Other Assets (Details 2) - USD ($) $ in Millions |
Dec. 31, 2015 |
Dec. 31, 2014 |
|---|---|---|
| Components of other intangible assets | ||
| Gross Carrying Amount | $ 1,737 | $ 1,710 |
| Accumulated Amortization | (941) | (856) |
| Net Carrying Amount | 796 | 854 |
| Other Contracts [Member] | ||
| Components of other intangible assets | ||
| Gross Carrying Amount | 231 | 255 |
| Accumulated Amortization | (105) | (102) |
| Customer Relationships [Member] | ||
| Components of other intangible assets | ||
| Gross Carrying Amount | 1,506 | 1,455 |
| Accumulated Amortization | $ (836) | $ (754) |