LOANS - Interest Income Recognized for Non-Accrual Consumer Loans (Details) - Consumer loans - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Financing Receivable, Nonaccrual [Line Items]
Interest income	$ 8	$ 9	$ 14	$ 15
Loans sold and/or reclassified to held-for-sale	1	2	59	1,830
In North America offices
Financing Receivable, Nonaccrual [Line Items]
Interest income	4	5	8	10
In offices outside North America
Financing Receivable, Nonaccrual [Line Items]
Interest income	4	4	6	5
Residential mortgages | In North America offices
Financing Receivable, Nonaccrual [Line Items]
Interest income	2	3	5	6
Residential mortgages | In offices outside North America
Financing Receivable, Nonaccrual [Line Items]
Interest income	3	4	5	5
Home equity loans | In North America offices
Financing Receivable, Nonaccrual [Line Items]
Interest income	2	1	3	3
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	0	1	0	1
Personal, small business and other | In offices outside North America
Financing Receivable, Nonaccrual [Line Items]
Interest income	$ 1	$ 0	$ 1	$ 0