Loans TDR Modifications (Details) $ in Millions		3 Months Ended				6 Months Ended
		Jun. 30, 2016 USD ($) contracts		Jun. 30, 2015 USD ($) contracts		Jun. 30, 2016 USD ($) contracts		Jun. 30, 2015 USD ($) contracts
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts | contracts		1,565	[1]	1,749	[2]	3,108	[1]	3,278	[2]
Financing Receivable, Amount Restructured During Period, Principal Forgiveness Granted		$ 1	[1]	$ 3	[2],[3]	$ 1	[1]	$ 7	[2],[3]
Financing Receivable, Amount Restructured During Period, Rate Modifications Granted		29	[1]	44	[2]	68	[1]	78	[2]
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted		134	[1]	35	[2]	202	[1]	83	[2]
Financing Receivable, Amount Restructured During Period		$ 164	[1]	$ 82	[2]	$ 271	[1]	$ 168	[2]
Commercial and Industrial [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts | contracts		23	[1]	23	[2]	35	[1]	45	[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]
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted		44	[1]	1	[2]	46	[1]	5	[2]
Financing Receivable, Amount Restructured During Period		$ 44	[1]	$ 1	[2]	$ 46	[1]	$ 6	[2]
Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts | contracts	[2]			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
Commercial Construction [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts | contracts	[1]					1
Financing Receivable, Amount Restructured During Period, Principal Forgiveness Granted						$ 0
Financing Receivable, Amount Restructured During Period, Rate Modifications Granted						0
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted						0
Financing Receivable, Amount Restructured During Period						$ 0
Residential Nonguaranteed [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts | contracts		119	[1]	241	[2]	239	[1]	457	[2]
Financing Receivable, Amount Restructured During Period, Principal Forgiveness Granted		$ 1	[1]	$ 3	[2],[3]	$ 1	[1]	$ 7	[2],[3]
Financing Receivable, Amount Restructured During Period, Rate Modifications Granted		26	[1]	34	[2]	58	[1]	63	[2]
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted		5	[1]	3	[2]	7	[1]	11	[2]
Financing Receivable, Amount Restructured During Period		$ 32	[1]	$ 40	[2]	$ 66	[1]	$ 81	[2]
Home Equity Line of Credit [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts | contracts		799	[1]	499	[2]	1,531	[1]	967	[2]
Financing Receivable, Amount Restructured During Period, Principal Forgiveness Granted		$ 0		$ 0		$ 0		$ 0
Financing Receivable, Amount Restructured During Period, Rate Modifications Granted		2	[1]	9	[2]	9	[1]	13	[2]
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted		75	[1]	17	[2]	127	[1]	41	[2]
Financing Receivable, Amount Restructured During Period		$ 77	[1]	$ 26	[2]	$ 136	[1]	$ 54	[2]
Residential Construction [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts | contracts	[2]			10				11
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
Consumer Other Direct [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts | contracts		9	[1]	20	[2]	32	[1]	37	[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		1	[1]	0
Financing Receivable, Amount Restructured During Period		$ 0		$ 0		$ 1	[1]	$ 0
Consumer Indirect [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts | contracts		432	[1]	819	[2]	918	[1]	1,388	[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		10	[1]	14	[2]	21	[1]	26	[2]
Financing Receivable, Amount Restructured During Period		$ 10	[1]	$ 14	[2]	$ 21	[1]	$ 26	[2]
Credit Card Receivable [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts | contracts		183	[1]	136	[2]	352	[1]	372	[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]	1	[2]	1	[1]	1	[2]
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 may have had other concessions including rate modifications and/or term extensions. The total amount of charge-offs associated with principal forgiveness during the three and six months ended June 30, 2015 was immaterial.