Non-Interest Revenue and Expense Detail (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Details Of Certain Statements Of Income Lines Details [Abstract]
Foreign currency conversion fee revenue	$ 207	$ 213	$ 610	$ 646
Delinquency fees	183	197	575	586
Loyalty Partner-related fees	106	100	304	279
Travel commissions and fees	89	87	256	271
Service fees	71	97	228	279
Other	38	33	103	101
Total Other fees and commissions	$ 694	$ 727	$ 2,076	$ 2,162