Stock-Based Compensation - Expense (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Stock-based compensation | $ 17 | $ 17 | $ 11 |
| Income tax benefit | (4) | (5) | (4) |
| Stock-based compensation expense, net of tax | 13 | 12 | 7 |
| Stock Options | |||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Stock-based compensation | 0 | 1 | 1 |
| Restricted Stock Units (RSUs) and Performance Conditions (PSU) | |||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Stock-based compensation | 15 | 15 | 9 |
| Employee Stock Purchase Plan | |||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Stock-based compensation | $ 2 | $ 1 | $ 1 |