Loans TDR Modifications (Details) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2019 USD ($) contracts	[1]	Jun. 30, 2018 USD ($) contracts	[2]	Jun. 30, 2019 USD ($) contracts	[3]	Jun. 30, 2018 USD ($) contracts	[4]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts | contracts	1,502		1,592		2,798		3,035
Financing Receivable, Amount Restructured During Period, Rate Modifications Granted	$ 4		$ 10		$ 11		$ 20
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	28		92		56		186
Financing Receivable, Amount Restructured During Period	$ 32		$ 102		$ 67		$ 206
Residential Construction [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts | contracts			3				4
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
Credit Card [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts | contracts	555		426		994		734
Financing Receivable, Amount Restructured During Period, Rate Modifications Granted	$ 3		$ 2		$ 5		$ 3
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	0		0		0		0
Financing Receivable, Amount Restructured During Period	$ 3		$ 2		$ 5		$ 3
Commercial and Industrial [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts | contracts	22		29		56		75
Financing Receivable, Amount Restructured During Period, Rate Modifications Granted	$ 0		$ 0		$ 1		$ 0
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	2		29		5		84
Financing Receivable, Amount Restructured During Period	$ 2		$ 29		$ 6		$ 84
Residential Nonguaranteed [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts | contracts	27		159		58		219
Financing Receivable, Amount Restructured During Period, Rate Modifications Granted	$ 1		$ 8		$ 3		$ 17
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	2		32		5		38
Financing Receivable, Amount Restructured During Period	$ 3		$ 40		$ 8		$ 55
Home Equity Line of Credit [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts | contracts	77		144		161		280
Financing Receivable, Amount Restructured During Period, Rate Modifications Granted	$ 0		$ 0		$ 2		$ 0
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	5		12		10		24
Financing Receivable, Amount Restructured During Period	$ 5		$ 12		$ 12		$ 24
Consumer Other Direct [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts | contracts	268		214		408		328
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	5		3		7		5
Financing Receivable, Amount Restructured During Period	$ 5		$ 3		$ 7		$ 5
Consumer Indirect [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts | contracts	553		617		1,121		1,395
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		16		29		35
Financing Receivable, Amount Restructured During Period	$ 14		$ 16		$ 29		$ 35

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

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