Credit Quality And Allowance For Credit Losses (Aging Analysis Of Loans) (Details) - USD ($) $ in Millions		Sep. 30, 2021	Dec. 31, 2020
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		$ 181	$ 449
Nonaccrual loans		291	347
Current loans	[1]	47,723	51,495
Total loans		48,195	52,291
30 to 59 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		143	243
60 to 89 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		26	161
90 days or more past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		12	45
Business loans | Commercial borrower
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		156	410
Nonaccrual loans		244	283
Current loans	[1]	43,880	47,574
Total loans		44,280	48,267
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		124	215
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		24	156
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		8	39
Business loans | Commercial borrower | Domestic loans
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		60	210
Nonaccrual loans		200	252
Current loans	[1]	28,095	32,291
Total loans		28,355	32,753
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		51	62
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		6	115
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		3	33
Business loans | Commercial borrower | International loans
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		11	0
Nonaccrual loans		8	0
Current loans	[1]	1,112	926
Total loans		1,131	926
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		9	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		1	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		1	0
Business loans | Commercial borrower | Real estate construction | Domestic loans
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		26	40
Nonaccrual loans		6	1
Current loans	[1]	2,978	4,041
Total loans		3,010	4,082
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		17	40
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		6	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		3	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	[2]	17	31
Nonaccrual loans	[2]	0	0
Current loans	[1],[2]	2,471	3,626
Total loans	[2]	2,488	3,657
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	[2]	17	31
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	[2]	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	[2]	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	[3]	9	9
Nonaccrual loans	[3]	6	1
Current loans	[1],[3]	507	415
Total loans	[3]	522	425
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	[3]	0	9
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	[3]	6	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	[3]	3	0
Business loans | Commercial borrower | Commercial mortgage | Domestic loans
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		53	145
Nonaccrual loans		30	29
Current loans	[1]	11,132	9,738
Total loans		11,215	9,912
Business loans | Commercial borrower | Commercial mortgage | Domestic loans | 30 to 59 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		41	99
Business loans | Commercial borrower | Commercial mortgage | Domestic loans | 60 to 89 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		11	41
Business loans | Commercial borrower | Commercial mortgage | Domestic loans | 90 days or more past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		1	5
Business loans | Commercial borrower | Commercial mortgage | Domestic loans | Commercial Real Estate business line
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing	[2]	7	52
Nonaccrual loans	[2]	2	3
Current loans	[1],[2]	3,404	2,218
Total loans	[2]	3,413	2,273
Business loans | Commercial borrower | Commercial 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	[2]	7	51
Business loans | Commercial borrower | Commercial 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	[2]	0	1
Business loans | Commercial borrower | Commercial 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	[2]	0	0
Business loans | Commercial borrower | Commercial mortgage | Domestic loans | Other business lines
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing	[3]	46	93
Nonaccrual loans	[3]	28	26
Current loans	[1],[3]	7,728	7,520
Total loans	[3]	7,802	7,639
Business loans | Commercial borrower | Commercial 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	[3]	34	48
Business loans | Commercial borrower | Commercial 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	[3]	11	40
Business loans | Commercial borrower | Commercial 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	[3]	1	5
Business loans | Commercial borrower | Lease financing | Domestic loans
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		6	15
Nonaccrual loans		0	1
Current loans	[1]	563	578
Total loans		569	594
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		6	14
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	1
Retail loans
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		25	39
Nonaccrual loans		47	64
Current loans	[1]	3,843	3,921
Total loans		3,915	4,024
Retail loans | 30 to 59 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		19	28
Retail loans | 60 to 89 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		2	5
Retail loans | 90 days or more past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		4	6
Retail loans | Residential mortgage
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		13	15
Nonaccrual loans		35	47
Current loans	[1]	1,765	1,768
Total loans		1,813	1,830
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		12	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		1	4
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 | Home equity
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		12	24
Nonaccrual loans		12	17
Current loans	[1]	2,078	2,153
Total loans		2,102	2,194
Retail loans | Home equity | 30 to 59 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		7	17
Retail loans | Home equity | 60 to 89 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		1	1
Retail loans | Home equity | 90 days or more past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		4	6
Retail loans | Home equity | Home equity
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		8	8
Nonaccrual loans		12	17
Current loans	[1]	1,537	1,563
Total loans		1,557	1,588
Retail loans | Home equity | Home equity | 30 to 59 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		7	7
Retail loans | Home equity | Home equity | 60 to 89 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		1	1
Retail loans | Home equity | 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 | Home equity | Other consumer
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		4	16
Nonaccrual loans		0	0
Current loans	[1]	541	590
Total loans		545	606
Retail loans | Home equity | Other consumer | 30 to 59 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		0	10
Retail loans | Home equity | Other consumer | 60 to 89 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		0	0
Retail loans | Home equity | Other consumer | 90 days or more past due and still accruing
Financing Receivable, Past Due [Line Items]
Loans past due and still accruing		$ 4	$ 6

[1] Includes $35 million and $141 million of loans with deferred payments not considered past due in accordance with the Coronavirus Aid, Relief, and Economic Security Act (CARES Act) at September 30, 2021 and December 31, 2020, respectively.

[2] Primarily loans to real estate developers.

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