Loans TDR Modifications (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013 contracts		Mar. 31, 2012 contracts
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts	2,325	[1]	1,278	[1]
Financing Receivable, Amount Restructured During Period, Principal Forgiveness Granted	$ 0	[1],[2]	$ 7	[1],[3]
Financing Receivable, Amount Restructured During Period, Other Concessions Granted	62	[1],[4]	56	[1],[5]
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	89	[1]	26	[1]
total modifications	151	[1]	89	[1]
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts	67	[1]	103	[1]
Financing Receivable, Amount Restructured During Period, Principal Forgiveness Granted	0	[1],[2]	0	[1],[3]
Financing Receivable, Amount Restructured During Period, Other Concessions Granted	2	[1],[4]	1	[1],[5]
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	35	[1]	12	[1]
total modifications	37	[1]	13	[1]
Commercial Portfolio Segment [Member] | Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts	4	[1]	10	[1]
Financing Receivable, Amount Restructured During Period, Principal Forgiveness Granted	0	[1],[2]	6	[1],[3]
Financing Receivable, Amount Restructured During Period, Other Concessions Granted	3	[1],[4]	1	[1],[5]
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	0	[1]	2	[1]
total modifications	3	[1]	9	[1]
Commercial Portfolio Segment [Member] | Commercial Construction [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts			7	[1]
Financing Receivable, Amount Restructured During Period, Principal Forgiveness Granted			1	[1],[3]
Financing Receivable, Amount Restructured During Period, Other Concessions Granted			0	[1],[5]
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted			1	[1]
total modifications			2	[1]
Residential Portfolio Segment [Member] | Residential Nonguaranteed [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts	276	[1]	225	[1]
Financing Receivable, Amount Restructured During Period, Principal Forgiveness Granted	0	[1],[2]	0	[1],[3]
Financing Receivable, Amount Restructured During Period, Other Concessions Granted	25	[1],[4]	20	[1],[5]
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	17	[1]	1	[1]
total modifications	42	[1]	21	[1]
Residential Portfolio Segment [Member] | Home Equity Line of Credit [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts	683	[1]	384	[1]
Financing Receivable, Amount Restructured During Period, Principal Forgiveness Granted	0	[1],[2]	0	[1],[3]
Financing Receivable, Amount Restructured During Period, Other Concessions Granted	19	[1],[4]	31	[1],[5]
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	18	[1]	1	[1]
total modifications	37	[1]	32	[1]
Residential Portfolio Segment [Member] | Residential Construction [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts	113	[1]	35	[1]
Financing Receivable, Amount Restructured During Period, Principal Forgiveness Granted	0	[1],[2]	0	[1],[3]
Financing Receivable, Amount Restructured During Period, Other Concessions Granted	12	[1],[4]	0	[1],[5]
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	1	[1]	9	[1]
total modifications	13	[1]	9	[1]
Consumer Portfolio Segment [Member] | Consumer Indirect
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts	903	[1]
Financing Receivable, Amount Restructured During Period, Principal Forgiveness Granted	0	[1],[2]
Financing Receivable, Amount Restructured During Period, Other Concessions Granted	0	[1],[4]
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	17	[1]
total modifications	17	[1]
Consumer Portfolio Segment [Member] | Consumer Other Direct [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts	48	[1]	12	[1]
Financing Receivable, Amount Restructured During Period, Principal Forgiveness Granted	0	[1],[2]	0	[1],[3]
Financing Receivable, Amount Restructured During Period, Other Concessions Granted	0	[1],[4]	0	[1],[5]
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	1	[1]	0	[1]
total modifications	1	[1]	0	[1]
Consumer Portfolio Segment [Member] | Consumer Credit Card Financing Receivable [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts	231	[1]	502	[1]
Financing Receivable, Amount Restructured During Period, Principal Forgiveness Granted	0	[1],[2]	0	[1],[3]
Financing Receivable, Amount Restructured During Period, Other Concessions Granted	1	[1],[4]	3	[1],[5]
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	0	[1]	0	[1]
total modifications	$ 1	[1]	$ 3	[1]

[1] Includes loans modified under the terms of a TDR that were charged-off during the period.

[2] There was no principal forgiveness for Commercial, Residential, or Consumer loans during the three months ended March 31, 2013

[3] Restructured loans which had forgiveness of amounts contractually due under the terms of the loan typically have had multiple concessions including rate modifications and/or term extensions. The total amount of charge-offs associated with principal forgiveness for the Commercial segment during the three months ended March 31, 2012, was less than $1 million. There was no principal forgiveness for Residential or Consumer loans during the three months ended March 31, 2012.

[4] Restructured loans which had a modification of the loan's contractual interest rate may also have had an extension of the loan's contractual maturity date and/or other concessions. The financial effect of modifying the interest rate on the loans modified as a TDR was immaterial to the financial statements during the three months ended March 31, 2013.

[5] Restructured loans which had a modification of the loan's contractual interest rate may also have had an extension of the loan's contractual maturity date and/or other concessions. The financial effect of modifying the interest rate on the loans modified as a TDR was immaterial to the financial statements during the three months ended March 31, 2012.