COMMITMENTS AND CONTINGENT LIABILITIES - Funding Agreements (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Federal Home Loan Bank (FHLB)
Restructuring Reserve [Roll Forward]
Outstanding Balance, period start	$ 6,890
Issued During the Period	60,257
Repaid During the Period	60,504
Long-term Agreements Maturing Within One Year	0
Long-term Agreements Maturing Within Five Years	0
Outstanding Balance, period end	6,643
Difference related to remaining amortization	4	$ 7
Funding Agreement-Backed Notes Program (FABN)
Restructuring Reserve [Roll Forward]
Outstanding Balance, period start	1,950
Issued During the Period	4,809
Repaid During the Period	0
Long-term Agreements Maturing Within One Year	0
Long-term Agreements Maturing Within Five Years	0
Foreign Currency Transaction Adjustment	(40)
Outstanding Balance, period end	6,719
Difference related to remaining amortization	70	$ 11
Due in one year or less | Federal Home Loan Bank (FHLB)
Restructuring Reserve [Roll Forward]
Outstanding Balance, period start	5,634
Issued During the Period	59,846
Repaid During the Period	60,504
Long-term Agreements Maturing Within One Year	377
Long-term Agreements Maturing Within Five Years	0
Outstanding Balance, period end	5,353
Due in one year or less | Funding Agreement-Backed Notes Program (FABN)
Restructuring Reserve [Roll Forward]
Outstanding Balance, period start	0
Issued During the Period	0
Repaid During the Period	0
Long-term Agreements Maturing Within One Year	0
Long-term Agreements Maturing Within Five Years	0
Foreign Currency Transaction Adjustment	0
Outstanding Balance, period end	0
Due in years two through five | Federal Home Loan Bank (FHLB)
Restructuring Reserve [Roll Forward]
Outstanding Balance, period start	722
Issued During the Period	411
Repaid During the Period	0
Long-term Agreements Maturing Within One Year	(377)
Long-term Agreements Maturing Within Five Years	534
Outstanding Balance, period end	1,290
Due in years two through five | Funding Agreement-Backed Notes Program (FABN)
Restructuring Reserve [Roll Forward]
Outstanding Balance, period start	1,150
Issued During the Period	3,450
Repaid During the Period	0
Long-term Agreements Maturing Within One Year	0
Long-term Agreements Maturing Within Five Years	0
Foreign Currency Transaction Adjustment	0
Outstanding Balance, period end	4,600
Due in more than five years | Federal Home Loan Bank (FHLB)
Restructuring Reserve [Roll Forward]
Outstanding Balance, period start	534
Issued During the Period	0
Repaid During the Period	0
Long-term Agreements Maturing Within One Year	0
Long-term Agreements Maturing Within Five Years	(534)
Outstanding Balance, period end	0
Due in more than five years | Funding Agreement-Backed Notes Program (FABN)
Restructuring Reserve [Roll Forward]
Outstanding Balance, period start	800
Issued During the Period	1,359
Repaid During the Period	0
Long-term Agreements Maturing Within One Year	0
Long-term Agreements Maturing Within Five Years	0
Foreign Currency Transaction Adjustment	(40)
Outstanding Balance, period end	2,119
Long-term funding agreements | Federal Home Loan Bank (FHLB)
Restructuring Reserve [Roll Forward]
Outstanding Balance, period start	1,256
Issued During the Period	411
Repaid During the Period	0
Long-term Agreements Maturing Within One Year	(377)
Long-term Agreements Maturing Within Five Years	0
Outstanding Balance, period end	1,290
Long-term funding agreements | Funding Agreement-Backed Notes Program (FABN)
Restructuring Reserve [Roll Forward]
Outstanding Balance, period start	1,950
Issued During the Period	4,809
Repaid During the Period	0
Long-term Agreements Maturing Within One Year	0
Long-term Agreements Maturing Within Five Years	0
Foreign Currency Transaction Adjustment	(40)
Outstanding Balance, period end	$ 6,719