Credit Quality And Allowance For Credit Losses (Troubled Debt Restructurings By Type Of Modification) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011
Troubled debt restructuring modifications recorded investment	$ 256
Business Loans [Member]
Troubled debt restructuring modifications recorded investment	241
Business Loans [Member] | Commercial [Member]
Troubled debt restructuring modifications recorded investment	98
Business Loans [Member] | Real Estate Construction [Member] | Commercial Real Estate Business Line [Member]
Troubled debt restructuring modifications recorded investment	38	[1]
Business Loans [Member] | Commercial Mortgage [Member]
Troubled debt restructuring modifications recorded investment	98
Business Loans [Member] | Commercial Mortgage [Member] | Commercial Real Estate Business Line [Member]
Troubled debt restructuring modifications recorded investment	29	[1]
Business Loans [Member] | Commercial Mortgage [Member] | Other Business Lines [Member]
Troubled debt restructuring modifications recorded investment	69	[2]
Business Loans [Member] | Lease Financing Loan [Member]
Troubled debt restructuring modifications recorded investment	3
Business Loans [Member] | International Loan [Member]
Troubled debt restructuring modifications recorded investment	4
Retail Loans [Member]
Troubled debt restructuring modifications recorded investment	15
Retail Loans [Member] | Residential Mortgage Loan [Member]
Troubled debt restructuring modifications recorded investment	11
Retail Loans [Member] | Consumer [Member] | Home Equity [Member]
Troubled debt restructuring modifications recorded investment	4
Principal Deferrals Modification Type [Member]
Extension Term, Minimum Period	90 days
Troubled debt restructuring modifications recorded investment	185	[3]
Principal Deferrals Modification Type [Member] | Business Loans [Member]
Troubled debt restructuring modifications recorded investment	181	[3]
Principal Deferrals Modification Type [Member] | Business Loans [Member] | Commercial [Member]
Troubled debt restructuring modifications recorded investment	91	[3]
Principal Deferrals Modification Type [Member] | Business Loans [Member] | Real Estate Construction [Member] | Commercial Real Estate Business Line [Member]
Troubled debt restructuring modifications recorded investment	20	[1],[3]
Principal Deferrals Modification Type [Member] | Business Loans [Member] | Commercial Mortgage [Member]
Troubled debt restructuring modifications recorded investment	70	[3]
Principal Deferrals Modification Type [Member] | Business Loans [Member] | Commercial Mortgage [Member] | Commercial Real Estate Business Line [Member]
Troubled debt restructuring modifications recorded investment	29	[1],[3]
Principal Deferrals Modification Type [Member] | Business Loans [Member] | Commercial Mortgage [Member] | Other Business Lines [Member]
Troubled debt restructuring modifications recorded investment	41	[2],[3]
Principal Deferrals Modification Type [Member] | Business Loans [Member] | Lease Financing Loan [Member]
Troubled debt restructuring modifications recorded investment	0
Principal Deferrals Modification Type [Member] | Business Loans [Member] | International Loan [Member]
Troubled debt restructuring modifications recorded investment	0	[3]
Principal Deferrals Modification Type [Member] | Retail Loans [Member]
Troubled debt restructuring modifications recorded investment	4	[3]
Principal Deferrals Modification Type [Member] | Retail Loans [Member] | Residential Mortgage Loan [Member]
Troubled debt restructuring modifications recorded investment	1	[3]
Principal Deferrals Modification Type [Member] | Retail Loans [Member] | Consumer [Member] | Home Equity [Member]
Troubled debt restructuring modifications recorded investment	3	[3]
Interest Rate Reduction Modification Type [Member]
Troubled debt restructuring modifications recorded investment	40
Interest Rate Reduction Modification Type [Member] | Business Loans [Member]
Troubled debt restructuring modifications recorded investment	29
Interest Rate Reduction Modification Type [Member] | Business Loans [Member] | Commercial [Member]
Troubled debt restructuring modifications recorded investment	1
