Non-Interest Revenue and Expense Detail (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Details Of Certain Statements Of Income Lines Details [Abstract]
Foreign currency conversion fee revenue	$ 213	$ 225	$ 646	$ 665
Delinquency fees	197	184	586	539
Loyalty Partner-related fees	101	100	280	286
Service fees	97	94	279	274
Other	32	39	100	120
Total other commissions and fees	$ 640	$ 642	$ 1,891	$ 1,884