Additional Information to Stock Options Exercised (Details) - Stock Options - 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 | $ 16 | $ 16 |
| Exercise proceeds | 14 | 25 |
| Income tax benefit | $ 6 | $ 5 |