Loans and Related Allowance for Credit Losses (Analysis of Loan Portfolio) (Details) - USD ($) $ in Millions		Jun. 30, 2023	Dec. 31, 2022
Financing Receivable, Past Due [Line Items]
Total loans	[1]	$ 321,761	$ 326,025
Percentage of total loans, past due		100.00%	100.00%
Accrued interest on loan portfolio		$ 1,300	$ 1,200
Unearned income, unamortized deferred fees and costs on originated loans, and premiums or discounts on purchased loans		800	900
Collateral Dependent
Financing Receivable, Past Due [Line Items]
Total loans		1,200	1,300
Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Total loans		$ 1,212	$ 1,490
Percentage of total loans, past due		0.38%	0.46%
Current or Less Than 30 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		$ 318,019	$ 321,904
Percentage of total loans, past due		98.84%	98.73%
30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		$ 555	$ 747
Percentage of total loans, past due		0.17%	0.23%
60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		$ 238	$ 261
Percentage of total loans, past due		0.07%	0.08%
90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Total loans		$ 419	$ 482
Percentage of total loans, past due		0.13%	0.15%
Nonperforming Loans
Financing Receivable, Past Due [Line Items]
Total loans		$ 1,913	$ 1,985
Percentage of total loans, past due		0.59%	0.61%
Fair Value Option Nonaccrual Loans
Financing Receivable, Past Due [Line Items]
Nonaccrual loans		$ 617	$ 646
Percentage of total loans, nonaccrual, past due		0.19%	0.20%
Total commercial
Financing Receivable, Past Due [Line Items]
Total loans		$ 219,957	$ 225,049
Total commercial | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Total loans		252	380
Total commercial | Current or Less Than 30 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		218,878	223,811
Total commercial | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		88	208
Total commercial | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		52	35
Total commercial | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Total loans		112	137
Total commercial | Nonperforming Loans
Financing Receivable, Past Due [Line Items]
Total loans		827	858
Total consumer
Financing Receivable, Past Due [Line Items]
Total loans		101,804	100,976
Total consumer | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Total loans		960	1,110
Total consumer | Current or Less Than 30 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		99,141	98,093
Total consumer | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		467	539
Total consumer | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		186	226
Total consumer | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Total loans		307	345
Total consumer | Nonperforming Loans
Financing Receivable, Past Due [Line Items]
Total loans		1,086	1,127
Total consumer | Fair Value Option Nonaccrual Loans
Financing Receivable, Past Due [Line Items]
Nonaccrual loans		617	646
Commercial and industrial | Total commercial
Financing Receivable, Past Due [Line Items]
Total loans		177,629	182,219
Commercial and industrial | Total commercial | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Total loans		223	333
Commercial and industrial | Total commercial | Current or Less Than 30 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		176,936	181,223
Commercial and industrial | Total commercial | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		64	169
Commercial and industrial | Total commercial | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		47	27
Commercial and industrial | Total commercial | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Total loans		112	137
Commercial and industrial | Total commercial | Nonperforming Loans
Financing Receivable, Past Due [Line Items]
Total loans		470	663
Commercial real estate | Total commercial
Financing Receivable, Past Due [Line Items]
Total loans		35,928	36,316
Commercial real estate | Total commercial | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Total loans		10	23
Commercial real estate | Total commercial | Current or Less Than 30 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		35,568	36,104
Commercial real estate | Total commercial | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		10	19
Commercial real estate | Total commercial | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans			4
Commercial real estate | Total commercial | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Total loans
Commercial real estate | Total commercial | Nonperforming Loans
Financing Receivable, Past Due [Line Items]
Total loans		350	189
Equipment lease financing | Total commercial
Financing Receivable, Past Due [Line Items]
Total loans		6,400	6,514
Equipment lease financing | Total commercial | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Total loans		19	24
Equipment lease financing | Total commercial | Current or Less Than 30 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		6,374	6,484
Equipment lease financing | Total commercial | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		14	20
Equipment lease financing | Total commercial | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		5	4
Equipment lease financing | Total commercial | Nonperforming Loans
Financing Receivable, Past Due [Line Items]
Total loans		7	6
Residential real estate
Financing Receivable, Past Due [Line Items]
Total loans		46,834	45,889
Residential real estate | Government insured or guaranteed loans
