Earnings Per Share (Reconciliation of Earnings (loss) to Earnings (loss) Attributable to Common Shares Used in Basic and Diluted (Loss) Earnings Per Share Calculation) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Earnings Per Share [Abstract]
Net earnings (loss) from continuing operations, as reported	$ 37.5	$ (222.6)
(Earnings) allocated to participating vested share awards	(0.1)
Earnings (loss) from continuing operations attributable to common shares	$ 37.4	$ (222.6)