Reserves for Losses (Details 3) - USD ($) $ in Millions |
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
|---|---|---|---|
| Card Member Receivables And Related Reserves Evaluated Separately and Collectively For Impairment [Abstract] | |||
| Card Member receivables evaluated separately for impairment | $ 55 | $ 33 | $ 48 |
| Reserves on Card Member receivables evaluated separately for impairment | 28 | 20 | 35 |
| Card Member receivables evaluated collectively for impairment | 47,253 | 44,100 | 44,803 |
| Reserves on Card Member receivables evaluated collectively for impairment | $ 439 | $ 442 | $ 430 |