Other Fees and Commissions and Other Expenses (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Non Interest Income [Line Items]
Delinquency fees	$ 260	$ 251
Foreign currency conversion fee revenue	193	230
Loyalty coalition-related fees	108	114
Travel commissions and fees	60	108
Service fees and other	99	100
Other fees and commissions [Member]
Non Interest Income [Line Items]
Total Other fees and commissions	$ 720	$ 803