LOANS - Consumer Loans Gross Credit Losses (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Financing Receivable, Credit Quality Indicator [Line Items]
Total	$ 1,634	$ 1,240
Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Total	1,595	$ 1,192
Consumer | Residential mortgages
Financing Receivable, Credit Quality Indicator [Line Items]
2023	0
2022	0
2021	0
2020	1
2019	1
Prior	12
Total	14
Consumer | Home equity loans (pre-reset)
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0
Consumer | Home equity loans (post-reset)
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0
Consumer | Home equity term loans
Financing Receivable, Credit Quality Indicator [Line Items]
Revolving loans converted to term loans	1
Consumer | Home equity loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total	1
Consumer | Credit cards
Financing Receivable, Credit Quality Indicator [Line Items]
Revolving loans converted to term loans	42
Total	1,366
Consumer | Credit cards
Financing Receivable, Credit Quality Indicator [Line Items]
Total	1,408
Consumer | Personal, small business and other
Financing Receivable, Credit Quality Indicator [Line Items]
2023	38
2022	37
2021	29
2020	13
2019	13
Prior	42
Total	$ 172