CREDIT QUALITY AND THE ALLOWANCE FOR CREDIT LOSSES - Accruing and Nonaccruing Past Due Amounts (Details) - USD ($) $ in Millions	Jun. 30, 2026	Dec. 31, 2025
Financing Receivable, Past Due [Line Items]
Loans and leases	$ 147,491	$ 142,692
Loans and leases, nonaccrual	1,435	1,504
Loans and leases, nonaccrual with no related ACL	406	496
Guaranteed residential mortgages
Financing Receivable, Past Due [Line Items]
Loans and leases	943	964
Loans and leases, nonaccrual	0	0
Loans and leases, nonaccrual with no related ACL	0	0
Current
Financing Receivable, Past Due [Line Items]
Loans and leases	145,411	140,248
Current \| Guaranteed residential mortgages
Financing Receivable, Past Due [Line Items]
Loans and leases	725	743
30-59
Financing Receivable, Past Due [Line Items]
Loans and leases	284	565
30-59 \| Guaranteed residential mortgages
Financing Receivable, Past Due [Line Items]
Loans and leases	28	53
60-89
Financing Receivable, Past Due [Line Items]
Loans and leases	178	206
60-89 \| Guaranteed residential mortgages
Financing Receivable, Past Due [Line Items]
Loans and leases	18	27
90+
Financing Receivable, Past Due [Line Items]
Loans and leases	183	169
90+ \| Guaranteed residential mortgages
Financing Receivable, Past Due [Line Items]
Loans and leases	172	141
Commercial
Financing Receivable, Past Due [Line Items]
Loans and leases	77,284	73,812
Loans and leases, nonaccrual	818	895
Loans and leases, nonaccrual with no related ACL	68	119
Commercial \| Commercial and industrial
Financing Receivable, Past Due [Line Items]
Loans and leases	53,467	49,232
Loans and leases, nonaccrual	244	277
Loans and leases, nonaccrual with no related ACL	24	34
Commercial \| Commercial real estate
Financing Receivable, Past Due [Line Items]
Loans and leases	23,817	24,580
Loans and leases, nonaccrual	574	618
Loans and leases, nonaccrual with no related ACL	44	85
Commercial \| Current
Financing Receivable, Past Due [Line Items]
Loans and leases	76,369	72,573
Commercial \| Current \| Commercial and industrial
Financing Receivable, Past Due [Line Items]
Loans and leases	53,190	48,873
Commercial \| Current \| Commercial real estate
Financing Receivable, Past Due [Line Items]
Loans and leases	23,179	23,700
Commercial \| 30-59
Financing Receivable, Past Due [Line Items]
Loans and leases	25	247
Commercial \| 30-59 \| Commercial and industrial
Financing Receivable, Past Due [Line Items]
Loans and leases	21	63
Commercial \| 30-59 \| Commercial real estate
Financing Receivable, Past Due [Line Items]
Loans and leases	4	184
Commercial \| 60-89
Financing Receivable, Past Due [Line Items]
Loans and leases	63	72
Commercial \| 60-89 \| Commercial and industrial
Financing Receivable, Past Due [Line Items]
Loans and leases	9	14
Commercial \| 60-89 \| Commercial real estate
Financing Receivable, Past Due [Line Items]
Loans and leases	54	58
Commercial \| 90+
Financing Receivable, Past Due [Line Items]
Loans and leases	9	25
Commercial \| 90+ \| Commercial and industrial
Financing Receivable, Past Due [Line Items]
Loans and leases	3	5
Commercial \| 90+ \| Commercial real estate
Financing Receivable, Past Due [Line Items]
Loans and leases	6	20
Retail
Financing Receivable, Past Due [Line Items]
Loans and leases	70,207	68,880
Loans and leases, nonaccrual	617	609
Loans and leases, nonaccrual with no related ACL	338	377
Retail \| Residential mortgages
Financing Receivable, Past Due [Line Items]
