Earnings Per Share (Reconciliation of Earnings (loss) to Earnings (loss) Attributable to Common Shares Used in Basic and Diluted Calculation) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Earnings Per Share [Abstract]
Earnings (loss) from continuing operations	$ 49.5	$ 63.7	$ (173.1)	$ 100.1
(Earnings) allocated to participating vested share awards	(0.1)	(0.1)		(0.2)
Earnings (loss) from continuing operations attributable to common shares	$ 49.4	$ 63.6	$ (173.1)	$ 99.9