Loans TDR Modifications (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2014 contracts		Sep. 30, 2013 contracts		Sep. 30, 2014 contracts		Sep. 30, 2013 contracts
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts	1,575	[1]	2,111	[1]	5,030	[1]	6,980	[1]
Financing Receivable, Amount Restructured During Period, Principal Forgiveness Granted	$ 0		$ 0		$ 4	[1],[2]	$ 18	[1],[3]
Financing Receivable, Amount Restructured During Period, Rate Modifications Granted	29	[1],[4]	84	[1],[5]	122	[1],[4]	208	[1],[5]
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	51	[1]	84	[1]	165	[1]	290	[1]
Financing Receivable, Amount Restructured During Period	80	[1]	168	[1]	291	[1]	516	[1]
Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts					4	[1]	5	[1]
Financing Receivable, Amount Restructured During Period, Principal Forgiveness Granted					3	[1],[2]	0
Financing Receivable, Amount Restructured During Period, Rate Modifications Granted					0		4	[1],[5]
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted					3	[1]	1	[1]
Financing Receivable, Amount Restructured During Period					6	[1]	5	[1]
Commercial and Industrial [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts	23	[1]	28	[1]	66	[1]	124	[1]
Financing Receivable, Amount Restructured During Period, Principal Forgiveness Granted	0		0		0		18	[1],[3]
Financing Receivable, Amount Restructured During Period, Rate Modifications Granted	0		0		0		2	[1],[5]
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	8	[1]	39	[1]	22	[1]	89	[1]
Financing Receivable, Amount Restructured During Period	8	[1]	39	[1]	22	[1]	109	[1]
Commercial Construction [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts			1	[1]			1	[1]
Financing Receivable, Amount Restructured During Period, Principal Forgiveness Granted			0				0
Financing Receivable, Amount Restructured During Period, Rate Modifications Granted			0				0
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted			0				0
Financing Receivable, Amount Restructured During Period			0				0
Residential Nonguaranteed [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts	266	[1]	332	[1]	944	[1]	1,245	[1]
Financing Receivable, Amount Restructured During Period, Principal Forgiveness Granted	0		0		1	[1],[2]	0
Financing Receivable, Amount Restructured During Period, Rate Modifications Granted	27	[1],[4]	61	[1],[5]	113	[1],[4]	122	[1],[5]
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	9	[1]	14	[1]	37	[1]	84	[1]
Financing Receivable, Amount Restructured During Period	36	[1]	75	[1]	151	[1]	206	[1]
Home Equity Line of Credit [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts	503	[1]	715	[1]	1,407	[1]	2,153	[1]
Financing Receivable, Amount Restructured During Period, Principal Forgiveness Granted	0		0		0		0
Financing Receivable, Amount Restructured During Period, Rate Modifications Granted	1	[1],[4]	19	[1],[5]	6	[1],[4]	56	[1],[5]
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	22	[1]	12	[1]	59	[1]	60	[1]
Financing Receivable, Amount Restructured During Period	23	[1]	31	[1]	65	[1]	116	[1]
Residential Construction [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts	1	[1]	25	[1]	11	[1]	242	[1]
Financing Receivable, Amount Restructured During Period, Principal Forgiveness Granted	0		0		0		0
Financing Receivable, Amount Restructured During Period, Rate Modifications Granted	0		4	[1],[5]	1	[1],[4]	22	[1],[5]
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	0		0		0		3	[1]
Financing Receivable, Amount Restructured During Period	0		4	[1]	1	[1]	25	[1]
Consumer Other Direct [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts	21	[1]	30	[1]	59	[1]	110	[1]
Financing Receivable, Amount Restructured During Period, Principal Forgiveness Granted	0		0		0		0
Financing Receivable, Amount Restructured During Period, Rate Modifications Granted	0		0		0		0
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	0		1	[1]	1	[1]	3	[1]
Financing Receivable, Amount Restructured During Period	0		1	[1]	1	[1]	3	[1]
Consumer Indirect [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts	638	[1]	883	[1]	2,189	[1]	2,617	[1]
Financing Receivable, Amount Restructured During Period, Principal Forgiveness Granted	0		0		0		0
Financing Receivable, Amount Restructured During Period, Rate Modifications Granted	0		0		0		0
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	12	[1]	18	[1]	43	[1]	50	[1]
Financing Receivable, Amount Restructured During Period	12	[1]	18	[1]	43	[1]	50	[1]
Consumer Credit Card Financing Receivable [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts	123	[1]	97	[1]	350	[1]	483	[1]
Financing Receivable, Amount Restructured During Period, Principal Forgiveness Granted	0		0		0		0
Financing Receivable, Amount Restructured During Period, Rate Modifications Granted	1	[1],[4]	0		2	[1],[4]	2	[1],[5]
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	0		0		0		0
Financing Receivable, Amount Restructured During Period	$ 1	[1]	$ 0		$ 2	[1]	$ 2	[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 both the three and nine months ended September 30, 2014 was immaterial.

[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. There were no charge-offs associated with principal forgiveness during the three months ended September 30, 2013. The total amount of charge-offs associated with principal forgiveness during the nine months ended September 30, 2013 was $2 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 nine months ended September 30, 2014.

[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 nine months ended September 30, 2013.