Credit Quality And Allowance For Credit Losses (Average Individually Evaluated Impaired Loans And Related Interest Recognized) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Financing Receivable, Impaired [Line Items]
Individually Evaluated Impaired Loans Average Balance for the Period		$ 242	$ 362	$ 551
Individually Evaluated Impaired Loans Interest Income Recognized for the Period		7	9	10
Business loans | Commercial borrower
Financing Receivable, Impaired [Line Items]
Individually Evaluated Impaired Loans Average Balance for the Period		212	329	511
Individually Evaluated Impaired Loans Interest Income Recognized for the Period		6	9	10
Business loans | Commercial borrower | Domestic loans
Financing Receivable, Impaired [Line Items]
Individually Evaluated Impaired Loans Average Balance for the Period		156	262	451
Individually Evaluated Impaired Loans Interest Income Recognized for the Period		2	5	8
Business loans | Commercial borrower | International loans
Financing Receivable, Impaired [Line Items]
Individually Evaluated Impaired Loans Average Balance for the Period		2	4	8
Individually Evaluated Impaired Loans Interest Income Recognized for the Period		0	0	0
Business loans | Commercial borrower | Real estate mortgage | Domestic loans
Financing Receivable, Impaired [Line Items]
Individually Evaluated Impaired Loans Average Balance for the Period		53	63	52
Individually Evaluated Impaired Loans Interest Income Recognized for the Period		4	4	2
Business loans | Commercial borrower | Real estate mortgage | Domestic loans | Commercial Real Estate business line
Financing Receivable, Impaired [Line Items]
Individually Evaluated Impaired Loans Average Balance for the Period	[1]	39	40	21
Individually Evaluated Impaired Loans Interest Income Recognized for the Period	[1]	3	4	2
Business loans | Commercial borrower | Real estate mortgage | Domestic loans | Other business lines
Financing Receivable, Impaired [Line Items]
Individually Evaluated Impaired Loans Average Balance for the Period	[2]	14	23	31
Individually Evaluated Impaired Loans Interest Income Recognized for the Period	[2]	1	0	0
Retail loans
Financing Receivable, Impaired [Line Items]
Individually Evaluated Impaired Loans Average Balance for the Period		30	33	40
Individually Evaluated Impaired Loans Interest Income Recognized for the Period		1	0	0
Retail loans | Residential mortgage
Financing Receivable, Impaired [Line Items]
Individually Evaluated Impaired Loans Average Balance for the Period		21	21	24
Individually Evaluated Impaired Loans Interest Income Recognized for the Period		1	0	0
Retail loans | Consumer borrower
Financing Receivable, Impaired [Line Items]
Individually Evaluated Impaired Loans Average Balance for the Period		9	12	16
Individually Evaluated Impaired Loans Interest Income Recognized for the Period		0	0	0
Retail loans | Consumer borrower | Home equity
Financing Receivable, Impaired [Line Items]
Individually Evaluated Impaired Loans Average Balance for the Period		9	11	13
Individually Evaluated Impaired Loans Interest Income Recognized for the Period		0	0	0
Retail loans | Consumer borrower | Other consumer
Financing Receivable, Impaired [Line Items]
Individually Evaluated Impaired Loans Average Balance for the Period		0	1	3
Individually Evaluated Impaired Loans Interest Income Recognized for the Period		0	0	0
Business Loans Member | Commercial borrower | Lease financing | Domestic loans
Financing Receivable, Impaired [Line Items]
Individually Evaluated Impaired Loans Average Balance for the Period		1	0	0
Individually Evaluated Impaired Loans Interest Income Recognized for the Period		$ 0	$ 0	$ 0

[1] Primarily loans to real estate developers.

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