FAIR VALUE DISCLOSURES - UNREALIZED GAINS (LOSSES) FOR LEVEL 3 INSTRUMENTS (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Level 3 Assets And Liabilities Held
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net Derivative Gains (Losses)	$ (1,928)	$ (1,854)	$ 1,661
OCI	6	(26)	40
Corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net Derivative Gains (Losses)	0	0	0
OCI	3	(18)	4
States and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net Derivative Gains (Losses)	0	0
OCI	3	(1)
Commercial mortgage-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net Derivative Gains (Losses)	0		0
OCI	0		45
Asset-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net Derivative Gains (Losses)	0	0	0
OCI	0	(7)	(9)
Total debt maturities available for sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net Derivative Gains (Losses)	0	0	0
OCI	6	(26)	40
GMIB reinsurance contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net Derivative Gains (Losses)	500	(1,068)	69
OCI	0	0	0
GMxB derivative features liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net Derivative Gains (Losses)	(2,428)	(786)	1,592
OCI	$ 0	$ 0	$ 0