Income Taxes Schedule of Income Tax Expense (Benefit) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Federal income tax provision (benefit)
Current	$ (189.5)	$ (32.2)	$ (71.3)
Deferred	116.0	55.7	(257.8)
State income tax provision (benefit)
Current	(1.0)	(15.1)	1.5
Deferred	(5.4)	(51.4)	10.2
Total income tax provision (benefit)	$ (79.9)	$ (43.0)	$ (317.4)