CREDIT QUALITY AND THE ALLOWANCE FOR CREDIT LOSSES - Amortized Cost Basis by Credit Quality Indicator (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Total	$ 142,692	$ 139,203
Gross charge-offs
Year one	44	43
Year two	34	35
Year three	37	72
Year four	134	118
Year five	110	184
Prior to year five	254	253
Within the Revolving Period	204	216
Converted to Term	0	2
Total	817	923	$ 757
Commercial
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	13,684	8,680
Year two	5,839	4,073
Year three	2,123	11,674
Year four	7,890	9,575
Year five	5,692	3,546
Prior to year five	8,748	8,223
Within the Revolving Period	29,616	23,790
Converted to Term	220	215
Total	73,812	69,776
Gross charge-offs
Year one	0	0
Year two	0	0
Year three	5	16
Year four	78	54
Year five	58	146
Prior to year five	152	165
Within the Revolving Period	58	38
Converted to Term	0	0
Total	351	419	285
Commercial | Pass
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	13,658	8,665
Year two	5,812	3,830
Year three	1,918	9,942
Year four	6,127	8,335
Year five	4,854	2,814
Prior to year five	6,771	6,265
Within the Revolving Period	28,297	22,757
Converted to Term	81	70
Total	67,518	62,678
Commercial | Special Mention
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	13	3
Year two	7	79
Year three	49	1,009
Year four	870	598
Year five	468	223
Prior to year five	290	305
Within the Revolving Period	432	291
Converted to Term	4	6
Total	2,133	2,514
Commercial | Substandard Accrual
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	13	12
Year two	16	86
Year three	138	566
Year four	709	522
Year five	312	414
Prior to year five	1,173	1,128
Within the Revolving Period	779	706
Converted to Term	126	133
Total	3,266	3,567
Commercial | Nonaccrual
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	0	0
Year two	4	78
Year three	18	157
Year four	184	120
Year five	58	95
Prior to year five	514	525
Within the Revolving Period	108	36
Converted to Term	9	6
Total	895	1,017
Commercial | Commercial and industrial
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	8,915	5,956
Year two	4,010	2,679
Year three	1,357	4,567
Year four	2,745	3,490
Year five	1,510	1,087
Prior to year five	2,420	2,422
Within the Revolving Period	28,169	22,265
Converted to Term	106	85
Total	49,232	42,551
Gross charge-offs
Year one	0	0
Year two	0	0
Year three	2	15
Year four	57	31
Year five	31	1
Prior to year five	5	22
Within the Revolving Period	51	38
Converted to Term	0	0
Total	146	107
Commercial | Commercial and industrial | Pass
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	8,889	5,945
Year two	3,985	2,525
Year three	1,196	4,194
Year four	2,415	2,923
Year five	1,174	895
Prior to year five	1,966	2,066
Within the Revolving Period	26,951	21,323
Converted to Term	77	66
Total	46,653	39,937
Commercial | Commercial and industrial | Special Mention
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	13	2
Year two	5	79
Year three	42	98
Year four	141	236
Year five	174	48
Prior to year five	124	48
Within the Revolving Period	359	211
Converted to Term	4	0
Total	862	722
Commercial | Commercial and industrial | Substandard Accrual
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	13	9
Year two	16	64
Year three	104	207
Year four	132	269
Year five	145	139
Prior to year five	258	253
Within the Revolving Period	752	697
Converted to Term	20	13
Total	1,440	1,651
Commercial | Commercial and industrial | Nonaccrual
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	0	0
Year two	4	11
Year three	15	68
Year four	57	62
Year five	17	5
Prior to year five	72	55
Within the Revolving Period	107	34
Converted to Term	5	6
Total	277	241
Commercial | Commercial real estate
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	4,769	2,724
Year two	1,829	1,394
Year three	766	7,107
Year four	5,145	6,085
Year five	4,182	2,459
Prior to year five	6,328	5,801
Within the Revolving Period	1,447	1,525
Converted to Term	114	130
Total	24,580	27,225
Gross charge-offs
Year one	0	0
Year two	0	0
Year three	3	1
Year four	21	23
Year five	27	145
Prior to year five	147	143
Within the Revolving Period	7	0
Converted to Term	0	0
Total	205	312
Commercial | Commercial real estate | Pass
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	4,769	2,720
Year two	1,827	1,305
Year three	722	5,748
Year four	3,712	5,412
Year five	3,680	1,919
Prior to year five	4,805	4,199
Within the Revolving Period	1,346	1,434
