Credit Quality And Allowance For Credit Losses Credit Quality And Allowance For Credit Losses (Troubled Debt Restructuring Subsequent Default) (Details) - Principal Deferrals - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Financing Receivable, Modifications [Line Items]
Balance		$ 247	$ 23	$ 247	$ 23
Subsequent default during period		22	1	29	8
Business loans | Commercial borrower
Financing Receivable, Modifications [Line Items]
Balance		245	21	245	21
Subsequent default during period		22	1	29	8
Business loans | Commercial borrower | Domestic loans
Financing Receivable, Modifications [Line Items]
Balance		233	10	233	10
Subsequent default during period		21	0	21	6
Business loans | Commercial borrower | International loans
Financing Receivable, Modifications [Line Items]
Balance		1	0	1	0
Subsequent default during period		0	0	1	0
Business loans | Real estate mortgage | Commercial borrower | Domestic loans
Financing Receivable, Modifications [Line Items]
Balance		11	11	11	11
Subsequent default during period		1	1	7	2
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Commercial Real Estate business line
Financing Receivable, Modifications [Line Items]
Balance	[1]	4	1	4	1
Subsequent default during period	[1]	1	0	1	0
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Other business lines
Financing Receivable, Modifications [Line Items]
Balance	[2]	7	10	7	10
Subsequent default during period	[2]	0	1	6	2
Retail loans | Home equity | Consumer borrower
Financing Receivable, Modifications [Line Items]
Balance	[3]	2	2	2	2
Subsequent default during period		$ 0	$ 0	$ 0	$ 0

[1] Primarily loans to real estate developers.

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

[3] Includes bankruptcy loans for which the court has discharged the borrower's obligation and the borrower has not reaffirmed the debt.