(3)
Fair Value End of Period, assets	31,298	29,070
Changes in Unrealized Gains (Losses) Included in Income on Instruments Held at End of Period, assets	28	(270)
Changes in Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss) for Recurring Level 3 Instruments Held at End of Period, assets	(175)	(2,100)
Liabilities
Fair value assets and liabilities measured on recurring basis, unobservable input reconciliation calculation
Fair Value Beginning of Period, liabilities	15,721	6,808
Net realized and unrealized gains (losses) included in income, liabilities	(4,679)	1,014
Other Comprehensive Income (Loss), liabilities	0	0
Purchases, Sales, Issuances and Settlements, Net, liabilities	(165)	113
Gross Transfers In, liabilities	0	0
Gross Transfers Out, liabilities	40	0
Reclassified to Held for Sale, liabilities	0	0
Fair Value End of Year, liabilities	10,917	7,935
Changes in Unrealized Gains (Losses) Included in Income on Instruments Held at End of Period, liabilities	5,419	(769)
Changes in Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss) for Recurring Level 3 Instruments Held at End of Period, liabilities	0	0
Policyholder contract deposits
Fair value assets and liabilities measured on recurring basis, unobservable input reconciliation calculation
Fair Value Beginning of Period, liabilities	9,798	6,910
Net realized and unrealized gains (losses) included in income, liabilities	(2,260)	1,171
Other Comprehensive Income (Loss), liabilities	0	0
Purchases, Sales, Issuances and Settlements, Net, liabilities	79	72
Gross Transfers In, liabilities	0	0
Gross Transfers Out, liabilities	0	0
Reclassified to Held for Sale, liabilities	0	0
Fair Value End of Year, liabilities	7,617	8,153
Changes in Unrealized Gains (Losses) Included in Income on Instruments Held at End of Period, liabilities	2,570	(884)
Changes in Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss) for Recurring Level 3 Instruments Held at End of Period, liabilities	0	0
Derivative liabilities, net
Fair value assets and liabilities measured on recurring basis, unobservable input reconciliation calculation
Fair Value Beginning of Period, liabilities	(119)	(102)
Net realized and unrealized gains (losses) included in income, liabilities	(37)	(157)
Other Comprehensive Income (Loss), liabilities	0	0
Purchases, Sales, Issuances and Settlements, Net, liabilities	(71)	41
Gross Transfers In, liabilities	0	0
Gross Transfers Out, liabilities	40	0
Reclassified to Held for Sale, liabilities	0	0
Fair Value End of Year, liabilities	(187)	(218)
Changes in Unrealized Gains (Losses) Included in Income on Instruments Held at End of Period, liabilities	(106)	115
Changes in Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss) for Recurring Level 3 Instruments Held at End of Period, liabilities	0	0
Interest rate contracts
Fair value assets and liabilities measured on recurring basis, unobservable input reconciliation calculation
Fair Value Beginning of Period, liabilities	0	0
Net realized and unrealized gains (losses) included in income, liabilities	0	0
Other Comprehensive Income (Loss), liabilities	0	0
Purchases, Sales, Issuances and Settlements, Net, liabilities	0	0
Gross Transfers In, liabilities	0	0
Gross Transfers Out, liabilities	0	0
Reclassified to Held for Sale, liabilities	0	0
Fair Value End of Year, liabilities	0	0
Changes in Unrealized Gains (Losses) Included in Income on Instruments Held at End of Period, liabilities	0	0
Changes in Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss) for Recurring Level 3 Instruments Held at End of Period, liabilities	0	0
Foreign exchange contracts
Fair value assets and liabilities measured on recurring basis, unobservable input reconciliation calculation
Fair Value Beginning of Period, liabilities	(2)	(6)
Net realized and unrealized gains (losses) included in income, liabilities	1	3
Other Comprehensive Income (Loss), liabilities	0	0
Purchases, Sales, Issuances and Settlements, Net, liabilities	1	6
Gross Transfers In, liabilities	0	0
Gross Transfers Out, liabilities	0	0
Reclassified to Held for Sale, liabilities	0	0
Fair Value End of Year, liabilities	0	3
Changes in Unrealized Gains (Losses) Included in Income on Instruments Held at End of Period, liabilities	(1)	1
Changes in Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss) for Recurring Level 3 Instruments Held at End of Period, liabilities	0	0
Equity contracts
Fair value assets and liabilities measured on recurring basis, unobservable input reconciliation calculation
Fair Value Beginning of Period, liabilities	(151)	(151)
Net realized and unrealized gains (losses) included in income, liabilities	(26)	(26)
Other Comprehensive Income (Loss), liabilities	0	0