Interest Rate Reduction Modification Type [Member] | Business Loans [Member] | Real Estate Construction [Member] | Commercial Real Estate Business Line [Member]
Troubled debt restructuring modifications recorded investment	3	[1]
Interest Rate Reduction Modification Type [Member] | Business Loans [Member] | Commercial Mortgage [Member]
Troubled debt restructuring modifications recorded investment	22
Interest Rate Reduction Modification Type [Member] | Business Loans [Member] | Commercial Mortgage [Member] | Commercial Real Estate Business Line [Member]
Troubled debt restructuring modifications recorded investment	0	[1]
Interest Rate Reduction Modification Type [Member] | Business Loans [Member] | Commercial Mortgage [Member] | Other Business Lines [Member]
Troubled debt restructuring modifications recorded investment	22	[2]
Interest Rate Reduction Modification Type [Member] | Business Loans [Member] | Lease Financing Loan [Member]
Troubled debt restructuring modifications recorded investment	3
Interest Rate Reduction Modification Type [Member] | Business Loans [Member] | International Loan [Member]
Troubled debt restructuring modifications recorded investment	0
Interest Rate Reduction Modification Type [Member] | Retail Loans [Member]
Troubled debt restructuring modifications recorded investment	11
Interest Rate Reduction Modification Type [Member] | Retail Loans [Member] | Residential Mortgage Loan [Member]
Troubled debt restructuring modifications recorded investment	10
Interest Rate Reduction Modification Type [Member] | Retail Loans [Member] | Consumer [Member] | Home Equity [Member]
Troubled debt restructuring modifications recorded investment	1
AB Note Restructures Modification Type [Member]
Troubled debt restructuring modifications recorded investment	31	[4]
AB Note Restructures Modification Type [Member] | Business Loans [Member]
Troubled debt restructuring modifications recorded investment	31	[4]
AB Note Restructures Modification Type [Member] | Business Loans [Member] | Commercial [Member]
Troubled debt restructuring modifications recorded investment	6	[4]
AB Note Restructures Modification Type [Member] | Business Loans [Member] | Real Estate Construction [Member] | Commercial Real Estate Business Line [Member]
Troubled debt restructuring modifications recorded investment	15	[1],[4]
AB Note Restructures Modification Type [Member] | Business Loans [Member] | Commercial Mortgage [Member]
Troubled debt restructuring modifications recorded investment	6	[4]
AB Note Restructures Modification Type [Member] | Business Loans [Member] | Commercial Mortgage [Member] | Commercial Real Estate Business Line [Member]
Troubled debt restructuring modifications recorded investment	0	[1],[4]
AB Note Restructures Modification Type [Member] | Business Loans [Member] | Commercial Mortgage [Member] | Other Business Lines [Member]
Troubled debt restructuring modifications recorded investment	6	[2],[4]
AB Note Restructures Modification Type [Member] | Business Loans [Member] | Lease Financing Loan [Member]
Troubled debt restructuring modifications recorded investment	0
AB Note Restructures Modification Type [Member] | Business Loans [Member] | International Loan [Member]
Troubled debt restructuring modifications recorded investment	4	[4]
AB Note Restructures Modification Type [Member] | Retail Loans [Member]
Troubled debt restructuring modifications recorded investment	0	[4]
AB Note Restructures Modification Type [Member] | Retail Loans [Member] | Residential Mortgage Loan [Member]
Troubled debt restructuring modifications recorded investment	0	[4]
AB Note Restructures Modification Type [Member] | Retail Loans [Member] | Consumer [Member] | Home Equity [Member]
Troubled debt restructuring modifications recorded investment	$ 0	[4]

[1] Primarily loans to real estate investors and developers.

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

[3] Primarily represents loan balances where terms were extended 90 days or more at or above contractual interest rates.

[4] Loan restructurings whereby the original loan is restructured into two notes: an "A" note, which generally reflects the portion of the modified loan which is expected to be collected; and a "B" note, which is either fully charged off or exchanged for an equity interest.