Description of Business and Significant Accounting Policies - Summary of Amounts Capitalized and Amortized (Details) - USD ($) $ in Millions |
12 Months Ended | |
|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
|
| Organization, Consolidation and Presentation of Financial Statements [Abstract] | ||
| Capitalized deferred commission costs | $ 45 | $ 33 |
| Amortized deferred commission costs | $ 10 | $ 2 |