Other Assets (Details 2) - USD ($) $ in Millions |
Dec. 31, 2016 |
Dec. 31, 2015 |
|---|---|---|
| Components of other intangible assets | ||
| Gross Carrying Amount | $ 1,885 | $ 1,737 |
| Accumulated Amortization | (1,017) | (941) |
| Net Carrying Amount | 868 | 796 |
| Customer Relationships [Member] | ||
| Components of other intangible assets | ||
| Gross Carrying Amount | 1,625 | 1,506 |
| Accumulated Amortization | (895) | (836) |
| Net Carrying Amount | 730 | 670 |
| Other Contracts [Member] | ||
| Components of other intangible assets | ||
| Gross Carrying Amount | 260 | 231 |
| Accumulated Amortization | (122) | (105) |
| Net Carrying Amount | $ 138 | $ 126 |