Financing Receivable, Past Due [Line Items]
Total loans		663	693
Residential real estate | Total consumer
Financing Receivable, Past Due [Line Items]
Total loans		46,834	45,889
Residential real estate | Total consumer | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Total loans		488	592
Residential real estate | Total consumer | Financial Asset, Past Due | Government insured or guaranteed loans
Financing Receivable, Past Due [Line Items]
Total loans		300	300
Residential real estate | Total consumer | Current or Less Than 30 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		45,374	44,306
Residential real estate | Total consumer | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		228	281
Residential real estate | Total consumer | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		86	112
Residential real estate | Total consumer | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Total loans		174	199
Residential real estate | Total consumer | Nonperforming Loans
Financing Receivable, Past Due [Line Items]
Total loans		429	424
Residential real estate | Total consumer | Fair Value Option Nonaccrual Loans
Financing Receivable, Past Due [Line Items]
Nonaccrual loans		543	567
Home equity
Financing Receivable, Past Due [Line Items]
Total loans		26,200	25,983
Home equity | Total consumer
Financing Receivable, Past Due [Line Items]
Total loans		26,200	25,983
Home equity | Total consumer | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Total loans		74	73
Home equity | Total consumer | Current or Less Than 30 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		25,546	25,305
Home equity | Total consumer | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		56	53
Home equity | Total consumer | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		18	20
Home equity | Total consumer | Nonperforming Loans
Financing Receivable, Past Due [Line Items]
Total loans		506	526
Home equity | Total consumer | Fair Value Option Nonaccrual Loans
Financing Receivable, Past Due [Line Items]
Nonaccrual loans		74	79
Automobile | Total consumer
Financing Receivable, Past Due [Line Items]
Total loans		15,065	14,836
Automobile | Total consumer | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Total loans		109	138
Automobile | Total consumer | Current or Less Than 30 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		14,823	14,543
Automobile | Total consumer | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		84	106
Automobile | Total consumer | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		20	25
Automobile | Total consumer | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Total loans		5	7
Automobile | Total consumer | Nonperforming Loans
Financing Receivable, Past Due [Line Items]
Total loans		133	155
Credit card | Total consumer
Financing Receivable, Past Due [Line Items]
Total loans		7,092	7,069
Credit card | Total consumer | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Total loans		156	155
Credit card | Total consumer | Current or Less Than 30 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		6,926	6,906
Credit card | Total consumer | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		49	50
Credit card | Total consumer | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		36	35
Credit card | Total consumer | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Total loans		71	70
Credit card | Total consumer | Nonperforming Loans
Financing Receivable, Past Due [Line Items]
Total loans		10	8
Education
Financing Receivable, Past Due [Line Items]
Total loans		2,058	2,173
Education | Total consumer
Financing Receivable, Past Due [Line Items]
Total loans		2,058	2,173
Education | Total consumer | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Total loans		98	115
Education | Total consumer | Financial Asset, Past Due | Government insured or guaranteed loans
Financing Receivable, Past Due [Line Items]
Total loans		100	100
Education | Total consumer | Current or Less Than 30 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		1,960	2,058
Education | Total consumer | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		33	34
Education | Total consumer | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		17	22
Education | Total consumer | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Total loans		48	59
Other consumer
Financing Receivable, Past Due [Line Items]
Total loans		4,555	5,026
Other consumer | Total consumer
Financing Receivable, Past Due [Line Items]
Total loans		4,555	5,026
Other consumer | Total consumer | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Total loans		35	37
Other consumer | Total consumer | Current or Less Than 30 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		4,512	4,975
Other consumer | Total consumer | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		17	15
Other consumer | Total consumer | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		9	12
Other consumer | Total consumer | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Total loans		9	10
Other consumer | Total consumer | Nonperforming Loans
Financing Receivable, Past Due [Line Items]
Total loans		$ 8	$ 14

[1] Our consolidated assets included the following for which we have elected the fair value option: Loans held for sale of $0.8 billion, Loans held for investment of $1.3 billion and Other assets of $0.1 billion at June 30, 2023. Comparable amounts at December 31, 2022 were $0.9 billion, $1.3 billion and $0.1 billion, respectively.