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LOANS - Interest Income Recognized for Non-Accrual Consumer Loans (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Financing Receivable, Nonaccrual [Line Items]
Acquisition of held-for-investment loans			$ 700	$ 0
Consumer loans
Financing Receivable, Nonaccrual [Line Items]
Interest income	$ 6	$ 7	20	22
Loans sold and/or reclassified to held-for-sale	2	1	61	1,831
Acquisition of held-for-investment loans	700
Consumer loans \| In North America offices
Financing Receivable, Nonaccrual [Line Items]
Interest income	4	5	12	15
Consumer loans \| In offices outside North America
Financing Receivable, Nonaccrual [Line Items]
Interest income	2	2	8	7
Consumer loans \| Residential mortgages \| In North America offices
Financing Receivable, Nonaccrual [Line Items]
Interest income	2	2	7	8
Consumer loans \| Residential mortgages \| In offices outside North America
Financing Receivable, Nonaccrual [Line Items]
Interest income	2	2	7	7
Consumer loans \| Home equity loans \| In North America offices
Financing Receivable, Nonaccrual [Line Items]
Interest income	1	2	4	5
Consumer loans \| Credit cards \| In North America offices
Financing Receivable, Nonaccrual [Line Items]
Interest income	0	0	0	0
Consumer loans \| Credit cards \| In offices outside North America
Financing Receivable, Nonaccrual [Line Items]
Interest income	0	0	0	0
Consumer loans \| Personal, small business and other \| In North America offices
Financing Receivable, Nonaccrual [Line Items]
Interest income	1	1	1	2
Consumer loans \| Personal, small business and other \| In offices outside North America
Financing Receivable, Nonaccrual [Line Items]
Interest income	$ 0	$ 0	$ 1	$ 0