Purchases, Sales, Issuances and Settlements, Net, liabilities	(85)	34
Gross Transfers In, liabilities	0	0
Gross Transfers Out, liabilities	40	0
Reclassified to Held for Sale, liabilities	0	0
Fair Value End of Year, liabilities	(222)	(143)
Changes in Unrealized Gains (Losses) Included in Income on Instruments Held at End of Period, liabilities	(118)	(14)
Changes in Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss) for Recurring Level 3 Instruments Held at End of Period, liabilities	0	0
Credit contracts
Fair value assets and liabilities measured on recurring basis, unobservable input reconciliation calculation
Fair Value Beginning of Period, liabilities	42	62
Net realized and unrealized gains (losses) included in income, liabilities	5	(124)
Other Comprehensive Income (Loss), liabilities	0	0
Purchases, Sales, Issuances and Settlements, Net, liabilities	(3)	(14)
Gross Transfers In, liabilities	0	0
Gross Transfers Out, liabilities	0	0
Reclassified to Held for Sale, liabilities	0	0
Fair Value End of Year, liabilities	44	(76)
Changes in Unrealized Gains (Losses) Included in Income on Instruments Held at End of Period, liabilities	(3)	118
Changes in Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss) for Recurring Level 3 Instruments Held at End of Period, liabilities	0	0
Other contracts
Fair value assets and liabilities measured on recurring basis, unobservable input reconciliation calculation
Fair Value Beginning of Period, liabilities	(8)	(7)
Net realized and unrealized gains (losses) included in income, liabilities	(17)	(10)
Other Comprehensive Income (Loss), liabilities	0	0
Purchases, Sales, Issuances and Settlements, Net, liabilities	16	15
Gross Transfers In, liabilities	0	0
Gross Transfers Out, liabilities	0	0
Reclassified to Held for Sale, liabilities	0	0
Fair Value End of Year, liabilities	(9)	(2)
Changes in Unrealized Gains (Losses) Included in Income on Instruments Held at End of Period, liabilities	16	10
Changes in Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss) for Recurring Level 3 Instruments Held at End of Period, liabilities	0	0
Fortitude Re funds withheld payable
Fair value assets and liabilities measured on recurring basis, unobservable input reconciliation calculation
Fair Value Beginning of Period, liabilities	6,042
Net realized and unrealized gains (losses) included in income, liabilities	(2,382)
Other Comprehensive Income (Loss), liabilities	0
Purchases, Sales, Issuances and Settlements, Net, liabilities	(173)
Gross Transfers In, liabilities	0
Gross Transfers Out, liabilities	0
Reclassified to Held for Sale, liabilities	0
Fair Value End of Year, liabilities	3,487
Changes in Unrealized Gains (Losses) Included in Income on Instruments Held at End of Period, liabilities	2,955
Changes in Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss) for Recurring Level 3 Instruments Held at End of Period, liabilities	0
Bonds available for sale
Fair value assets and liabilities measured on recurring basis, unobservable input reconciliation calculation
Fair Value Beginning of Period, assets	26,889	25,931
Net Realized and Unrealized Gains (Losses) Included in Income, assets	194	94
Other Comprehensive Income (Loss), assets	(175)	(2,297)
Purchases, Sales, Issuances and Settlements, Net, assets	(298)	12
Gross Transfers In, assets	698	1,781
Gross Transfers Out, assets	(666)	(597)
Reclassification of Held for Sale, assets	0	0
Fair Value End of Period, assets	26,642	24,924
Changes in Unrealized Gains (Losses) Included in Income on Instruments Held at End of Period, assets	0	0
Changes in Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss) for Recurring Level 3 Instruments Held at End of Period, assets	(175)	(2,100)
Bonds available for sale | Obligations of states, municipalities and political subdivisions
Fair value assets and liabilities measured on recurring basis, unobservable input reconciliation calculation
Fair Value Beginning of Period, assets	2,105	2,121
Net Realized and Unrealized Gains (Losses) Included in Income, assets	3	5
Other Comprehensive Income (Loss), assets	(159)	(55)
Purchases, Sales, Issuances and Settlements, Net, assets	(53)	137
Gross Transfers In, assets	0	27
Gross Transfers Out, assets	0	(133)
Reclassification of Held for Sale, assets	0	0
Fair Value End of Period, assets	1,896	2,102
Changes in Unrealized Gains (Losses) Included in Income on Instruments Held at End of Period, assets	0	0
Changes in Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss) for Recurring Level 3 Instruments Held at End of Period, assets	(10)	(51)
Bonds available for sale | Non-U.S. governments
Fair value assets and liabilities measured on recurring basis, unobservable input reconciliation calculation
Fair Value Beginning of Period, assets	5	0
