Loans and Related Allowance for Credit Losses (Analysis of Loan Portfolio) (Details) - USD ($) $ in Millions		Sep. 30, 2024	Dec. 31, 2023
Financing Receivable, Past Due [Line Items]
Total loans	[1]	$ 321,381	$ 321,508
Percentage of total loans, past due		100.00%	100.00%
Accrued interest on loan portfolio		$ 1,400	$ 1,500
Unearned income, unamortized deferred fees and costs on originated loans, and premiums or discounts on purchased loans		900	1,000
Collateral Dependent
Financing Receivable, Past Due [Line Items]
Total loans		1,900	1,400
Current or Less Than 30 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		$ 316,978	$ 317,359
Percentage of total loans, past due		98.63%	98.71%
30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		$ 614	$ 685
Percentage of total loans, past due		0.19%	0.21%
60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		$ 252	$ 270
Percentage of total loans, past due		0.08%	0.08%
90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Total loans		$ 409	$ 429
Percentage of total loans, past due		0.13%	0.13%
Total Past Due
Financing Receivable, Past Due [Line Items]
Total loans		$ 1,275	$ 1,384
Percentage of total loans, past due		0.40%	0.43%
Nonperforming Loans
Financing Receivable, Past Due [Line Items]
Total loans		$ 2,578	$ 2,180
Percentage of total loans, past due		0.80%	0.68%
Fair Value Option Nonaccrual Loans
Financing Receivable, Past Due [Line Items]
Nonaccrual loans		$ 550	$ 585
Percentage of total loans, nonaccrual, past due		0.17%	0.18%
Total commercial
Financing Receivable, Past Due [Line Items]
Total loans		$ 220,721	$ 219,558
Total commercial | Current or Less Than 30 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		218,706	217,961
Total commercial | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		137	152
Total commercial | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		52	53
Total commercial | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Total loans		97	85
Total commercial | Total Past Due
Financing Receivable, Past Due [Line Items]
Total loans		286	290
Total commercial | Nonperforming Loans
Financing Receivable, Past Due [Line Items]
Total loans		1,729	1,307
Total consumer
Financing Receivable, Past Due [Line Items]
Total loans		100,660	101,950
Total consumer | Current or Less Than 30 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		98,272	99,398
Total consumer | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		477	533
Total consumer | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		200	217
Total consumer | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Total loans		312	344
Total consumer | Total Past Due
Financing Receivable, Past Due [Line Items]
Total loans		989	1,094
Total consumer | Nonperforming Loans
Financing Receivable, Past Due [Line Items]
Total loans		849	873
Total consumer | Fair Value Option Nonaccrual Loans
Financing Receivable, Past Due [Line Items]
Nonaccrual loans		550	585
Commercial and industrial | Total commercial
Financing Receivable, Past Due [Line Items]
Total loans		178,891	177,580
Commercial and industrial | Total commercial | Current or Less Than 30 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		177,926	176,796
Commercial and industrial | Total commercial | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		106	104
Commercial and industrial | Total commercial | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		40	45
Commercial and industrial | Total commercial | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Total loans		97	76
Commercial and industrial | Total commercial | Total Past Due
Financing Receivable, Past Due [Line Items]
Total loans		243	225
Commercial and industrial | Total commercial | Nonperforming Loans
Financing Receivable, Past Due [Line Items]
Total loans		722	559
Commercial real estate | Total commercial
Financing Receivable, Past Due [Line Items]
Total loans		35,104	35,436
Commercial real estate | Total commercial | Current or Less Than 30 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		34,102	34,685
Commercial real estate | Total commercial | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		9	7
Commercial real estate | Total commercial | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans
Commercial real estate | Total commercial | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Total loans			9
Commercial real estate | Total commercial | Total Past Due
Financing Receivable, Past Due [Line Items]
Total loans		9	16
Commercial real estate | Total commercial | Nonperforming Loans
Financing Receivable, Past Due [Line Items]
Total loans		993	735
Equipment lease financing | Total commercial
Financing Receivable, Past Due [Line Items]
Total loans		6,726	6,542
Equipment lease financing | Total commercial | Current or Less Than 30 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		6,678	6,480
Equipment lease financing | Total commercial | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		22	41
Equipment lease financing | Total commercial | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		12	8
Equipment lease financing | Total commercial | Total Past Due
Financing Receivable, Past Due [Line Items]
Total loans		34	49
Equipment lease financing | Total commercial | Nonperforming Loans
Financing Receivable, Past Due [Line Items]
Total loans		14	13
Residential real estate
Financing Receivable, Past Due [Line Items]
Total loans		46,972	47,544
Residential real estate | Government insured or guaranteed loans
