Reserves for Losses (Details 3) - USD ($) $ in Millions |
Jun. 30, 2016 |
Dec. 31, 2015 |
|---|---|---|
| Card Member Receivables And Related Reserves Evaluated Separately and Collectively For Impairment [Abstract] | ||
| Card Member receivables evaluated individually for impairment | $ 37 | $ 33 |
| Reserves on Card Member receivables evaluated individually for impairment | 19 | 20 |
| Card Member receivables evaluated collectively for impairment | 45,186 | 44,100 |
| Reserves on Card Member receivables evaluated collectively for impairment | $ 404 | $ 442 |