LOANS AND LEASES - Modifications (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Financing Receivable, Modified [Line Items]
Total	$ 724	$ 734	$ 705
% of total loan class	0.48%	0.59%	0.58%
Total
Financing Receivable, Modified [Line Items]
Total	$ 103	$ 78	$ 92
30-59 Days
Financing Receivable, Modified [Line Items]
Total	29	31	33
60-89  Days
Financing Receivable, Modified [Line Items]
Total	20	12	35
90 or  more days
Financing Receivable, Modified [Line Items]
Total	54	35	24
Current
Financing Receivable, Modified [Line Items]
Total	621	656	613
Interest rate reduction
Financing Receivable, Modified [Line Items]
Total	106	115	67
Term extension
Financing Receivable, Modified [Line Items]
Total	571	511	613
Payment deferral
Financing Receivable, Modified [Line Items]
Total	27	6	2
Combo - interest rate reduction and term extension
Financing Receivable, Modified [Line Items]
Total	20	102	23
Commercial portfolio | Commercial and industrial
Financing Receivable, Modified [Line Items]
Total	$ 377	$ 386	$ 455
% of total loan class	0.54%	0.68%	0.90%
Commercial portfolio | Commercial and industrial | Total
Financing Receivable, Modified [Line Items]
Total	$ 51	$ 13	$ 53
Commercial portfolio | Commercial and industrial | 30-59 Days
Financing Receivable, Modified [Line Items]
Total	8	6	21
Commercial portfolio | Commercial and industrial | 60-89  Days
Financing Receivable, Modified [Line Items]
Total	11	3	25
Commercial portfolio | Commercial and industrial | 90 or  more days
Financing Receivable, Modified [Line Items]
Total	32	4	7
Commercial portfolio | Commercial and industrial | Current
Financing Receivable, Modified [Line Items]
Total	326	373	402
Commercial portfolio | Commercial and industrial | Interest rate reduction
Financing Receivable, Modified [Line Items]
Total	$ 77	$ 113	$ 64
Commercial portfolio | Commercial and industrial | Interest rate reduction | Minimum
Financing Receivable, Modified [Line Items]
Weighted-average contractual interest rate	8.52%	8.16%	8.62%
Commercial portfolio | Commercial and industrial | Interest rate reduction | Maximum
Financing Receivable, Modified [Line Items]
Weighted-average contractual interest rate	7.11%	7.12%	8.05%
Commercial portfolio | Commercial and industrial | Term extension
Financing Receivable, Modified [Line Items]
Total	$ 294	$ 209	$ 387
Weighted-average years added to the life	1 year 1 month 6 days	1 year	1 year
Commercial portfolio | Commercial and industrial | Payment deferral
Financing Receivable, Modified [Line Items]
Total	$ 1	$ 0	$ 0
Commercial portfolio | Commercial and industrial | Combo - interest rate reduction and term extension
Financing Receivable, Modified [Line Items]
Total	5	64	4
Commercial portfolio | Commercial real estate
Financing Receivable, Modified [Line Items]
Total	$ 239	$ 257	$ 157
% of total loan class	1.57%	2.32%	1.26%
Commercial portfolio | Commercial real estate | Total
Financing Receivable, Modified [Line Items]
Total	$ 5	$ 25	$ 5
Commercial portfolio | Commercial real estate | 30-59 Days
Financing Receivable, Modified [Line Items]
Total	5	12	0
Commercial portfolio | Commercial real estate | 60-89  Days
Financing Receivable, Modified [Line Items]
Total	0	0	0
Commercial portfolio | Commercial real estate | 90 or  more days
Financing Receivable, Modified [Line Items]
Total	0	13	5
Commercial portfolio | Commercial real estate | Current
Financing Receivable, Modified [Line Items]
Total	234	232	152