Financing Receivable, Past Due [Line Items]
Total loans		624	653
Residential real estate | Total consumer
Financing Receivable, Past Due [Line Items]
Total loans		46,972	47,544
Residential real estate | Total consumer | Current or Less Than 30 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		45,719	46,159
Residential real estate | Total consumer | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		238	282
Residential real estate | Total consumer | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		85	101
Residential real estate | Total consumer | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Total loans		179	192
Residential real estate | Total consumer | Total Past Due
Financing Receivable, Past Due [Line Items]
Total loans		502	575
Residential real estate | Total consumer | Total Past Due | Government insured or guaranteed loans
Financing Receivable, Past Due [Line Items]
Total loans		200	300
Residential real estate | Total consumer | Nonperforming Loans
Financing Receivable, Past Due [Line Items]
Total loans		265	294
Residential real estate | Total consumer | Fair Value Option Nonaccrual Loans
Financing Receivable, Past Due [Line Items]
Nonaccrual loans		486	516
Home equity
Financing Receivable, Past Due [Line Items]
Total loans		25,970	26,150
Home equity | Total consumer
Financing Receivable, Past Due [Line Items]
Total loans		25,970	26,150
Home equity | Total consumer | Current or Less Than 30 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		25,341	25,533
Home equity | Total consumer | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		65	63
Home equity | Total consumer | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		27	27
Home equity | Total consumer | Total Past Due
Financing Receivable, Past Due [Line Items]
Total loans		92	90
Home equity | Total consumer | Nonperforming Loans
Financing Receivable, Past Due [Line Items]
Total loans		473	458
Home equity | Total consumer | Fair Value Option Nonaccrual Loans
Financing Receivable, Past Due [Line Items]
Nonaccrual loans		64	69
Automobile | Total consumer
Financing Receivable, Past Due [Line Items]
Total loans		15,135	14,860
Automobile | Total consumer | Current or Less Than 30 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		14,937	14,638
Automobile | Total consumer | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		81	91
Automobile | Total consumer | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		21	20
Automobile | Total consumer | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Total loans		6	7
Automobile | Total consumer | Total Past Due
Financing Receivable, Past Due [Line Items]
Total loans		108	118
Automobile | Total consumer | Nonperforming Loans
Financing Receivable, Past Due [Line Items]
Total loans		90	104
Credit card | Total consumer
Financing Receivable, Past Due [Line Items]
Total loans		6,827	7,180
Credit card | Total consumer | Current or Less Than 30 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		6,639	6,991
Credit card | Total consumer | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		55	54
Credit card | Total consumer | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		39	39
Credit card | Total consumer | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Total loans		79	86
Credit card | Total consumer | Total Past Due
Financing Receivable, Past Due [Line Items]
Total loans		173	179
Credit card | Total consumer | Nonperforming Loans
Financing Receivable, Past Due [Line Items]
Total loans		15	10
Education
Financing Receivable, Past Due [Line Items]
Total loans		1,693	1,945
Education | Total consumer
Financing Receivable, Past Due [Line Items]
Total loans		1,693	1,945
Education | Total consumer | Current or Less Than 30 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		1,611	1,850
Education | Total consumer | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		26	27
Education | Total consumer | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		16	19
Education | Total consumer | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Total loans		40	49
Education | Total consumer | Total Past Due
Financing Receivable, Past Due [Line Items]
Total loans		82	95
Education | Total consumer | Total Past Due | Government insured or guaranteed loans
Financing Receivable, Past Due [Line Items]
Total loans		100	100
Other consumer
Financing Receivable, Past Due [Line Items]
Total loans		4,063	4,271
Other consumer | Total consumer
Financing Receivable, Past Due [Line Items]
Total loans		4,063	4,271
Other consumer | Total consumer | Current or Less Than 30 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		4,025	4,227
Other consumer | Total consumer | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		12	16
Other consumer | Total consumer | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		12	11
Other consumer | Total consumer | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Total loans		8	10
Other consumer | Total consumer | Total Past Due
Financing Receivable, Past Due [Line Items]
Total loans		32	37
Other consumer | Total consumer | Nonperforming Loans
Financing Receivable, Past Due [Line Items]
Total loans		$ 6	$ 7

[1] Our consolidated assets included the following for which we have elected the fair value option: Loans held for sale of $0.7 billion, Loans held for investment of $1.2 billion and Other assets of $0.1 billion at September 30, 2024. Comparable amounts at December 31, 2023 were $0.7 billion, $1.2 billion and $0.1 billion, respectively.