INSURANCE LIABILITIES - Change in Liability for Variable Annuity Contracts (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
GMDB
Movement in Liabilities for Guarantees on Long-Duration Contracts, Guaranteed Benefit Liability, Gross [Roll Forward]
Opening Balance	$ 4,654	$ 4,054	$ 3,159
Opening Balance	(107)	(2,030)	(1,558)
Paid guarantee benefits	(438)	(394)	(354)
Paid guarantee benefits	14	70	171
Other changes in reserves	563	994	1,249
Other changes in reserve	(5)	1,853	(643)
Closing Balance	4,779	4,654	4,054
Closing Balance	(98)	(107)	(2,030)
GMIB
Movement in Liabilities for Guarantees on Long-Duration Contracts, Guaranteed Benefit Liability, Gross [Roll Forward]
Opening Balance	3,741	4,754	3,808
Opening Balance	(1,991)	(10,488)	(10,314)
Paid guarantee benefits	(257)	(153)	(151)
Paid guarantee benefits	72	61	115
Other changes in reserves	1,204	(860)	1,097
Other changes in reserve	(547)	8,436	(289)
Closing Balance	4,688	3,741	4,754
Closing Balance	$ (2,466)	$ (1,991)	$ (10,488)