Stock-Based Compensation (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions |
3 Months Ended | 9 Months Ended | ||
---|---|---|---|---|
Sep. 30, 2016 |
Sep. 30, 2015 |
Sep. 30, 2016 |
Sep. 30, 2015 |
|
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
Total stock-based compensation expense | $ 20 | $ 18 | $ 54 | $ 55 |
Stock option expense | ||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
Total stock-based compensation expense | 2 | 2 | 6 | 11 |
Restricted stock and unit awards expense | ||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
Total stock-based compensation expense | 18 | $ 16 | $ 48 | $ 44 |
Award grants (in shares) | 0.6 | |||
Award grants, weighted average grant date fair value (in dollars per share) | $ 100.31 | |||
Unrecognized compensation expense | $ 65 | $ 65 | ||
Unrecognized compensation expense, period for recognition | 1 year 8 months 60 days |