Goodwill and Intangible Assets, Net - Summary of Changes in Net Carrying Amount of Goodwill (Details) $ in Millions |
6 Months Ended |
|---|---|
|
Jun. 30, 2021
USD ($)
| |
| Goodwill [Line Items] | |
| Balance as of December 31, 2020 | $ 2,245 |
| Measurement period adjustments | 2 |
| Foreign currency translation | 3 |
| Balance as of June 30, 2021 | 2,250 |
| Employer Solutions | |
| Goodwill [Line Items] | |
| Balance as of December 31, 2020 | 1,985 |
| Measurement period adjustments | 2 |
| Foreign currency translation | 2 |
| Balance as of June 30, 2021 | 1,989 |
| Professional Services | |
| Goodwill [Line Items] | |
| Balance as of December 31, 2020 | 260 |
| Foreign currency translation | 1 |
| Balance as of June 30, 2021 | $ 261 |