Net Income (Loss) Per Share - Schedule of EPS (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Earnings Per Share, Basic [Abstract]
Net income (loss) attributable to common stockholders	$ 39.3	$ (7.7)
Weighted-average shares used in computing net loss per share attributable to common stockholders, basic (in shares)	417.3	410.5
Net income (loss) per share attributable to common stockholders, basic (in dollars per share)	$ 0.09	$ (0.02)
Earnings Per Share, Diluted [Abstract]
Net income (loss) attributable to common stockholders	$ 39.3	$ (7.7)
Weighted-average shares used in computing net loss per share attributable to common stockholders, basic (in shares)	417.3	410.5
Weighted-average shares used in computing net loss per share attributable to common stockholders,diluted (in shares)	419.3	410.5
Net income (loss) per share attributable to common stockholders, diluted (in dollars per share)	$ 0.09	$ (0.02)
Class A
Earnings Per Share, Basic [Abstract]
Net income (loss) attributable to common stockholders	$ 24.5	$ (4.0)
Weighted-average shares used in computing net loss per share attributable to common stockholders, basic (in shares)	260.0	215.1
Net income (loss) per share attributable to common stockholders, basic (in dollars per share)	$ 0.09	$ (0.02)
Earnings Per Share, Diluted [Abstract]
Net income (loss) attributable to common stockholders	$ 24.5	$ (4.0)
Reallocation of net income as a result of conversion of Class B to Class A common stock	14.8	0.0
Net income (loss) attributable to common stockholders for diluted EPS	$ 39.3	$ (4.0)
Weighted-average shares used in computing net loss per share attributable to common stockholders, basic (in shares)	260.0	215.1
Weighted-average effect of dilutive RSUs and employee stock options (in shares)	1.6	0.0
Conversion of Class B to Class A common stock (in shares)	157.3	0.0
Weighted-average shares used in computing net loss per share attributable to common stockholders,diluted (in shares)	418.9	215.1
Net income (loss) per share attributable to common stockholders, diluted (in dollars per share)	$ 0.09	$ (0.02)
Class B
Earnings Per Share, Basic [Abstract]
Net income (loss) attributable to common stockholders	$ 14.8	$ (3.7)
Weighted-average shares used in computing net loss per share attributable to common stockholders, basic (in shares)	157.3	195.4
Net income (loss) per share attributable to common stockholders, basic (in dollars per share)	$ 0.09	$ (0.02)
Earnings Per Share, Diluted [Abstract]
Net income (loss) attributable to common stockholders	$ 14.8	$ (3.7)
Reallocation of net income as a result of conversion of Class B to Class A common stock	0.0	0.0
Net income (loss) attributable to common stockholders for diluted EPS	$ 14.8	$ (3.7)
Weighted-average shares used in computing net loss per share attributable to common stockholders, basic (in shares)	157.3	195.4
Weighted-average effect of dilutive RSUs and employee stock options (in shares)	0.4	0.0
Conversion of Class B to Class A common stock (in shares)	0.0	0.0
Weighted-average shares used in computing net loss per share attributable to common stockholders,diluted (in shares)	157.7	195.4
Net income (loss) per share attributable to common stockholders, diluted (in dollars per share)	$ 0.09	$ (0.02)