Asset Quality - Schedule of Aging Analysis of Past Due and Current Loans (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Financing Receivable, Past Due [Line Items]
Total loans	$ 107,078	$ 112,606
Accrued interest	502	522
Total commercial loans
Financing Receivable, Past Due [Line Items]
Total loans	73,525	77,591
Accrued interest	365	383
Total consumer loans
Financing Receivable, Past Due [Line Items]
Total loans	33,553	35,015
Accrued interest	137	139
Non-performing Loans
Financing Receivable, Past Due [Line Items]
Total loans	710	574
Non-performing Loans | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total loans	532	397
Non-performing Loans | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total loans	178	177
Current
Financing Receivable, Past Due [Line Items]
Total loans	105,949	111,703
Current | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total loans	72,683	76,988
Current | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total loans	33,266	34,715
30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans	213	156
30-59 Days Past Due | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total loans	159	90
30-59 Days Past Due | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total loans	54	66
60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans	69	66
60-89 Days Past Due | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total loans	40	34
60-89 Days Past Due | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total loans	29	32
90 and Greater Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans	137	107
90 and Greater Days Past Due | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total loans	111	82
90 and Greater Days Past Due | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total loans	26	25
Total Past Due and Non-performing Loans
Financing Receivable, Past Due [Line Items]
Total loans	1,129	903
Total Past Due and Non-performing Loans | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total loans	842	603
Total Past Due and Non-performing Loans | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total loans	287	300
Commercial and industrial | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total loans	53,129	55,815
Commercial and industrial | Non-performing Loans | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total loans	358	297
Commercial and industrial | Current | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total loans	52,576	55,354
Commercial and industrial | 30-59 Days Past Due | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total loans	76	62
Commercial and industrial | 60-89 Days Past Due | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total loans	28	30
Commercial and industrial | 90 and Greater Days Past Due | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total loans	91	72
Commercial and industrial | Total Past Due and Non-performing Loans | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total loans	553	461
Total commercial real estate loans | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total loans	17,295	18,253
Total commercial real estate loans | Non-performing Loans | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total loans	173	100
Total commercial real estate loans | Current | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total loans	17,010	18,114
Total commercial real estate loans | 30-59 Days Past Due | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total loans	80	26
Total commercial real estate loans | 60-89 Days Past Due | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total loans	12	3
Total commercial real estate loans | 90 and Greater Days Past Due | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total loans	20	10
Total commercial real estate loans | Total Past Due and Non-performing Loans | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total loans	285	139
Commercial mortgage | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total loans	14,218	15,187
Commercial mortgage | Non-performing Loans | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total loans	173	100
Commercial mortgage | Current | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total loans	13,939	15,049
Commercial mortgage | Current | Total commercial loans | Government National Mortgage Association (GNMA)
Financing Receivable, Past Due [Line Items]
Total loans	105
Commercial mortgage | 30-59 Days Past Due | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total loans	78	25
Commercial mortgage | 60-89 Days Past Due | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total loans	10	3
Commercial mortgage | 90 and Greater Days Past Due | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total loans	18	10
Commercial mortgage | Total Past Due and Non-performing Loans | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total loans	279	138
Construction | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total loans	3,077	3,066
Construction | Non-performing Loans | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total loans	0	0
Construction | Current | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total loans	3,071	3,065
Construction | 30-59 Days Past Due | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total loans	2	1
Construction | 60-89 Days Past Due | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total loans	2	0
Construction | 90 and Greater Days Past Due | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total loans	2	0
Construction | Total Past Due and Non-performing Loans | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total loans	6	1
Commercial lease financing | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total loans	3,101	3,523
Commercial lease financing | Non-performing Loans | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total loans	1	0
Commercial lease financing | Current | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total loans	3,097	3,520
Commercial lease financing | 30-59 Days Past Due | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total loans	3	2
Commercial lease financing | 60-89 Days Past Due | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total loans	0	1
Commercial lease financing | 90 and Greater Days Past Due | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total loans	0	0
Commercial lease financing | Total Past Due and Non-performing Loans | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total loans	4	3
Real estate — residential mortgage | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total loans	20,380	20,958
Real estate — residential mortgage | Non-performing Loans | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total loans	77	71
Real estate — residential mortgage | Current | Total commercial loans | Government National Mortgage Association (GNMA)
Financing Receivable, Past Due [Line Items]
Total loans	4
Real estate — residential mortgage | Current | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total loans	20,283	20,863
Real estate — residential mortgage | 30-59 Days Past Due | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total loans	10	17
Real estate — residential mortgage | 60-89 Days Past Due | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total loans	6	7
Real estate — residential mortgage | 90 and Greater Days Past Due | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total loans	4	0
Real estate — residential mortgage | Total Past Due and Non-performing Loans | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total loans	97	95
Home equity loans | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total loans	6,729	7,139
Home equity loans | Non-performing Loans | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total loans	91	97
Home equity loans | Current | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total loans	6,607	7,001
Home equity loans | 30-59 Days Past Due | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total loans	21	27
Home equity loans | 60-89 Days Past Due | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total loans	7	10
Home equity loans | 90 and Greater Days Past Due | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total loans	3	4
Home equity loans | Total Past Due and Non-performing Loans | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total loans	122	138
Other consumer loans | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total loans	5,514	5,916
Other consumer loans | Non-performing Loans | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total loans	4	4
Other consumer loans | Current | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total loans	5,475	5,877
Other consumer loans | 30-59 Days Past Due | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total loans	16	16
Other consumer loans | 60-89 Days Past Due | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total loans	11	10
Other consumer loans | 90 and Greater Days Past Due | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total loans	8	9
Other consumer loans | Total Past Due and Non-performing Loans | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total loans	39	39
Credit cards | Total commercial loans
Financing Receivable, Past Due [Line Items]
Total loans	217	207
Credit cards | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total loans	930	1,002
Credit cards | Non-performing Loans | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total loans	6	5
Credit cards | Current | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total loans	901	974
Credit cards | 30-59 Days Past Due | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total loans	7	6
Credit cards | 60-89 Days Past Due | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total loans	5	5
Credit cards | 90 and Greater Days Past Due | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total loans	11	12
Credit cards | Total Past Due and Non-performing Loans | Total consumer loans
Financing Receivable, Past Due [Line Items]
Total loans	$ 29	$ 28