Credit Quality And Allowance For Credit Losses (Aging Analysis Of Loans) (Details) - USD ($) $ in Millions		Dec. 31, 2019	Dec. 31, 2018
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		$ 153	$ 149
Nonaccrual loans		199	221
Current loans		50,017	49,793
Total loans		50,369	50,163
30 to 59 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		80	98
60 to 89 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		47	35
90 days or more past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		26	16
Real estate construction
Financing Receivable, Past Due [Line Items]
Total loans		3,455	3,077
Real estate mortgage
Financing Receivable, Past Due [Line Items]
Total loans		9,559	9,106
Business loans | Commercial borrower
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		122	129
Nonaccrual loans		162	166
Current loans		45,800	45,384
Total loans		46,084	45,679
Business loans | Commercial borrower | 30 to 59 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		59	82
Business loans | Commercial borrower | 60 to 89 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		37	31
Business loans | Commercial borrower | 90 days or more past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		26	16
Business loans | Commercial borrower | Domestic loans
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		51	68
Nonaccrual loans		148	141
Current loans		31,274	31,767
Total loans		31,473	31,976
Business loans | Commercial borrower | Domestic loans | 30 to 59 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		27	34
Business loans | Commercial borrower | Domestic loans | 60 to 89 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		7	26
Business loans | Commercial borrower | Domestic loans | 90 days or more past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		17	8
Business loans | Commercial borrower | International loans
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		5	0
Nonaccrual loans		0	3
Current loans		1,004	1,010
Total loans		1,009	1,013
Business loans | Commercial borrower | International loans | 30 to 59 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		0	0
Business loans | Commercial borrower | International loans | 60 to 89 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		5	0
Business loans | Commercial borrower | International loans | 90 days or more past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		0	0
Business loans | Commercial borrower | Real estate construction | Domestic loans
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		13	12
Nonaccrual loans		0	0
Current loans		3,442	3,065
Total loans		3,455	3,077
Business loans | Commercial borrower | Real estate construction | Domestic loans | 30 to 59 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		6	12
Business loans | Commercial borrower | Real estate construction | Domestic loans | 60 to 89 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		7	0
Business loans | Commercial borrower | Real estate construction | Domestic loans | 90 days or more past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		0	0
Business loans | Commercial borrower | Real estate construction | Domestic loans | Commercial Real Estate business line
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing	[1]	6	6
Nonaccrual loans	[1]	0	0
Current loans	[1]	3,038	2,681
Total loans	[1]	3,044	2,687
Business loans | Commercial borrower | Real estate construction | Domestic loans | Commercial Real Estate business line | 30 to 59 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing	[1]	6	6
Business loans | Commercial borrower | Real estate construction | Domestic loans | Commercial Real Estate business line | 60 to 89 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing	[1]	0	0
Business loans | Commercial borrower | Real estate construction | Domestic loans | Commercial Real Estate business line | 90 days or more past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing	[1]	0	0
Business loans | Commercial borrower | Real estate construction | Domestic loans | Other business lines
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing	[2]	7	6
Nonaccrual loans	[2]	0	0
Current loans	[2]	404	384
Total loans	[2]	411	390
Business loans | Commercial borrower | Real estate construction | Domestic loans | Other business lines | 30 to 59 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing	[2]	0	6
Business loans | Commercial borrower | Real estate construction | Domestic loans | Other business lines | 60 to 89 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing	[2]	7	0
Business loans | Commercial borrower | Real estate construction | Domestic loans | Other business lines | 90 days or more past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing	[2]	0	0
Business loans | Commercial borrower | Real estate mortgage | Domestic loans
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		52	49
Nonaccrual loans		14	20
Current loans		9,493	9,037
Total loans		9,559	9,106
Business loans | Commercial borrower | Real estate mortgage | Domestic loans | 30 to 59 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		25	36
