Additional Information to Stock Options Activity (Details) - Restricted Stock Units - USD ($) $ in Millions |
9 Months Ended | |
|---|---|---|
Sep. 30, 2016 |
Sep. 30, 2015 |
|
| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||
| Intrinsic value | $ 17 | $ 17 |
| Income tax benefit | $ 2 | $ 2 |