LOANS - Interest Income Recognized for Non-Accrual Consumer Loans (Details) - Consumer - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Financing Receivable, Nonaccrual [Line Items]
Interest income	$ 9	$ 5	$ 15	$ 9
Loans sold and/or reclassified to held-for-sale	2	367	1,800	374
In North America offices
Financing Receivable, Nonaccrual [Line Items]
Interest income	5	5	10	9
In offices outside North America
Financing Receivable, Nonaccrual [Line Items]
Interest income	4	0	5	0
Residential mortgages | In North America offices
Financing Receivable, Nonaccrual [Line Items]
Interest income	3	3	6	6
Residential mortgages | In offices outside North America
Financing Receivable, Nonaccrual [Line Items]
Interest income	4	0	5	0
Home equity loans | In North America offices
Financing Receivable, Nonaccrual [Line Items]
Interest income	1	1	3	2
Credit cards | In North America offices
Financing Receivable, Nonaccrual [Line Items]
Interest income	0	0	0	0
Credit cards | In offices outside North America
Financing Receivable, Nonaccrual [Line Items]
Interest income	0	0	0	0
Personal, small business and other | In North America offices
Financing Receivable, Nonaccrual [Line Items]
Interest income	1	1	1	1
Personal, small business and other | In offices outside North America
Financing Receivable, Nonaccrual [Line Items]
Interest income	$ 0	$ 0	$ 0	$ 0