Business loans | Commercial borrower | Real estate mortgage | Domestic loans | 60 to 89 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		18	5
Business loans | Commercial borrower | Real estate mortgage | Domestic loans | 90 days or more past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		9	8
Business loans | Commercial borrower | Real estate mortgage | Domestic loans | Commercial Real Estate business line
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing	[1]	9	4
Nonaccrual loans	[1]	2	2
Current loans	[1]	2,165	1,737
Total loans	[1]	2,176	1,743
Business loans | Commercial borrower | Real estate mortgage | Domestic loans | Commercial Real Estate business line | 30 to 59 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing	[1]	9	4
Business loans | Commercial borrower | Real estate mortgage | Domestic loans | Commercial Real Estate business line | 60 to 89 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing	[1]	0	0
Business loans | Commercial borrower | Real estate mortgage | Domestic loans | Commercial Real Estate business line | 90 days or more past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing	[1]	0	0
Business loans | Commercial borrower | Real estate mortgage | Domestic loans | Other business lines
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing	[2]	43	45
Nonaccrual loans	[2]	12	18
Current loans	[2]	7,328	7,300
Total loans	[2]	7,383	7,363
Business loans | Commercial borrower | Real estate mortgage | Domestic loans | Other business lines | 30 to 59 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing	[2]	16	32
Business loans | Commercial borrower | Real estate mortgage | Domestic loans | Other business lines | 60 to 89 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing	[2]	18	5
Business loans | Commercial borrower | Real estate mortgage | Domestic loans | Other business lines | 90 days or more past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing	[2]	9	8
Business loans | Commercial borrower | Lease financing | Domestic loans
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		1	0
Nonaccrual loans		0	2
Current loans		587	505
Total loans		588	507
Business loans | Commercial borrower | Lease financing | Domestic loans | 30 to 59 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		1	0
Business loans | Commercial borrower | Lease financing | Domestic loans | 60 to 89 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		0	0
Business loans | Commercial borrower | Lease financing | Domestic loans | 90 days or more past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		0	0
Retail loans
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		31	20
Nonaccrual loans		37	55
Current loans		4,217	4,409
Total loans		4,285	4,484
Retail loans | 30 to 59 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		21	16
Retail loans | 60 to 89 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		10	4
Retail loans | 90 days or more past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		0	0
Retail loans | Residential mortgage
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		17	14
Nonaccrual loans		20	36
Current loans		1,808	1,920
Total loans		1,845	1,970
Retail loans | Residential mortgage | 30 to 59 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		15	11
Retail loans | Residential mortgage | 60 to 89 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		2	3
Retail loans | Residential mortgage | 90 days or more past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		0	0
Retail loans | Consumer borrower
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		14	6
Nonaccrual loans		17	19
Current loans		2,409	2,489
Total loans		2,440	2,514
Retail loans | Consumer borrower | 30 to 59 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		6	5
Retail loans | Consumer borrower | 60 to 89 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		8	1
Retail loans | Consumer borrower | 90 days or more past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		0	0
Retail loans | Consumer borrower | Home equity
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		9	5
Nonaccrual loans		17	19
Current loans		1,685	1,741
Total loans		1,711	1,765
Retail loans | Consumer borrower | Home equity | 30 to 59 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		4	4
Retail loans | Consumer borrower | Home equity | 60 to 89 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		5	1
Retail loans | Consumer borrower | Home equity | 90 days or more past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		0	0
Retail loans | Consumer borrower | Other consumer
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		5	1
Nonaccrual loans		0	0
Current loans		724	748
Total loans		729	749
Retail loans | Consumer borrower | Other consumer | 30 to 59 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		2	1
Retail loans | Consumer borrower | Other consumer | 60 to 89 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		3	0
Retail loans | Consumer borrower | Other consumer | 90 days or more past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		$ 0	$ 0

[1] Primarily loans to real estate developers.

[2] Primarily loans secured by owner-occupied real estate.