Reserves For Losses (Details 1) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Card Member Loans And Related Reserves Evaluated Separately And Collectively For Impairment [Abstract]
Card Member loans evaluated individually for impairment	$ 344	$ 279
Reserves on Card Member loans evaluated individually for impairment	60	53
Card Member loans evaluated collectively for impairment	60,274	58,294
Reserves on Card Member loans evaluated collectively for impairment	$ 1,054	$ 975