Fair Values (Details) - USD ($) $ in Millions |
Dec. 31, 2015 |
Dec. 31, 2014 |
|---|---|---|
| Investment securities: | ||
| Equity securities | $ 1 | $ 1 |
| Debt securities and other | 3,758 | 4,430 |
| Derivative assets | 544 | 991 |
| Total assets | 4,303 | 5,422 |
| Level 1 [Member] | ||
| Investment securities: | ||
| Equity securities | 1 | 1 |
| Debt securities and other | 409 | 350 |
| Derivative assets | 0 | 0 |
| Total assets | 410 | 351 |
| Level 2 [Member] | ||
| Investment securities: | ||
| Equity securities | 0 | 0 |
| Debt securities and other | 3,349 | 4,080 |
| Derivative assets | 545 | 991 |
| Total assets | 3,894 | 5,071 |
| Level 3 [Member] | ||
| Investment securities: | ||
| Total assets | $ 0 | $ 0 |