Income Taxes - Provision for Income Taxes (Details) - USD ($) $ in Millions	1 Months Ended		12 Months Ended
	Feb. 07, 2019		Dec. 31, 2020	Dec. 31, 2019		Dec. 31, 2018
Current tax provision:
U.S. Federal	$ (11.1)		$ (28.8)	$ (0.3)		$ (5.7)
State and local	(3.4)		7.4	1.6		1.0
Non-U.S.	4.8		28.6	15.8		23.5
Total current tax provision	(9.7)		7.2	17.1		18.8
Deferred tax provision:
U.S. Federal	(14.8)		(100.7)	(109.8)		54.2
State and local	(3.0)		(16.9)	(23.5)		9.8
Non-U.S.	0.0		(0.1)	(2.0)		(1.2)
Total deferred tax provision	(17.8)		(117.7)	(135.3)		62.8
Provision (benefit) for income taxes	$ (27.5)	[1]	$ (110.5)	$ (118.2)	[1]	$ 81.6

[1] See Note 1 "Basis of Presentation" for further discussion.