Other Fees and Commissions and Other Expenses (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Fees charged to Card Members:
Delinquency fees	$ 146	$ 196	$ 294	$ 456
Foreign currency conversion fee revenue	109	57	205	250
Other customer fees:
Loyalty coalition-related fees	121	90	245	198
Travel commissions and fees	57	5	90	65
Service fees and other	127	101	246	200
Other fees and commissions
Other customer fees:
Total Other fees and commissions	$ 560	$ 449	$ 1,080	$ 1,169