LOANS - Consumer Loans Gross Credit Losses (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Financing Receivable, Credit Quality Indicator [Line Items]
Total	$ 2,609	$ 2,000	$ 8,014	$ 5,513
Consumer loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total	$ 2,496	$ 1,928	7,594	5,316
Consumer loans | Residential mortgages
Financing Receivable, Credit Quality Indicator [Line Items]
Current year			0	0
Prior year			1	2
Two years prior			0	0
Three years prior			0	1
Four years prior			0	5
Prior			27	31
Total			28	39
Consumer loans | Home equity loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total			7	4
Consumer loans | Home equity line of credit (pre-reset)
Financing Receivable, Credit Quality Indicator [Line Items]
Total			5	2
Consumer loans | Home equity line of credit (post-reset)
Financing Receivable, Credit Quality Indicator [Line Items]
Total			1	0
Consumer loans | Home equity term loans
Financing Receivable, Credit Quality Indicator [Line Items]
Revolving loans converted to term loans			1	2
Consumer loans | Credit cards
Financing Receivable, Credit Quality Indicator [Line Items]
Revolving loans converted to term loans			188	132
Total			6,787	4,598
Consumer loans | Credit cards
Financing Receivable, Credit Quality Indicator [Line Items]
Total			6,975	4,730
Consumer loans | Personal, small business and other
Financing Receivable, Credit Quality Indicator [Line Items]
Current year			101	110
Prior year			152	146
Two years prior			131	83
Three years prior			51	34
Four years prior			20	38
Prior			129	132
Total			$ 584	$ 543