Commercial portfolio | Commercial real estate | Interest rate reduction
Financing Receivable, Modified [Line Items]
Total	$ 28	$ 0	$ 2
Commercial portfolio | Commercial real estate | Interest rate reduction | Minimum
Financing Receivable, Modified [Line Items]
Weighted-average contractual interest rate	8.02%	8.26%	13.42%
Commercial portfolio | Commercial real estate | Interest rate reduction | Maximum
Financing Receivable, Modified [Line Items]
Weighted-average contractual interest rate	6.99%	7.90%	8.75%
Commercial portfolio | Commercial real estate | Term extension
Financing Receivable, Modified [Line Items]
Total	$ 203	$ 233	$ 151
Weighted-average years added to the life	10 months 24 days	10 months 24 days	1 year
Commercial portfolio | Commercial real estate | Payment deferral
Financing Receivable, Modified [Line Items]
Total	$ 7	$ 0	$ 0
Commercial portfolio | Commercial real estate | Combo - interest rate reduction and term extension
Financing Receivable, Modified [Line Items]
Total	1	24	4
Consumer portfolio | Residential mortgage
Financing Receivable, Modified [Line Items]
Total	$ 78	$ 61	$ 64
% of total loan class	0.31%	0.25%	0.27%
Consumer portfolio | Residential mortgage | Total
Financing Receivable, Modified [Line Items]
Total	$ 42	$ 33	$ 28
Consumer portfolio | Residential mortgage | 30-59 Days
Financing Receivable, Modified [Line Items]
Total	14	11	9
Consumer portfolio | Residential mortgage | 60-89  Days
Financing Receivable, Modified [Line Items]
Total	8	7	8
Consumer portfolio | Residential mortgage | 90 or  more days
Financing Receivable, Modified [Line Items]
Total	20	15	11
Consumer portfolio | Residential mortgage | Current
Financing Receivable, Modified [Line Items]
Total	36	28	36
Consumer portfolio | Residential mortgage | Interest rate reduction
Financing Receivable, Modified [Line Items]
Total	0	0	0
Consumer portfolio | Residential mortgage | Term extension
Financing Receivable, Modified [Line Items]
Total	$ 54	$ 51	$ 58
Weighted-average years added to the life	6 years 3 months 18 days	6 years 9 months 18 days	7 years 8 months 12 days
Consumer portfolio | Residential mortgage | Payment deferral
Financing Receivable, Modified [Line Items]
Total	$ 19	$ 6	$ 2
Consumer portfolio | Residential mortgage | Combo - interest rate reduction and term extension
Financing Receivable, Modified [Line Items]
Total	5	4	4
Consumer portfolio | Automobile
Financing Receivable, Modified [Line Items]
Total	$ 11	$ 12	$ 15
% of total loan class	0.07%	0.08%	0.12%
Consumer portfolio | Automobile | Total
Financing Receivable, Modified [Line Items]
Total	$ 1	$ 2	$ 3
Consumer portfolio | Automobile | 30-59 Days
Financing Receivable, Modified [Line Items]
Total	1	1	2
Consumer portfolio | Automobile | 60-89  Days
Financing Receivable, Modified [Line Items]
Total	0	1	1
Consumer portfolio | Automobile | 90 or  more days
Financing Receivable, Modified [Line Items]
Total	0	0	0
Consumer portfolio | Automobile | Current
Financing Receivable, Modified [Line Items]
Total	10	10	12
Consumer portfolio | Automobile | Interest rate reduction
Financing Receivable, Modified [Line Items]
Total	0	0	0
Consumer portfolio | Automobile | Term extension
Financing Receivable, Modified [Line Items]
Total	10	11	14
Consumer portfolio | Automobile | Payment deferral
Financing Receivable, Modified [Line Items]
Total	0	0	0
Consumer portfolio | Automobile | Combo - interest rate reduction and term extension
Financing Receivable, Modified [Line Items]
