Income Taxes (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended					9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Entity Information [Line Items]
Effective Income Tax Rate Reconciliation, at Combined Federal and State Statutory Income Tax Rate, Percent						22.30%
Estimated annual effective income tax rate							(10.10%)
Effective Income Tax Rate Reconciliation, Including Discontinued Operations, Percent	55.20%		(35.60%)			71.10%	(9.80%)
Non-cash capital contribution	$ 0.1	$ 98.0	$ 2.7	$ (1.5)	$ 1.5	$ 0.0	$ 2.7
Payment against tax receivable balance from Parent						$ (52.0)
Subsidiaries [Member]
Entity Information [Line Items]
Effective income tax rates			(19.10%)				4.70%
Effective Income Tax Rate Reconciliation, at Combined Federal and State Statutory Income Tax Rate, Percent						22.30%
Effective Income Tax Rate Reconciliation, Including Discontinued Operations, Percent	16.40%					4.80%	4.50%