INVESTMENTS - Available-for-sale Securities (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 70,307		$ 70,307		$ 62,937
Allowance for Credit Losses	13		13		0
Gross Unrealized Gains	9,288		9,288		3,789
Gross Unrealized Losses	203		203		383
Fixed maturities available for sale, at fair value	79,379		79,379		66,343
Amortized Cost
Due in one year or less	4,326		4,326
Due in years two through five	15,844		15,844
Due in years six through ten	18,836		18,836
Due after ten years	27,072		27,072
Subtotal	66,078		66,078
Amortized cost	70,294		70,294
Fair Value
Due in one year or less	4,362		4,362
Due in years two through five	16,772		16,772
Due in years six through ten	20,887		20,887
Due after ten years	33,042		33,042
Subtotal	75,063		75,063
Fair Value	79,379		79,379
Fixed Maturities Proceeds Gross Gains And Gross Losses From Sales And Other Than Temporary Impairments
Proceeds from sales	1,433	$ 3,849	6,200	$ 6,913
Gross gains on sales	26	205	303	223
Gross losses on sales	(5)	(4)	(39)	(29)
Credit losses	0	0	(13)	0
Fixed Maturities - Credit Loss Impairments
Balances, beginning of period	32	25	21	58
Previously recognized impairments on securities that matured, paid, prepaid or sold	0	(4)	(2)	(37)
Recognized impairments on securities impaired to fair value this period	0	0	0	0
Credit losses recognized this period on securities for which credit losses were not previously recognized	(3)	0	7	0
Additional impairments this period on securities previously impaired	3	0	6	0
Increases due to passage of time on previously recorded credit losses	0	0	0	0
Accretion of previously recognized impairments due to increases in expected cash flows	0	0	0	0
Balances, end of period	32	$ 21	32	$ 21
Corporate
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	51,340		51,340		45,900
Allowance for Credit Losses	13		13		0
Gross Unrealized Gains	4,661		4,661		2,361
Gross Unrealized Losses	176		176		62
Fixed maturities available for sale, at fair value	55,812		55,812		48,199
U.S. Treasury, government and agency
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	13,160		13,160		14,410
Allowance for Credit Losses	0		0		0
Gross Unrealized Gains	4,308		4,308		1,289
Gross Unrealized Losses	0		0		305
Fixed maturities available for sale, at fair value	17,468		17,468		15,394
States and political subdivisions
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	762		762		638
Allowance for Credit Losses	0		0		0
Gross Unrealized Gains	116		116		70
Gross Unrealized Losses	0		0		3
Fixed maturities available for sale, at fair value	878		878		705
Foreign governments
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	829		829		462
Allowance for Credit Losses	0		0		0
Gross Unrealized Gains	82		82		35
Gross Unrealized Losses	6		6		5
Fixed maturities available for sale, at fair value	905		905		492
Residential mortgage-backed
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	146		146		178
Allowance for Credit Losses	0		0		0
Gross Unrealized Gains	14		14		13
Gross Unrealized Losses	0		0		0
Fixed maturities available for sale, at fair value	160		160		191
Amortized Cost
Without single maturity date	146		146
Fair Value
Without single maturity date	160		160
Asset-backed
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	2,588		2,588		848
Allowance for Credit Losses	0		0		0
Gross Unrealized Gains	26		26		4
Gross Unrealized Losses	18		18		3
Fixed maturities available for sale, at fair value	2,596		2,596		849
Amortized Cost
Without single maturity date	2,588		2,588
Fair Value
Without single maturity date	2,596		2,596
Commercial mortgage-backed
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	1,067		1,067
Allowance for Credit Losses	0		0
Gross Unrealized Gains	50		50
Gross Unrealized Losses	0		0
Fixed maturities available for sale, at fair value	1,117		1,117
Amortized Cost
Without single maturity date	1,067		1,067
Fair Value
Without single maturity date	1,117		1,117
Redeemable preferred stock
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	415		415		501
Allowance for Credit Losses	0		0		0
Gross Unrealized Gains	31		31		17
Gross Unrealized Losses	3		3		5
Fixed maturities available for sale, at fair value	443		443		$ 513
Amortized Cost
Without single maturity date	415		415
Fair Value
Without single maturity date	$ 443		$ 443