Credit Quality And Allowance For Credit Losses (Nonaccrual Loans) (Details) - USD ($) $ in Millions		Jun. 30, 2021	Dec. 31, 2020
Financing Receivable, Nonaccrual [Line Items]
Financing Receivable, Nonaccrual, No Allowance		$ 104	$ 127
Financing Receivable, Nonaccrual		207	220
Nonaccrual loans		311	347
Business loans | Commercial borrower
Financing Receivable, Nonaccrual [Line Items]
Financing Receivable, Nonaccrual, No Allowance		49	63
Financing Receivable, Nonaccrual		207	220
Nonaccrual loans		256	283
Business loans | Commercial borrower | Domestic loans
Financing Receivable, Nonaccrual [Line Items]
Financing Receivable, Nonaccrual, No Allowance		42	57
Financing Receivable, Nonaccrual		179	195
Nonaccrual loans		221	252
Business loans | Commercial borrower | International loans
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual loans		0	0
Retail loans
Financing Receivable, Nonaccrual [Line Items]
Financing Receivable, Nonaccrual, No Allowance		55	64
Financing Receivable, Nonaccrual		0	0
Nonaccrual loans		55	64
Retail loans | Home equity
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual loans		14	17
Real estate construction | Business loans | Commercial borrower | Domestic loans
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual loans		4	1
Real estate construction | Commercial Real Estate business line | Business loans | Commercial borrower | Domestic loans
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual loans	[1]	0	0
Real estate construction | Other business lines | Business loans | Commercial borrower | Domestic loans
Financing Receivable, Nonaccrual [Line Items]
Financing Receivable, Nonaccrual, No Allowance	[2]	0	0
Financing Receivable, Nonaccrual	[2]	4	1
Nonaccrual loans	[2]	4	1
Commercial mortgage | Business loans | Commercial borrower | Domestic loans
Financing Receivable, Nonaccrual [Line Items]
Financing Receivable, Nonaccrual, No Allowance		7	6
Financing Receivable, Nonaccrual		24	23
Nonaccrual loans		31	29
Commercial mortgage | Commercial Real Estate business line | Business loans | Commercial borrower | Domestic loans
Financing Receivable, Nonaccrual [Line Items]
Financing Receivable, Nonaccrual, No Allowance	[1]	1	1
Financing Receivable, Nonaccrual	[1]	1	2
Nonaccrual loans	[1]	2	3
Commercial mortgage | Other business lines | Business loans | Commercial borrower | Domestic loans
Financing Receivable, Nonaccrual [Line Items]
Financing Receivable, Nonaccrual, No Allowance	[2]	6	5
Financing Receivable, Nonaccrual	[2]	23	21
Nonaccrual loans	[2]	29	26
Residential mortgage | Retail loans
Financing Receivable, Nonaccrual [Line Items]
Financing Receivable, Nonaccrual, No Allowance		41	47
Financing Receivable, Nonaccrual		0	0
Nonaccrual loans		41	47
Home equity | Retail loans | Home equity
Financing Receivable, Nonaccrual [Line Items]
Financing Receivable, Nonaccrual, No Allowance		14	17
Financing Receivable, Nonaccrual		0	0
Nonaccrual loans		14	17
Other consumer | Retail loans | Home equity
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual loans		$ 0	0
Business Loans | Lease financing | Commercial borrower | Domestic loans
Financing Receivable, Nonaccrual [Line Items]
Financing Receivable, Nonaccrual, No Allowance			0
Financing Receivable, Nonaccrual			1
Nonaccrual loans			$ 1

[1] Primarily loans to real estate developers.

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