Other Fees and Commissions and Other Expenses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Non Interest Revenues [Line Items]
Delinquency fees	$ 772	$ 1,028	$ 959
Foreign currency conversion fee revenue	433	982	921
Loyalty coalition-related fees	435	456	461
Service fees and other	421	407	417
Travel commissions and fees	102	424	395
Other Fees and Commissions [Member]
Non Interest Revenues [Line Items]
Total Other fees and commissions	$ 2,163	$ 3,297	$ 3,153