Fair Value Measurements and Financial Instruments (Details 2) - USD ($) $ in Millions |
Jun. 30, 2017 |
Dec. 31, 2016 |
|---|---|---|
| Carrying Value | ||
| Debt Instrument [Line Items] | ||
| Carrying value of long-term debt | $ 6,506 | $ 6,520 |
| Fair Value, Inputs, Level 2 | ||
| Debt Instrument [Line Items] | ||
| Estimated fair value of long-term debt | $ 6,710 | $ 6,717 |