Employee Benefit Plan	6 Months Ended
	Jun. 30, 2020
Retirement Benefits [Abstract]
Employee Benefit Plan	Employee Benefit PlanWe have a defined contribution 401(k) retirement plan covering Zillow Group employees who have met certain eligibility requirements (the “Zillow Group 401(k) Plan”). Eligible employees may contribute pretax compensation up to a maximum amount allowable under the Internal Revenue Service limitations. Employee contributions and earnings thereon vest immediately. We currently match up to 4% of employee contributions under the Zillow Group 401(k) Plan. The total expense related to the Zillow Group 401(k) Plan was $6.4 million and $5.2 million, respectively, for the three months ended June 30, 2020 and 2019, and $12.8 million and $10.1 million, respectively, for the six months ended June 30, 2020 and 2019.