Net Realized and Unrealized Gains (Losses) Included in Income, assets	0	0
Other Comprehensive Income (Loss), assets	0	0
Purchases, Sales, Issuances and Settlements, Net, assets	0	0
Gross Transfers In, assets	1	6
Gross Transfers Out, assets	0	0
Reclassification of Held for Sale, assets	0	0
Fair Value End of Period, assets	6	6
Changes in Unrealized Gains (Losses) Included in Income on Instruments Held at End of Period, assets	0	0
Changes in Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss) for Recurring Level 3 Instruments Held at End of Period, assets	0	0
Bonds available for sale | Corporate debt
Fair value assets and liabilities measured on recurring basis, unobservable input reconciliation calculation
Fair Value Beginning of Period, assets	2,349	1,663
Net Realized and Unrealized Gains (Losses) Included in Income, assets	(1)	(67)
Other Comprehensive Income (Loss), assets	(10)	(81)
Purchases, Sales, Issuances and Settlements, Net, assets	177	7
Gross Transfers In, assets	187	103
Gross Transfers Out, assets	(132)	(410)
Reclassification of Held for Sale, assets	0	0
Fair Value End of Period, assets	2,570	1,215
Changes in Unrealized Gains (Losses) Included in Income on Instruments Held at End of Period, assets	0	0
Changes in Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss) for Recurring Level 3 Instruments Held at End of Period, assets	(159)	(29)
Bonds available for sale | Residential mortgage-backed securities (RMBS)
Fair value assets and liabilities measured on recurring basis, unobservable input reconciliation calculation
Fair Value Beginning of Period, assets	11,694	13,408
Net Realized and Unrealized Gains (Losses) Included in Income, assets	167	132
Other Comprehensive Income (Loss), assets	64	(1,623)
Purchases, Sales, Issuances and Settlements, Net, assets	(431)	(223)
Gross Transfers In, assets	0	19
Gross Transfers Out, assets	(30)	(26)
Reclassification of Held for Sale, assets	0	0
Fair Value End of Period, assets	11,464	11,687
Changes in Unrealized Gains (Losses) Included in Income on Instruments Held at End of Period, assets	0	0
Changes in Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss) for Recurring Level 3 Instruments Held at End of Period, assets	(14)	(1,505)
Bonds available for sale | Commercial mortgage-backed securities (CMBS)
Fair value assets and liabilities measured on recurring basis, unobservable input reconciliation calculation
Fair Value Beginning of Period, assets	922	1,053
Net Realized and Unrealized Gains (Losses) Included in Income, assets	9	7
Other Comprehensive Income (Loss), assets	(56)	19
Purchases, Sales, Issuances and Settlements, Net, assets	173	44
Gross Transfers In, assets	56	23
Gross Transfers Out, assets	0	0
Reclassification of Held for Sale, assets	0	0
Fair Value End of Period, assets	1,104	1,146
Changes in Unrealized Gains (Losses) Included in Income on Instruments Held at End of Period, assets	0	0
Changes in Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss) for Recurring Level 3 Instruments Held at End of Period, assets	(56)	21
Bonds available for sale | Collateralized Debt Obligations/Asset Backed Securities (CDO/ABS)
Fair value assets and liabilities measured on recurring basis, unobservable input reconciliation calculation
Fair Value Beginning of Period, assets	9,814	7,686
Net Realized and Unrealized Gains (Losses) Included in Income, assets	16	17
Other Comprehensive Income (Loss), assets	(14)	(557)
Purchases, Sales, Issuances and Settlements, Net, assets	(164)	47
Gross Transfers In, assets	454	1,603
Gross Transfers Out, assets	(504)	(28)
Reclassification of Held for Sale, assets	0	0
Fair Value End of Period, assets	9,602	8,768
Changes in Unrealized Gains (Losses) Included in Income on Instruments Held at End of Period, assets	0	0
Changes in Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss) for Recurring Level 3 Instruments Held at End of Period, assets	64	(536)
Other bond securities
Fair value assets and liabilities measured on recurring basis, unobservable input reconciliation calculation
Fair Value Beginning of Period, assets	2,698	3,738
Net Realized and Unrealized Gains (Losses) Included in Income, assets	(9)	(194)
Other Comprehensive Income (Loss), assets	0	0
Purchases, Sales, Issuances and Settlements, Net, assets	(177)	(975)
Gross Transfers In, assets	6	0
Gross Transfers Out, assets	0	0
Reclassification of Held for Sale, assets	0	0
Fair Value End of Period, assets	2,518	2,569
Changes in Unrealized Gains (Losses) Included in Income on Instruments Held at End of Period, assets	(98)	(284)
Changes in Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss) for Recurring Level 3 Instruments Held at End of Period, assets	0	0