Loans and leases	36,374	35,024
Loans and leases, nonaccrual	220	196
Loans and leases, nonaccrual with no related ACL	128	155
Retail \| Home equity
Financing Receivable, Past Due [Line Items]
Loans and leases	20,276	19,069
Loans and leases, nonaccrual	316	319
Loans and leases, nonaccrual with no related ACL	205	215
Retail \| Automobile
Financing Receivable, Past Due [Line Items]
Loans and leases	1,482	2,310
Loans and leases, nonaccrual	21	28
Loans and leases, nonaccrual with no related ACL	3	4
Retail \| Education
Financing Receivable, Past Due [Line Items]
Loans and leases	8,044	8,416
Loans and leases, nonaccrual	21	20
Loans and leases, nonaccrual with no related ACL	2	2
Retail \| Other retail
Financing Receivable, Past Due [Line Items]
Loans and leases	4,031	4,061
Loans and leases, nonaccrual	39	46
Loans and leases, nonaccrual with no related ACL	0	1
Retail \| Current
Financing Receivable, Past Due [Line Items]
Loans and leases	69,042	67,675
Retail \| Current \| Residential mortgages
Financing Receivable, Past Due [Line Items]
Loans and leases	35,873	34,547
Retail \| Current \| Home equity
Financing Receivable, Past Due [Line Items]
Loans and leases	19,841	18,626
Retail \| Current \| Automobile
Financing Receivable, Past Due [Line Items]
Loans and leases	1,405	2,203
Retail \| Current \| Education
Financing Receivable, Past Due [Line Items]
Loans and leases	7,973	8,342
Retail \| Current \| Other retail
Financing Receivable, Past Due [Line Items]
Loans and leases	3,950	3,957
Retail \| 30-59
Financing Receivable, Past Due [Line Items]
Loans and leases	259	318
Retail \| 30-59 \| Residential mortgages
Financing Receivable, Past Due [Line Items]
Loans and leases	71	93
Retail \| 30-59 \| Home equity
Financing Receivable, Past Due [Line Items]
Loans and leases	91	95
Retail \| 30-59 \| Automobile
Financing Receivable, Past Due [Line Items]
Loans and leases	41	59
Retail \| 30-59 \| Education
Financing Receivable, Past Due [Line Items]
Loans and leases	31	36
Retail \| 30-59 \| Other retail
Financing Receivable, Past Due [Line Items]
Loans and leases	25	35
Retail \| 60-89
Financing Receivable, Past Due [Line Items]
Loans and leases	115	134
Retail \| 60-89 \| Residential mortgages
Financing Receivable, Past Due [Line Items]
Loans and leases	38	47
Retail \| 60-89 \| Home equity
Financing Receivable, Past Due [Line Items]
Loans and leases	28	28
Retail \| 60-89 \| Automobile
Financing Receivable, Past Due [Line Items]
Loans and leases	15	20
Retail \| 60-89 \| Education
Financing Receivable, Past Due [Line Items]
Loans and leases	17	16
Retail \| 60-89 \| Other retail
Financing Receivable, Past Due [Line Items]
Loans and leases	17	23
Retail \| 90+
Financing Receivable, Past Due [Line Items]
Loans and leases	174	144
Retail \| 90+ \| Residential mortgages
Financing Receivable, Past Due [Line Items]
Loans and leases	172	141
Retail \| 90+ \| Home equity
Financing Receivable, Past Due [Line Items]
Loans and leases	0	1
Retail \| 90+ \| Automobile
Financing Receivable, Past Due [Line Items]
Loans and leases	0	0
Retail \| 90+ \| Education
Financing Receivable, Past Due [Line Items]
Loans and leases	2	2
Retail \| 90+ \| Other retail
Financing Receivable, Past Due [Line Items]
Loans and leases	$ 0	$ 0

Amortized cost excluding accrued interest, before allowance for credit loss, of financing receivable. Excludes net investment in lease.

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