DERIVATIVES AND HEDGING - Offsetting Assets and Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Derivative instruments
Offsetting of Financial Assets:
Gross Amounts of Recognized Financial Instruments	$ 721	$ 811
Counterparty Netting	(483)	(694)
Cash Collateral	0	0
Net Amounts Presented in the Statements of Financial Position	238	117
Financial Instruments/Collateral	0	0
Net Amount	238	117
Offsetting of Financial Liabilities:
Gross Amounts of Recognized Financial Instruments	1,093	1,302
Counterparty Netting	(483)	(694)
Cash Collateral	(557)	(514)
Net Amounts Presented in the Statements of Financial Position	53	94
Financial Instruments/Collateral	(53)	(94)
Net Amount	0	0
Repurchase agreements
Offsetting of Financial Liabilities:
Gross Amounts of Recognized Financial Instruments	1,121	967
Counterparty Netting	0	0
Cash Collateral	0	0
Net Amounts Presented in the Statements of Financial Position	1,121	967
Financial Instruments/Collateral	(1,121)	(967)
Net Amount	0	0
Retained Business | Derivative instruments
Offsetting of Financial Assets:
Gross Amounts of Recognized Financial Instruments	454	638
Counterparty Netting	(438)	(638)
Cash Collateral	0	0
Net Amounts Presented in the Statements of Financial Position	16	0
Financial Instruments/Collateral	0	0
Net Amount	16	0
Offsetting of Financial Liabilities:
Gross Amounts of Recognized Financial Instruments	1,046	1,246
Counterparty Netting	(438)	(638)
Cash Collateral	(555)	(514)
Net Amounts Presented in the Statements of Financial Position	53	94
Financial Instruments/Collateral	(53)	(94)
Net Amount	0	0
Ceded Business | Derivative instruments
Offsetting of Financial Assets:
Gross Amounts of Recognized Financial Instruments	267	173
Counterparty Netting	(45)	(56)
Cash Collateral	0	0
Net Amounts Presented in the Statements of Financial Position	222	117
Financial Instruments/Collateral	0	0
Net Amount	222	117
Offsetting of Financial Liabilities:
Gross Amounts of Recognized Financial Instruments	47	56
Counterparty Netting	(45)	(56)
Cash Collateral	(2)	0
Net Amounts Presented in the Statements of Financial Position	0	0
Financial Instruments/Collateral	0	0
Net Amount	$ 0	$ 0