Loans TDR Modifications (Details) $ in Millions	3 Months Ended
	Mar. 31, 2019 USD ($) contracts	[1]	Mar. 31, 2018 USD ($) contracts	[2]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts | contracts	1,296		1,443
Financing Receivable, Amount Restructured During Period, Rate Modifications Granted	$ 5		$ 10
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	83		99
Financing Receivable, Amount Restructured During Period	$ 88		$ 109
Credit Card [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts | contracts	439		308
Financing Receivable, Amount Restructured During Period, Rate Modifications Granted	$ 2		$ 1
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	0		1
Financing Receivable, Amount Restructured During Period	$ 2		$ 2
Commercial and Industrial [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts | contracts	34		46
Financing Receivable, Amount Restructured During Period, Rate Modifications Granted	$ 1		$ 0
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	56		56
Financing Receivable, Amount Restructured During Period	$ 57		$ 56
Residential Nonguaranteed [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts | contracts	31		61
Financing Receivable, Amount Restructured During Period, Rate Modifications Granted	$ 1		$ 9
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	4		8
Financing Receivable, Amount Restructured During Period	$ 5		$ 17
Home Equity Line of Credit [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts | contracts	84		136
Financing Receivable, Amount Restructured During Period, Rate Modifications Granted	$ 1		$ 0
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	6		13
Financing Receivable, Amount Restructured During Period	$ 7		$ 13
Consumer Other Direct [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts | contracts	140		114
Financing Receivable, Amount Restructured During Period, Rate Modifications Granted	$ 0		$ 0
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	2		1
Financing Receivable, Amount Restructured During Period	$ 2		$ 1
Consumer Indirect [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Restructured During Period, Number Of Contracts | contracts	568		778
Financing Receivable, Amount Restructured During Period, Rate Modifications Granted	$ 0		$ 0
Financing Receivable, Amount Restructured During Period, Term Extension and/or Other Concessions Granted	15		20
Financing Receivable, Amount Restructured During Period	$ 15		$ 20

[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.