Credit Quality And Allowance For Credit Losses (Aging Analysis Of Loans) (Details) - USD ($) $ in Millions		Jun. 30, 2016	Dec. 31, 2015
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		$ 145	$ 146
Nonaccrual loans		605	367
Current loans		49,630	48,571
Total loans		50,380	49,084
30 to 59 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		97	108
60 to 89 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		13	21
90 days or more past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		35	17
Business loans | Commercial borrower
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		103	104
Nonaccrual loans		550	313
Current loans		45,347	44,312
Total loans		46,000	44,729
Business loans | Commercial borrower | 30 to 59 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		83	70
Business loans | Commercial borrower | 60 to 89 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		7	17
Business loans | Commercial borrower | 90 days or more past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		13	17
Business loans | Commercial borrower | Domestic loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		63	71
Nonaccrual loans		482	238
Current loans		31,815	31,350
Total loans		32,360	31,659
Business loans | Commercial borrower | Domestic loans | 30 to 59 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		51	46
Business loans | Commercial borrower | Domestic loans | 60 to 89 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		4	12
Business loans | Commercial borrower | Domestic loans | 90 days or more past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		8	13
Business loans | Commercial borrower | International loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		17	2
Nonaccrual loans		18	8
Current loans		1,330	1,358
Total loans		1,365	1,368
Business loans | Commercial borrower | International loans | 30 to 59 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		16	2
Business loans | Commercial borrower | International loans | 60 to 89 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		0	0
Business loans | Commercial borrower | International loans | 90 days or more past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		1	0
Business loans | Real estate construction | Commercial borrower | Domestic loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		0	8
Nonaccrual loans		0	1
Current loans		2,553	1,992
Total loans		2,553	2,001
Business loans | Real estate construction | Commercial borrower | Domestic loans | 30 to 59 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		0	8
Business loans | Real estate construction | Commercial borrower | Domestic loans | 60 to 89 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		0	0
Business loans | Real estate construction | Commercial borrower | Domestic loans | 90 days or more past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		0	0
Business loans | Real estate construction | Commercial borrower | Domestic loans | Commercial Real Estate business line
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing	[1]	0	5
Nonaccrual loans	[1]	0	0
Current loans	[1]	2,197	1,676
Total loans	[1],[2]	2,197	1,681
Business loans | Real estate construction | Commercial borrower | Domestic loans | Commercial Real Estate business line | 30 to 59 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing	[1]	0	5
Business loans | Real estate construction | Commercial borrower | Domestic loans | Commercial Real Estate business line | 60 to 89 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing	[1]	0	0
Business loans | Real estate construction | Commercial borrower | Domestic loans | Commercial Real Estate business line | 90 days or more past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing	[1]	0	0
Business loans | Real estate construction | Commercial borrower | Domestic loans | Other business lines
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing	[3]	0	3
Nonaccrual loans	[3]	0	1
Current loans	[3]	356	316
Total loans	[3],[4]	356	320
Business loans | Real estate construction | Commercial borrower | Domestic loans | Other business lines | 30 to 59 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing	[3]	0	3
Business loans | Real estate construction | Commercial borrower | Domestic loans | Other business lines | 60 to 89 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing	[3]	0	0
Business loans | Real estate construction | Commercial borrower | Domestic loans | Other business lines | 90 days or more past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing	[3]	0	0
Business loans | Real estate mortgage | Commercial borrower | Domestic loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		23	23
Nonaccrual loans		44	60
Current loans		8,971	8,894
Total loans		9,038	8,977
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | 30 to 59 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		16	14
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | 60 to 89 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		3	5
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | 90 days or more past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		4	4
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Commercial Real Estate business line
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing	[1]	5	8
Nonaccrual loans	[1]	8	16
Current loans	[1]	2,223	2,080
Total loans	[1],[2]	2,236	2,104
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Commercial Real Estate business line | 30 to 59 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing	[1]	4	7
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Commercial Real Estate business line | 60 to 89 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing	[1]	0	0
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Commercial Real Estate business line | 90 days or more past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing	[1]	1	1
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Other business lines
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing	[3]	18	15
Nonaccrual loans	[3]	36	44
Current loans	[3]	6,748	6,814
Total loans	[3],[4]	6,802	6,873
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Other business lines | 30 to 59 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing	[3]	12	7
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Other business lines | 60 to 89 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing	[3]	3	5
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Other business lines | 90 days or more past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing	[3]	3	3
Business loans | Lease financing | Commercial borrower | Domestic loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		0	0
Nonaccrual loans		6	6
Current loans		678	718
Total loans		684	724
Business loans | Lease financing | Commercial borrower | Domestic loans | 30 to 59 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		0	0
Business loans | Lease financing | Commercial borrower | Domestic loans | 60 to 89 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		0	0
Business loans | Lease financing | Commercial borrower | Domestic loans | 90 days or more past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		0	0
Retail loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		42	42
Nonaccrual loans		55	54
Current loans		4,283	4,259
Total loans		4,380	4,355
Retail loans | 30 to 59 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		14	38
Retail loans | 60 to 89 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		6	4
Retail loans | 90 days or more past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		22	0
Retail loans | Consumer borrower
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		23	15
Nonaccrual loans		29	27
Current loans		2,472	2,443
Total loans		2,524	2,485
Retail loans | Consumer borrower | 30 to 59 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		5	12
Retail loans | Consumer borrower | 60 to 89 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		5	3
Retail loans | Consumer borrower | 90 days or more past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		13	0
Retail loans | Real estate mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		19	27
Nonaccrual loans		26	27
Current loans		1,811	1,816
Total loans		1,856	1,870
Retail loans | Real estate mortgage | 30 to 59 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		9	26
Retail loans | Real estate mortgage | 60 to 89 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		1	1
Retail loans | Real estate mortgage | 90 days or more past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		9	0
Retail loans | Home equity | Consumer borrower
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		7	8
Nonaccrual loans		28	27
Current loans		1,744	1,685
Total loans		1,779	1,720
Retail loans | Home equity | Consumer borrower | 30 to 59 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		4	5
Retail loans | Home equity | Consumer borrower | 60 to 89 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		2	3
Retail loans | Home equity | Consumer borrower | 90 days or more past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		1	0
Retail loans | Other consumer | Consumer borrower
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		16	7
Nonaccrual loans		1	0
Current loans		728	758
Total loans		745	765
Retail loans | Other consumer | Consumer borrower | 30 to 59 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		1	7
Retail loans | Other consumer | Consumer borrower | 60 to 89 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		3	0
Retail loans | Other consumer | Consumer borrower | 90 days or more past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		$ 12	$ 0

[1] Primarily loans to real estate developers.

[2] Primarily loans to real estate developers.

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

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