LOANS - Defaults of Modified Consumer Loans (Details) - Consumer - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
In North America offices
Loans receivable
Loans in default	$ 147	$ 290
In North America offices | Interest rate reduction
Loans receivable
Loans in default	135
In North America offices | Term extension
Loans receivable
Loans in default	10
In North America offices | Payment delay
Loans receivable
Loans in default	1
In North America offices | Combination: interest rate reduction and term extension
Loans receivable
Loans in default	1
In North America offices | Combination: term extension and payment delay
Loans receivable
Loans in default	0
In North America offices | Combination: interest rate reduction, term extension and payment delay
Loans receivable
Loans in default	0
In offices outside the U.S.
Loans receivable
Loans in default	11	25
In offices outside the U.S. | Interest rate reduction
Loans receivable
Loans in default	5
In offices outside the U.S. | Term extension
Loans receivable
Loans in default	0
In offices outside the U.S. | Payment delay
Loans receivable
Loans in default	3
In offices outside the U.S. | Combination: interest rate reduction and term extension
Loans receivable
Loans in default	3
In offices outside the U.S. | Combination: term extension and payment delay
Loans receivable
Loans in default	0
In offices outside the U.S. | Combination: interest rate reduction, term extension and payment delay
Loans receivable
Loans in default	0
Residential first mortgages | In North America offices
Loans receivable
Loans in default	12	35
Residential first mortgages | In North America offices | Interest rate reduction
Loans receivable
Loans in default	1
Residential first mortgages | In North America offices | Term extension
Loans receivable
Loans in default	10
Residential first mortgages | In North America offices | Payment delay
Loans receivable
Loans in default	1
Residential first mortgages | In North America offices | Combination: interest rate reduction and term extension
Loans receivable
Loans in default	0
Residential first mortgages | In North America offices | Combination: term extension and payment delay
Loans receivable
Loans in default	0
Residential first mortgages | In North America offices | Combination: interest rate reduction, term extension and payment delay
Loans receivable
Loans in default	0
Residential first mortgages | In offices outside the U.S.
Loans receivable
Loans in default	3	10
Residential first mortgages | In offices outside the U.S. | Interest rate reduction
Loans receivable
Loans in default	0
Residential first mortgages | In offices outside the U.S. | Term extension
Loans receivable
Loans in default	0
Residential first mortgages | In offices outside the U.S. | Payment delay
Loans receivable
Loans in default	3
Residential first mortgages | In offices outside the U.S. | Combination: interest rate reduction and term extension
Loans receivable
Loans in default	0
Residential first mortgages | In offices outside the U.S. | Combination: term extension and payment delay
Loans receivable
Loans in default	0
Residential first mortgages | In offices outside the U.S. | Combination: interest rate reduction, term extension and payment delay
Loans receivable
Loans in default	0
Home equity loans | In North America offices
Loans receivable
Loans in default	0	4
Home equity loans | In North America offices | Interest rate reduction
Loans receivable
Loans in default	0
Home equity loans | In North America offices | Term extension
Loans receivable
Loans in default	0
Home equity loans | In North America offices | Payment delay
Loans receivable
Loans in default	0
Home equity loans | In North America offices | Combination: interest rate reduction and term extension
Loans receivable
Loans in default	0
Home equity loans | In North America offices | Combination: term extension and payment delay
Loans receivable
Loans in default	0
Home equity loans | In North America offices | Combination: interest rate reduction, term extension and payment delay
Loans receivable
Loans in default	0
Total credit cards | In North America offices
Loans receivable
Loans in default	134	250
Total credit cards | In North America offices | Interest rate reduction
Loans receivable
Loans in default	134
Total credit cards | In North America offices | Term extension
Loans receivable
Loans in default	0
Total credit cards | In North America offices | Payment delay
Loans receivable
Loans in default	0
Total credit cards | In North America offices | Combination: interest rate reduction and term extension
Loans receivable
Loans in default	0
Total credit cards | In North America offices | Combination: term extension and payment delay
Loans receivable
Loans in default	0
Total credit cards | In North America offices | Combination: interest rate reduction, term extension and payment delay
Loans receivable
Loans in default	0
Total credit cards | In offices outside the U.S.
Loans receivable
Loans in default	5	12
Total credit cards | In offices outside the U.S. | Interest rate reduction
Loans receivable
Loans in default	5
Total credit cards | In offices outside the U.S. | Term extension
Loans receivable
Loans in default	0
Total credit cards | In offices outside the U.S. | Payment delay
Loans receivable
Loans in default	0
Total credit cards | In offices outside the U.S. | Combination: interest rate reduction and term extension
Loans receivable
Loans in default	0
Total credit cards | In offices outside the U.S. | Combination: term extension and payment delay
Loans receivable
Loans in default	0
Total credit cards | In offices outside the U.S. | Combination: interest rate reduction, term extension and payment delay
Loans receivable
Loans in default	0
Personal, small business and other | In North America offices
Loans receivable
Loans in default	1	1
Personal, small business and other | In North America offices | Interest rate reduction
Loans receivable
Loans in default	0
Personal, small business and other | In North America offices | Term extension
Loans receivable
Loans in default	0
Personal, small business and other | In North America offices | Payment delay
Loans receivable
Loans in default	0
Personal, small business and other | In North America offices | Combination: interest rate reduction and term extension
Loans receivable
Loans in default	1
Personal, small business and other | In North America offices | Combination: term extension and payment delay
Loans receivable
Loans in default	0
Personal, small business and other | In North America offices | Combination: interest rate reduction, term extension and payment delay
Loans receivable
Loans in default	0
Personal, small business and other | In offices outside the U.S.
Loans receivable
Loans in default	3	$ 3
Personal, small business and other | In offices outside the U.S. | Interest rate reduction
Loans receivable
Loans in default	0
Personal, small business and other | In offices outside the U.S. | Term extension
Loans receivable
Loans in default	0
Personal, small business and other | In offices outside the U.S. | Payment delay
Loans receivable
Loans in default	0
Personal, small business and other | In offices outside the U.S. | Combination: interest rate reduction and term extension
Loans receivable
Loans in default	3
Personal, small business and other | In offices outside the U.S. | Combination: term extension and payment delay
Loans receivable
Loans in default	0
Personal, small business and other | In offices outside the U.S. | Combination: interest rate reduction, term extension and payment delay
Loans receivable
Loans in default	$ 0