Loss per share (Tables)

9 Months Ended

Sep. 30, 2023

Earnings per share [abstract]

Summary of earnings per share

For the three and nine months ended September 30,	2023		2022		2023		2022
$ millions, except number of shares and per share amounts
Total net loss	$	(130.5)	$	(20.6)	$	(205.2)	$	(58.8)
Weighted average number of common shares	178.0		175.5		177.2		171.8
Basic and diluted loss per common share	$	(0.73)	$	(0.12)	$	(1.16)	$	(0.34)