LOANS - Consumer Loans Gross Credit Losses (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Financing Receivable, Credit Quality Indicator [Line Items]
Total	$ 2,926	$ 2,690
Consumer loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total	2,727	2,512
Consumer loans | Residential mortgages
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	0	0
Prior year	0	0
Two years prior	0	0
Three years prior	0	0
Four years prior	0	0
Prior	17	14
Total	17	14
Consumer loans | Home equity loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total	2	2
Consumer loans | Home equity line of credit (pre-reset)
Financing Receivable, Credit Quality Indicator [Line Items]
Total	2	1
Consumer loans | Home equity line of credit (post-reset)
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0	1
Consumer loans | Home equity term loans
Financing Receivable, Credit Quality Indicator [Line Items]
Revolving loans converted to term loans	0	0
Consumer loans | Credit cards
Financing Receivable, Credit Quality Indicator [Line Items]
Total	2,420	2,237
Consumer loans | Revolving loans converted to term loans
Financing Receivable, Credit Quality Indicator [Line Items]
Revolving loans converted to term loans	84	57
Consumer loans | Total credit cards
Financing Receivable, Credit Quality Indicator [Line Items]
Total	2,504	2,294
Consumer loans | Personal, small business and other
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	32	29
Prior year	49	46
Two years prior	46	52
Three years prior	27	20
Four years prior	10	8
Prior	40	47
Total	$ 204	$ 202