Loans TDR Modifications (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012 contracts		Dec. 31, 2011 contracts
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts	11,916	[1]	6,272	[1]
Financing Receivable, Amount Restructured During Period, Principal Forgiveness Granted	$ 29	[1],[2]	$ 106	[1],[3]
Financing Receivable, Amount Restructured During Period, Other Concessions Granted	202	[1],[4]	478	[1],[5]
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	385	[1],[6]	235	[1]
total modifications	616	[1]	819	[1]
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts	358	[1]	510	[1]
Financing Receivable, Amount Restructured During Period, Principal Forgiveness Granted	5	[1],[2]	28	[1],[3]
Financing Receivable, Amount Restructured During Period, Other Concessions Granted	4	[1],[4]	45	[1],[5]
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	23	[1],[6]	55	[1]
total modifications	32	[1]	128	[1]
Commercial Portfolio Segment [Member] | Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts	33	[1]	43	[1]
Financing Receivable, Amount Restructured During Period, Principal Forgiveness Granted	20	[1],[2]	40	[1],[3]
Financing Receivable, Amount Restructured During Period, Other Concessions Granted	7	[1],[4]	26	[1],[5]
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	6	[1],[6]	22	[1]
total modifications	33	[1]	88	[1]
Commercial Portfolio Segment [Member] | Commercial Construction [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts	16	[1]	102	[1]
Financing Receivable, Amount Restructured During Period, Principal Forgiveness Granted	4	[1],[2]	38	[1],[3]
Financing Receivable, Amount Restructured During Period, Other Concessions Granted	0	[1],[4]	8	[1],[5]
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	14	[1],[6]	97	[1]
total modifications	18	[1]	143	[1]
Residential Portfolio Segment [Member] | Residential Nonguaranteed [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts	2,804	[1]	967	[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	72	[1],[4]	233	[1],[5]
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	125	[1],[6]	16	[1]
total modifications	197	[1]	249	[1]
Residential Portfolio Segment [Member] | Home Equity Line of Credit [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts	3,790	[1]	1,737	[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	110	[1],[4]	134	[1],[5]
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	91	[1],[6]	6	[1]
total modifications	201	[1]	140	[1]
Residential Portfolio Segment [Member] | Residential Construction [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts	564	[1]	367	[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]	17	[1],[5]
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	73	[1],[6]	36	[1]
total modifications	74	[1]	53	[1]
Consumer Portfolio Segment [Member] | Consumer Indirect
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts	2,803	[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	49	[1],[6]
total modifications	49	[1]
Consumer Portfolio Segment [Member] | Consumer Other Direct [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts	127	[1]	78	[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]	1	[1],[5]
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	4	[1],[6]	3	[1]
total modifications	4	[1]	4	[1]
Consumer Portfolio Segment [Member] | Consumer Credit Card Financing Receivable [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts	1,421	[1]	2,468	[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	8	[1],[4]	14	[1],[5]
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	0	[1],[6]	0	[1]
total modifications	$ 8	[1]	$ 14	[1]

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

[2] 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 during the year ended December 31, 2012 was $9 million.

[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 during the year ended December 31, 2011 was $17 million.

[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 year ended December 31, 2012.

[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 year ended December 31, 2011.

[6] 4 Approximately 4,231 of the residential loans, with an amortized cost of $201 million as of December 31, 2012, relate to loans discharged in Chapter 7 bankruptcy that were reclassified as TDRs during 2012.