DERIVATIVE INSTRUMENTS - Offsetting of Financial Assets and Derivative Assets (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Offsetting Assets [Line Items]
Gross amount of recognized derivative assets	$ 1,051	$ 858
Gross amount of liabilities offset in balance sheet	0	0
Net amount of derivative assets presented in balance sheet	1,051	858
Financial instruments, amount not offset	(503)	(471)
Derivative, collateral, obligation to return securities	(3)	(53)
Derivative, collateral, obligation to return cash	(532)	(334)
Derivative asset, fair value, amount offset against collateral, subject to master netting agreement	13	0
Derivative asset, not subject to master netting arrangement	75	78
Derivative asset, fair value, amount offset against collateral, not subject to master netting agreement	75	78
Derivative asset, fair value, gross asset including not subject to master netting arrangement	1,126	936
Net amount of derivative assets presented in balance sheet	1,126	936
Derivative asset, fair value, amount offset against collateral	88	78
Gross amounts of recognized financial instruments	3,344	3,060
Gross amounts offset in balance sheet	0	0
Net amounts of assets presented in balance sheet	3,344	3,060
Carrying value of financial instruments not offset in balance sheet	(503)	(471)
Securities collateral, not offset in balance sheet	(3)	(53)
Cash collateral, not offset in balance sheet	(2,750)	(2,458)
Financial instruments, amount of assets offset against collateral	88	78
Over the Counter - Bilateral
Offsetting Assets [Line Items]
Gross amount of recognized derivative assets	1,051	858
Gross amount of liabilities offset in balance sheet	0	0
Net amount of derivative assets presented in balance sheet	1,051	858
Financial instruments, amount not offset	(503)	(471)
Derivative, collateral, obligation to return securities	(3)	(53)
Derivative, collateral, obligation to return cash	(532)	(334)
Derivative asset, fair value, amount offset against collateral, subject to master netting agreement	13	0
Derivative asset, not subject to master netting arrangement	75	78
Derivative asset, fair value, amount offset against collateral, not subject to master netting agreement	75	78
Securities Lending and Similar Arrangements
Offsetting Assets [Line Items]
Gross amounts of recognized financial instruments	2,218	2,124
Gross amounts offset in balance sheet	0	0
Net amounts of assets presented in balance sheet	2,218	2,124
Carrying value of financial instruments not offset in balance sheet	0	0
Securities collateral, not offset in balance sheet	0	0
Cash collateral, not offset in balance sheet	(2,218)	(2,124)
Financial instruments, amount of assets offset against collateral	$ 0	$ 0