Other Fees and Commissions and Other Expenses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Non Interest Revenues [Line Items]
Delinquency fees	$ 1,028	$ 959	$ 888
Foreign currency conversion fee revenue	982	921	851
Loyalty coalition-related fees	456	461	452
Travel commissions and fees	424	395	364
Service fees and other	407	417	435
Other Fees and Commissions [Member]
Non Interest Revenues [Line Items]
Total Other fees and commissions	$ 3,297	$ 3,153	$ 2,990