Loans TDR Modifications (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2013 contracts		Jun. 30, 2012 contracts		Jun. 30, 2013 contracts		Jun. 30, 2012 contracts
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts	2,544	[1]	2,077	[1]	4,869	[1]	3,355	[1]
Financing Receivable, Amount Restructured During Period, Principal Forgiveness Granted	$ 18	[1],[2]	$ 7	[1],[3]	$ 18	[1],[2]	$ 14	[1],[3]
Financing Receivable, Amount Restructured During Period, Rate Modifications Granted	61	[1],[4]	64	[1],[5]	123	[1],[4]	120	[1],[5]
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	118	[1]	50	[1]	208	[1]	76	[1]
Financing Receivable, Amount Restructured During Period	197	[1],[2],[4]	121	[1],[3],[5]	349	[1],[2],[4]	210	[1],[3],[5]
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts	29	[1]	80	[1]	96	[1]	183	[1]
Financing Receivable, Amount Restructured During Period, Principal Forgiveness Granted	18	[1],[2]	0	[1],[3]	18	[1],[2]	0	[1],[3]
Financing Receivable, Amount Restructured During Period, Rate Modifications Granted	0	[1],[4]	1	[1],[5]	2	[1],[4]	2	[1],[5]
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	15	[1]	3	[1]	49	[1]	15	[1]
Financing Receivable, Amount Restructured During Period	33	[1],[2],[4]	4	[1],[3],[5]	69	[1],[2],[4]	17	[1],[3],[5]
Commercial Portfolio Segment [Member] | Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts	1	[1]	13	[1]	5	[1]	23	[1]
Financing Receivable, Amount Restructured During Period, Principal Forgiveness Granted	0	[1],[2]	6	[1],[3]	0	[1],[2]	12	[1],[3]
Financing Receivable, Amount Restructured During Period, Rate Modifications Granted	0	[1],[4]	6	[1],[5]	4	[1],[4]	7	[1],[5]
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	0	[1]	0	[1]	1	[1]	2	[1]
Financing Receivable, Amount Restructured During Period	0	[1],[2],[4]	12	[1],[3],[5]	5	[1],[2],[4]	21	[1],[3],[5]
Commercial Portfolio Segment [Member] | Commercial Construction [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts	0	[1]	5	[1]	0	[1]	12	[1]
Financing Receivable, Amount Restructured During Period, Principal Forgiveness Granted	0	[1],[2]	1	[1],[3]	0	[1],[2]	2	[1],[3]
Financing Receivable, Amount Restructured During Period, Rate Modifications Granted	0	[1],[4]	0	[1],[5]	0	[1],[4]	0	[1],[5]
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	0	[1]	10	[1]	0	[1]	11	[1]
Financing Receivable, Amount Restructured During Period	0	[1],[2],[4]	11	[1],[3],[5]	0	[1],[2],[4]	13	[1],[3],[5]
Residential Portfolio Segment [Member] | Residential Nonguaranteed [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts	637	[1]	199	[1]	913	[1]	424	[1]
Financing Receivable, Amount Restructured During Period, Principal Forgiveness Granted	0	[1],[2]	0	[1],[3]	0	[1],[2]	0	[1],[3]
Financing Receivable, Amount Restructured During Period, Rate Modifications Granted	36	[1],[4]	21	[1],[5]	61	[1],[4]	41	[1],[5]
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	53	[1]	0	[1]	70	[1]	1	[1]
Financing Receivable, Amount Restructured During Period	89	[1],[2],[4]	21	[1],[3],[5]	131	[1],[2],[4]	42	[1],[3],[5]
Residential Portfolio Segment [Member] | Home Equity Line of Credit [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts	755	[1]	457	[1]	1,438	[1]	841	[1]
Financing Receivable, Amount Restructured During Period, Principal Forgiveness Granted	0	[1],[2]	0	[1],[3]	0	[1],[2]	0	[1],[3]
Financing Receivable, Amount Restructured During Period, Rate Modifications Granted	17	[1],[4]	33	[1],[5]	36	[1],[4]	64	[1],[5]
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	31	[1]	2	[1]	48	[1]	3	[1]
Financing Receivable, Amount Restructured During Period	48	[1],[2],[4]	35	[1],[3],[5]	84	[1],[2],[4]	67	[1],[3],[5]
Residential Portfolio Segment [Member] | Residential Construction [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts	104	[1]	140	[1]	217	[1]	175	[1]
Financing Receivable, Amount Restructured During Period, Principal Forgiveness Granted	0	[1],[2]	0	[1],[3]	0	[1],[2]	0	[1],[3]
Financing Receivable, Amount Restructured During Period, Rate Modifications Granted	7	[1],[4]	1	[1],[5]	18	[1],[4]	1	[1],[5]
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	2	[1]	20	[1]	4	[1]	29	[1]
Financing Receivable, Amount Restructured During Period	9	[1],[2],[4]	21	[1],[3],[5]	22	[1],[2],[4]	30	[1],[3],[5]
Consumer Portfolio Segment [Member] | Consumer Indirect
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts	831	[1]	795	[1]	1,734	[1]	795	[1]
Financing Receivable, Amount Restructured During Period, Principal Forgiveness Granted	0	[1],[2]			0	[1],[2]	0	[1],[3]
Financing Receivable, Amount Restructured During Period, Rate Modifications Granted	0	[1],[4]	0	[1],[5]	0	[1],[4]	0	[1],[5]
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	16	[1]	14	[1]	33	[1]	14	[1]
Financing Receivable, Amount Restructured During Period	16	[1],[2],[4]	14	[1],[3],[5]	33	[1],[2],[4]	14	[1],[3],[5]
Consumer Portfolio Segment [Member] | Consumer Other Direct [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts	32	[1]	27	[1]	80	[1]	39	[1]
Financing Receivable, Amount Restructured During Period, Principal Forgiveness Granted	0	[1],[2]	0	[1],[3]	0	[1],[2]	0	[1],[3]
Financing Receivable, Amount Restructured During Period, Rate Modifications Granted	0	[1],[4]	0	[1],[5]	0	[1],[4]	0	[1],[5]
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	1	[1]	1	[1]	3	[1]	1	[1]
Financing Receivable, Amount Restructured During Period	1	[1],[2],[4]	1	[1],[3],[5]	3	[1],[2],[4]	1	[1],[3],[5]
Consumer Portfolio Segment [Member] | Consumer Credit Card Financing Receivable [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts	155	[1]	361	[1]	386	[1]	863	[1]
Financing Receivable, Amount Restructured During Period, Principal Forgiveness Granted	0	[1],[2]	0	[1],[3]	0	[1],[2]	0	[1],[3]
Financing Receivable, Amount Restructured During Period, Rate Modifications Granted	1	[1],[4]	2	[1],[5]	2	[1],[4]	5	[1],[5]
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	0	[1]	0	[1]	0	[1]	0	[1]
Financing Receivable, Amount Restructured During Period	$ 1	[1],[2],[4]	$ 2	[1],[3],[5]	$ 2	[1],[2],[4]	$ 5	[1],[3],[5]

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

[2] 2Restructured 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 both the three and six months ended June 30, 2013, was $2 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 both the three and six months ended June 30, 2012, was $1 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 three and six months ended June 30, 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 and six months ended June 30, 2012.