Loans TDR Modifications (Details) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2015 USD ($) contracts		Jun. 30, 2014 USD ($) contracts		Jun. 30, 2015 USD ($) contracts		Jun. 30, 2014 USD ($) contracts
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts | contracts	1,749	[1]	1,732	[2]	3,278	[1]	3,455	[2]
Financing Receivable, Amount Restructured During Period, Principal Forgiveness Granted	$ 3	[1],[3]	$ 7	[2],[4]	$ 7	[1],[3]	$ 10	[2],[4]
Financing Receivable, Amount Restructured During Period, Rate Modifications Granted	44	[1],[3],[5]	44	[2],[4],[6]	78	[1],[3],[5]	86	[2],[4],[6]
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	35	[1]	56	[2]	83	[1]	115	[2]
Financing Receivable, Amount Restructured During Period	$ 82	[1]	$ 107	[2]	$ 168	[1]	$ 211	[2]
Commercial and Industrial [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts | contracts	23	[1]	27	[2]	45	[1]	43	[2]
Financing Receivable, Amount Restructured During Period, Principal Forgiveness Granted	$ 0		$ 0		$ 0		$ 0
Financing Receivable, Amount Restructured During Period, Rate Modifications Granted	0		0		1	[1],[3],[5]	0
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	1	[1]	12	[2]	5	[1]	14	[2]
Financing Receivable, Amount Restructured During Period	$ 1	[1]	$ 12	[2]	$ 6	[1]	$ 14	[2]
Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts | contracts	1	[1]	2	[2]	1	[1]	4	[2]
Financing Receivable, Amount Restructured During Period, Principal Forgiveness Granted	$ 0		$ 3	[2],[4]	$ 0		$ 3	[2],[4]
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		0		0		3	[2]
Financing Receivable, Amount Restructured During Period	$ 0		$ 3	[2]	$ 0		$ 6	[2]
Residential Nonguaranteed [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts | contracts	241	[1]	365	[2]	457	[1]	678	[2]
Financing Receivable, Amount Restructured During Period, Principal Forgiveness Granted	$ 3	[1],[3]	$ 4	[2],[4]	$ 7	[1],[3]	$ 7	[2],[4]
Financing Receivable, Amount Restructured During Period, Rate Modifications Granted	34	[1],[3],[5]	41	[2],[4],[6]	63	[1],[3],[5]	79	[2],[4],[6]
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	3	[1]	10	[2]	11	[1]	29	[2]
Financing Receivable, Amount Restructured During Period	$ 40	[1]	$ 55	[2]	$ 81	[1]	$ 115	[2]
Home Equity Line of Credit [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts | contracts	499	[1]	471	[2]	967	[1]	904	[2]
Financing Receivable, Amount Restructured During Period, Principal Forgiveness Granted	$ 0		$ 0		$ 0		$ 0
Financing Receivable, Amount Restructured During Period, Rate Modifications Granted	9	[1],[3],[5]	2	[2],[4],[6]	13	[1],[3],[5]	5	[2],[4],[6]
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	17	[1]	20	[2]	41	[1]	38	[2]
Financing Receivable, Amount Restructured During Period	$ 26	[1]	$ 22	[2]	$ 54	[1]	$ 43	[2]
Residential Construction [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts | contracts	10	[1]	4	[2]	11	[1]	10	[2]
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		1	[2],[4],[6]
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	0		0		0		0
Financing Receivable, Amount Restructured During Period	$ 0		$ 0	[2]	$ 0		$ 1	[2]
Consumer Other Direct [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts | contracts	20	[1]	21	[2]	37	[1]	38	[2]
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		0		0		1	[2]
Financing Receivable, Amount Restructured During Period	$ 0		$ 0		$ 0		$ 1	[2]
Consumer Indirect [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts | contracts	819	[1]	712	[2]	1,388	[1]	1,551	[2]
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	14	[1]	14	[2]	26	[1]	30	[2]
Financing Receivable, Amount Restructured During Period	$ 14	[1]	$ 14	[2]	$ 26	[1]	$ 30	[2]
Consumer Credit Card Financing Receivable [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts | contracts	136	[1]	130	[2]	372	[1]	227	[2]
Financing Receivable, Amount Restructured During Period, Principal Forgiveness Granted	$ 0		$ 0		$ 0		$ 0
Financing Receivable, Amount Restructured During Period, Rate Modifications Granted	1	[1],[3],[5]	1	[2],[4],[6]	1	[1],[3],[5]	1	[2],[4],[6]
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]	$ 1	[2]	$ 1	[1]	$ 1	[2]

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

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

[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, 2015 was immaterial.

[4] 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, 2014 was immaterial.

[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 both the three and six months ended June 30, 2015.

[6] 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 both the three and six months ended June 30, 2014.