LOANS - Corporate Loan Delinquency and Non-Accruals (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Loans receivable
Total loans	$ 689,362	$ 657,221
Loans held at fair value	7,594	5,360
Unallocated portfolio layer cumulative basis adjustments	93
Lease financing
Loans receivable
Total loans	$ 300	400
Corporate
Loans receivable
Number of days past due, non-accrual status	90 days
Number of days past due for reversal of accrued interest and charging to earnings	90 days
Total loans past due and accruing	$ 594	1,898
Loans, total non-accrual	1,882	1,122
Total loans	300,165	289,154
Loans held at fair value	7,281	5,123
Loans held at fair value, excluding accrued interest	$ 300,072
Loans less than this number of days past due are considered current	30 days
Unallocated portfolio layer cumulative basis adjustments	$ 93	0
Corporate | Commercial and industrial
Loans receivable
Total loans past due and accruing	426	1,357
Loans, total non-accrual	717	860
Total loans	151,451	147,803
Corporate | Financial institutions
Loans receivable
Total loans past due and accruing	16	335
Loans, total non-accrual	51	152
Total loans	65,060	64,907
Corporate | Mortgage and real estate
Loans receivable
Total loans past due and accruing	69	42
Loans, total non-accrual	868	33
Total loans	24,938	21,949
Corporate | Lease financing
Loans receivable
Total loans past due and accruing	0	1
Loans, total non-accrual	0	10
Total loans	275	354
Corporate | Other
Loans receivable
Total loans past due and accruing	83	163
Loans, total non-accrual	246	67
Total loans	51,067	49,018
Corporate | 30–89 days past due
Loans receivable
Total loans past due and accruing	449	1,171
Corporate | 30–89 days past due | Commercial and industrial
Loans receivable
Total loans past due and accruing	308	763
Corporate | 30–89 days past due | Financial institutions
Loans receivable
Total loans past due and accruing	9	233
Corporate | 30–89 days past due | Mortgage and real estate
Loans receivable
Total loans past due and accruing	66	30
Corporate | 30–89 days past due | Lease financing
Loans receivable
Total loans past due and accruing	0	0
Corporate | 30–89 days past due | Other
Loans receivable
Total loans past due and accruing	66	145
Corporate | 90+ days past due
Loans receivable
Total loans past due and accruing	145	727
Corporate | 90+ days past due | Commercial and industrial
Loans receivable
Total loans past due and accruing	118	594
Corporate | 90+ days past due | Financial institutions
Loans receivable
Total loans past due and accruing	7	102
Corporate | 90+ days past due | Mortgage and real estate
Loans receivable
Total loans past due and accruing	3	12
Corporate | 90+ days past due | Lease financing
Loans receivable
Total loans past due and accruing	0	1
Corporate | 90+ days past due | Other
Loans receivable
Total loans past due and accruing	17	18
Corporate | Current
Loans receivable
Total loans	290,315	281,011
Corporate | Current | Commercial and industrial
Loans receivable
Total loans	150,308	145,586
Corporate | Current | Financial institutions
Loans receivable
Total loans	64,993	64,420
Corporate | Current | Mortgage and real estate
Loans receivable
Total loans	24,001	21,874
Corporate | Current | Lease financing
Loans receivable
Total loans	275	343
Corporate | Current | Other
Loans receivable
Total loans	$ 50,738	$ 48,788