ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) - Reclassifications (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Reclassifications Out of Accumulated Other Comprehensive Income (Loss)
Benefits and settlement expenses, net of reinsurance ceded	$ (1,350)	$ (1,259)	$ (3,748)	$ (3,737)
Tax (expense) benefit	(10)	(29)	(74)	(31)
Change in net expected credit losses - fixed maturities	0	(38)	5	(121)
Net income	49	131	313	144
Amount Reclassified from Accumulated Other Comprehensive Income (Loss) | Gains and losses on derivative instruments
Reclassifications Out of Accumulated Other Comprehensive Income (Loss)
Benefits and settlement expenses, net of reinsurance ceded	1	0	1	(3)
Tax (expense) benefit	0	0	0	1
Net income	1	0	1	(2)
Amount Reclassified from Accumulated Other Comprehensive Income (Loss) | Unrealized gains and losses on available-for-sale securities
Reclassifications Out of Accumulated Other Comprehensive Income (Loss)
Tax (expense) benefit	(1)	7	(10)	16
Realized gains (losses) - investments	5	3	44	45
Change in net expected credit losses - fixed maturities	0	(38)	5	(121)
Net income	$ 4	$ (28)	$ 39	$ (60)