Loans and Related Allowance for Credit Losses (Analysis of Loan Portfolio) (Details) - USD ($) $ in Millions		Mar. 31, 2023	Dec. 31, 2022
Financing Receivable, Past Due [Line Items]
Total loans	[1]	$ 326,475	$ 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		$ 1,326	$ 1,490
Percentage of total loans, past due		0.41%	0.46%
Current or Less Than 30 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		$ 322,506	$ 321,904
Percentage of total loans, past due		98.78%	98.73%
30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		$ 645	$ 747
Percentage of total loans, past due		0.20%	0.23%
60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		$ 225	$ 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		$ 456	$ 482
Percentage of total loans, past due		0.14%	0.15%
Nonperforming Loans
Financing Receivable, Past Due [Line Items]
Total loans		$ 2,010	$ 1,985
Percentage of total loans, past due		0.62%	0.61%
Fair Value Option Nonaccrual Loans
Financing Receivable, Past Due [Line Items]
Nonaccrual loans		$ 633	$ 646
Percentage of total loans, nonaccrual, past due		0.19%	0.20%
Total commercial
Financing Receivable, Past Due [Line Items]
Total loans		$ 225,412	$ 225,049
Total commercial | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Total loans		338	380
Total commercial | Current or Less Than 30 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		224,183	223,811
Total commercial | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		177	208
Total commercial | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		27	35
Total commercial | 90 Days Or More Past Due
Financing Receivable, Past Due [Line Items]
Total loans		134	137
Total commercial | Nonperforming Loans
Financing Receivable, Past Due [Line Items]
Total loans		891	858
Total consumer
Financing Receivable, Past Due [Line Items]
Total loans		101,063	100,976
Total consumer | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Total loans		988	1,110
Total consumer | Current or Less Than 30 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		98,323	98,093
Total consumer | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		468	539
Total consumer | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		198	226
Total consumer | 90 Days Or More Past Due
Financing Receivable, Past Due [Line Items]
Total loans		322	345
Total consumer | Nonperforming Loans
Financing Receivable, Past Due [Line Items]
Total loans		1,119	1,127
Total consumer | Fair Value Option Nonaccrual Loans
Financing Receivable, Past Due [Line Items]
Nonaccrual loans		633	646
Commercial and industrial | Total commercial
Financing Receivable, Past Due [Line Items]
Total loans		182,997	182,219
Commercial and industrial | Total commercial | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Total loans		274	333
Commercial and industrial | Total commercial | Current or Less Than 30 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		182,175	181,223
Commercial and industrial | Total commercial | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		119	169
Commercial and industrial | Total commercial | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		21	27
Commercial and industrial | Total commercial | 90 Days Or More Past Due
Financing Receivable, Past Due [Line Items]
Total loans		134	137
Commercial and industrial | Total commercial | Nonperforming Loans
Financing Receivable, Past Due [Line Items]
Total loans		548	663
Commercial real estate | Total commercial
Financing Receivable, Past Due [Line Items]
Total loans		35,991	36,316
Commercial real estate | Total commercial | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Total loans		26	23
Commercial real estate | Total commercial | Current or Less Than 30 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		35,628	36,104
Commercial real estate | Total commercial | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		25	19
Commercial real estate | Total commercial | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		1	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		337	189
Equipment lease financing | Total commercial
Financing Receivable, Past Due [Line Items]
Total loans		6,424	6,514
Equipment lease financing | Total commercial | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Total loans		38	24
Equipment lease financing | Total commercial | Current or Less Than 30 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		6,380	6,484
Equipment lease financing | Total commercial | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		33	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		6	6
Residential real estate
Financing Receivable, Past Due [Line Items]
Total loans		46,067	45,889
Residential real estate | Government insured or guaranteed loans
Financing Receivable, Past Due [Line Items]
Total loans		684	693
Residential real estate | Total consumer
Financing Receivable, Past Due [Line Items]
Total loans		46,067	45,889
Residential real estate | Total consumer | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Total loans		521	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		44,558	44,306
Residential real estate | Total consumer | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		245	281
Residential real estate | Total consumer | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		98	112
Residential real estate | Total consumer | 90 Days Or More Past Due
Financing Receivable, Past Due [Line Items]
Total loans		178	199
Residential real estate | Total consumer | Nonperforming Loans
Financing Receivable, Past Due [Line Items]
Total loans		432	424
Residential real estate | Total consumer | Fair Value Option Nonaccrual Loans
Financing Receivable, Past Due [Line Items]
Nonaccrual loans		556	567
Home equity
Financing Receivable, Past Due [Line Items]
Total loans		26,203	25,983
Home equity | Total consumer
Financing Receivable, Past Due [Line Items]
Total loans		26,203	25,983
Home equity | Total consumer | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Total loans		66	73
Home equity | Total consumer | Current or Less Than 30 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		25,537	25,305
Home equity | Total consumer | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		48	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		523	526
Home equity | Total consumer | Fair Value Option Nonaccrual Loans
Financing Receivable, Past Due [Line Items]
Nonaccrual loans		77	79
Automobile | Total consumer
Financing Receivable, Past Due [Line Items]
Total loans		14,923	14,836
Automobile | Total consumer | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Total loans		102	138
Automobile | Total consumer | Current or Less Than 30 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		14,676	14,543
Automobile | Total consumer | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		79	106
Automobile | Total consumer | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		18	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		145	155
Credit card | Total consumer
Financing Receivable, Past Due [Line Items]
Total loans		6,961	7,069
Credit card | Total consumer | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Total loans		157	155
Credit card | Total consumer | Current or Less Than 30 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		6,795	6,906
Credit card | Total consumer | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		48	50
Credit card | Total consumer | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		35	35
Credit card | Total consumer | 90 Days Or More Past Due
Financing Receivable, Past Due [Line Items]
Total loans		74	70
Credit card | Total consumer | Nonperforming Loans
Financing Receivable, Past Due [Line Items]
Total loans		9	8
Education
Financing Receivable, Past Due [Line Items]
Total loans		2,131	2,173
Education | Total consumer
Financing Receivable, Past Due [Line Items]
Total loans		2,131	2,173
Education | Total consumer | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Total loans		112	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		2,019	2,058
Education | Total consumer | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		35	34
Education | Total consumer | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		21	22
Education | Total consumer | 90 Days Or More Past Due
Financing Receivable, Past Due [Line Items]
Total loans		56	59
Other consumer
Financing Receivable, Past Due [Line Items]
Total loans		4,778	5,026
Other consumer | Total consumer
Financing Receivable, Past Due [Line Items]
Total loans		4,778	5,026
Other consumer | Total consumer | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Total loans		30	37
Other consumer | Total consumer | Current or Less Than 30 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		4,738	4,975
Other consumer | Total consumer | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		13	15
Other consumer | Total consumer | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans		8	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		$ 10	$ 14

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