Stock Based Compensation - Summary of Stock Option Activity (Details) - Stock Options - USD ($)
$ / shares in Units, shares in Thousands, $ in Millions |
12 Months Ended |
Dec. 31, 2019 |
Dec. 31, 2018 |
| Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] |
|
|
| December 31, 2018 (in shares) |
517
|
|
| Granted (in shares) |
0
|
|
| Forfeited or expired (in shares) |
0
|
|
| Exercised (in shares) |
(223)
|
|
| December 31, 2019 (in shares) |
294
|
517
|
| Options exercisable as of December 31, 2019 (in shares) |
294
|
|
| Weighted Average Exercise Price |
|
|
| Options outstanding at December 31, 2018 (in USD per share) |
$ 54.92
|
|
| Granted (in USD per share) |
0
|
|
| Forfeited or expired (in USD per share) |
0
|
|
| Exercised (in USD per share) |
52.45
|
|
| Options outstanding at December 31, 2019 (in USD per share) |
56.80
|
$ 54.92
|
| Options exercisable at December 31, 2019 (in USD per share) |
$ 56.80
|
|
| Options outstanding, Weighted Average Remaining Life |
2 years 14 days
|
2 years 11 months 15 days
|
| Options exercisable as of December 31, 2019, Weighted Average Remaining Life |
2 years 14 days
|
|
| Options outstanding, Aggregate intrinsic value |
$ 19
|
$ 19
|
| Options exercisable as of December 31, 2019, Aggregate intrinsic value |
$ 19
|
|