Net income (loss) per common share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Net income (loss) per common share
Income from continuing operations	$ (84)	$ (78)
Income from discontinued operations, net of tax		30
Net loss	$ (84)	$ (48)
Weighted average number of common shares outstanding - basic (in shares)	64.8	60.1
Weighted average number of common shares outstanding-diluted	64.8	60.1
Basic net income per common share:
Income from continuing operations (in dollars per share)	$ (1.30)	$ (1.30)
Income from discontinued operations, net of tax (in dollars per share)		0.50
Basic net loss per common share (in dollars per share)	(1.30)	(0.80)
Diluted net income per common share:
Loss from continuing operations (in dollars per share)	(1.30)	(1.30)
Income from discontinued operations, net of tax (in dollars per share)		0.50
Diluted net loss per common share (in dollars per share)	$ (1.30)	$ (0.80)