VARIABLE INTEREST ENTITIES - Assets and Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021
Variable Interest Entity [Line Items]
Assets	$ 42,022	$ 39,513	$ 38,475
Liabilities	36,583	34,363
Variable Interest Entity, Primary Beneficiary
Variable Interest Entity [Line Items]
Assets	151	150
Liabilities	103	107
Maximum Exposure to Loss	150	149
Trust Preferred Securities | Variable Interest Entity, Primary Beneficiary
Variable Interest Entity [Line Items]
Assets	1	1
Liabilities	67	67
Maximum Exposure to Loss	0	0
Affordable Housing Tax Credit Partnerships | Variable Interest Entity, Primary Beneficiary
Variable Interest Entity [Line Items]
Assets	118	121
Liabilities	31	34
Maximum Exposure to Loss	118	121
Other Investments | Variable Interest Entity, Primary Beneficiary
Variable Interest Entity [Line Items]
Assets	32	28
Liabilities	5	6
Maximum Exposure to Loss	$ 32	$ 28