Non-Interest Revenue and Expense Detail (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Details Of Certain Statements Of Income Lines Details [Abstract]
Foreign currency conversion fee revenue	$ 222	$ 227	$ 433	$ 440
Delinquency fees	194	174	389	355
Loyalty Partner-related fees	88	95	179	186
Service fees	95	90	182	180
Other	33	38	68	81
Total other commissions and fees	$ 632	$ 624	$ 1,251	$ 1,242