Derivative and Financial Instruments - Financial Instruments (Details 6) - USD ($) $ in Millions |
Mar. 31, 2017 |
Dec. 31, 2016 |
Mar. 31, 2016 |
Dec. 31, 2015 |
|---|---|---|---|---|
| Schedule of Held-to-maturity Securities [Line Items] | ||||
| Cash and cash equivalents Total | $ 3,109 | $ 3,610 | $ 4,866 | $ 2,368 |
| Short-term Investment [Member] | ||||
| Schedule of Held-to-maturity Securities [Line Items] | ||||
| Cash and cash equivalents Total | 252 | 50 | ||
| Remaining maturities from 1 to 90 days [Member] | ||||
| Schedule of Held-to-maturity Securities [Line Items] | ||||
| Time Deposits | 190 | 39 | ||
| Remaining maturities from 91 to 180 days [Member] | ||||
| Schedule of Held-to-maturity Securities [Line Items] | ||||
| Time Deposits | 62 | 11 | ||
| Cash and Cash Equivalents [Member] | ||||
| Schedule of Held-to-maturity Securities [Line Items] | ||||
| Cash | 842 | 623 | ||
| Cash and cash equivalents Total | 3,109 | 3,610 | ||
| Cash and Cash Equivalents [Member] | Remaining maturities from 1 to 90 days [Member] | ||||
| Schedule of Held-to-maturity Securities [Line Items] | ||||
| Time Deposits | $ 2,267 | $ 2,987 |