Net Loss Per Share - Computation of Basic and Diluted Net Loss Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Basic and diluted net loss per share:
Net loss attributable to common stockholders, basic	$ (67.1)	$ (186.6)	$ (193.1)	$ (802.2)
Net loss attributable to common stockholders, diluted	$ (67.1)	$ (186.6)	$ (193.1)	$ (802.2)
Weighted average shares outstanding:
Common stock, basic (in shares)	240.4	226.4	236.8	223.6
Common stock, diluted (in shares)	240.4	226.4	236.8	223.6
Net loss per share, basic (in dollars per share)	$ (0.28)	$ (0.82)	$ (0.82)	$ (3.59)
Net loss per share, diluted (in dollars per share)	$ (0.28)	$ (0.82)	$ (0.82)	$ (3.59)