Converted to Term	4	4
Total	20,865	22,741
Commercial | Commercial real estate | Special Mention
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	0	1
Year two	2	0
Year three	7	911
Year four	729	362
Year five	294	175
Prior to year five	166	257
Within the Revolving Period	73	80
Converted to Term	0	6
Total	1,271	1,792
Commercial | Commercial real estate | Substandard Accrual
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	0	3
Year two	0	22
Year three	34	359
Year four	577	253
Year five	167	275
Prior to year five	915	875
Within the Revolving Period	27	9
Converted to Term	106	120
Total	1,826	1,916
Commercial | Commercial real estate | Nonaccrual
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	0	0
Year two	0	67
Year three	3	89
Year four	127	58
Year five	41	90
Prior to year five	442	470
Within the Revolving Period	1	2
Converted to Term	4	0
Total	618	776
Retail
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	6,449	4,904
Year two	4,022	4,171
Year three	3,547	8,885
Year four	7,583	13,112
Year five	10,651	7,659
Prior to year five	14,823	11,367
Within the Revolving Period	20,718	18,318
Converted to Term	1,087	1,011
Total	68,880	69,427
Gross charge-offs
Year one	44	43
Year two	34	35
Year three	32	56
Year four	56	64
Year five	52	38
Prior to year five	102	88
Within the Revolving Period	146	178
Converted to Term	0	2
Total	466	504	$ 472
Retail | Residential mortgages
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	5,153	3,459
Year two	3,040	2,554
Year three	2,400	5,621
Year four	5,408	8,318
Year five	7,923	4,833
Prior to year five	11,100	7,941
Within the Revolving Period	0	0
Converted to Term	0	0
Total	35,024	32,726
Gross charge-offs
Year one	0	0
Year two	0	0
Year three	0	0
Year four	0	0
Year five	0	0
Prior to year five	7	4
Within the Revolving Period	0	0
Converted to Term	0	0
Total	7	4
Retail | Home equity
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	0	1
Year two	10	3
Year three	15	15
Year four	17	12
Year five	16	6
Prior to year five	183	336
Within the Revolving Period	17,742	15,115
Converted to Term	1,086	1,007
Total	19,069	16,495
Gross charge-offs
Year one	0	0
Year two	0	0
Year three	0	0
Year four	1	0
Year five	0	0
Prior to year five	4	5
Within the Revolving Period	12	11
Converted to Term	0	2
Total	17	18
Retail | Automobile
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	0	0
Year two	0	346
Year three	227	1,534
Year four	877	2,041
Year five	982	592
Prior to year five	224	231
Within the Revolving Period	0	0
Converted to Term	0	0
Total	2,310	4,744
Gross charge-offs
Year one	0	0
Year two	0	6
Year three	5	34
Year four	25	34
Year five	20	10
Prior to year five	9	10
Within the Revolving Period	0	0
Converted to Term	0	0
Total	59	94
Retail | Education
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	870	664
Year two	717	942
Year three	758	1,533
Year four	1,136	2,668
Year five	1,690	2,180
Prior to year five	3,245	2,825
Within the Revolving Period	0	0
Converted to Term	0	0
Total	8,416	10,812
Gross charge-offs
Year one	0	1
Year two	4	5
Year three	9	12
Year four	19	24
Year five	27	25
Prior to year five	74	59
Within the Revolving Period	0	0
Converted to Term	0	0
Total	133	126
Retail | Other retail
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	426	780
Year two	255	326
Year three	147	182
Year four	145	73
Year five	40	48
Prior to year five	71	34
Within the Revolving Period	2,976	3,203
Converted to Term	1	4
Total	4,061	4,650
Gross charge-offs
Year one	44	42
Year two	30	24
Year three	18	10
Year four	11	6
Year five	5	3
Prior to year five	8	10
Within the Revolving Period	134	167
Converted to Term	0	0
Total	250	262
Greater than 800 | Retail
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	2,489	1,644
Year two	1,997	1,805
Year three	1,682	4,375
Year four	4,053	7,310
Year five	6,252	4,370
Prior to year five	8,054	5,488
Within the Revolving Period	7,194	6,146
Converted to Term	193	200
Total	31,914	31,338
Greater than 800 | Retail | Residential mortgages
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	2,075	1,230
Year two	1,664	1,302
Year three	1,290	3,299
Year four	3,276	5,109
Year five	4,919	2,919
Prior to year five	6,099	3,869
Within the Revolving Period	0	0
Converted to Term	0	0
Total	19,323	17,728
Greater than 800 | Retail | Home equity
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	0	1
Year two	2	0
