DERIVATIVE INSTRUMENTS - Offsetting of Financial Assets and Derivative Assets (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Offsetting Assets [Line Items]
Gross amount of recognized derivative assets	$ 264	$ 282
Gross amount of liabilities offset in balance sheet	0	0
Net amount of derivative assets presented in balance sheet	264	282
Financial instruments, amount not offset	(38)	(96)
Derivative, collateral, obligation to return securities	(78)	(53)
Derivative, collateral, obligation to return cash	(148)	(130)
Derivative asset, fair value, amount offset against collateral, subject to master netting agreement	0	3
Derivative asset, not subject to master netting arrangement	57	55
Derivative asset, fair value, gross asset including not subject to master netting arrangement	321	337
Net amount of derivative assets presented in balance sheet	321	337
Derivative asset, fair value, amount offset against collateral	57	58
Securities lending, gross amounts of recognized financial instruments	3,334	1,480
Securities lending, gross amounts offset in balance sheet	0	0
Securities lending, net amounts of assets presented in balance sheet	3,334	1,480
Securities lending, carrying value of financial instruments not offset in balance sheet	0	0
Securities lending, securities collateral, not offset in balance sheet	0	0
Securities lending, cash collateral, not offset in balance sheet	(3,334)	(1,480)
Securities lending, financial instruments, amount of assets offset against collateral	0	0
Gross amount of recognized assets	3,655	1,817
Gross amounts offset in balance sheet	0	0
Net amounts of assets presented in balance sheet	3,655	1,817
Carrying value of financial instruments not offset in balance sheet	(38)	(96)
Securities collateral, not offset in balance sheet	(78)	(53)
Cash collateral, not offset in balance sheet	(3,482)	(1,610)
Financial instruments, amount of assets offset against collateral	57	58
OTC - Bilateral
Offsetting Assets [Line Items]
Gross amount of recognized derivative assets	264	271
Gross amount of liabilities offset in balance sheet	0	0
Net amount of derivative assets presented in balance sheet	264	271
Financial instruments, amount not offset	(38)	(85)
Derivative, collateral, obligation to return securities	(78)	(53)
Derivative, collateral, obligation to return cash	(148)	(130)
Derivative asset, fair value, amount offset against collateral, subject to master netting agreement	0	3
Derivative asset, not subject to master netting arrangement	$ 57	55
OTC- Cleared
Offsetting Assets [Line Items]
Gross amount of recognized derivative assets		11
Gross amount of liabilities offset in balance sheet		0
Net amount of derivative assets presented in balance sheet		11
Financial instruments, amount not offset		(11)
Derivative, collateral, obligation to return securities		0
Derivative, collateral, obligation to return cash		0
Derivative asset, fair value, amount offset against collateral, subject to master netting agreement		$ 0