Reserves For Losses (Details 3) - USD ($) $ in Millions |
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
|---|---|---|---|
| Card Member Loans And Related Reserves Evaluated Separately And Collectively For Impairment [Abstract] | |||
| Card Member loans evaluated separately for impairment | $ 279 | $ 286 | $ 356 |
| Reserves on Card Member loans evaluated separately for impairment | 53 | 67 | 78 |
| Card Member loans evaluated collectively for impairment | 58,294 | 70,099 | 66,882 |
| Reserves on Card Member loans evaluated collectively for impairment | $ 975 | $ 1,134 | $ 1,183 |