Net loss per common share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Net loss per common share
Net loss	$ (7)	$ (84)
Weighted average number of common shares outstanding - basic (in shares)	73.2	64.8
Weighted average number of common shares outstanding - diluted (in shares)	73.2	64.8
Basic net loss per common share:
Basic net loss per common share (in dollars per share)	$ (0.10)	$ (1.30)
Diluted net loss per common share:
Diluted net loss per common share (in dollars per share)	$ (0.10)	$ (1.30)