Other bond securities | Residential mortgage-backed securities (RMBS)
Fair value assets and liabilities measured on recurring basis, unobservable input reconciliation calculation
Fair Value Beginning of Period, assets	139	143
Net Realized and Unrealized Gains (Losses) Included in Income, assets	3	(14)
Other Comprehensive Income (Loss), assets	0	0
Purchases, Sales, Issuances and Settlements, Net, assets	(16)	20
Gross Transfers In, assets	0	0
Gross Transfers Out, assets	0	0
Reclassification of Held for Sale, assets	0	0
Fair Value End of Period, assets	126	149
Changes in Unrealized Gains (Losses) Included in Income on Instruments Held at End of Period, assets	(98)	(14)
Changes in Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss) for Recurring Level 3 Instruments Held at End of Period, assets	0	0
Other bond securities | Commercial mortgage-backed securities (CMBS)
Fair value assets and liabilities measured on recurring basis, unobservable input reconciliation calculation
Fair Value Beginning of Period, assets	47	50
Net Realized and Unrealized Gains (Losses) Included in Income, assets	(1)	(7)
Other Comprehensive Income (Loss), assets	0	0
Purchases, Sales, Issuances and Settlements, Net, assets	(6)	(1)
Gross Transfers In, assets	6	0
Gross Transfers Out, assets	0	0
Reclassification of Held for Sale, assets	0	0
Fair Value End of Period, assets	46	42
Changes in Unrealized Gains (Losses) Included in Income on Instruments Held at End of Period, assets	(2)	(8)
Changes in Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss) for Recurring Level 3 Instruments Held at End of Period, assets	0	0
Other bond securities | Collateralized Debt Obligations/Asset Backed Securities (CDO/ABS)
Fair value assets and liabilities measured on recurring basis, unobservable input reconciliation calculation
Fair Value Beginning of Period, assets	2,512	3,545
Net Realized and Unrealized Gains (Losses) Included in Income, assets	(11)	(173)
Other Comprehensive Income (Loss), assets	0	0
Purchases, Sales, Issuances and Settlements, Net, assets	(155)	(994)
Gross Transfers In, assets	0	0
Gross Transfers Out, assets	0	0
Reclassification of Held for Sale, assets	0	0
Fair Value End of Period, assets	2,346	2,378
Changes in Unrealized Gains (Losses) Included in Income on Instruments Held at End of Period, assets	2	(262)
Changes in Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss) for Recurring Level 3 Instruments Held at End of Period, assets	0	0
Equity securities
Fair value assets and liabilities measured on recurring basis, unobservable input reconciliation calculation
Fair Value Beginning of Period, assets	51	8
Net Realized and Unrealized Gains (Losses) Included in Income, assets	11	(1)
Other Comprehensive Income (Loss), assets	3	1
Purchases, Sales, Issuances and Settlements, Net, assets	(11)	10
Gross Transfers In, assets	75	1
Gross Transfers Out, assets	(1)	0
Reclassification of Held for Sale, assets	0	0
Fair Value End of Period, assets	128	19
Changes in Unrealized Gains (Losses) Included in Income on Instruments Held at End of Period, assets	3	0
Changes in Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss) for Recurring Level 3 Instruments Held at End of Period, assets	0	0
Other invested assets
Fair value assets and liabilities measured on recurring basis, unobservable input reconciliation calculation
Fair Value Beginning of Period, assets	1,827	1,192
Net Realized and Unrealized Gains (Losses) Included in Income, assets	142	(4)
Other Comprehensive Income (Loss), assets	(6)	0
Purchases, Sales, Issuances and Settlements, Net, assets	(66)	129
Gross Transfers In, assets	0	150
Gross Transfers Out, assets	0	0
Reclassification of Held for Sale, assets	0	0
Fair Value End of Period, assets	1,897	1,467
Changes in Unrealized Gains (Losses) Included in Income on Instruments Held at End of Period, assets	123	14
Changes in Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss) for Recurring Level 3 Instruments Held at End of Period, assets	0	0
Other assets
Fair value assets and liabilities measured on recurring basis, unobservable input reconciliation calculation
Fair Value Beginning of Period, assets	113	89
Net Realized and Unrealized Gains (Losses) Included in Income, assets	0	0
Other Comprehensive Income (Loss), assets	0	0
Purchases, Sales, Issuances and Settlements, Net, assets	0	5
Gross Transfers In, assets	0	0
Gross Transfers Out, assets	0	0
Reclassification of Held for Sale, assets	0	(3)
Fair Value End of Period, assets	113	91
Changes in Unrealized Gains (Losses) Included in Income on Instruments Held at End of Period, assets	0	0
Changes in Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss) for Recurring Level 3 Instruments Held at End of Period, assets	$ 0	$ 0