Outstanding Loans and Leases - Credit Card and Other Consumer - TDRs Modified by Program Type (Details) - Credit card and other consumer - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Financing Receivable, Troubled Debt Restructuring [Line Items]
Carrying Value	$ 110	$ 115
Internal Programs
Financing Receivable, Troubled Debt Restructuring [Line Items]
Carrying Value	74	75
External Programs
Financing Receivable, Troubled Debt Restructuring [Line Items]
Carrying Value	27	30
Other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Carrying Value	$ 9	$ 10