Total	1	1	1
Consumer portfolio | Home equity
Financing Receivable, Modified [Line Items]
Total	$ 17	$ 15	$ 12
% of total loan class	0.16%	0.15%	0.12%
Consumer portfolio | Home equity | Total
Financing Receivable, Modified [Line Items]
Total	$ 4	$ 5	$ 3
Consumer portfolio | Home equity | 30-59 Days
Financing Receivable, Modified [Line Items]
Total	1	1	1
Consumer portfolio | Home equity | 60-89  Days
Financing Receivable, Modified [Line Items]
Total	1	1	1
Consumer portfolio | Home equity | 90 or  more days
Financing Receivable, Modified [Line Items]
Total	2	3	1
Consumer portfolio | Home equity | Current
Financing Receivable, Modified [Line Items]
Total	13	10	9
Consumer portfolio | Home equity | Interest rate reduction
Financing Receivable, Modified [Line Items]
Total	0	0	0
Consumer portfolio | Home equity | Term extension
Financing Receivable, Modified [Line Items]
Total	9	6	2
Consumer portfolio | Home equity | Payment deferral
Financing Receivable, Modified [Line Items]
Total	0	0	0
Consumer portfolio | Home equity | Combo - interest rate reduction and term extension
Financing Receivable, Modified [Line Items]
Total	8	9	10
Consumer portfolio | RV and marine
Financing Receivable, Modified [Line Items]
Total	$ 1	$ 1	$ 1
% of total loan class	0.02%	0.02%	0.02%
Consumer portfolio | RV and marine | Total
Financing Receivable, Modified [Line Items]
Total	$ 0	$ 0	$ 0
Consumer portfolio | RV and marine | 30-59 Days
Financing Receivable, Modified [Line Items]
Total	0	0	0
Consumer portfolio | RV and marine | 60-89  Days
Financing Receivable, Modified [Line Items]
Total	0	0	0
Consumer portfolio | RV and marine | 90 or  more days
Financing Receivable, Modified [Line Items]
Total	0	0	0
Consumer portfolio | RV and marine | Current
Financing Receivable, Modified [Line Items]
Total	1	1	1
Consumer portfolio | RV and marine | Interest rate reduction
Financing Receivable, Modified [Line Items]
Total	0	0	0
Consumer portfolio | RV and marine | Term extension
Financing Receivable, Modified [Line Items]
Total	1	1	1
Consumer portfolio | RV and marine | Payment deferral
Financing Receivable, Modified [Line Items]
Total	0	0	0
Consumer portfolio | RV and marine | Combo - interest rate reduction and term extension
Financing Receivable, Modified [Line Items]
Total	0	0	0
Consumer portfolio | Other consumer
Financing Receivable, Modified [Line Items]
Total	$ 1	$ 2	$ 1
% of total loan class	0.04%	0.11%	0.07%
Consumer portfolio | Other consumer | Total
Financing Receivable, Modified [Line Items]
Total	$ 0	$ 0	$ 0
Consumer portfolio | Other consumer | 30-59 Days
Financing Receivable, Modified [Line Items]
Total	0	0	0
Consumer portfolio | Other consumer | 60-89  Days
Financing Receivable, Modified [Line Items]
Total	0	0	0
Consumer portfolio | Other consumer | 90 or  more days
Financing Receivable, Modified [Line Items]
Total	0	0	0
Consumer portfolio | Other consumer | Current
Financing Receivable, Modified [Line Items]
Total	1	2	1
Consumer portfolio | Other consumer | Interest rate reduction
Financing Receivable, Modified [Line Items]
Total	1	2	1
Consumer portfolio | Other consumer | Term extension
Financing Receivable, Modified [Line Items]
Total	0	0	0
Consumer portfolio | Other consumer | Payment deferral
Financing Receivable, Modified [Line Items]
Total	0	0	0
Consumer portfolio | Other consumer | Combo - interest rate reduction and term extension
Financing Receivable, Modified [Line Items]
Total	$ 0	$ 0	$ 0