Year three	3	3
Year four	5	4
Year five	6	1
Prior to year five	66	76
Within the Revolving Period	6,686	5,634
Converted to Term	193	200
Total	6,961	5,919
Greater than 800 | Retail | Automobile
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	0	0
Year two	0	65
Year three	47	380
Year four	224	665
Year five	316	183
Prior to year five	63	58
Within the Revolving Period	0	0
Converted to Term	0	0
Total	650	1,351
Greater than 800 | Retail | Education
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	287	227
Year two	271	373
Year three	311	657
Year four	517	1,517
Year five	1,002	1,256
Prior to year five	1,817	1,475
Within the Revolving Period	0	0
Converted to Term	0	0
Total	4,205	5,505
Greater than 800 | Retail | Other retail
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	127	186
Year two	60	65
Year three	31	36
Year four	31	15
Year five	9	11
Prior to year five	9	10
Within the Revolving Period	508	512
Converted to Term	0	0
Total	775	835
740-799 | Retail
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	2,902	2,306
Year two	1,314	1,420
Year three	1,028	2,616
Year four	2,030	3,618
Year five	2,741	2,165
Prior to year five	3,774	2,871
Within the Revolving Period	6,941	6,170
Converted to Term	217	225
Total	20,947	21,391
740-799 | Retail | Residential mortgages
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	2,377	1,757
Year two	960	873
Year three	656	1,568
Year four	1,375	2,213
Year five	2,004	1,338
Prior to year five	2,759	1,923
Within the Revolving Period	0	0
Converted to Term	0	0
Total	10,131	9,672
740-799 | Retail | Home equity
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	0	0
Year two	4	0
Year three	3	1
Year four	4	2
Year five	3	1
Prior to year five	49	65
Within the Revolving Period	6,148	5,275
Converted to Term	217	224
Total	6,428	5,568
740-799 | Retail | Automobile
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	0	0
Year two	0	92
Year three	58	430
Year four	233	581
Year five	266	176
Prior to year five	61	61
Within the Revolving Period	0	0
Converted to Term	0	0
Total	618	1,340
740-799 | Retail | Education
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	393	290
Year two	268	359
Year three	268	571
Year four	385	804
Year five	459	637
Prior to year five	886	811
Within the Revolving Period	0	0
Converted to Term	0	0
Total	2,659	3,472
740-799 | Retail | Other retail
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	132	259
Year two	82	96
Year three	43	46
Year four	33	18
Year five	9	13
Prior to year five	19	11
Within the Revolving Period	793	895
Converted to Term	0	1
Total	1,111	1,339
680-739 | Retail
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	874	736
Year two	514	609
Year three	451	1,159
Year four	858	1,358
Year five	992	723
Prior to year five	1,568	1,403
Within the Revolving Period	4,186	3,840
Converted to Term	194	184
Total	9,637	10,012
680-739 | Retail | Residential mortgages
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	621	425
Year two	324	281
Year three	239	552
Year four	483	697
Year five	646	385
Prior to year five	1,136	938
Within the Revolving Period	0	0
Converted to Term	0	0
Total	3,449	3,278
680-739 | Retail | Home equity
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	0	0
Year two	3	0
Year three	3	1
Year four	4	0
Year five	3	1
Prior to year five	36	76
Within the Revolving Period	3,453	2,995
Converted to Term	193	183
Total	3,695	3,256
680-739 | Retail | Automobile
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	0	0
Year two	0	91
Year three	53	338
Year four	180	385
Year five	175	115
Prior to year five	41	45
Within the Revolving Period	0	0
Converted to Term	0	0
Total	449	974
680-739 | Retail | Education
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	160	110
Year two	125	150
Year three	120	229
Year four	161	261
Year five	160	211
Prior to year five	335	337
Within the Revolving Period	0	0
Converted to Term	0	0
Total	1,061	1,298
680-739 | Retail | Other retail
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	93	201
Year two	62	87
Year three	36	39
Year four	30	15
Year five	8	11
Prior to year five	20	7
Within the Revolving Period	733	845
Converted to Term	1	1
Total	983	1,206
620-679 | Retail
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	151	155
Year two	144	208
Year three	174	401
Year four	320	416
Year five	321	216
Prior to year five	662	697
Within the Revolving Period	1,171	1,087
