DERIVATIVE INSTRUMENTS - Offsetting of Financial Liabilities and Derivative Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Offsetting Liabilities [Line Items]
Gross amount of recognized derivative liabilities	$ 552	$ 923
Gross amount of assets offset in balance sheet	0	0
Derivative liability, fair value, amount not offset against collateral	552	923
Financial instruments, amount not offset	(38)	(96)
Derivative, collateral, right to reclaim securities	(58)	(400)
Derivative, collateral, right to reclaim cash	(456)	(426)
Derivative liability, fair value, amount offset against collateral, subject to master netting agreement	0	1
Derivative liability, not subject to master netting arrangement	583	507
Derivative liability, fair value, gross liability including not subject to master netting arrangement	1,135	1,430
Net amount of derivative liabilities presented in balance sheet	1,135	1,430
Derivative liability, fair value, amount offset against collateral	583	508
Securities lending, gross amounts of recognized financial instruments, offsetting liabilities	3,366	1,503
Securities lending, gross amounts offset in statement of financial position, offsetting liabilities	0	0
Securities lending, net amounts of financial instruments presented in balance sheet, offsetting liabilities	3,366	1,503
Securities lending, carrying value of financial instruments, liabilities not offset in balance sheet	(3,334)	(1,480)
Securities lending, securities collateral, liabilities not offset in balance sheet	0	0
Securities lending, cash collateral, liabilities not offset in balance sheet	0	0
Securities lending, financial instruments, amount of liabilities offset against collateral	32	23
Gross amounts of recognized financial instruments, offsetting liabilities	4,501	2,933
Gross amounts offset in statement of financial position, offsetting liabilities	0	0
Net amounts of financial instruments presented in balance sheet, offsetting liabilities	4,501	2,933
Carrying value of financial instruments, liabilities not offset in balance sheet	(3,372)	(1,576)
Securities collateral, liabilities not offset in balance sheet	(58)	(400)
Cash collateral, liabilities not offset in balance sheet	(456)	(426)
Financial instruments, amount of liabilities offset against collateral	615	531
OTC - Bilateral
Offsetting Liabilities [Line Items]
Gross amount of recognized derivative liabilities	69	504
Gross amount of assets offset in balance sheet	0	0
Derivative liability, fair value, amount not offset against collateral	69	504
Financial instruments, amount not offset	(38)	(85)
Derivative, collateral, right to reclaim securities	(31)	(381)
Derivative, collateral, right to reclaim cash	0	(37)
Derivative liability, fair value, amount offset against collateral, subject to master netting agreement	0	1
Derivative liability, not subject to master netting arrangement	583	507
OTC- Cleared
Offsetting Liabilities [Line Items]
Gross amount of recognized derivative liabilities	483	419
Gross amount of assets offset in balance sheet	0	0
Derivative liability, fair value, amount not offset against collateral	483	419
Financial instruments, amount not offset	0	(11)
Derivative, collateral, right to reclaim securities	(27)	(19)
Derivative, collateral, right to reclaim cash	(456)	(389)
Derivative liability, fair value, amount offset against collateral, subject to master netting agreement	$ 0	$ 0