Fair Values (Details) - USD ($) $ in Millions |
Dec. 31, 2016 |
Dec. 31, 2015 |
|---|---|---|
| Investment securities: | ||
| Equity securities | $ 49 | $ 49 |
| Debt securities and other | 3,108 | 3,710 |
| Derivative assets | 765 | 544 |
| Total assets | 3,922 | 4,303 |
| Liabilities | ||
| Derivative liabilities | 280 | 201 |
| Total liabilities | 280 | 201 |
| Level 1 [Member] | ||
| Investment securities: | ||
| Equity securities | 1 | 1 |
| Debt securities and other | 460 | 409 |
| Derivative assets | 0 | 0 |
| Total assets | 461 | 410 |
| Liabilities | ||
| Derivative liabilities | 0 | 0 |
| Total liabilities | 0 | 0 |
| Level 2 [Member] | ||
| Investment securities: | ||
| Equity securities | 48 | 48 |
| Debt securities and other | 2,648 | 3,301 |
| Derivative assets | 765 | 544 |
| Total assets | 3,461 | 3,893 |
| Liabilities | ||
| Derivative liabilities | 280 | 201 |
| Total liabilities | 280 | 201 |
| Level 3 [Member] | ||
| Investment securities: | ||
| Equity securities | 0 | 0 |
| Debt securities and other | 0 | 0 |
| Derivative assets | 0 | 0 |
| Total assets | 0 | 0 |
| Liabilities | ||
| Derivative liabilities | 0 | 0 |
| Total liabilities | $ 0 | $ 0 |