Converted to Term	162	142
Total	3,105	3,322
620-679 | Retail | Residential mortgages
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	74	31
Year two	74	61
Year three	80	126
Year four	141	151
Year five	169	101
Prior to year five	491	494
Within the Revolving Period	0	0
Converted to Term	0	0
Total	1,029	964
620-679 | Retail | Home equity
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	0	0
Year two	0	1
Year three	2	4
Year four	2	3
Year five	2	2
Prior to year five	16	60
Within the Revolving Period	900	752
Converted to Term	162	141
Total	1,084	963
620-679 | Retail | Automobile
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	0	0
Year two	0	51
Year three	30	189
Year four	107	194
Year five	98	56
Prior to year five	25	29
Within the Revolving Period	0	0
Converted to Term	0	0
Total	260	519
620-679 | Retail | Education
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	23	27
Year two	40	48
Year three	42	55
Year four	48	58
Year five	46	51
Prior to year five	119	111
Within the Revolving Period	0	0
Converted to Term	0	0
Total	318	350
620-679 | Retail | Other retail
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	54	97
Year two	30	47
Year three	20	27
Year four	22	10
Year five	6	6
Prior to year five	11	3
Within the Revolving Period	271	335
Converted to Term	0	1
Total	414	526
Less than 620 | Retail
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	27	52
Year two	52	129
Year three	212	334
Year four	319	409
Year five	344	184
Prior to year five	724	863
Within the Revolving Period	744	693
Converted to Term	321	260
Total	2,743	2,924
Less than 620 | Retail | Residential mortgages
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	6	15
Year two	18	37
Year three	135	76
Year four	130	147
Year five	184	89
Prior to year five	605	703
Within the Revolving Period	0	0
Converted to Term	0	0
Total	1,078	1,067
Less than 620 | Retail | Home equity
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	0	0
Year two	0	2
Year three	4	6
Year four	2	3
Year five	2	1
Prior to year five	14	59
Within the Revolving Period	554	459
Converted to Term	321	259
Total	897	789
Less than 620 | Retail | Automobile
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	0	0
Year two	0	47
Year three	39	197
Year four	133	216
Year five	127	62
Prior to year five	34	38
Within the Revolving Period	0	0
Converted to Term	0	0
Total	333	560
Less than 620 | Retail | Education
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	5	5
Year two	13	12
Year three	17	21
Year four	25	28
Year five	23	25
Prior to year five	61	60
Within the Revolving Period	0	0
Converted to Term	0	0
Total	144	151
Less than 620 | Retail | Other retail
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	16	32
Year two	21	31
Year three	17	34
Year four	29	15
Year five	8	7
Prior to year five	10	3
Within the Revolving Period	190	234
Converted to Term	0	1
Total	291	357
No FICO available | Retail
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	6	11
Year two	1	0
Year three	0	0
Year four	3	1
Year five	1	1
Prior to year five	41	45
Within the Revolving Period	482	382
Converted to Term	0	0
Total	534	440
No FICO available | Retail | Residential mortgages
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	0	1
Year two	0	0
Year three	0	0
Year four	3	1
Year five	1	1
Prior to year five	10	14
Within the Revolving Period	0	0
Converted to Term	0	0
Total	14	17
No FICO available | Retail | Home equity
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	0	0
Year two	1	0
Year three	0	0
Year four	0	0
Year five	0	0
Prior to year five	2	0
Within the Revolving Period	1	0
Converted to Term	0	0
Total	4	0
No FICO available | Retail | Automobile
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	0	0
Year two	0	0
Year three	0	0
Year four	0	0
Year five	0	0
Prior to year five	0	0
Within the Revolving Period	0	0
Converted to Term	0	0
Total	0	0
No FICO available | Retail | Education
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	2	5
Year two	0	0
Year three	0	0
Year four	0	0
Year five	0	0
Prior to year five	27	31
Within the Revolving Period	0	0
Converted to Term	0	0
Total	29	36
No FICO available | Retail | Other retail
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one	4	5
Year two	0	0
Year three	0	0
Year four	0	0
Year five	0	0
Prior to year five	2	0
Within the Revolving Period	481	382
Converted to Term	0	0
Total	$ 487	$ 387