DERIVATIVE INSTRUMENTS - Offsetting of Financial Liabilities and Derivative Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Offsetting Liabilities [Line Items]
Gross amount of recognized derivative liabilities	$ 1,033	$ 1,205
Gross amount of assets offset in balance sheet	0	0
Derivative liability, fair value, amount not offset against collateral	1,033	1,205
Financial instruments, amount not offset	(503)	(471)
Derivative, collateral, right to reclaim securities	(278)	(662)
Derivative, collateral, right to reclaim cash	(171)	(49)
Derivative liability, fair value, amount offset against collateral, subject to master netting agreement	81	23
Derivative liability, not subject to master netting arrangement	427	414
Derivative liability, fair value, amount offset against collateral, not subject to master netting agreement	427	414
Derivative liability, fair value, gross liability including not subject to master netting arrangement	1,460	1,619
Net amount of derivative liabilities presented in balance sheet	1,460	1,619
Derivative liability, fair value, amount offset against collateral	508	437
Gross Amounts of Recognized Financial Instruments, Offsetting Liabilities	3,658	3,781
Gross Amounts Offset in Statement of Financial Position, Offsetting Liabilities	0	0
Net Amounts of Financial Instruments Presented in Balance Sheet, Offsetting Liabilities	3,658	3,781
Carrying value of financial instruments, liabilities not offset in balance sheet	(2,721)	(2,595)
Securities Collateral, Liabilities Not Offset in Balance Sheet	(278)	(662)
Cash Collateral, Liabilities Not Offset in Balance Sheet	(171)	(49)
Financial instruments, amount of liabilities offset against collateral	488	475
Over the Counter - Bilateral
Offsetting Liabilities [Line Items]
Gross amount of recognized derivative liabilities	817	1,151
Gross amount of assets offset in balance sheet	0	0
Derivative liability, fair value, amount not offset against collateral	817	1,151
Financial instruments, amount not offset	(503)	(471)
Derivative, collateral, right to reclaim securities	(278)	(662)
Derivative, collateral, right to reclaim cash	(21)	(14)
Derivative liability, fair value, amount offset against collateral, subject to master netting agreement	15	4
Derivative liability, not subject to master netting arrangement	427	414
Derivative liability, fair value, amount offset against collateral, not subject to master netting agreement	427	414
Securities Lending and Similar Arrangements
Offsetting Liabilities [Line Items]
Gross Amounts of Recognized Financial Instruments, Offsetting Liabilities	2,198	2,162
Gross Amounts Offset in Statement of Financial Position, Offsetting Liabilities	0	0
Net Amounts of Financial Instruments Presented in Balance Sheet, Offsetting Liabilities	2,198	2,162
Carrying value of financial instruments, liabilities not offset in balance sheet	(2,218)	(2,124)
Securities Collateral, Liabilities Not Offset in Balance Sheet	0	0
Cash Collateral, Liabilities Not Offset in Balance Sheet	0	0
Financial instruments, amount of liabilities offset against collateral	(20)	38
OTC- Cleared
Offsetting Liabilities [Line Items]
Gross amount of recognized derivative liabilities	216	54
Gross amount of assets offset in balance sheet	0	0
Derivative liability, fair value, amount not offset against collateral	216	54
Financial instruments, amount not offset	0	0
Derivative, collateral, right to reclaim securities	0	0
Derivative, collateral, right to reclaim cash	(150)	(35)
Derivative liability, fair value, amount offset against collateral, subject to master netting agreement	$ 66	$ 19