Asset Quality - Schedule of Aging Analysis of Past Due and Current Loans (Details) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Financing Receivable, Past Due [Line Items]
Total	$ 119,011	$ 119,394
Accrued interest	500	417
Total commercial loans
Financing Receivable, Past Due [Line Items]
Total	82,554	82,465
Accrued interest	365	314
Total consumer loans
Financing Receivable, Past Due [Line Items]
Total	36,457	36,929
Accrued interest	135	103
Non-performing Loans
Financing Receivable, Past Due [Line Items]
Total	431	387
Non-performing Loans | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total	254	196
Non-performing Loans | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total	177	191
Current
Financing Receivable, Past Due [Line Items]
Total	118,368	118,767
Current | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total	82,182	82,129
Current | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total	36,186	36,638
30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	93	122
30-59 Days Past Due | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total	46	62
30-59 Days Past Due | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total	47	60
60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	46	58
60-89 Days Past Due | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total	21	36
60-89 Days Past Due | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total	25	22
90 and Greater Days Past Due
Financing Receivable, Past Due [Line Items]
Total	73	60
90 and Greater Days Past Due | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total	51	42
90 and Greater Days Past Due | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total	22	18
Total Past Due and Non-performing Loans
Financing Receivable, Past Due [Line Items]
Total	643	627
Total Past Due and Non-performing Loans | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total	372	336
Total Past Due and Non-performing Loans | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total	271	291
Total commercial real estate loans | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total	18,694	18,882
Total commercial real estate loans | Non-performing Loans | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total	65	21
Total commercial real estate loans | Current | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total	18,610	18,835
Total commercial real estate loans | 30-59 Days Past Due | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total	7	16
Total commercial real estate loans | 60-89 Days Past Due | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total	2	2
Total commercial real estate loans | 90 and Greater Days Past Due | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total	10	8
Total commercial real estate loans | Total Past Due and Non-performing Loans | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total	84	47
Commercial and industrial | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total	60,059	59,647
Commercial and industrial | Non-performing Loans | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total	188	174
Commercial and industrial | Current | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total	59,794	59,366
Commercial and industrial | 30-59 Days Past Due | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total	17	43
Commercial and industrial | 60-89 Days Past Due | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total	19	33
Commercial and industrial | 90 and Greater Days Past Due | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total	41	31
Commercial and industrial | Total Past Due and Non-performing Loans | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total	265	281
Commercial mortgage | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total	16,048	16,352
Commercial mortgage | Non-performing Loans | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total	65	21
Commercial mortgage | Current | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total	15,964	16,305
Commercial mortgage | 30-59 Days Past Due | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total	7	16
Commercial mortgage | 60-89 Days Past Due | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total	2	2
Commercial mortgage | 90 and Greater Days Past Due | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total	10	8
Commercial mortgage | Total Past Due and Non-performing Loans | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total	84	47
Construction | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total	2,646	2,530
Construction | Non-performing Loans | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total	0	0
Construction | Current | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total	2,646	2,530
Construction | 30-59 Days Past Due | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total	0	0
Construction | 60-89 Days Past Due | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total	0	0
Construction | 90 and Greater Days Past Due | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total	0	0
Construction | Total Past Due and Non-performing Loans | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total	0	0
Commercial lease financing | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total	3,801	3,936
Commercial lease financing | Non-performing Loans | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total	1	1
Commercial lease financing | Current | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total	3,778	3,928
Commercial lease financing | 30-59 Days Past Due | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total	22	3
Commercial lease financing | 60-89 Days Past Due | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total	0	1
Commercial lease financing | 90 and Greater Days Past Due | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total	0	3
Commercial lease financing | Total Past Due and Non-performing Loans | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total	23	8
Real estate — residential mortgage | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total	21,637	21,401
Real estate — residential mortgage | Non-performing Loans | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total	73	77
Real estate — residential mortgage | Current | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total	21,553	21,307
Real estate — residential mortgage | 30-59 Days Past Due | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total	6	13
Real estate — residential mortgage | 60-89 Days Past Due | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total	5	3
Real estate — residential mortgage | 90 and Greater Days Past Due | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total	0	1
Real estate — residential mortgage | Total Past Due and Non-performing Loans | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total	84	94
Home equity loans | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total	7,529	7,951
Home equity loans | Non-performing Loans | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total	97	107
Home equity loans | Current | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total	7,395	7,804
Home equity loans | 30-59 Days Past Due | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total	24	27
Home equity loans | 60-89 Days Past Due | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total	7	8
Home equity loans | 90 and Greater Days Past Due | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total	6	5
Home equity loans | Total Past Due and Non-performing Loans | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total	134	147
Consumer direct loans | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total	6,257	6,508
Consumer direct loans | Non-performing Loans | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total	3	3
Consumer direct loans | Current | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total	6,227	6,478
Consumer direct loans | 30-59 Days Past Due | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total	11	15
Consumer direct loans | 60-89 Days Past Due | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total	9	7
Consumer direct loans | 90 and Greater Days Past Due | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total	7	5
Consumer direct loans | Total Past Due and Non-performing Loans | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total	30	30
Credit cards | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total	200	172
Credit cards | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total	1,001	1,026
Credit cards | Non-performing Loans | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total	3	3
Credit cards | Current | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total	979	1,007
Credit cards | 30-59 Days Past Due | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total	6	5
Credit cards | 60-89 Days Past Due | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total	4	4
Credit cards | 90 and Greater Days Past Due | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total	9	7
Credit cards | Total Past Due and Non-performing Loans | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total	22	19
Consumer indirect loans | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total	33	43
Consumer indirect loans | Non-performing Loans | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total	1	1
Consumer indirect loans | Current | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total	32	42
Consumer indirect loans | 30-59 Days Past Due | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total	0	0
Consumer indirect loans | 60-89 Days Past Due | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total	0	0
Consumer indirect loans | 90 and Greater Days Past Due | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total	0	0
Consumer indirect loans | Total Past Due and Non-performing Loans | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total	$ 1	$ 1