(Loss) Earnings per Common Share - Computation of Weighted Average Basic and Diluted Loss per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Numerator
Loss from continuing operations	$ (39.8)	$ (142.7)
Loss from discontinued operations	(85.4)	(51.3)
Net loss	$ (125.2)	$ (194.0)
Denominator
Weighted average number of common shares outstanding during the period (in shares)	3.7	4.0
Dilutive effect of stock-based compensation plans (in shares)	0.0	0.0
Weighted average number of diluted shares outstanding during the period (in shares)	3.7	4.0
Loss per common share — basic and diluted
Continuing operations, basic and diluted (in dollars per share)	$ (10.76)	$ (35.68)
Discontinued operations, basic and diluted (in dollars per share)	(23.08)	(12.82)
Net loss, basic and diluted (in dollars per share)	$ (33.84)	$ (48.50)
Anti-dilutive shares excluded from calculation (in shares)	0.4	0.4