INVESTMENTS - Fixed Maturities Available-for-sale (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Available For Sale Securities Continuous Unrealized Loss Position [Line Items]
Less than Twelve Months, Fair Value	$ 16,315	$ 7,553
Less than 12 Months, Gross unrealized Losses	903	351
12 Months or Longer, Fair Value	415	672
12 Months or Longer, Gross unrealized Losses	111	32
Total Fair Value	16,730	8,225
Total Gross unrealized losses	1,014	383
Corporate
Available For Sale Securities Continuous Unrealized Loss Position [Line Items]
Less than Twelve Months, Fair Value	14,516	2,773
Less than 12 Months, Gross unrealized Losses	750	42
12 Months or Longer, Fair Value	265	373
12 Months or Longer, Gross unrealized Losses	90	20
Total Fair Value	14,781	3,146
Total Gross unrealized losses	840	62
U.S. Treasury, government and agency
Available For Sale Securities Continuous Unrealized Loss Position [Line Items]
Less than Twelve Months, Fair Value	0	4,309
Less than 12 Months, Gross unrealized Losses	0	305
12 Months or Longer, Fair Value	0	2
12 Months or Longer, Gross unrealized Losses	0	0
Total Fair Value	0	4,311
Total Gross unrealized losses	0	305
States and political subdivisions
Available For Sale Securities Continuous Unrealized Loss Position [Line Items]
Less than Twelve Months, Fair Value	188	112
Less than 12 Months, Gross unrealized Losses	7	3
12 Months or Longer, Fair Value	0	0
12 Months or Longer, Gross unrealized Losses	0	0
Total Fair Value	188	112
Total Gross unrealized losses	7	3
Foreign governments
Available For Sale Securities Continuous Unrealized Loss Position [Line Items]
Less than Twelve Months, Fair Value	127	11
Less than 12 Months, Gross unrealized Losses	5	0
12 Months or Longer, Fair Value	36	47
12 Months or Longer, Gross unrealized Losses	8	5
Total Fair Value	163	58
Total Gross unrealized losses	13	5
Residential mortgage-backed
Available For Sale Securities Continuous Unrealized Loss Position [Line Items]
Less than Twelve Months, Fair Value	17	0
Less than 12 Months, Gross unrealized Losses	0	0
12 Months or Longer, Fair Value	10	0
12 Months or Longer, Gross unrealized Losses	0	0
Total Fair Value	27	0
Total Gross unrealized losses	0	0
Asset-backed
Available For Sale Securities Continuous Unrealized Loss Position [Line Items]
Less than Twelve Months, Fair Value	1,202	319
Less than 12 Months, Gross unrealized Losses	116	1
12 Months or Longer, Fair Value	61	201
12 Months or Longer, Gross unrealized Losses	7	2
Total Fair Value	1,263	520
Total Gross unrealized losses	123	3
Commercial mortgage-backed
Available For Sale Securities Continuous Unrealized Loss Position [Line Items]
Less than Twelve Months, Fair Value	0	0
Less than 12 Months, Gross unrealized Losses	0	0
12 Months or Longer, Fair Value	0	0
12 Months or Longer, Gross unrealized Losses	0	0
Total Fair Value	0	0
Total Gross unrealized losses	0	0
Redeemable preferred stock
Available For Sale Securities Continuous Unrealized Loss Position [Line Items]
Less than Twelve Months, Fair Value	265	29
Less than 12 Months, Gross unrealized Losses	25	0
12 Months or Longer, Fair Value	43	49
12 Months or Longer, Gross unrealized Losses	6	5
Total Fair Value	308	78
Total Gross unrealized losses	$ 31	$ 5