Income Taxes - Reconciliation of Beginning and Ending Unrecognized Tax Benefits (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|
| Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] | |||
| Unrecognized tax benefits at January 1 | $ 6 | $ 6 | $ 1 |
| Additions for tax positions of prior periods | 1 | 1 | 4 |
| Additions for tax positions of current period | 1 | 0 | 1 |
| Lapse of applicable statute of limitations | (1) | (1) | 0 |
| Unrecognized tax benefits at December 31 | $ 7 | $ 6 | $ 6 |