Income Tax Matters - Income Tax Benefit (Provision) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Income Tax Disclosure [Abstract]
Domestic	$ 0.6	$ (9.5)
Foreign	(0.3)	(0.1)
Total	$ 0.3	$ (9.6)