LOANS - Corporate Loan Delinquency and Non-Accruals (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Loans receivable
Total loans	$ 667,767	$ 675,883
Loans held at fair value	6,082	6,854
Lease financing
Loans receivable
Total loans	$ 500	700
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	$ 2,525	2,144
Loans, total non-accrual	1,877	3,527
Total loans	396,531	387,044
Loans held at fair value	$ 6,070	6,840
Loans less than this number of days past due are considered current	30 days
Corporate | Commercial and industrial
Loans receivable
Total loans past due and accruing	$ 1,349	509
Loans, total non-accrual	1,264	2,795
Total loans	151,072	156,340
Corporate | Financial institutions
Loans receivable
Total loans past due and accruing	738	733
Loans, total non-accrual	33	92
Total loans	98,943	87,689
Corporate | Mortgage and real estate
Loans receivable
Total loans past due and accruing	284	697
Loans, total non-accrual	419	505
Total loans	73,769	72,038
Corporate | Lease financing
Loans receivable
Total loans past due and accruing	0	74
Loans, total non-accrual	14	24
Total loans	455	738
Corporate | Other
Loans receivable
Total loans past due and accruing	154	131
Loans, total non-accrual	147	111
Total loans	66,222	63,399
Corporate | 30 to 89 days past due
Loans receivable
Total loans past due and accruing	2,016	1,692
Corporate | 30 to 89 days past due | Commercial and industrial
Loans receivable
Total loans past due and accruing	1,100	400
Corporate | 30 to 89 days past due | Financial institutions
Loans receivable
Total loans past due and accruing	505	668
Corporate | 30 to 89 days past due | Mortgage and real estate
Loans receivable
Total loans past due and accruing	283	450
Corporate | 30 to 89 days past due | Lease financing
Loans receivable
Total loans past due and accruing	0	62
Corporate | 30 to 89 days past due | Other
Loans receivable
Total loans past due and accruing	128	112
Corporate | Equal to greater than 90 days past due
Loans receivable
Total loans past due and accruing	509	452
Corporate | Equal to greater than 90 days past due | Commercial and industrial
Loans receivable
Total loans past due and accruing	249	109
Corporate | Equal to greater than 90 days past due | Financial institutions
Loans receivable
Total loans past due and accruing	233	65
Corporate | Equal to greater than 90 days past due | Mortgage and real estate
Loans receivable
Total loans past due and accruing	1	247
Corporate | Equal to greater than 90 days past due | Lease financing
Loans receivable
Total loans past due and accruing	0	12
Corporate | Equal to greater than 90 days past due | Other
Loans receivable
Total loans past due and accruing	26	19
Corporate | Current
Loans receivable
Total loans	386,059	374,533
Corporate | Current | Commercial and industrial
Loans receivable
Total loans	148,459	153,036
Corporate | Current | Financial institutions
Loans receivable
Total loans	98,172	86,864
Corporate | Current | Mortgage and real estate
Loans receivable
Total loans	73,066	70,836
Corporate | Current | Lease financing
Loans receivable
Total loans	441	640
Corporate | Current | Other
Loans receivable
Total loans	$ 65,921	$ 63,157